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[ Upstream commit e1505c1cc8d527fcc5bcaf9c1ad82eed817e3e10 ]
Some netdevices may get unregistered before late_initcall(),
we have to move the hashtable init earlier.
Fixes: f1fc43d03946 ("bpf: Move offload initialization into late_initcall")
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=217399
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20230505215836.491485-1-kuba@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit b34ffb0c6d23583830f9327864b9c1f486003305 upstream.
The LRU and LRU_PERCPU maps allocate a new element on update before locking the
target hash table bucket. Right after that the maps try to lock the bucket.
If this fails, then maps return -EBUSY to the caller without releasing the
allocated element. This makes the element untracked: it doesn't belong to
either of free lists, and it doesn't belong to the hash table, so can't be
re-used; this eventually leads to the permanent -ENOMEM on LRU map updates,
which is unexpected. Fix this by returning the element to the local free list
if bucket locking fails.
Fixes: 20b6cc34ea74 ("bpf: Avoid hashtab deadlock with map_locked")
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/r/20230522154558.2166815-1-aspsk@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0613d8ca9ab382caabe9ed2dceb429e9781e443f upstream.
A narrow load from a 64-bit context field results in a 64-bit load
followed potentially by a 64-bit right-shift and then a bitwise AND
operation to extract the relevant data.
In the case of a 32-bit access, an immediate mask of 0xffffffff is used
to construct a 64-bit BPP_AND operation which then sign-extends the mask
value and effectively acts as a glorified no-op. For example:
0: 61 10 00 00 00 00 00 00 r0 = *(u32 *)(r1 + 0)
results in the following code generation for a 64-bit field:
ldr x7, [x7] // 64-bit load
mov x10, #0xffffffffffffffff
and x7, x7, x10
Fix the mask generation so that narrow loads always perform a 32-bit AND
operation:
ldr x7, [x7] // 64-bit load
mov w10, #0xffffffff
and w7, w7, w10
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: Krzesimir Nowak <krzesimir@kinvolk.io>
Cc: Andrey Ignatov <rdna@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Fixes: 31fd85816dbe ("bpf: permits narrower load from bpf program context fields")
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20230518102528.1341-1-will@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit c11bd046485d7bf1ca200db0e7d0bdc4bafdd395 ]
The recursion check in __bpf_prog_enter* and __bpf_prog_exit*
leave preempt_count_{sub,add} unprotected. When attaching trampoline to
them we get panic as follows,
[ 867.843050] BUG: TASK stack guard page was hit at 0000000009d325cf (stack is 0000000046a46a15..00000000537e7b28)
[ 867.843064] stack guard page: 0000 [#1] PREEMPT SMP NOPTI
[ 867.843067] CPU: 8 PID: 11009 Comm: trace Kdump: loaded Not tainted 6.2.0+ #4
[ 867.843100] Call Trace:
[ 867.843101] <TASK>
[ 867.843104] asm_exc_int3+0x3a/0x40
[ 867.843108] RIP: 0010:preempt_count_sub+0x1/0xa0
[ 867.843135] __bpf_prog_enter_recur+0x17/0x90
[ 867.843148] bpf_trampoline_6442468108_0+0x2e/0x1000
[ 867.843154] ? preempt_count_sub+0x1/0xa0
[ 867.843157] preempt_count_sub+0x5/0xa0
[ 867.843159] ? migrate_enable+0xac/0xf0
[ 867.843164] __bpf_prog_exit_recur+0x2d/0x40
[ 867.843168] bpf_trampoline_6442468108_0+0x55/0x1000
...
[ 867.843788] preempt_count_sub+0x5/0xa0
[ 867.843793] ? migrate_enable+0xac/0xf0
[ 867.843829] __bpf_prog_exit_recur+0x2d/0x40
[ 867.843837] BUG: IRQ stack guard page was hit at 0000000099bd8228 (stack is 00000000b23e2bc4..000000006d95af35)
[ 867.843841] BUG: IRQ stack guard page was hit at 000000005ae07924 (stack is 00000000ffd69623..0000000014eb594c)
[ 867.843843] BUG: IRQ stack guard page was hit at 00000000028320f0 (stack is 00000000034b6438..0000000078d1bcec)
[ 867.843842] bpf_trampoline_6442468108_0+0x55/0x1000
...
That is because in __bpf_prog_exit_recur, the preempt_count_{sub,add} are
called after prog->active is decreased.
Fixing this by adding these two functions into btf ids deny list.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yafang <laoar.shao@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20230413025248.79764-1-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 0a09a2f933c73dc76ab0b72da6855f44342a8903 ]
There are a few cases where hlist_node is checked to be unhashed without
holding the lock protecting its modification. In this case, one must use
hlist_unhashed_lockless to avoid load tearing and KCSAN reports. Fix
this by using lockless variant in places not protected by the lock.
Since this is not prompted by any actual KCSAN reports but only from
code review, I have not included a fixes tag.
Cc: Martin KaFai Lau <martin.lau@kernel.org>
Cc: KP Singh <kpsingh@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20230221200646.2500777-4-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 00e74ae0863827d944e36e56a4ce1e77e50edb91 ]
Some socket options do getsockopt with optval=NULL to estimate the size
of the final buffer (which is returned via optlen). This breaks BPF
getsockopt assumptions about permitted optval buffer size. Let's enforce
these assumptions only when non-NULL optval is provided.
Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks")
Reported-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/ZD7Js4fj5YyI2oLd@google.com/T/#mb68daf700f87a9244a15d01d00c3f0e5b08f49f7
Link: https://lore.kernel.org/bpf/20230418225343.553806-2-sdf@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit acf1c3d68e9a31f10d92bc67ad4673cdae5e8d92 ]
Florian and Eduard reported hard dead lock:
[ 58.433327] _raw_spin_lock_irqsave+0x40/0x50
[ 58.433334] btf_put+0x43/0x90
[ 58.433338] bpf_find_btf_id+0x157/0x240
[ 58.433353] btf_parse_fields+0x921/0x11c0
This happens since btf->refcount can be 1 at the time of btf_put() and
btf_put() will call btf_free_id() which will try to grab btf_idr_lock
and will dead lock.
Avoid the issue by doing btf_put() without locking.
Fixes: 3d78417b60fb ("bpf: Add bpf_btf_find_by_name_kind() helper.")
Fixes: 1e89106da253 ("bpf: Add bpf_core_add_cands() and wire it into bpf_core_apply_relo_insn().")
Reported-by: Florian Westphal <fw@strlen.de>
Reported-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20230421014901.70908-1-alexei.starovoitov@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 91f2dc6838c19342f7f2993627c622835cc24890 ]
When tracing a kernel function with arg type is u32*, btf_ctx_access()
would report error: arg2 type INT is not a struct.
The commit bb6728d75611 ("bpf: Allow access to int pointer arguments
in tracing programs") added support for int pointer, but did not skip
modifiers before checking it's type. This patch fixes it.
Fixes: bb6728d75611 ("bpf: Allow access to int pointer arguments in tracing programs")
Co-developed-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20230410085908.98493-2-zhoufeng.zf@bytedance.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f6a6a5a976288e4d0d94eb1c6c9e983e8e5cdb31 ]
bpf_obj_drop_impl has a void return type. In check_kfunc_call, the "else
if" which sets insn_aux->kptr_struct_meta for bpf_obj_drop_impl is
surrounded by a larger if statement which checks btf_type_is_ptr. As a
result:
* The bpf_obj_drop_impl-specific code will never execute
* The btf_struct_meta input to bpf_obj_drop is always NULL
* __bpf_obj_drop_impl will always see a NULL btf_record when called
from BPF program, and won't call bpf_obj_free_fields
* program-allocated kptrs which have fields that should be cleaned up
by bpf_obj_free_fields may instead leak resources
This patch adds a btf_type_is_void branch to the larger if and moves
special handling for bpf_obj_drop_impl there, fixing the issue.
Fixes: ac9f06050a35 ("bpf: Introduce bpf_obj_drop")
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230403200027.2271029-1-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 07236eab7a3139da97aef9f5f21f403be82a82ea ]
Factor out logic to fetch basic kfunc metadata based on struct bpf_insn.
This is not exactly short or trivial code to just copy/paste and this
information is sometimes necessary in other parts of the verifier logic.
Subsequent patches will rely on this to determine if an instruction is
a kfunc call to iterator next method.
No functional changes intended, including that verbose() warning
behavior when kfunc is not allowed for a particular program type.
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230308184121.1165081-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: f6a6a5a97628 ("bpf: Fix struct_meta lookup for bpf_obj_free_fields kfunc call")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 7be14c1c9030f73cc18b4ff23b78a0a081f16188 ]
Xu reports that after commit 3f50f132d840 ("bpf: Verifier, do explicit ALU32
bounds tracking"), the following BPF program is rejected by the verifier:
0: (61) r2 = *(u32 *)(r1 +0) ; R2_w=pkt(off=0,r=0,imm=0)
1: (61) r3 = *(u32 *)(r1 +4) ; R3_w=pkt_end(off=0,imm=0)
2: (bf) r1 = r2
3: (07) r1 += 1
4: (2d) if r1 > r3 goto pc+8
5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff))
6: (18) r0 = 0x7fffffffffffff10
8: (0f) r1 += r0 ; R1_w=scalar(umin=0x7fffffffffffff10,umax=0x800000000000000f)
9: (18) r0 = 0x8000000000000000
11: (07) r0 += 1
12: (ad) if r0 < r1 goto pc-2
13: (b7) r0 = 0
14: (95) exit
And the verifier log says:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (61) r2 = *(u32 *)(r1 +0) ; R1=ctx(off=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
1: (61) r3 = *(u32 *)(r1 +4) ; R1=ctx(off=0,imm=0) R3_w=pkt_end(off=0,imm=0)
2: (bf) r1 = r2 ; R1_w=pkt(off=0,r=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
3: (07) r1 += 1 ; R1_w=pkt(off=1,r=0,imm=0)
4: (2d) if r1 > r3 goto pc+8 ; R1_w=pkt(off=1,r=1,imm=0) R3_w=pkt_end(off=0,imm=0)
5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) R2_w=pkt(off=0,r=1,imm=0)
6: (18) r0 = 0x7fffffffffffff10 ; R0_w=9223372036854775568
8: (0f) r1 += r0 ; R0_w=9223372036854775568 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775823,s32_min=-240,s32_max=15)
9: (18) r0 = 0x8000000000000000 ; R0_w=-9223372036854775808
11: (07) r0 += 1 ; R0_w=-9223372036854775807
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775809)
13: (b7) r0 = 0 ; R0_w=0
14: (95) exit
from 12 to 11: R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775810,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775806
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775806 R1_w=scalar(umin=9223372036854775810,umax=9223372036854775810,var_off=(0x8000000000000000; 0xffffffff))
13: safe
[...]
from 12 to 11: R0_w=-9223372036854775795 R1=scalar(umin=9223372036854775822,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775794
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775822,umax=9223372036854775822,var_off=(0x8000000000000000; 0xffffffff))
13: safe
from 12 to 11: R0_w=-9223372036854775794 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775793
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775823,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff))
13: safe
from 12 to 11: R0_w=-9223372036854775793 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff)) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775792
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775792 R1=scalar(umin=9223372036854775824,umax=9223372036854775823,var_off=(0x8000000000000000; 0xffffffff))
13: safe
[...]
