From 895b5c9f206eb7d25dc1360a8ccfc5958895eb89 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Sun, 29 Sep 2019 20:54:03 +0200 Subject: netfilter: drop bridge nf reset from nf_reset commit 174e23810cd31 ("sk_buff: drop all skb extensions on free and skb scrubbing") made napi recycle always drop skb extensions. The additional skb_ext_del() that is performed via nf_reset on napi skb recycle is not needed anymore. Most nf_reset() calls in the stack are there so queued skb won't block 'rmmod nf_conntrack' indefinitely. This removes the skb_ext_del from nf_reset, and renames it to a more fitting nf_reset_ct(). In a few selected places, add a call to skb_ext_reset to make sure that no active extensions remain. I am submitting this for "net", because we're still early in the release cycle. The patch applies to net-next too, but I think the rename causes needless divergence between those trees. Suggested-by: Eric Dumazet Signed-off-by: Florian Westphal Signed-off-by: Pablo Neira Ayuso --- net/sctp/input.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/sctp/input.c') diff --git a/net/sctp/input.c b/net/sctp/input.c index 1008cdc44dd6..5a070fb5b278 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -201,7 +201,7 @@ int sctp_rcv(struct sk_buff *skb) if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) goto discard_release; - nf_reset(skb); + nf_reset_ct(skb); if (sk_filter(sk, skb)) goto discard_release; -- cgit v1.2.3 From 819be8108fded0b9e710bbbf81193e52f7bab2f7 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Tue, 8 Oct 2019 19:09:23 +0800 Subject: sctp: add chunks to sk_backlog when the newsk sk_socket is not set This patch is to fix a NULL-ptr deref in selinux_socket_connect_helper: [...] kasan: GPF could be caused by NULL-ptr deref or user memory access [...] RIP: 0010:selinux_socket_connect_helper+0x94/0x460 [...] Call Trace: [...] selinux_sctp_bind_connect+0x16a/0x1d0 [...] security_sctp_bind_connect+0x58/0x90 [...] sctp_process_asconf+0xa52/0xfd0 [sctp] [...] sctp_sf_do_asconf+0x785/0x980 [sctp] [...] sctp_do_sm+0x175/0x5a0 [sctp] [...] sctp_assoc_bh_rcv+0x285/0x5b0 [sctp] [...] sctp_backlog_rcv+0x482/0x910 [sctp] [...] __release_sock+0x11e/0x310 [...] release_sock+0x4f/0x180 [...] sctp_accept+0x3f9/0x5a0 [sctp] [...] inet_accept+0xe7/0x720 It was caused by that the 'newsk' sk_socket was not set before going to security sctp hook when processing asconf chunk with SCTP_PARAM_ADD_IP or SCTP_PARAM_SET_PRIMARY: inet_accept()-> sctp_accept(): lock_sock(): lock listening 'sk' do_softirq(): sctp_rcv(): <-- [1] asconf chunk arrives and enqueued in 'sk' backlog sctp_sock_migrate(): set asoc's sk to 'newsk' release_sock(): sctp_backlog_rcv(): lock 'newsk' sctp_process_asconf() <-- [2] unlock 'newsk' sock_graft(): set sk_socket <-- [3] As it shows, at [1] the asconf chunk would be put into the listening 'sk' backlog, as accept() was holding its sock lock. Then at [2] asconf would get processed with 'newsk' as asoc's sk had been set to 'newsk'. However, 'newsk' sk_socket is not set until [3], while selinux_sctp_bind_connect() would deref it, then kernel crashed. Here to fix it by adding the chunk to sk_backlog until newsk sk_socket is set when .accept() is done. Note that sk->sk_socket can be NULL when the sock is closed, so SOCK_DEAD flag is also needed to check in sctp_newsk_ready(). Thanks to Ondrej for reviewing the code. Fixes: d452930fd3b9 ("selinux: Add SCTP support") Reported-by: Ying Xu Suggested-by: Marcelo Ricardo Leitner Signed-off-by: Xin Long Acked-by: Marcelo Ricardo Leitner Acked-by: Neil Horman Signed-off-by: Jakub Kicinski --- include/net/sctp/sctp.h | 5 +++++ net/sctp/input.c | 12 +++++++++--- 2 files changed, 14 insertions(+), 3 deletions(-) (limited to 'net/sctp/input.c') diff --git a/include/net/sctp/sctp.h b/include/net/sctp/sctp.h index 5d60f13d2347..3ab5c6bbb90b 100644 --- a/include/net/sctp/sctp.h +++ b/include/net/sctp/sctp.h @@ -610,4 +610,9 @@ static inline __u32 