From 671a2781ff01abf4fdc8904881fc3abd3a8279af Mon Sep 17 00:00:00 2001 From: Jeff Vander Stoep Date: Fri, 10 Jul 2015 17:19:55 -0400 Subject: security: add ioctl specific auditing to lsm_audit Add information about ioctl calls to the LSM audit data. Log the file path and command number. Signed-off-by: Jeff Vander Stoep Acked-by: Nick Kralevich [PM: subject line tweak] Signed-off-by: Paul Moore --- include/linux/lsm_audit.h | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'include') diff --git a/include/linux/lsm_audit.h b/include/linux/lsm_audit.h index 1cc89e9df480..ffb9c9da4f39 100644 --- a/include/linux/lsm_audit.h +++ b/include/linux/lsm_audit.h @@ -40,6 +40,11 @@ struct lsm_network_audit { } fam; }; +struct lsm_ioctlop_audit { + struct path path; + u16 cmd; +}; + /* Auxiliary data to use in generating the audit record. */ struct common_audit_data { char type; @@ -53,6 +58,7 @@ struct common_audit_data { #define LSM_AUDIT_DATA_KMOD 8 #define LSM_AUDIT_DATA_INODE 9 #define LSM_AUDIT_DATA_DENTRY 10 +#define LSM_AUDIT_DATA_IOCTL_OP 11 union { struct path path; struct dentry *dentry; @@ -68,6 +74,7 @@ struct common_audit_data { } key_struct; #endif char *kmod_name; + struct lsm_ioctlop_audit *op; } u; /* this union contains LSM specific data */ union { -- cgit v1.2.3 From 13c4a90119d28cfcb6b5bdd820c233b86c2b0237 Mon Sep 17 00:00:00 2001 From: Tycho Andersen Date: Sat, 13 Jun 2015 09:02:48 -0600 Subject: seccomp: add ptrace options for suspend/resume This patch is the first step in enabling checkpoint/restore of processes with seccomp enabled. One of the things CRIU does while dumping tasks is inject code into them via ptrace to collect information that is only available to the process itself. However, if we are in a seccomp mode where these processes are prohibited from making these syscalls, then what CRIU does kills the task. This patch adds a new ptrace option, PTRACE_O_SUSPEND_SECCOMP, that enables a task from the init user namespace which has CAP_SYS_ADMIN and no seccomp filters to disable (and re-enable) seccomp filters for another task so that they can be successfully dumped (and restored). We restrict the set of processes that can disable seccomp through ptrace because although today ptrace can be used to bypass seccomp, there is some discussion of closing this loophole in the future and we would like this patch to not depend on that behavior and be future proofed for when it is removed. Note that seccomp can be suspended before any filters are actually installed; this behavior is useful on criu restore, so that we can suspend seccomp, restore the filters, unmap our restore code from the restored process' address space, and then resume the task by detaching and have the filters resumed as well. v2 changes: * require that the tracer have no seccomp filters installed * drop TIF_NOTSC manipulation from the patch * change from ptrace command to a ptrace option and use this ptrace option as the flag to check. This means that as soon as the tracer detaches/dies, seccomp is re-enabled and as a corrollary that one can not disable seccomp across PTRACE_ATTACHs. v3 changes: * get rid of various #ifdefs everywhere * report more sensible errors when PTRACE_O_SUSPEND_SECCOMP is incorrectly used v4 changes: * get rid of may_suspend_seccomp() in favor of a capable() check in ptrace directly v5 changes: * check