The 64bit umin=9223372036854775810 bound continuously bumps by +1 while
umax=9223372036854775823 stays as-is until the verifier complexity limit
is reached and the program gets finally rejected. During this simulation,
the umin also eventually surpasses umax. Looking at the first 'from 12
to 11' output line from the loop, R1 has the following state:
R1_w=scalar(umin=0x8000000000000002 (9223372036854775810),
umax=0x800000000000000f (9223372036854775823),
var_off=(0x8000000000000000;
0xffffffff))
The var_off has technically not an inconsistent state but it's very
imprecise and far off surpassing 64bit umax bounds whereas the expected
output with refined known bits in var_off should have been like:
R1_w=scalar(umin=0x8000000000000002 (9223372036854775810),
umax=0x800000000000000f (9223372036854775823),
var_off=(0x8000000000000000;
0xf))
In the above log, var_off stays as var_off=(0x8000000000000000; 0xffffffff)
and does not converge into a narrower mask where more bits become known,
eventually transforming R1 into a constant upon umin=9223372036854775823,
umax=9223372036854775823 case where the verifier would have terminated and
let the program pass.
The __reg_combine_64_into_32() marks the subregister unknown and propagates
64bit {s,u}min/{s,u}max bounds to their 32bit equivalents iff they are within
the 32bit universe. The question came up whether __reg_combine_64_into_32()
should special case the situation that when 64bit {s,u}min bounds have
the same value as 64bit {s,u}max bounds to then assign the latter as
well to the 32bit reg->{s,u}32_{min,max}_value. As can be seen from the
above example however, that is just /one/ special case and not a /generic/
solution given above example would still not be addressed this way and
remain at an imprecise var_off=(0x8000000000000000; 0xffffffff).
The improvement is needed in __reg_bound_offset() to refine var32_off with
the updated var64_off instead of the prior reg->var_off. The reg_bounds_sync()
code first refines information about the register's min/max bounds via
__update_reg_bounds() from the current var_off, then in __reg_deduce_bounds()
from sign bit and with the potentially learned bits from bounds it'll
update the var_off tnum in __reg_bound_offset(). For example, intersecting
with the old var_off might have improved bounds slightly, e.g. if umax
was 0x7f...f and var_off was (0; 0xf...fc), then new var_off will then
result in (0; 0x7f...fc). The intersected var64_off holds then the
universe which is a superset of var32_off. The point for the latter is
not to broaden, but to further refine known bits based on the intersection
of var_off with 32 bit bounds, so that we later construct the final var_off
from upper and lower 32 bits. The final __update_reg_bounds() can then
potentially still slightly refine bounds if more bits became known from the
new var_off.
After the improvement, we can see R1 converging successively:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (61) r2 = *(u32 *)(r1 +0) ; R1=ctx(off=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
1: (61) r3 = *(u32 *)(r1 +4) ; R1=ctx(off=0,imm=0) R3_w=pkt_end(off=0,imm=0)
2: (bf) r1 = r2 ; R1_w=pkt(off=0,r=0,imm=0) R2_w=pkt(off=0,r=0,imm=0)
3: (07) r1 += 1 ; R1_w=pkt(off=1,r=0,imm=0)
4: (2d) if r1 > r3 goto pc+8 ; R1_w=pkt(off=1,r=1,imm=0) R3_w=pkt_end(off=0,imm=0)
5: (71) r1 = *(u8 *)(r2 +0) ; R1_w=scalar(umax=255,var_off=(0x0; 0xff)) R2_w=pkt(off=0,r=1,imm=0)
6: (18) r0 = 0x7fffffffffffff10 ; R0_w=9223372036854775568
8: (0f) r1 += r0 ; R0_w=9223372036854775568 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775823,s32_min=-240,s32_max=15)
9: (18) r0 = 0x8000000000000000 ; R0_w=-9223372036854775808
11: (07) r0 += 1 ; R0_w=-9223372036854775807
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775568,umax=9223372036854775809)
13: (b7) r0 = 0 ; R0_w=0
14: (95) exit
from 12 to 11: R0_w=-9223372036854775807 R1_w=scalar(umin=9223372036854775810,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775806
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775806 R1_w=-9223372036854775806
13: safe
from 12 to 11: R0_w=-9223372036854775806 R1_w=scalar(umin=9223372036854775811,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775805
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775805 R1_w=-9223372036854775805
13: safe
[...]
from 12 to 11: R0_w=-9223372036854775798 R1=scalar(umin=9223372036854775819,umax=9223372036854775823,var_off=(0x8000000000000008; 0x7),s32_min=8,s32_max=15,u32_min=8,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775797
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775797 R1=-9223372036854775797
13: safe
from 12 to 11: R0_w=-9223372036854775797 R1=scalar(umin=9223372036854775820,umax=9223372036854775823,var_off=(0x800000000000000c; 0x3),s32_min=12,s32_max=15,u32_min=12,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775796
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775796 R1=-9223372036854775796
13: safe
from 12 to 11: R0_w=-9223372036854775796 R1=scalar(umin=9223372036854775821,umax=9223372036854775823,var_off=(0x800000000000000c; 0x3),s32_min=12,s32_max=15,u32_min=12,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775795
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775795 R1=-9223372036854775795
13: safe
from 12 to 11: R0_w=-9223372036854775795 R1=scalar(umin=9223372036854775822,umax=9223372036854775823,var_off=(0x800000000000000e; 0x1),s32_min=14,s32_max=15,u32_min=14,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775794
12: (ad) if r0 < r1 goto pc-2 ; R0_w=-9223372036854775794 R1=-9223372036854775794
13: safe
from 12 to 11: R0_w=-9223372036854775794 R1=-9223372036854775793 R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
11: (07) r0 += 1 ; R0_w=-9223372036854775793
12: (ad) if r0 < r1 goto pc-2
last_idx 12 first_idx 12
parent didn't have regs=1 stack=0 marks: R0_rw=P-9223372036854775801 R1_r=scalar(umin=9223372036854775815,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
last_idx 11 first_idx 11
regs=1 stack=0 before 11: (07) r0 += 1
parent didn't have regs=1 stack=0 marks: R0_rw=P-9223372036854775805 R1_rw=scalar(umin=9223372036854775812,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
last_idx 12 first_idx 0
regs=1 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=1 stack=0 before 11: (07) r0 += 1
regs=1 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=1 stack=0 before 11: (07) r0 += 1
regs=1 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=1 stack=0 before 11: (07) r0 += 1
regs=1 stack=0 before 9: (18) r0 = 0x8000000000000000
last_idx 12 first_idx 12
parent didn't have regs=2 stack=0 marks: R0_rw=P-9223372036854775801 R1_r=Pscalar(umin=9223372036854775815,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2=pkt(off=0,r=1,imm=0) R3=pkt_end(off=0,imm=0) R10=fp0
last_idx 11 first_idx 11
regs=2 stack=0 before 11: (07) r0 += 1
parent didn't have regs=2 stack=0 marks: R0_rw=P-9223372036854775805 R1_rw=Pscalar(umin=9223372036854775812,umax=9223372036854775823,var_off=(0x8000000000000000; 0xf),s32_min=0,s32_max=15,u32_max=15) R2_w=pkt(off=0,r=1,imm=0) R3_w=pkt_end(off=0,imm=0) R10=fp0
last_idx 12 first_idx 0
regs=2 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=2 stack=0 before 11: (07) r0 += 1
regs=2 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=2 stack=0 before 11: (07) r0 += 1
regs=2 stack=0 before 12: (ad) if r0 < r1 goto pc-2
regs=2 stack=0 before 11: (07) r0 += 1
regs=2 stack=0 before 9: (18) r0 = 0x8000000000000000
regs=2 stack=0 before 8: (0f) r1 += r0
regs=3 stack=0 before 6: (18) r0 = 0x7fffffffffffff10
regs=2 stack=0 before 5: (71) r1 = *(u8 *)(r2 +0)
13: safe
from 4 to 13: safe
verification time 322 usec
stack depth 0
processed 56 insns (limit 1000000) max_states_per_insn 1 total_states 3 peak_states 3 mark_read 1
This also fixes up a test case along with this improvement where we match
on the verifier log. The updated log now has a refined var_off, too.
Fixes: 3f50f132d840 ("bpf: Verifier, do explicit ALU32 bounds tracking")
Reported-by: Xu Kuohai <xukuohai@huaweicloud.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20230314203424.4015351-2-xukuohai@huaweicloud.com
Link: https://lore.kernel.org/bpf/20230322213056.2470-1-daniel@iogearbox.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit d7ba4cc900bf1eea2d8c807c6b1fc6bd61f41237 ]
This patch changes the return types of bpf_map_ops functions to long, where
previously int was returned. Using long allows for bpf programs to maintain
the sign bit in the absence of sign extension during situations where
inlined bpf helper funcs make calls to the bpf_map_ops funcs and a negative
error is returned.
The definitions of the helper funcs are generated from comments in the bpf
uapi header at `include/uapi/linux/bpf.h`. The return type of these
helpers was previously changed from int to long in commit bdb7b79b4ce8. For
any case where one of the map helpers call the bpf_map_ops funcs that are
still returning 32-bit int, a compiler might not include sign extension
instructions to properly convert the 32-bit negative value a 64-bit
negative value.
For example:
bpf assembly excerpt of an inlined helper calling a kernel function and
checking for a specific error:
; err = bpf_map_update_elem(&mymap, &key, &val, BPF_NOEXIST);
...