sctp_min_frag_point(struct sctp_sock *sp, __u16 datasize) return sctp_mtu_payload(sp, SCTP_DEFAULT_MINSEGMENT, datasize); } +static inline bool sctp_newsk_ready(const struct sock *sk) +{ + return sock_flag(sk, SOCK_DEAD) || sk->sk_socket; +} + #endif /* __net_sctp_h__ */ diff --git a/net/sctp/input.c b/net/sctp/input.c index 5a070fb5b278..f2771375bfc0 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -243,7 +243,7 @@ int sctp_rcv(struct sk_buff *skb) bh_lock_sock(sk); } - if (sock_owned_by_user(sk)) { + if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) { if (sctp_add_backlog(sk, skb)) { bh_unlock_sock(sk); sctp_chunk_free(chunk); @@ -321,7 +321,7 @@ int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) local_bh_disable(); bh_lock_sock(sk); - if (sock_owned_by_user(sk)) { + if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) { if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) sctp_chunk_free(chunk); else @@ -336,7 +336,13 @@ int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) if (backloged) return 0; } else { - sctp_inq_push(inqueue, chunk); + if (!sctp_newsk_ready(sk)) { + if (!sk_add_backlog(sk, skb, sk->sk_rcvbuf)) + return 0; + sctp_chunk_free(chunk); + } else { + sctp_inq_push(inqueue, chunk); + } } done: -- cgit v1.2.3 From 8265792bf8871acc2d00fd03883d830e2249d395 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 9 Oct 2019 15:21:13 -0700 Subject: net: silence KCSAN warnings around sk_add_backlog() calls sk_add_backlog() callers usually read sk->sk_rcvbuf without owning the socket lock. This means sk_rcvbuf value can be changed by other cpus, and KCSAN complains. Add READ_ONCE() annotations to document the lockless nature of these reads. Note that writes over sk_rcvbuf should also use WRITE_ONCE(), but this will be done in separate patches to ease stable backports (if we decide this is relevant for stable trees). BUG: KCSAN: data-race in tcp_add_backlog / tcp_recvmsg write to 0xffff88812ab369f8 of 8 bytes by interrupt on cpu 1: __sk_add_backlog include/net/sock.h:902 [inline] sk_add_backlog include/net/sock.h:933 [inline] tcp_add_backlog+0x45a/0xcc0 net/ipv4/tcp_ipv4.c:1737 tcp_v4_rcv+0x1aba/0x1bf0 net/ipv4/tcp_ipv4.c:1925 ip_protocol_deliver_rcu+0x51/0x470 net/ipv4/ip_input.c:204 ip_local_deliver_finish+0x110/0x140 net/ipv4/ip_input.c:231 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_local_deliver+0x133/0x210 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_rcv_finish+0x121/0x160 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:305 [inline] NF_HOOK include/linux/netfilter.h:299 [inline] ip_rcv+0x18f/0x1a0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0xa7/0xe0 net/core/dev.c:5004 __netif_receive_skb+0x37/0xf0 net/core/dev.c:5118 netif_receive_skb_internal+0x59/0x190 net/core/dev.c:5208 napi_skb_finish net/core/dev.c:5671 [inline] napi_gro_receive+0x28f/0x330 net/core/dev.c:5704 receive_buf+0x284/0x30b0 drivers/net/virtio_net.c:1061 virtnet_receive drivers/net/virtio_net.c:1323 [inline] virtnet_poll+0x436/0x7d0 drivers/net/virtio_net.c:1428 napi_poll net/core/dev.c:6352 [inline] net_rx_action+0x3ae/0xa50 net/core/dev.c:6418 read to 0xffff88812ab369f8 of 8 bytes by task 7271 on cpu 0: tcp_recvmsg+0x470/0x1a30 net/ipv4/tcp.c:2047 inet_recvmsg+0xbb/0x250 net/ipv4/af_inet.c:838 sock_recvmsg_nosec net/socket.c:871 [inline] sock_recvmsg net/socket.c:889 [inline] sock_recvmsg+0x92/0xb0 net/socket.c:885 sock_read_iter+0x15f/0x1e0 net/socket.c:967 call_read_iter include/linux/fs.h:1864 [inline] new_sync_read+0x389/0x4f0 fs/read_write.c:414 __vfs_read+0xb1/0xc0 fs/read_write.c:427 vfs_read fs/read_write.c:461 [inline] vfs_read+0x143/0x2c0 fs/read_write.c:446 ksys_read+0xd5/0x1b0 fs/read_write.c:587 __do_sys_read fs/read_write.c:597 [inline] __se_sys_read fs/read_write.c:595 [inline] __x64_sys_read+0x4c/0x60 fs/read_write.c:595 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 7271 Comm: syz-fuzzer Not tainted 5.3.0+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Signed-off-by: Eric Dumazet Reported-by: syzbot Signed-off-by: Jakub Kicinski --- net/core/sock.c | 2 +- net/ipv4/tcp_ipv4.c | 2 +- net/llc/llc_conn.c | 2 +- net/sctp/input.c | 6 +++--- net/tipc/socket.c | 6 +++--- net/x25/x25_dev.c | 2 +- 6 files changed, 10 insertions(+), 10 deletions(-) (limited to 'net/sctp/input.c') diff --git a/net/core/sock.c b/net/core/sock.c index 50647a10fdb7..1cf06934da50 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -522,7 +522,7 @@ int __sk_receive_skb(struct sock *sk, struct sk_buff *skb, rc = sk_backlog_rcv(sk, skb); mutex_release(&sk->sk_lock.dep_map, 1, _RET_IP_); - } else if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) { + } else if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) { bh_unlock_sock(sk); atomic_inc(&sk->sk_drops); goto discard_and_relse; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index bf124b1742df..492bf6a6b023 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1644,7 +1644,7 @@ int tcp_v4_early_demux(struct sk_buff *skb) bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb) { - u32 limit = sk->sk_rcvbuf + sk->sk_sndbuf; + u32 limit = READ_ONCE(sk->sk_rcvbuf) + READ_ONCE(sk->sk_sndbuf); struct skb_shared_info *shinfo; const struct tcphdr *th; struct tcphdr *thtail; diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c index a79b739eb223..7b620acaca9e 100644 --- a/net/llc/llc_conn.c +++ b/net/llc/llc_conn.c @@ -813,7 +813,7 @@ void llc_conn_handler(struct llc_sap *sap, struct sk_buff *skb) else { dprintk("%s: adding to backlog...\n", __func__); llc_set_backlog_type(skb, LLC_PACKET); - if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) + if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) goto drop_unlock; } out: diff --git a/net/sctp/input.c b/net/sctp/input.c index f2771375bfc0..2277981559d0 100644 --- a/net/sctp/input.c +++ b/net/sctp/input.c @@ -322,7 +322,7 @@ int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) bh_lock_sock(sk); if (sock_owned_by_user(sk) || !sctp_newsk_ready(sk)) { - if (sk_add_backlog(sk, skb, sk->sk_rcvbuf)) + if (sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) sctp_chunk_free(chunk); else backloged = 1; @@ -337,7 +337,7 @@ int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) return 0; } else { if (!sctp_newsk_ready(sk)) { - if (!sk_add_backlog(sk, skb, sk->sk_rcvbuf)) + if (!sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf))) return 0; sctp_chunk_free(chunk); } else { @@ -364,7 +364,7 @@ static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb) struct sctp_ep_common *rcvr = chunk->rcvr; int ret; - ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf); + ret = sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)); if (!ret) { /* Hold the assoc/ep while hanging on the backlog queue. * This way, we know structures we need will not disappear diff --git a/net/tipc/socket.c b/net/tipc/socket.c index 3b9f8cc328f5..7c736cfec57f 100644 --- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -2119,13 +2119,13 @@ static unsigned int rcvbuf_limit(struct sock *sk, struct sk_buff *skb) struct tipc_msg *hdr = buf_msg(skb); if (unlikely(msg_in_group(hdr))) - return sk->sk_rcvbuf; + return READ_ONCE(sk->sk_rcvbuf); if (unlikely(!msg_connected(hdr))) - return sk->sk_rcvbuf << msg_importance(hdr); + return READ_ONCE(sk->sk_rcvbuf) << msg_importance(hdr); if (likely(tsk->peer_caps & TIPC_BLOCK_FLOWCTL)) - return sk->sk_rcvbuf; + return READ_ONCE(sk->sk_rcvbuf); return FLOWCTL_MSG_LIM; } diff --git a/net/x25/x25_dev.c b/net/x25/x25_dev.c index 5c111bc3c8ea..00e782335cb0 100644 --- a/net/x25/x25_dev.c +++ b/net/x25/x25_dev.c @@ -55,7 +55,7 @@ static int x25_receive_data(struct sk_buff *skb, struct x25_neigh *nb) if (!sock_owned_by_user(sk)) { queued = x25_process_rx_frame(sk, skb); } else { - queued = !sk_add_backlog(sk, skb, sk->sk_rcvbuf); + queued = !sk_add_backlog(sk, skb, READ_ONCE(sk->sk_rcvbuf)); } bh_unlock_sock(sk); sock_put(sk); -- cgit v1.2.3