that seccomp is not enabled (or suspended) on the tracer Signed-off-by: Tycho Andersen CC: Will Drewry CC: Roland McGrath CC: Pavel Emelyanov CC: Serge E. Hallyn Acked-by: Oleg Nesterov Acked-by: Andy Lutomirski [kees: access seccomp.mode through seccomp_mode() instead] Signed-off-by: Kees Cook --- include/linux/ptrace.h | 1 + include/uapi/linux/ptrace.h | 6 ++++-- kernel/ptrace.c | 13 +++++++++++++ kernel/seccomp.c | 8 ++++++++ 4 files changed, 26 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h index 987a73a40ef8..061265f92876 100644 --- a/include/linux/ptrace.h +++ b/include/linux/ptrace.h @@ -34,6 +34,7 @@ #define PT_TRACE_SECCOMP PT_EVENT_FLAG(PTRACE_EVENT_SECCOMP) #define PT_EXITKILL (PTRACE_O_EXITKILL << PT_OPT_FLAG_SHIFT) +#define PT_SUSPEND_SECCOMP (PTRACE_O_SUSPEND_SECCOMP << PT_OPT_FLAG_SHIFT) /* single stepping state bits (used on ARM and PA-RISC) */ #define PT_SINGLESTEP_BIT 31 diff --git a/include/uapi/linux/ptrace.h b/include/uapi/linux/ptrace.h index cf1019e15f5b..a7a697986614 100644 --- a/include/uapi/linux/ptrace.h +++ b/include/uapi/linux/ptrace.h @@ -89,9 +89,11 @@ struct ptrace_peeksiginfo_args { #define PTRACE_O_TRACESECCOMP (1 << PTRACE_EVENT_SECCOMP) /* eventless options */ -#define PTRACE_O_EXITKILL (1 << 20) +#define PTRACE_O_EXITKILL (1 << 20) +#define PTRACE_O_SUSPEND_SECCOMP (1 << 21) -#define PTRACE_O_MASK (0x000000ff | PTRACE_O_EXITKILL) +#define PTRACE_O_MASK (\ + 0x000000ff | PTRACE_O_EXITKILL | PTRACE_O_SUSPEND_SECCOMP) #include diff --git a/kernel/ptrace.c b/kernel/ptrace.c index c8e0e050a36a..787320de68e0 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -556,6 +556,19 @@ static int ptrace_setoptions(struct task_struct *child, unsigned long data) if (data & ~(unsigned long)PTRACE_O_MASK) return -EINVAL; + if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) { + if (!config_enabled(CONFIG_CHECKPOINT_RESTORE) || + !config_enabled(CONFIG_SECCOMP)) + return -EINVAL; + + if (!capable(CAP_SYS_ADMIN)) + return -EPERM; + + if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED || + current->ptrace & PT_SUSPEND_SECCOMP) + return -EPERM; + } + /* Avoid intermediate state when all opts are cleared */ flags = child->ptrace; flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT); diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 980fd26da22e..645e42d6fa4d 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -590,6 +590,10 @@ void secure_computing_strict(int this_syscall) { int mode = current->seccomp.mode; + if (config_enabled(CONFIG_CHECKPOINT_RESTORE) && + unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) + return; + if (mode == 0) return; else if (mode == SECCOMP_MODE_STRICT) @@ -691,6 +695,10 @@ u32 seccomp_phase1(struct seccomp_data *sd) int this_syscall = sd ? sd->nr : syscall_get_nr(current, task_pt_regs(current)); + if (config_enabled(CONFIG_CHECKPOINT_RESTORE) && + unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) + return SECCOMP_PHASE1_OK; + switch (mode) { case SECCOMP_MODE_STRICT: __secure_computing_strict(this_syscall); /* may call do_exit */ -- cgit v1.2.3 From 221272f97ca528048a577a3ff23d7774286ca5fd Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 15 Jun 2015 15:29:16 -0700 Subject: seccomp: swap hard-coded zeros to defined name For clarity, if CONFIG_SECCOMP isn't defined, seccomp_mode() is returning "disabled". This makes that more clear, along with another 0-use, and results in no operational change. Signed-off-by: Kees Cook --- include/linux/seccomp.h | 2 +- kernel/seccomp.