46: call 0xffffffffe103291c ; htab_map_update_elem
; if (err && err != -EEXIST) {
4b: cmp $0xffffffffffffffef,%rax ; cmp -EEXIST,%rax
kernel function assembly excerpt of return value from
`htab_map_update_elem` returning 32-bit int:
movl $0xffffffef, %r9d
...
movl %r9d, %eax
...results in the comparison:
cmp $0xffffffffffffffef, $0x00000000ffffffef
Fixes: bdb7b79b4ce8 ("bpf: Switch most helper return values from 32-bit int to 64-bit long")
Tested-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Link: https://lore.kernel.org/r/20230322194754.185781-3-inwardvessel@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 082cdc69a4651dd2a77539d69416a359ed1214f5 ]
For every BPF_ADD/SUB involving a pointer, adjust_ptr_min_max_vals()
ensures that the resulting pointer has a constant offset if
bypass_spec_v1 is false. This is ensured by calling sanitize_check_bounds()
which in turn calls check_stack_access_for_ptr_arithmetic(). There,
-EACCESS is returned if the register's offset is not constant, thereby
rejecting the program.
In summary, an unprivileged user must never be able to create stack
pointers with a variable offset. That is also the case, because a
respective check in check_stack_write() is missing. If they were able
to create a variable-offset pointer, users could still use it in a
stack-write operation to trigger unsafe speculative behavior [1].
Because unprivileged users must already be prevented from creating
variable-offset stack pointers, viable options are to either remove
this check (replacing it with a clarifying comment), or to turn it
into a "verifier BUG"-message, also adding a similar check in
check_stack_write() (for consistency, as a second-level defense).
This patch implements the first option to reduce verifier bloat.
This check was introduced by commit 01f810ace9ed ("bpf: Allow
variable-offset stack access") which correctly notes that
"variable-offset reads and writes are disallowed (they were already
disallowed for the indirect access case) because the speculative
execution checking code doesn't support them". However, it does not
further discuss why the check in check_stack_read() is necessary.
The code which made this check obsolete was also introduced in this
commit.
I have compiled ~650 programs from the Linux selftests, Linux samples,
Cilium, and libbpf/examples projects and confirmed that none of these
trigger the check in check_stack_read() [2]. Instead, all of these
programs are, as expected, already rejected when constructing the
variable-offset pointers. Note that the check in
check_stack_access_for_ptr_arithmetic() also prints "off=%d" while the
code removed by this patch does not (the error removed does not appear
in the "verification_error" values). For reproducibility, the
repository linked includes the raw data and scripts used to create
the plot.
[1] https://arxiv.org/pdf/1807.03757.pdf
[2] https://gitlab.cs.fau.de/un65esoq/bpf-spectre/-/raw/53dc19fcf459c186613b1156a81504b39c8d49db/data/plots/23-02-26_23-56_bpftool/bpftool/0004-errors.pdf?inline=false
Fixes: 01f810ace9ed ("bpf: Allow variable-offset stack access")
Signed-off-by: Luis Gerhorst <gerhorst@cs.fau.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230315165358.23701-1-gerhorst@cs.fau.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 77473d1a962f3d4f7ba48324502b6d27b8ef2591 ]
The struct bpf_cpumask type uses the bpf_mem_cache_{alloc,free}() APIs
to allocate and free its cpumasks. The bpf_mem allocator may currently
immediately reuse some memory when its freed, without waiting for an RCU
read cycle to elapse. We want to be able to treat struct bpf_cpumask
objects as completely RCU safe.
This is necessary for two reasons:
1. bpf_cpumask_kptr_get() currently does an RCU-protected
refcnt_inc_not_zero(). This of course assumes that the underlying
memory is not reused, and is therefore unsafe in its current form.
2. We want to be able to get rid of bpf_cpumask_kptr_get() entirely, and
intead use the superior kptr RCU semantics now afforded by the
verifier.
This patch fixes (1), and enables (2), by making struct bpf_cpumask RCU
safe. A subsequent patch will update the verifier to allow struct
bpf_cpumask * pointers to be passed to KF_RCU kfuncs, and then a latter
patch will remove bpf_cpumask_kptr_get().
Fixes: 516f4d3397c9 ("bpf: Enable cpumasks to be queried and used as kptrs")
Signed-off-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230316054028.88924-2-void@manifault.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 5d5de3a431d87ac51d43da8d796891d014975ab7 ]
The size of bpf_cpumask is fixed, so there is no need to allocate many
bpf_mem_caches for bpf_cpumask_ma, just one bpf_mem_cache is enough.
Also add comments for bpf_mem_alloc_init() in bpf_mem_alloc.h to prevent
future miuse.
Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230216024821.2202916-1-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Stable-dep-of: 77473d1a962f ("bpf: Free struct bpf_cpumask in call_rcu handler")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 34f0677e7afd3a292bc1aadda7ce8e35faedb204 ]
Fix wrong order of frame index vs register/slot index in precision
propagation verbose (level 2) output. It's wrong and very confusing as is.
Fixes: 529409ea92d5 ("bpf: propagate precision across all frames, not just the last one")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230313184017.4083374-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 52c2b005a3c18c565fc70cfd0ca49375f301e952 ]
When doing state comparison, if old state has register that is not
marked as REG_LIVE_READ, then we just skip comparison, regardless what's
the state of corresponing register in current state. This is because not
REG_LIVE_READ register is irrelevant for further program execution and
correctness. All good here.
But when we get to precision propagation, after two states were declared
equivalent, we don't take into account old register's liveness, and thus
attempt to propagate precision for register in current state even if
that register in old state was not REG_LIVE_READ anymore. This is bad,
because register in current state could be anything at all and this
could cause -EFAULT due to internal logic bugs.
Fix by taking into account REG_LIVE_READ liveness mark to keep the logic
in state comparison in sync with precision propagation.
Fixes: a3ce685dd01a ("bpf: fix precision tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230309224131.57449-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Juan Jose et al reported an issue found via fuzzing where the verifier's
pruning logic prematurely marks a program path as safe.
Consider the following program:
0: (b7) r6 = 1024
1: (b7) r7 = 0
2: (b7) r8 = 0
3: (b7) r9 = -2147483648
4: (97) r6 %= 1025
5: (05) goto pc+0
6: (bd) if r6 <= r9 goto pc+2
7: (97) r6 %= 1
8: (b7) r9 = 0
9: (bd) if r6 <= r9 goto pc+1
10: (b7) r6 = 0
11: (b7) r0 = 0
12: (63) *(u32 *)(r10 -4) = r0
13: (18) r4 = 0xffff888103693400 // map_ptr(ks=4,vs=48)
15: (bf) r1 = r4
16: (bf) r2 = r10
17: (07) r2 += -4
18: (85) call bpf_map_lookup_elem#1
19: (55) if r0 != 0x0 goto pc+1
20: (95) exit
21: (77) r6 >>= 10
22: (27) r6 *= 8192
23: (bf) r1 = r0
24: (0f) r0 += r6
25: (79) r3 = *(u64 *)(r0 +0)
26: (7b) *(u64 *)(r1 +0) = r3
27: (95) exit
The verifier treats this as safe, leading to oob read/write access due
to an incorrect verifier conclusion:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (b7) r6 = 1024 ; R6_w=1024
1: (b7) r7 = 0 ; R7_w=0
2: (b7) r8 = 0 ; R8_w=0
3: (b7) r9 = -2147483648 ; R9_w=-2147483648
4: (97) r6 %= 1025 ; R6_w=scalar()
5: (05) goto pc+0
6: (bd) if r6 <= r9 goto pc+2 ; R6_w=scalar(umin=18446744071562067969,var_off=(0xffffffff00000000; 0xffffffff)) R9_w=-2147483648
7: (97) r6 %= 1 ; R6_w=scalar()
8: (b7) r9 = 0 ; R9=0
9: (bd) if r6 <= r9 goto pc+1 ; R6=scalar(umin=1) R9=0
10: (b7) r6 = 0 ; R6_w=0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 9
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff8ad3886c2a00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1 ; R0=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0)
19: (55) if r0 != 0x0 goto pc+1 ; R0=0
20: (95) exit
from 19 to 21: R0=map_value(off=0,ks=4,vs=48,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
21: (77) r6 >>= 10 ; R6_w=0
22: (27) r6 *= 8192 ; R6_w=0
23: (bf) r1 = r0 ; R0=map_value(off=0,ks=4,vs=48,imm=0) R1_w=map_value(off=0,ks=4,vs=48,imm=0)
24: (0f) r0 += r6
last_idx 24 first_idx 19
regs=40 stack=0 before 23: (bf) r1 = r0
regs=40 stack=0 before 22: (27) r6 *= 8192
regs=40 stack=0 before 21: (77) r6 >>= 10
regs=40 stack=0 before 19: (55) if r0 != 0x0 goto pc+1
parent didn't have regs=40 stack=0 marks: R0_rw=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0) R6_rw=P0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
last_idx 18 first_idx 9
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff8ad3886c2a00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
regs=40 stack=0 before 10: (b7) r6 = 0
25: (79) r3 = *(u64 *)(r0 +0) ; R0_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
26: (7b) *(u64 *)(r1 +0) = r3 ; R1_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
27: (95) exit
from 9 to 11: R1=ctx(off=0,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 11
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff8ad3886c2a00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1
frame 0: propagating r6
last_idx 19 first_idx 11
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff8ad3886c2a00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_r=P0 R7=0 R8=0 R9=0 R10=fp0
last_idx 9 first_idx 9
regs=40 stack=0 before 9: (bd) if r6 <= r9 goto pc+1
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_rw=Pscalar() R7_w=0 R8_w=0 R9_rw=0 R10=fp0
last_idx 8 first_idx 0
regs=40 stack=0 before 8: (b7) r9 = 0
regs=40 stack=0 before 7: (97) r6 %= 1
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=40 stack=0 before 5: (05) goto pc+0
regs=40 stack=0 before 4: (97) r6 %= 1025
regs=40 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
19: safe
frame 0: propagating r6
last_idx 9 first_idx 0
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=40 stack=0 before 5: (05) goto pc+0
regs=40 stack=0 before 4: (97) r6 %= 1025
regs=40 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
from 6 to 9: safe
verification time 110 usec
stack depth 4
processed 36 insns (limit 1000000) max_states_per_insn 0 total_states 3 peak_states 3 mark_read 2
The verifier considers this program as safe by mistakenly pruning unsafe
code paths. In the above func#0, code lines 0-10 are of interest. In line
0-3 registers r6 to r9 are initialized with known scalar values. In line 4
the register r6 is reset to an unknown scalar given the verifier does not
track modulo operations. Due to this, the verifier can also not determine
precisely which branches in line 6 and 9 are taken, therefore it needs to
explore them both.
As can be seen, the verifier starts with exploring the false/fall-through
paths first. The 'from 19 to 21' path has both r6=0 and r9=0 and the pointer
arithmetic on r0 += r6 is therefore considered safe. Given the arithmetic,
r6 is correctly marked for precision tracking where backtracking kicks in
where it walks back the current path all the way where r6 was set to 0 in
the fall-through branch.
Next, the pruning logics pops the path 'from 9 to 11' from the stack. Also
here, the state of the registers is the same, that is, r6=0 and r9=0, so
that at line 19 the path can be pruned as it is considered safe. It is
interesting to note that the conditional in line 9 turned r6 into a more
precise state, that is, in the fall-through path at the beginning of line
10, it is R6=scalar(umin=1), and in the branch-taken path (which is analyzed
here) at the beginning of line 11, r6 turned into a known const r6=0 as
r9=0 prior to that and therefore (unsigned) r6 <= 0 concludes that r6 must
be 0 (**):
[...] ; R6_w=scalar()
9: (bd) if r6 <= r9 goto pc+1 ; R6=scalar(umin=1) R9=0
[...]
from 9 to 11: R1=ctx(off=0,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0
[...]
The next path is 'from 6 to 9'. The verifier considers the old and current
state equivalent, and therefore prunes the search incorrectly. Looking into
the two states which are being compared by the pruning logic at line 9, the
old state consists of R6_rwD=Pscalar() R9_rwD=0 R10=fp0 and the new state
consists of R1=ctx(off=0,imm=0) R6_w=scalar(umax=18446744071562067968)
R7_w=0 R8_w=0 R9_w=-2147483648 R10=fp0. While r6 had the reg->precise flag
correctly set in the old state, r9 did not. Both r6'es are considered as
equivalent given the old one is a superset of the current, more precise one,
however, r9's actual values (0 vs 0x80000000) mismatch. Given the old r9
did not have reg->precise flag set, the verifier does not consider the
register as contributing to the precision state of r6, and therefore it
considered both r9 states as equivalent. However, for this specific pruned
path (which is also the actual path taken at runtime), register r6 will be
0x400 and r9 0x80000000 when reaching line 21, thus oob-accessing the map.
The purpose of precision tracking is to initially mark registers (including
spilled ones) as imprecise to help verifier's pruning logic finding equivalent
states it can then prune if they don't contribute to the program's safety
aspects. For example, if registers are used for pointer arithmetic or to pass
constant length to a helper, then the verifier sets reg->precise flag and
backtracks the BPF program instruction sequence and chain of verifier states
to ensure that the given register or stack slot including their dependencies
are marked as precisely tracked scalar. This also includes any other registers
and slots that contribute to a tracked state of given registers/stack slot.
This backtracking relies on recorded jmp_history and is able to traverse
entire chain of parent states. This process ends only when all the necessary
registers/slots and their transitive dependencies are marked as precise.
The backtrack_insn() is called from the current instruction up to the first
instruction, and its purpose is to compute a bitmask of registers and stack
slots that need precision tracking in the parent's verifier state. For example,
if a current instruction is r6 = r7, then r6 needs precision after this
instruction and r7 needs precision before this instruction, that is, in the
parent state. Hence for the latter r7 is marked and r6 unmarked.
For the class of jmp/jmp32 instructions, backtrack_insn() today only looks
at call and exit instructions and for all other conditionals the masks
remain as-is. However, in the given situation register r6 has a dependency
on r9 (as described above in **), so also that one needs to be marked for
precision tracking. In other words, if an imprecise register influences a
precise one, then the imprecise register should also be marked precise.
Meaning, in the parent state both dest and src register need to be tracked
for precision and therefore the marking must be more conservative by setting
reg->precise flag for both. The precision propagation needs to cover both
for the conditional: if the src reg was marked but not the dst reg and vice
versa.
After the fix the program is correctly rejected:
func#0 @0
0: R1=ctx(off=0,imm=0) R10=fp0
0: (b7) r6 = 1024 ; R6_w=1024
1: (b7) r7 = 0 ; R7_w=0
2: (b7) r8 = 0 ; R8_w=0
3: (b7) r9 = -2147483648 ; R9_w=-2147483648
4: (97) r6 %= 1025 ; R6_w=scalar()
5: (05) goto pc+0
6: (bd) if r6 <= r9 goto pc+2 ; R6_w=scalar(umin=18446744071562067969,var_off=(0xffffffff80000000; 0x7fffffff),u32_min=-2147483648) R9_w=-2147483648
7: (97) r6 %= 1 ; R6_w=scalar()
8: (b7) r9 = 0 ; R9=0
9: (bd) if r6 <= r9 goto pc+1 ; R6=scalar(umin=1) R9=0
10: (b7) r6 = 0 ; R6_w=0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 9
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff9290dc5bfe00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1 ; R0=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0)
19: (55) if r0 != 0x0 goto pc+1 ; R0=0
20: (95) exit
from 19 to 21: R0=map_value(off=0,ks=4,vs=48,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
21: (77) r6 >>= 10 ; R6_w=0
22: (27) r6 *= 8192 ; R6_w=0
23: (bf) r1 = r0 ; R0=map_value(off=0,ks=4,vs=48,imm=0) R1_w=map_value(off=0,ks=4,vs=48,imm=0)
24: (0f) r0 += r6
last_idx 24 first_idx 19
regs=40 stack=0 before 23: (bf) r1 = r0
regs=40 stack=0 before 22: (27) r6 *= 8192
regs=40 stack=0 before 21: (77) r6 >>= 10
regs=40 stack=0 before 19: (55) if r0 != 0x0 goto pc+1
parent didn't have regs=40 stack=0 marks: R0_rw=map_value_or_null(id=1,off=0,ks=4,vs=48,imm=0) R6_rw=P0 R7=0 R8=0 R9=0 R10=fp0 fp-8=mmmm????
last_idx 18 first_idx 9
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff9290dc5bfe00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
regs=40 stack=0 before 10: (b7) r6 = 0
25: (79) r3 = *(u64 *)(r0 +0) ; R0_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
26: (7b) *(u64 *)(r1 +0) = r3 ; R1_w=map_value(off=0,ks=4,vs=48,imm=0) R3_w=scalar()
27: (95) exit
from 9 to 11: R1=ctx(off=0,imm=0) R6=0 R7=0 R8=0 R9=0 R10=fp0
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 11
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff9290dc5bfe00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1
frame 0: propagating r6
last_idx 19 first_idx 11
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff9290dc5bfe00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_r=P0 R7=0 R8=0 R9=0 R10=fp0
last_idx 9 first_idx 9
regs=40 stack=0 before 9: (bd) if r6 <= r9 goto pc+1
parent didn't have regs=240 stack=0 marks: R1=ctx(off=0,imm=0) R6_rw=Pscalar() R7_w=0 R8_w=0 R9_rw=P0 R10=fp0
last_idx 8 first_idx 0
regs=240 stack=0 before 8: (b7) r9 = 0
regs=40 stack=0 before 7: (97) r6 %= 1
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
19: safe
from 6 to 9: R1=ctx(off=0,imm=0) R6_w=scalar(umax=18446744071562067968) R7_w=0 R8_w=0 R9_w=-2147483648 R10=fp0
9: (bd) if r6 <= r9 goto pc+1
last_idx 9 first_idx 0
regs=40 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
last_idx 9 first_idx 0
regs=200 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
11: R6=scalar(umax=18446744071562067968) R9=-2147483648
11: (b7) r0 = 0 ; R0_w=0
12: (63) *(u32 *)(r10 -4) = r0
last_idx 12 first_idx 11
regs=1 stack=0 before 11: (b7) r0 = 0
13: R0_w=0 R10=fp0 fp-8=0000????
13: (18) r4 = 0xffff9290dc5bfe00 ; R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
15: (bf) r1 = r4 ; R1_w=map_ptr(off=0,ks=4,vs=48,imm=0) R4_w=map_ptr(off=0,ks=4,vs=48,imm=0)
16: (bf) r2 = r10 ; R2_w=fp0 R10=fp0
17: (07) r2 += -4 ; R2_w=fp-4
18: (85) call bpf_map_lookup_elem#1 ; R0_w=map_value_or_null(id=3,off=0,ks=4,vs=48,imm=0)
19: (55) if r0 != 0x0 goto pc+1 ; R0_w=0
20: (95) exit
from 19 to 21: R0=map_value(off=0,ks=4,vs=48,imm=0) R6=scalar(umax=18446744071562067968) R7=0 R8=0 R9=-2147483648 R10=fp0 fp-8=mmmm????
21: (77) r6 >>= 10 ; R6_w=scalar(umax=18014398507384832,var_off=(0x0; 0x3fffffffffffff))
22: (27) r6 *= 8192 ; R6_w=scalar(smax=9223372036854767616,umax=18446744073709543424,var_off=(0x0; 0xffffffffffffe000),s32_max=2147475456,u32_max=-8192)
23: (bf) r1 = r0 ; R0=map_value(off=0,ks=4,vs=48,imm=0) R1_w=map_value(off=0,ks=4,vs=48,imm=0)
24: (0f) r0 += r6
last_idx 24 first_idx 21
regs=40 stack=0 before 23: (bf) r1 = r0
regs=40 stack=0 before 22: (27) r6 *= 8192
regs=40 stack=0 before 21: (77) r6 >>= 10
parent didn't have regs=40 stack=0 marks: R0_rw=map_value(off=0,ks=4,vs=48,imm=0) R6_r=Pscalar(umax=18446744071562067968) R7=0 R8=0 R9=-2147483648 R10=fp0 fp-8=mmmm????