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index a19ddacdac30..f4265039a94c 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -78,7 +78,7 @@ static inline long prctl_set_seccomp(unsigned long arg2, char __user *arg3) static inline int seccomp_mode(struct seccomp *s) { - return 0; + return SECCOMP_MODE_DISABLED; } #endif /* CONFIG_SECCOMP */ diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 645e42d6fa4d..383bd6caca81 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -594,7 +594,7 @@ void secure_computing_strict(int this_syscall) unlikely(current->ptrace & PT_SUSPEND_SECCOMP)) return; - if (mode == 0) + if (mode == SECCOMP_MODE_DISABLED) return; else if (mode == SECCOMP_MODE_STRICT) __secure_computing_strict(this_syscall); -- cgit v1.2.3 From 730daa164e7c7e31c08fab940549f4acc3329432 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 23 Jul 2015 18:02:48 -0700 Subject: Yama: remove needless CONFIG_SECURITY_YAMA_STACKED Now that minor LSMs can cleanly stack with major LSMs, remove the unneeded config for Yama to be made to explicitly stack. Just selecting the main Yama CONFIG will allow it to work, regardless of the major LSM. Since distros using Yama are already forcing it to stack, this is effectively a no-op change. Additionally add MAINTAINERS entry. Signed-off-by: Kees Cook Signed-off-by: James Morris --- Documentation/security/Yama.txt | 10 ++++------ MAINTAINERS | 6 ++++++ arch/mips/configs/pistachio_defconfig | 1 - include/linux/lsm_hooks.h | 6 ++++-- security/Kconfig | 5 ----- security/security.c | 11 +++-------- security/yama/Kconfig | 9 +-------- security/yama/yama_lsm.c | 32 ++++++++++---------------------- 8 files changed, 28 insertions(+), 52 deletions(-) (limited to 'include') diff --git a/Documentation/security/Yama.txt b/Documentation/security/Yama.txt index 227a63f018a2..d9ee7d7a6c7f 100644 --- a/Documentation/security/Yama.txt +++ b/Documentation/security/Yama.txt @@ -1,9 +1,7 @@ -Yama is a Linux Security Module that collects a number of system-wide DAC -security protections that are not handled by the core kernel itself. To -select it at boot time, specify "security=yama" (though this will disable -any other LSM). - -Yama is controlled through sysctl in /proc/sys/kernel/yama: +Yama is a Linux Security Module that collects system-wide DAC security +protections that are not handled by the core kernel itself. This is +selectable at build-time with CONFIG_SECURITY_YAMA, and can be controlled +at run-time through sysctls in /proc/sys/kernel/yama: - ptrace_scope diff --git a/MAINTAINERS b/MAINTAINERS index a2264167791a..f8be2f797197 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -9102,6 +9102,12 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/jj/apparmor-dev.git S: Supported F: security/apparmor/ +YAMA SECURITY MODULE +M: Kees Cook +T: git git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux.git yama/tip +S: Supported +F: security/yama/ + SENSABLE PHANTOM M: Jiri Slaby S: Maintained diff --git a/arch/mips/configs/pistachio_defconfig b/arch/mips/configs/pistachio_defconfig index 1646cce032c3..642b50946943 100644 --- a/arch/mips/configs/pistachio_defconfig +++ b/arch/mips/configs/pistachio_defconfig @@ -320,7 +320,6 @@ CONFIG_KEYS=y CONFIG_SECURITY=y CONFIG_SECURITY_NETWORK=y CONFIG_SECURITY_YAMA=y -CONFIG_SECURITY_YAMA_STACKED=y CONFIG_DEFAULT_SECURITY_DAC=y CONFIG_CRYPTO_AUTHENC=y CONFIG_CRYPTO_HMAC=y diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 9429f054c323..ec3a6bab29de 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1881,8 +1881,10 @@ static inline void security_delete_hooks(struct security_hook_list *hooks, extern int __init security_module_enable(const char *module); extern void __init capability_add_hooks(void); -#ifdef CONFIG_SECURITY_YAMA_STACKED -void __init yama_add_hooks(void); +#ifdef CONFIG_SECURITY_YAMA +extern void __init yama_add_hooks(void); +#else +static inline void __init yama_add_hooks(void) { } #endif #endif /* ! __LINUX_LSM_HOOKS_H */ diff --git a/security/Kconfig b/security/Kconfig index bf4ec46474b6..e45237897b43 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -132,7 +132,6 @@ choice default DEFAULT_SECURITY_SMACK if SECURITY_SMACK default DEFAULT_SECURITY_TOMOYO if SECURITY_TOMOYO default DEFAULT_SECURITY_APPARMOR if SECURITY_APPARMOR - default DEFAULT_SECURITY_YAMA if SECURITY_YAMA default DEFAULT_SECURITY_DAC help @@ -151,9 +150,6 @@ choice config DEFAULT_SECURITY_APPARMOR bool "AppArmor" if SECURITY_APPARMOR=y - config DEFAULT_SECURITY_YAMA - bool "Yama" if SECURITY_YAMA=y - config DEFAULT_SECURITY_DAC bool "Unix Discretionary Access Controls" @@ -165,7 +161,6 @@ config DEFAULT_SECURITY default "smack" if DEFAULT_SECURITY_SMACK default "tomoyo" if DEFAULT_SECURITY_TOMOYO default "apparmor" if DEFAULT_SECURITY_APPARMOR - default "yama" if DEFAULT_SECURITY_YAMA default "" if DEFAULT_SECURITY_DAC endmenu diff --git a/security/security.c b/security/security.c index 595fffab48b0..e693ffcf9266 100644 --- a/security/security.c +++ b/security/security.c @@ -56,18 +56,13 @@ int __init security_init(void) pr_info("Security Framework initialized\n"); /* - * Always load the capability module. + * Load minor LSMs, with the capability module always first. */ capability_add_hooks(); -#ifdef CONFIG_SECURITY_YAMA_STACKED - /* - * If Yama is configured for stacking load it next. - */ yama_add_hooks(); -#endif + /* - * Load the chosen module if there is one. - * This will also find yama if it is stacking + * Load all the remaining security modules. */ do_security_initcalls(); diff --git a/security/yama/Kconfig b/security/yama/Kconfig index 3123e1da2fed..90c605eea892 100644 --- a/security/yama/Kconfig +++ b/security/yama/Kconfig @@ -6,14 +6,7 @@ config SECURITY_YAMA This selects Yama, which extends DAC support with additional system-wide security settings beyond regular Linux discretionary access controls. Currently available is ptrace scope restriction. + Like capabilities, this security module stacks with other LSMs. Further information can be found in Documentation/security/Yama.txt. If you are unsure how to answer this question, answer N. - -config SECURITY_YAMA_STACKED - bool "Yama stacked with other LSMs" - depends on SECURITY_YAMA - default n - help - When Yama is built into the kernel, force it to stack with the - selected primary LSM. diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c index 9ed32502470e..d3c19c970a06 100644 --- a/security/yama/yama_lsm.c +++ b/security/yama/yama_lsm.c @@ -353,11 +353,6 @@ static struct security_hook_list