last_idx 19 first_idx 11
regs=40 stack=0 before 19: (55) if r0 != 0x0 goto pc+1
regs=40 stack=0 before 18: (85) call bpf_map_lookup_elem#1
regs=40 stack=0 before 17: (07) r2 += -4
regs=40 stack=0 before 16: (bf) r2 = r10
regs=40 stack=0 before 15: (bf) r1 = r4
regs=40 stack=0 before 13: (18) r4 = 0xffff9290dc5bfe00
regs=40 stack=0 before 12: (63) *(u32 *)(r10 -4) = r0
regs=40 stack=0 before 11: (b7) r0 = 0
parent didn't have regs=40 stack=0 marks: R1=ctx(off=0,imm=0) R6_rw=Pscalar(umax=18446744071562067968) R7_w=0 R8_w=0 R9_w=-2147483648 R10=fp0
last_idx 9 first_idx 0
regs=40 stack=0 before 9: (bd) if r6 <= r9 goto pc+1
regs=240 stack=0 before 6: (bd) if r6 <= r9 goto pc+2
regs=240 stack=0 before 5: (05) goto pc+0
regs=240 stack=0 before 4: (97) r6 %= 1025
regs=240 stack=0 before 3: (b7) r9 = -2147483648
regs=40 stack=0 before 2: (b7) r8 = 0
regs=40 stack=0 before 1: (b7) r7 = 0
regs=40 stack=0 before 0: (b7) r6 = 1024
math between map_value pointer and register with unbounded min value is not allowed
verification time 886 usec
stack depth 4
processed 49 insns (limit 1000000) max_states_per_insn 1 total_states 5 peak_states 5 mark_read 2
Fixes: b5dc0163d8fd ("bpf: precise scalar_value tracking")
Reported-by: Juan Jose Lopez Jaimez <jjlopezjaimez@google.com>
Reported-by: Meador Inge <meadori@google.com>
Reported-by: Simon Scannell <simonscannell@google.com>
Reported-by: Nenad Stojanovski <thenenadx@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Co-developed-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Reviewed-by: Juan Jose Lopez Jaimez <jjlopezjaimez@google.com>
Reviewed-by: Meador Inge <meadori@google.com>
Reviewed-by: Simon Scannell <simonscannell@google.com>
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We've seen recent AWS EKS (Kubernetes) user reports like the following:
After upgrading EKS nodes from v20230203 to v20230217 on our 1.24 EKS
clusters after a few days a number of the nodes have containers stuck
in ContainerCreating state or liveness/readiness probes reporting the
following error:
Readiness probe errored: rpc error: code = Unknown desc = failed to
exec in container: failed to start exec "4a11039f730203ffc003b7[...]":
OCI runtime exec failed: exec failed: unable to start container process:
unable to init seccomp: error loading seccomp filter into kernel:
error loading seccomp filter: errno 524: unknown
However, we had not been seeing this issue on previous AMIs and it only
started to occur on v20230217 (following the upgrade from kernel 5.4 to
5.10) with no other changes to the underlying cluster or workloads.
We tried the suggestions from that issue (sysctl net.core.bpf_jit_limit=452534528)
which helped to immediately allow containers to be created and probes to
execute but after approximately a day the issue returned and the value
returned by cat /proc/vmallocinfo | grep bpf_jit | awk '{s+=$2} END {print s}'
was steadily increasing.
I tested bpf tree to observe bpf_jit_charge_modmem, bpf_jit_uncharge_modmem
their sizes passed in as well as bpf_jit_current under tcpdump BPF filter,
seccomp BPF and native (e)BPF programs, and the behavior all looks sane
and expected, that is nothing "leaking" from an upstream perspective.
The bpf_jit_limit knob was originally added in order to avoid a situation
where unprivileged applications loading BPF programs (e.g. seccomp BPF
policies) consuming all the module memory space via BPF JIT such that loading
of kernel modules would be prevented. The default limit was defined back in
2018 and while good enough back then, we are generally seeing far more BPF
consumers today.
Adjust the limit for the BPF JIT pool from originally 1/4 to now 1/2 of the
module memory space to better reflect today's needs and avoid more users
running into potentially hard to debug issues.
Fixes: fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE >= 64K")
Reported-by: Stephen Haynes <sh@synk.net>
Reported-by: Lefteris Alexakis <lefteris.alexakis@kpn.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://github.com/awslabs/amazon-eks-ami/issues/1179
Link: https://github.com/awslabs/amazon-eks-ami/issues/1219
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230320143725.8394-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Merge commit bf9bec4cb3a4 ("Merge branch 'bpf: Allow reads from uninit stack'")
from bpf-next to bpf tree to address verification issues in some programs
due to stack usage.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:
====================
pull-request: bpf 2023-03-06
We've added 8 non-merge commits during the last 7 day(s) which contain
a total of 9 files changed, 64 insertions(+), 18 deletions(-).
The main changes are:
1) Fix BTF resolver for DATASEC sections when a VAR points at a modifier,
that is, keep resolving such instances instead of bailing out,
from Lorenz Bauer.
2) Fix BPF test framework with regards to xdp_frame info misplacement
in the "live packet" code, from Alexander Lobakin.
3) Fix an infinite loop in BPF sockmap code for TCP/UDP/AF_UNIX,
from Liu Jian.
4) Fix a build error for riscv BPF JIT under PERF_EVENTS=n,
from Randy Dunlap.
5) Several BPF doc fixes with either broken links or external instead
of internal doc links, from Bagas Sanjaya.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: check that modifier resolves after pointer
btf: fix resolving BTF_KIND_VAR after ARRAY, STRUCT, UNION, PTR
bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES
bpf, doc: Link to submitting-patches.rst for general patch submission info
bpf, doc: Do not link to docs.kernel.org for kselftest link
bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser()
riscv, bpf: Fix patch_text implicit declaration
bpf, docs: Fix link to BTF doc
====================
Link: https://lore.kernel.org/r/20230306215944.11981-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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|
btf_datasec_resolve contains a bug that causes the following BTF
to fail loading:
[1] DATASEC a size=2 vlen=2
type_id=4 offset=0 size=1
type_id=7 offset=1 size=1
[2] INT (anon) size=1 bits_offset=0 nr_bits=8 encoding=(none)
[3] PTR (anon) type_id=2
[4] VAR a type_id=3 linkage=0
[5] INT (anon) size=1 bits_offset=0 nr_bits=8 encoding=(none)
[6] TYPEDEF td type_id=5
[7] VAR b type_id=6 linkage=0
This error message is printed during btf_check_all_types:
[1] DATASEC a size=2 vlen=2
type_id=7 offset=1 size=1 Invalid type
By tracing btf_*_resolve we can pinpoint the problem:
btf_datasec_resolve(depth: 1, type_id: 1, mode: RESOLVE_TBD) = 0
btf_var_resolve(depth: 2, type_id: 4, mode: RESOLVE_TBD) = 0
btf_ptr_resolve(depth: 3, type_id: 3, mode: RESOLVE_PTR) = 0
btf_var_resolve(depth: 2, type_id: 4, mode: RESOLVE_PTR) = 0
btf_datasec_resolve(depth: 1, type_id: 1, mode: RESOLVE_PTR) = -22
The last invocation of btf_datasec_resolve should invoke btf_var_resolve
by means of env_stack_push, instead it returns EINVAL. The reason is that
env_stack_push is never executed for the second VAR.
if (!env_type_is_resolve_sink(env, var_type) &&
!env_type_is_resolved(env, var_type_id)) {
env_stack_set_next_member(env, i + 1);
return env_stack_push(env, var_type, var_type_id);
}
env_type_is_resolve_sink() changes its behaviour based on resolve_mode.
For RESOLVE_PTR, we can simplify the if condition to the following:
(btf_type_is_modifier() || btf_type_is_ptr) && !env_type_is_resolved()
Since we're dealing with a VAR the clause evaluates to false. This is
not sufficient to trigger the bug however. The log output and EINVAL
are only generated if btf_type_id_size() fails.
if (!btf_type_id_size(btf, &type_id, &type_size)) {
btf_verifier_log_vsi(env, v->t, vsi, "Invalid type");
return -EINVAL;
}
Most types are sized, so for example a VAR referring to an INT is not a
problem. The bug is only triggered if a VAR points at a modifier. Since
we skipped btf_var_resolve that modifier was also never resolved, which
means that btf_resolved_type_id returns 0 aka VOID for the modifier.
This in turn causes btf_type_id_size to return NULL, triggering EINVAL.
To summarise, the following conditions are necessary:
- VAR pointing at PTR, STRUCT, UNION or ARRAY
- Followed by a VAR pointing at TYPEDEF, VOLATILE, CONST, RESTRICT or
TYPE_TAG
The fix is to reset resolve_mode to RESOLVE_TBD before attempting to
resolve a VAR from a DATASEC.
Fixes: 1dc92851849c ("bpf: kernel side support for BTF Var and DataSec")
Signed-off-by: Lorenz Bauer <lmb@isovalent.com>
Link: https://lore.kernel.org/r/20230306112138.155352-2-lmb@isovalent.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- Daniel Verkamp has contributed a memfd series ("mm/memfd: add
F_SEAL_EXEC") which permits the setting of the memfd execute bit at
memfd creation time, with the option of sealing the state of the X
bit.
- Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
thread-safe for pmd unshare") which addresses a rare race condition
related to PMD unsharing.
- Several folioification patch serieses from Matthew Wilcox, Vishal
Moola, Sidhartha Kumar and Lorenzo Stoakes
- Johannes Weiner has a series ("mm: push down lock_page_memcg()")
which does perform some memcg maintenance and cleanup work.
- SeongJae Park has added DAMOS filtering to DAMON, with the series
"mm/damon/core: implement damos filter".
These filters provide users with finer-grained control over DAMOS's
actions. SeongJae has also done some DAMON cleanup work.
- Kairui Song adds a series ("Clean up and fixes for swap").
- Vernon Yang contributed the series "Clean up and refinement for maple
tree".
- Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
adds to MGLRU an LRU of memcgs, to improve the scalability of global
reclaim.
- David Hildenbrand has added some userfaultfd cleanup work in the
series "mm: uffd-wp + change_protection() cleanups".
- Christoph Hellwig has removed the generic_writepages() library
function in the series "remove generic_writepages".
- Baolin Wang has performed some maintenance on the compaction code in
his series "Some small improvements for compaction".
- Sidhartha Kumar is doing some maintenance work on struct page in his
series "Get rid of tail page fields".
- David Hildenbrand contributed some cleanup, bugfixing and
generalization of pte management and of pte debugging in his series
"mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
swap PTEs".
- Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
flag in the series "Discard __GFP_ATOMIC".
- Sergey Senozhatsky has improved zsmalloc's memory utilization with
his series "zsmalloc: make zspage chain size configurable".
- Joey Gouly has added prctl() support for prohibiting the creation of
writeable+executable mappings.
The previous BPF-based approach had shortcomings. See "mm: In-kernel
support for memory-deny-write-execute (MDWE)".
- Waiman Long did some kmemleak cleanup and bugfixing in the series
"mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".
- T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
"mm: multi-gen LRU: improve".
- Jiaqi Yan has provided some enhancements to our memory error
statistics reporting, mainly by presenting the statistics on a
per-node basis. See the series "Introduce per NUMA node memory error
statistics".
- Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
regression in compaction via his series "Fix excessive CPU usage
during compaction".
- Christoph Hellwig does some vmalloc maintenance work in the series
"cleanup vfree and vunmap".
- Christoph Hellwig has removed block_device_operations.rw_page() in
ths series "remove ->rw_page".
- We get some maple_tree improvements and cleanups in Liam Howlett's
series "VMA tree type safety and remove __vma_adjust()".
- Suren Baghdasaryan has done some work on the maintainability of our
vm_flags handling in the series "introduce vm_flags modifier
functions".
- Some pagemap cleanup and generalization work in Mike Rapoport's
series "mm, arch: add generic implementation of pfn_valid() for
FLATMEM" and "fixups for generic implementation of pfn_valid()"
- Baoquan He has done some work to make /proc/vmallocinfo and
/proc/kcore better represent the real state of things in his series
"mm/vmalloc.c: allow vread() to read out vm_map_ram areas".
- Jason Gunthorpe rationalized the GUP system's interface to the rest
of the kernel in the series "Simplify the external interface for
GUP".
- SeongJae Park wishes to migrate people from DAMON's debugfs interface
over to its sysfs interface. To support this, we'll temporarily be
printing warnings when people use the debugfs interface. See the
series "mm/damon: deprecate DAMON debugfs interface".
- Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
and clean-ups" series.
- Huang Ying has provided a dramatic reduction in migration's TLB flush
IPI rates with the series "migrate_pages(): batch TLB flushing".
- Arnd Bergmann has some objtool fixups in "objtool warning fixes".
* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
include/linux/migrate.h: remove unneeded externs
mm/memory_hotplug: cleanup return value handing in do_migrate_range()
mm/uffd: fix comment in handling pte markers
mm: change to return bool for isolate_movable_page()
mm: hugetlb: change to return bool for isolate_hugetlb()
mm: change to return bool for isolate_lru_page()
mm: change to return bool for folio_isolate_lru()
objtool: add UACCESS exceptions for __tsan_volatile_read/write
kmsan: disable ftrace in kmsan core code
kasan: mark addr_has_metadata __always_inline
mm: memcontrol: rename memcg_kmem_enabled()
sh: initialize max_mapnr
m68k/nommu: add missing definition of ARCH_PFN_OFFSET
mm: percpu: fix incorrect size in pcpu_obj_full_size()
maple_tree: reduce stack usage with gcc-9 and earlier
mm: page_alloc: call panic() when memoryless node allocation fails
mm: multi-gen LRU: avoid futile retries
migrate_pages: move THP/hugetlb migration support check to simplify code
migrate_pages: batch flushing TLB
migrate_pages: share more code between _unmap and _move
...
|
|
This commits updates the following functions to allow reads from
uninitialized stack locations when env->allow_uninit_stack option is
enabled:
- check_stack_read_fixed_off()
- check_stack_range_initialized(), called from:
- check_stack_read_var_off()
- check_helper_mem_access()
Such change allows to relax logic in stacksafe() to treat STACK_MISC
and STACK_INVALID in a same way and make the following stack slot
configurations equivalent:
| Cached state | Current state |
| stack slot | stack slot |
|------------------+------------------|
| STACK_INVALID or | STACK_INVALID or |
| STACK_MISC | STACK_SPILL or |
| | STACK_MISC or |
| | STACK_ZERO or |
| | STACK_DYNPTR |
This leads to significant verification speed gains (see below).
The idea was suggested by Andrii Nakryiko [1] and initial patch was
created by Alexei Starovoitov [2].
Currently the env->allow_uninit_stack is allowed for programs loaded
by users with CAP_PERFMON or CAP_SYS_ADMIN capabilities.
A number of test cases from verifier/*.c were expecting uninitialized
stack access to be an error. These test cases were updated to execute
in unprivileged mode (thus preserving the tests).
The test progs/test_global_func10.c expected "invalid indirect read
from stack" error message because of the access to uninitialized
memory region. This error is no longer possible in privileged mode.
The test is updated to provoke an error "invalid indirect access to
stack" because of access to invalid stack address (such error is not
verified by progs/test_global_func*.c series of tests).
The following tests had to be removed because these can't be made
unprivileged:
- verifier/sock.c:
- "sk_storage_get(map, skb->sk, &stack_value, 1): partially init
stack_value"
BPF_PROG_TYPE_SCHED_CLS programs are not executed in unprivileged mode.
- verifier/var_off.c:
- "indirect variable-offset stack access, max_off+size > max_initialized"
- "indirect variable-offset stack access, uninitialized"
These tests verify that access to uninitialized stack values is
detected when stack offset is not a constant. However, variable
stack access is prohibited in unprivileged mode, thus these tests
are no longer valid.
* * *
Here is veristat log comparing this patch with current master on a
set of selftest binaries listed in tools/testing/selftests/bpf/veristat.cfg
and cilium BPF binaries (see [3]):
$ ./veristat -e file,prog,states -C -f 'states_pct<-30' master.log current.log
File Program States (A) States (B) States (DIFF)
-------------------------- -------------------------- ---------- ---------- ----------------
bpf_host.o tail_handle_ipv6_from_host 349 244 -105 (-30.09%)
bpf_host.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%)
bpf_lxc.o tail_handle_nat_fwd_ipv4 1320 895 -425 (-32.20%)
bpf_sock.o cil_sock4_connect 70 48 -22 (-31.43%)
bpf_sock.o cil_sock4_sendmsg 68 46 -22 (-32.35%)
bpf_xdp.o tail_handle_nat_fwd_ipv4 1554 803 -751 (-48.33%)
bpf_xdp.o tail_lb_ipv4 6457 2473 -3984 (-61.70%)
bpf_xdp.o tail_lb_ipv6 7249 3908 -3341 (-46.09%)
pyperf600_bpf_loop.bpf.o on_event 287 145 -142 (-49.48%)
strobemeta.bpf.o on_event 15915 4772 -11143 (-70.02%)
strobemeta_nounroll2.bpf.o on_event 17087 3820 -13267 (-77.64%)
xdp_synproxy_kern.bpf.o syncookie_tc 21271 6635 -14636 (-68.81%)
xdp_synproxy_kern.bpf.o syncookie_xdp 23122 6024 -17098 (-73.95%)
-------------------------- -------------------------- ---------- ---------- ----------------
Note: I limited selection by states_pct<-30%.
Inspection of differences in pyperf600_bpf_loop behavior shows that
the following patch for the test removes almost all differences:
- a/tools/testing/selftests/bpf/progs/pyperf.h
+ b/tools/testing/selftests/bpf/progs/pyperf.h
@ -266,8 +266,8 @ int __on_event(struct bpf_raw_tracepoint_args *ctx)
}
if (event->pthread_match || !pidData->use_tls) {
- void* frame_ptr;
- FrameData frame;
+ void* frame_ptr = 0;
+ FrameData frame = {};
Symbol sym = {};
int cur_cpu = bpf_get_smp_processor_id();
W/o this patch the difference comes from the following pattern
(for different variables):
static bool get_frame_data(... FrameData *frame ...)
{
...
bpf_probe_read_user(&frame->f_code, ...);
if (!frame->f_code)
return false;
...
bpf_probe_read_user(&frame->co_name, ...);
if (frame->co_name)
...;
}
int __on_event(struct bpf_raw_tracepoint_args *ctx)
{
FrameData frame;
...
get_frame_data(... &frame ...) // indirectly via a bpf_loop & callback
...
}
SEC("raw_tracepoint/kfree_skb")
int on_event(struct bpf_raw_tracepoint_args* ctx)
{
...
ret |= __on_event(ctx);
ret |= __on_event(ctx);
...
}
With regards to value `frame->co_name` the following is important:
- Because of the conditional `if (!frame->f_code)` each call to
__on_event() produces two states, one with `frame->co_name` marked
as STACK_MISC, another with it as is (and marked STACK_INVALID on a
first call).
- The call to bpf_probe_read_user() does not mark stack slots
corresponding to `&frame->co_name` as REG_LIVE_WRITTEN but it marks
these slots as BPF_MISC, this happens because of the following loop
in the check_helper_call():
for (i = 0; i < meta.access_size; i++) {
err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
BPF_WRITE, -1, false);
if (err)
return err;
}
Note the size of the write, it is a one byte write for each byte
touched by a helper. The BPF_B write does not lead to write marks
for the target stack slot.
- Which means that w/o this patch when second __on_event() call is
verified `if (frame->co_name)` will propagate read marks first to a
stack slot with STACK_MISC marks and second to a stack slot with
STACK_INVALID marks and these states would be considered different.
[1] https://lore.kernel.org/bpf/CAEf4BzY3e+ZuC6HUa8dCiUovQRg2SzEk7M-dSkqNZyn=xEmnPA@mail.gmail.com/
[2] https://lore.kernel.org/bpf/CAADnVQKs2i1iuZ5SUGuJtxWVfGYR9kDgYKhq3rNV+kBLQCu7rA@mail.gmail.com/
[3] git@github.com:anakryiko/cilium.git
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Co-developed-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230219200427.606541-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Commit 74e19ef0ff80 ("uaccess: Add speculation barrier to
copy_from_user()") built fine on x86-64 and arm64, and that's the extent
of my local build testing.
It turns out those got the <linux/nospec.h> include incidentally through
other header files (<linux/kvm_host.h> in particular), but that was not
true of other architectures, resulting in build errors
kernel/bpf/core.c: In function ‘___bpf_prog_run’:
kernel/bpf/core.c:1913:3: error: implicit declaration of function ‘barrier_nospec’
so just make sure to explicitly include the proper <linux/nospec.h>
header file to make everybody see it.
Fixes: 74e19ef0ff80 ("uaccess: Add speculation barrier to copy_from_user()")
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Reported-by: Huacai Chen <chenhuacai@loongson.cn>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
|
|
The results of "access_ok()" can be mis-speculated. The result is that
you can end speculatively:
if (access_ok(from, size))
// Right here
even for bad from/size combinations. On first glance, it would be ideal
to just add a speculation barrier to "access_ok()" so that its results
can never be mis-speculated.
But there are lots of system calls just doing access_ok() via
"copy_to_user()" and friends (example: fstat() and friends). Those are
generally not problematic because they do not _consume_ data from
userspace other than the pointer. They are also very quick and common
system calls that should not be needlessly slowed down.
"copy_from_user()" on the other hand uses a user-controller pointer and
is frequently followed up with code that might affect caches. Take
something like this:
if (!copy_from_user(&kernelvar, uptr, size))
do_something_with(kernelvar);
If userspace passes in an evil 'uptr' that *actually* points to a kernel
addresses, and then do_something_with() has cache (or other)
side-effects, it could allow userspace to infer kernel data values.