yama_hooks[] = { LSM_HOOK_INIT(task_free, yama_task_free), }; -void __init yama_add_hooks(void) -{ - security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks)); -} - #ifdef CONFIG_SYSCTL static int yama_dointvec_minmax(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) @@ -396,25 +391,18 @@ static struct ctl_table yama_sysctl_table[] = { }, { } }; -#endif /* CONFIG_SYSCTL */ - -static __init int yama_init(void) +static void __init yama_init_sysctl(void) { -#ifndef CONFIG_SECURITY_YAMA_STACKED - /* - * If yama is being stacked this is already taken care of. - */ - if (!security_module_enable("yama")) - return 0; -#endif - pr_info("Yama: becoming mindful.\n"); - -#ifdef CONFIG_SYSCTL if (!register_sysctl_paths(yama_sysctl_path, yama_sysctl_table)) panic("Yama: sysctl registration failed.\n"); -#endif - - return 0; } +#else +static inline void yama_init_sysctl(void) { } +#endif /* CONFIG_SYSCTL */ -security_initcall(yama_init); +void __init yama_add_hooks(void) +{ + pr_info("Yama: becoming mindful.\n"); + security_add_hooks(yama_hooks, ARRAY_SIZE(yama_hooks)); + yama_init_sysctl(); +} -- cgit v1.2.3 From 3f3af97d8225a58ecdcde7217c030b17e5198226 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 5 Aug 2015 12:54:46 +0100 Subject: ASN.1: Fix actions on CHOICE elements with IMPLICIT tags In an ASN.1 description where there is a CHOICE construct that contains elements with IMPLICIT tags that refer to constructed types, actions to be taken on those elements should be conditional on the corresponding element actually being matched. Currently, however, such actions are performed unconditionally in the middle of processing the CHOICE. For example, look at elements 'b' and 'e' here: A ::= SEQUENCE { CHOICE { b [0] IMPLICIT B ({ do_XXXXXXXXXXXX_b }), c [1] EXPLICIT C ({ do_XXXXXXXXXXXX_c }), d [2] EXPLICIT B ({ do_XXXXXXXXXXXX_d }), e [3] IMPLICIT C ({ do_XXXXXXXXXXXX_e }), f [4] IMPLICIT INTEGER ({ do_XXXXXXXXXXXX_f }) } } ({ do_XXXXXXXXXXXX_A }) B ::= SET OF OBJECT IDENTIFIER ({ do_XXXXXXXXXXXX_oid }) C ::= SET OF INTEGER ({ do_XXXXXXXXXXXX_int }) They each have an action (do_XXXXXXXXXXXX_b and do_XXXXXXXXXXXX_e) that should only be processed if that element is matched. The problem is that there's no easy place to hang the action off in the subclause (type B for element 'b' and type C for element 'e') because subclause opcode sequences can be shared. To fix this, introduce a conditional action opcode(ASN1_OP_MAYBE_ACT) that the decoder only processes if the preceding match was successful. This can be seen in an excerpt from the output of the fixed ASN.1 compiler for the above ASN.1 description: [ 13] = ASN1_OP_COND_MATCH_JUMP_OR_SKIP, // e [ 14] = _tagn(CONT, CONS, 3), [ 15] = _jump_target(45), // --> C [ 16] = ASN1_OP_MAYBE_ACT, [ 17] = _action(ACT_do_XXXXXXXXXXXX_e), In this, if the op at [13] is matched (ie. element 'e' above) then the action at [16] will be performed. However, if the op at [13] doesn't match or is skipped because it is conditional and some previous op matched, then the action at [16] will be ignored. Note that to make this work in the decoder, the ASN1_OP_RETURN op must set the flag to indicate that a match happened. This is necessary because the _jump_target() seen above introduces a subclause (in this case an object of type 'C') which is likely to alter the flag. Setting the flag here is okay because to