Add a barrier to the common copy_from_user() code to prevent
mis-speculated values which happen after the copy.
Also add a stub for architectures that do not define barrier_nospec().
This makes the macro usable in generic code.
Since the barrier is now usable in generic code, the x86 #ifdef in the
BPF code can also go away.
Reported-by: Jordy Zomer <jordyzomer@google.com>
Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Daniel Borkmann <daniel@iogearbox.net> # BPF bits
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping
Pull vfs idmapping updates from Christian Brauner:
- Last cycle we introduced the dedicated struct mnt_idmap type for
mount idmapping and the required infrastucture in 256c8aed2b42 ("fs:
introduce dedicated idmap type for mounts"). As promised in last
cycle's pull request message this converts everything to rely on
struct mnt_idmap.
Currently we still pass around the plain namespace that was attached
to a mount. This is in general pretty convenient but it makes it easy
to conflate namespaces that are relevant on the filesystem with
namespaces that are relevant on the mount level. Especially for
non-vfs developers without detailed knowledge in this area this was a
potential source for bugs.
This finishes the conversion. Instead of passing the plain namespace
around this updates all places that currently take a pointer to a
mnt_userns with a pointer to struct mnt_idmap.
Now that the conversion is done all helpers down to the really
low-level helpers only accept a struct mnt_idmap argument instead of
two namespace arguments.
Conflating mount and other idmappings will now cause the compiler to
complain loudly thus eliminating the possibility of any bugs. This
makes it impossible for filesystem developers to mix up mount and
filesystem idmappings as they are two distinct types and require
distinct helpers that cannot be used interchangeably.
Everything associated with struct mnt_idmap is moved into a single
separate file. With that change no code can poke around in struct
mnt_idmap. It can only be interacted with through dedicated helpers.
That means all filesystems are and all of the vfs is completely
oblivious to the actual implementation of idmappings.
We are now also able to extend struct mnt_idmap as we see fit. For
example, we can decouple it completely from namespaces for users that
don't require or don't want to use them at all. We can also extend
the concept of idmappings so we can cover filesystem specific
requirements.
In combination with the vfs{g,u}id_t work we finished in v6.2 this
makes this feature substantially more robust and thus difficult to
implement wrong by a given filesystem and also protects the vfs.
- Enable idmapped mounts for tmpfs and fulfill a longstanding request.
A long-standing request from users had been to make it possible to
create idmapped mounts for tmpfs. For example, to share the host's
tmpfs mount between multiple sandboxes. This is a prerequisite for
some advanced Kubernetes cases. Systemd also has a range of use-cases
to increase service isolation. And there are more users of this.
However, with all of the other work going on this was way down on the
priority list but luckily someone other than ourselves picked this
up.
As usual the patch is tiny as all the infrastructure work had been
done multiple kernel releases ago. In addition to all the tests that
we already have I requested that Rodrigo add a dedicated tmpfs
testsuite for idmapped mounts to xfstests. It is to be included into
xfstests during the v6.3 development cycle. This should add a slew of
additional tests.
* tag 'fs.idmapped.v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping: (26 commits)
shmem: support idmapped mounts for tmpfs
fs: move mnt_idmap
fs: port vfs{g,u}id helpers to mnt_idmap
fs: port fs{g,u}id helpers to mnt_idmap
fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap
fs: port i_{g,u}id_{needs_}update() to mnt_idmap
quota: port to mnt_idmap
fs: port privilege checking helpers to mnt_idmap
fs: port inode_owner_or_capable() to mnt_idmap
fs: port inode_init_owner() to mnt_idmap
fs: port acl to mnt_idmap
fs: port xattr to mnt_idmap
fs: port ->permission() to pass mnt_idmap
fs: port ->fileattr_set() to pass mnt_idmap
fs: port ->set_acl() to pass mnt_idmap
fs: port ->get_acl() to pass mnt_idmap
fs: port ->tmpfile() to pass mnt_idmap
fs: port ->rename() to pass mnt_idmap
fs: port ->mknod() to pass mnt_idmap
fs: port ->mkdir() to pass mnt_idmap
...
|
|
KPROBE program's user-facing context type is defined as typedef
bpf_user_pt_regs_t. This leads to a problem when trying to passing
kprobe/uprobe/usdt context argument into global subprog, as kernel
always strip away mods and typedefs of user-supplied type, but takes
expected type from bpf_ctx_convert as is, which causes mismatch.
Current way to work around this is to define a fake struct with the same
name as expected typedef:
struct bpf_user_pt_regs_t {};
__noinline my_global_subprog(struct bpf_user_pt_regs_t *ctx) { ... }
This patch fixes the issue by resolving expected type, if it's not
a struct. It still leaves the above work-around working for backwards
compatibility.
Fixes: 91cc1a99740e ("bpf: Annotate context types")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230216045954.3002473-2-andrii@kernel.org
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Currently the freed element in bpf memory allocator may be immediately
reused, for htab map the reuse will reinitialize special fields in map
value (e.g., bpf_spin_lock), but lookup procedure may still access
these special fields, and it may lead to hard-lockup as shown below:
NMI backtrace for cpu 16
CPU: 16 PID: 2574 Comm: htab.bin Tainted: G L 6.1.0+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
RIP: 0010:queued_spin_lock_slowpath+0x283/0x2c0
......
Call Trace:
<TASK>
copy_map_value_locked+0xb7/0x170
bpf_map_copy_value+0x113/0x3c0
__sys_bpf+0x1c67/0x2780
__x64_sys_bpf+0x1c/0x20
do_syscall_64+0x30/0x60
entry_SYSCALL_64_after_hwframe+0x46/0xb0
......
</TASK>
For htab map, just like the preallocated case, these is no need to
initialize these special fields in map value again once these fields
have been initialized. For preallocated htab map, these fields are
initialized through __GFP_ZERO in bpf_map_area_alloc(), so do the
similar thing for non-preallocated htab in bpf memory allocator. And
there is no need to use __GFP_ZERO for per-cpu bpf memory allocator,
because __alloc_percpu_gfp() does it implicitly.
Fixes: 0fd7c5d43339 ("bpf: Optimize call_rcu in non-preallocated hash map.")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20230215082132.3856544-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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BPF_STX instruction preserves STACK_ZERO marks for variable offset
writes in situations like below:
*(u64*)(r10 - 8) = 0 ; STACK_ZERO marks for fp[-8]
r0 = random(-7, -1) ; some random number in range of [-7, -1]
r0 += r10 ; r0 is now a variable offset pointer to stack
r1 = 0
*(u8*)(r0) = r1 ; BPF_STX writing zero, STACK_ZERO mark for
; fp[-8] is preserved
This commit updates verifier.c:check_stack_write_var_off() to process
BPF_ST in a similar manner, e.g. the following example:
*(u64*)(r10 - 8) = 0 ; STACK_ZERO marks for fp[-8]
r0 = random(-7, -1) ; some random number in range of [-7, -1]
r0 += r10 ; r0 is now variable offset pointer to stack
*(u8*)(r0) = 0 ; BPF_ST writing zero, STACK_ZERO mark for
; fp[-8] is preserved
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-4-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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For aligned stack writes using BPF_ST instruction track stored values
in a same way BPF_STX is handled, e.g. make sure that the following
commands produce similar verifier knowledge:
fp[-8] = 42; r1 = 42;
fp[-8] = r1;
This covers two cases:
- non-null values written to stack are stored as spill of fake
registers;
- null values written to stack are stored as STACK_ZERO marks.
Previously both cases above used STACK_MISC marks instead.
Some verifier test cases relied on the old logic to obtain STACK_MISC
marks for some stack values. These test cases are updated in the same
commit to avoid failures during bisect.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20230214232030.1502829-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Newly-added bpf_rbtree_{remove,first} kfuncs have some special properties
that require handling in the verifier:
* both bpf_rbtree_remove and bpf_rbtree_first return the type containing
the bpf_rb_node field, with the offset set to that field's offset,
instead of a struct bpf_rb_node *
* mark_reg_graph_node helper added in previous patch generalizes
this logic, use it
* bpf_rbtree_remove's node input is a node that's been inserted
in the tree - a non-owning reference.
* bpf_rbtree_remove must invalidate non-owning references in order to
avoid aliasing issue. Use previously-added
invalidate_non_owning_refs helper to mark this function as a
non-owning ref invalidation point.
* Unlike other functions, which convert one of their input arg regs to
non-owning reference, bpf_rbtree_first takes no arguments and just
returns a non-owning reference (possibly null)
* For now verifier logic for this is special-cased instead of
adding new kfunc flag.
This patch, along with the previous one, complete special verifier
handling for all rbtree API functions added in this series.
With functional verifier handling of rbtree_remove, under current
non-owning reference scheme, a node type with both bpf_{list,rb}_node
fields could cause the verifier to accept programs which remove such
nodes from collections they haven't been added to.
In order to prevent this, this patch adds a check to btf_parse_fields
which rejects structs with both bpf_{list,rb}_node fields. This is a
temporary measure that can be removed after "collection identity"
followup. See comment added in btf_parse_fields. A linked_list BTF test
exercising the new check is added in this patch as well.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-6-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Some BPF helpers take a callback function which the helper calls. For
each helper that takes such a callback, there's a special call to
__check_func_call with a callback-state-setting callback that sets up
verifier bpf_func_state for the callback's frame.
kfuncs don't have any of this infrastructure yet, so let's add it in
this patch, following existing helper pattern as much as possible. To
validate functionality of this added plumbing, this patch adds
callback handling for the bpf_rbtree_add kfunc and hopes to lay
groundwork for future graph datastructure callbacks.
In the "general plumbing" category we have:
* check_kfunc_call doing callback verification right before clearing
CALLER_SAVED_REGS, exactly like check_helper_call
* recognition of func_ptr BTF types in kfunc args as
KF_ARG_PTR_TO_CALLBACK + propagation of subprogno for this arg type
In the "rbtree_add / graph datastructure-specific plumbing" category:
* Since bpf_rbtree_add must be called while the spin_lock associated
with the tree is held, don't complain when callback's func_state
doesn't unlock it by frame exit
* Mark rbtree_add callback's args with ref_set_non_owning
to prevent rbtree api functions from being called in the callback.
Semantically this makes sense, as less() takes no ownership of its
args when determining which comes first.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-5-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Now that we find bpf_rb_root and bpf_rb_node in structs, let's give args
that contain those types special classification and properly handle
these types when checking kfunc args.
"Properly handling" these types largely requires generalizing similar
handling for bpf_list_{head,node}, with little new logic added in this
patch.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-4-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This patch adds implementations of bpf_rbtree_{add,remove,first}
and teaches verifier about their BTF_IDs as well as those of
bpf_rb_{root,node}.
All three kfuncs have some nonstandard component to their verification
that needs to be addressed in future patches before programs can
properly use them:
* bpf_rbtree_add: Takes 'less' callback, need to verify it
* bpf_rbtree_first: Returns ptr_to_node_type(off=rb_node_off) instead
of ptr_to_rb_node(off=0). Return value ref is
non-owning.
* bpf_rbtree_remove: Returns ptr_to_node_type(off=rb_node_off) instead
of ptr_to_rb_node(off=0). 2nd arg (node) is a
non-owning reference.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-3-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This patch adds special BPF_RB_{ROOT,NODE} btf_field_types similar to
BPF_LIST_{HEAD,NODE}, adds the necessary plumbing to detect the new
types, and adds bpf_rb_root_free function for freeing bpf_rb_root in
map_values.
structs bpf_rb_root and bpf_rb_node are opaque types meant to
obscure structs rb_root_cached rb_node, respectively.
btf_struct_access will prevent BPF programs from touching these special
fields automatically now that they're recognized.
btf_check_and_fixup_fields now groups list_head and rb_root together as
"graph root" fields and {list,rb}_node as "graph node", and does same
ownership cycle checking as before. Note that this function does _not_
prevent ownership type mixups (e.g. rb_root owning list_node) - that's
handled by btf_parse_graph_root.
After this patch, a bpf program can have a struct bpf_rb_root in a
map_value, but not add anything to nor do anything useful with it.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230214004017.2534011-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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This patch introduces non-owning reference semantics to the verifier,
specifically linked_list API kfunc handling. release_on_unlock logic for
refs is refactored - with small functional changes - to implement these
semantics, and bpf_list_push_{front,back} are migrated to use them.
When a list node is pushed to a list, the program still has a pointer to
the node:
n = bpf_obj_new(typeof(*n));
bpf_spin_lock(&l);
bpf_list_push_back(&l, n);
/* n still points to the just-added node */
bpf_spin_unlock(&l);
What the verifier considers n to be after the push, and thus what can be
done with n, are changed by this patch.
Common properties both before/after this patch:
* After push, n is only a valid reference to the node until end of
critical section
* After push, n cannot be pushed to any list
* After push, the program can read the node's fields using n
Before:
* After push, n retains the ref_obj_id which it received on
bpf_obj_new, but the associated bpf_reference_state's
release_on_unlock field is set to true
* release_on_unlock field and associated logic is used to implement
"n is only a valid ref until end of critical section"
* After push, n cannot be written to, the node must be removed from
the list before writing to its fields
* After push, n is marked PTR_UNTRUSTED
After:
* After push, n's ref is released and ref_obj_id set to 0. NON_OWN_REF
type flag is added to reg's type, indicating that it's a non-owning
reference.
* NON_OWN_REF flag and logic is used to implement "n is only a
valid ref until end of critical section"
* n can be written to (except for special fields e.g. bpf_list_node,
timer, ...)
Summary of specific implementation changes to achieve the above:
* release_on_unlock field, ref_set_release_on_unlock helper, and logic
to "release on unlock" based on that field are removed
* The anonymous active_lock struct used by bpf_verifier_state is
pulled out into a named struct bpf_active_lock.
* NON_OWN_REF type flag is introduced along with verifier logic
changes to handle non-owning refs
* Helpers are added to use NON_OWN_REF flag to implement non-owning
ref semantics as described above
* invalidate_non_owning_refs - helper to clobber all non-owning refs
matching a particular bpf_active_lock identity. Replaces
release_on_unlock logic in process_spin_lock.
* ref_set_non_owning - set NON_OWN_REF type flag after doing some
sanity checking
* ref_convert_owning_non_owning - convert owning reference w/
specified ref_obj_id to non-owning references. Set NON_OWN_REF
flag for each reg with that ref_obj_id and 0-out its ref_obj_id
* Update linked_list selftests to account for minor semantic
differences introduced by this patch
* Writes to a release_on_unlock node ref are not allowed, while
writes to non-owning reference pointees are. As a result the
linked_list "write after push" failure tests are no longer scenarios
that should fail.
* The test##missing_lock##op and test##incorrect_lock##op
macro-generated failure tests need to have a valid node argument in
order to have the same error output as before. Otherwise
verification will fail early and the expected error output won't be seen.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230212092715.1422619-2-davemarchevsky@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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|
We can simply disable the bpf prog memory accouting by not setting the
GFP_ACCOUNT.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-5-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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We can simply set root memcg as the map's memcg to disable bpf memory
accounting. bpf_map_area_alloc is a little special as it gets the memcg
from current rather than from the map, so we need to disable GFP_ACCOUNT
specifically for it.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-4-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Introduce new helper bpf_map_kvcalloc() for the memory allocation in
bpf_local_storage(). Then the allocation will charge the memory from the
map instead of from current, though currently they are the same thing as
it is only used in map creation path now. By charging map's memory into
the memcg from the map, it will be more clear.
Signed-off-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20230210154734.4416-3-laoar.shao@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
====================
pull-request: bpf-next 2023-02-11
We've added 96 non-merge commits during the last 14 day(s) which contain
a total of 152 files changed, 4884 insertions(+), 962 deletions(-).
There is a minor conflict in drivers/net/ethernet/intel/ice/ice_main.c
between commit 5b246e533d01 ("ice: split probe into smaller functions")
from the net-next tree and commit 66c0e13ad236 ("drivers: net: turn on
XDP features") from the bpf-next tree. Remove the hunk given ice_cfg_netdev()
is otherwise there a 2nd time, and add XDP features to the existing
ice_cfg_netdev() one:
[...]
ice_set_netdev_features(netdev);
netdev->xdp_features = NETDEV_XDP_ACT_BASIC | NETDEV_XDP_ACT_REDIRECT |
NETDEV_XDP_ACT_XSK_ZEROCOPY;
ice_set_ops(netdev);
[...]
Stephen's merge conflict mail:
https://lore.kernel.org/bpf/20230207101951.21a114fa@canb.auug.org.au/
The main changes are:
1) Add support for BPF trampoline on s390x which finally allows to remove many
test cases from the BPF CI's DENYLIST.s390x, from Ilya Leoshkevich.
2) Add multi-buffer XDP support to ice driver, from Maciej Fijalkowski.
3) Add capability to export the XDP features supported by the NIC.
Along with that, add a XDP compliance test tool,
from Lorenzo Bianconi & Marek Majtyka.
4) Add __bpf_kfunc tag for marking kernel functions as kfuncs,
from David Vernet.
5) Add a deep dive documentation about the verifier's register
liveness tracking algorithm, from Eduard Zingerman.
6) Fix and follow-up cleanups for resolve_btfids to be compiled
as a host program to avoid cross compile issues,
from Jiri Olsa & Ian Rogers.
7) Batch of fixes to the BPF selftest for xdp_hw_metadata which resulted
when testing on different NICs, from Jesper Dangaard Brouer.
8) Fix libbpf to better detect kernel version code on Debian, from Hao Xiang.
9) Extend libbpf to add an option for when the perf buffer should
wake up, from Jon Doron.
10) Follow-up fix on xdp_metadata selftest to just consume on TX
completion, from Stanislav Fomichev.
11) Extend the kfuncs.rst document with description on kfunc
lifecycle & stability expectations, from David Vernet.
12) Fix bpftool prog profile to skip attaching to offline CPUs,
from Tonghao Zhang.
====================
Link: https://lore.kernel.org/r/20230211002037.8489-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
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skbuff_head_cache is misnamed (perhaps for historical reasons?)
because it does not hold heads. Head is the buffer which skb->data
points to, and also where shinfo lives. struct sk_buff is a metadata
structure, not the head.
Eric recently added skb_small_head_cache (which allocates actual
head buffers), let that serve as an excuse to finally clean this up :)
Leave the user-space visible name intact, it could possibly be uAPI.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Replace direct modifications to vma->vm_flags with calls to modifier
functions to be able to track flag changes and to keep vma locking
correctness.
[akpm@linux-foundation.org: fix drivers/misc/open-dice.c, per Hyeonggon Yoo]
Link: https://lkml.kernel.org/r/20230126193752.297968-5-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Acked-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Minchan Kim <minchan@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Peter Oskolkov <posk@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Soheil Hassas Yeganeh <soheil@google.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
Check if the destination device implements ndo_xdp_xmit callback relying
on NETDEV_XDP_ACT_NDO_XMIT flags. Moreover, check if the destination device
supports XDP non-linear frame in __xdp_enqueue and is_valid_dst routines.
This patch allows to perform XDP_REDIRECT on non-linear XDP buffers.
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://lore.kernel.org/r/26a94c33520c0bfba021b3fbb2cb8c1e69bf53b8.1675245258.git.lorenzo@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
The do_idr_lock parameter to bpf_map_free_id was introduced by commit
bd5f5f4ecb78 ("bpf: Add BPF_MAP_GET_FD_BY_ID"). However, all callers set
do_idr_lock = true since commit 1e0bd5a091e5 ("bpf: Switch bpf_map ref
counter to atomic64_t so bpf_map_inc() never fails").
While at it also inline __bpf_map_put into its only caller bpf_map_put
now that do_idr_lock can be dropped from its signature.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20230202141921.4424-1-tklauser@distanz.ch
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
net/core/gro.c
7d2c89b32587 ("skb: Do mix page pool and page referenced frags in GRO")
b1a78b9b9886 ("net: add support for ipv4 big tcp")
https://lore.kernel.org/all/20230203094454.5766f160@canb.auug.org.au/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
Now that we have the __bpf_kfunc tag, we should use add it to all
existing kfuncs to ensure that they'll never be elided in LTO builds.
Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/bpf/20230201173016.342758-4-void@manifault.com
|
|
s390x eBPF JIT needs to know whether a function return value is signed
and which function arguments are signed, in order to generate code
compliant with the s390x ABI.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-26-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
iterators.lskel.h is little-endian, therefore bpf iterator is currently
broken on big-endian systems. Introduce a big-endian version and add
instructions regarding its generation. Unfortunately bpftool's
cross-endianness capabilities are limited to BTF right now, so the
procedure requires access to a big-endian machine or a configured
emulator.
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Link: https://lore.kernel.org/r/20230128000650.1516334-25-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