process a subclause, a match must have happened and caused a jump. This cannot be tested with the code as it stands, but rather affects future code. Signed-off-by: David Howells Reviewed-by: David Woodhouse --- include/linux/asn1_ber_bytecode.h | 3 ++- lib/asn1_decoder.c | 14 +++++++++++++- scripts/asn1_compiler.c | 3 ++- 3 files changed, 17 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/asn1_ber_bytecode.h b/include/linux/asn1_ber_bytecode.h index 945d44ae529c..27f35780aecf 100644 --- a/include/linux/asn1_ber_bytecode.h +++ b/include/linux/asn1_ber_bytecode.h @@ -61,7 +61,8 @@ enum asn1_opcode { ASN1_OP_COND_FAIL = 0x1b, ASN1_OP_COMPLETE = 0x1c, ASN1_OP_ACT = 0x1d, - ASN1_OP_RETURN = 0x1e, + ASN1_OP_MAYBE_ACT = 0x1e, + ASN1_OP_RETURN = 0x1f, /* The following eight have bit 0 -> SET, 1 -> OF, 2 -> ACT */ ASN1_OP_END_SEQ = 0x20, diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c index 1a000bb050f9..55980d7e1ac0 100644 --- a/lib/asn1_decoder.c +++ b/lib/asn1_decoder.c @@ -33,6 +33,7 @@ static const unsigned char asn1_op_lengths[ASN1_OP__NR] = { [ASN1_OP_COND_FAIL] = 1, [ASN1_OP_COMPLETE] = 1, [ASN1_OP_ACT] = 1 + 1, + [ASN1_OP_MAYBE_ACT] = 1 + 1, [ASN1_OP_RETURN] = 1, [ASN1_OP_END_SEQ] = 1, [ASN1_OP_END_SEQ_OF] = 1 + 1, @@ -177,6 +178,7 @@ int asn1_ber_decoder(const struct asn1_decoder *decoder, unsigned char flags = 0; #define FLAG_INDEFINITE_LENGTH 0x01 #define FLAG_MATCHED 0x02 +#define FLAG_LAST_MATCHED 0x04 /* Last tag matched */ #define FLAG_CONS 0x20 /* Corresponds to CONS bit in the opcode tag * - ie. whether or not we are going to parse * a compound type. @@ -211,6 +213,7 @@ next_op: if ((op & ASN1_OP_MATCH__COND && flags & FLAG_MATCHED) || dp == datalen) { + flags &= ~FLAG_LAST_MATCHED; pc += asn1_op_lengths[op]; goto next_op; } @@ -422,8 +425,15 @@ next_op: pc += asn1_op_lengths[op]; goto next_op; + case ASN1_OP_MAYBE_ACT: + if (!(flags & FLAG_LAST_MATCHED)) { + pc += asn1_op_lengths[op]; + goto next_op; + } case ASN1_OP_ACT: ret = actions[machine[pc + 1]](context, hdr, tag, data + tdp, len); + if (ret < 0) + return ret; pc += asn1_op_lengths[op]; goto next_op; @@ -431,6 +441,7 @@ next_op: if (unlikely(jsp <= 0)) goto jump_stack_underflow; pc = jump_stack[--jsp]; + flags |= FLAG_MATCHED | FLAG_LAST_MATCHED; goto next_op; default: @@ -438,7 +449,8 @@ next_op: } /* Shouldn't reach here */ - pr_err("ASN.1 decoder error: Found reserved opcode (%u)\n", op); + pr_err("ASN.1 decoder error: Found reserved opcode (%u) pc=%zu\n", + op, pc); return -EBADMSG; data_overrun_error: diff --git a/scripts/asn1_compiler.c b/scripts/asn1_compiler.c index e87359cd23c0..0515bced929a 100644 --- a/scripts/asn1_compiler.c +++ b/scripts/asn1_compiler.c @@ -1468,7 +1468,8 @@ dont_render_tag: case TYPE_REF: render_element(out, e->type->type->element, tag); if (e->action) - render_opcode(out, "ASN1_OP_ACT,\n"); + render_opcode(out, "ASN1_OP_%sACT,\n", + skippable ? "MAYBE_" : ""); break; case SEQUENCE: -- cgit v1.2.3 From 233ce79db4b23a174bcf30bde5d6ad913d5f46d3 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 5 Aug 2015 12:54:46 +0100 Subject: ASN.1: Handle 'ANY OPTIONAL' in grammar An ANY object in an ASN.1 grammar that is marked OPTIONAL should be skipped if there is no more data to be had. This can be tested by editing X.509 certificates or PKCS#7 messages to remove the NULL from subobjects that look like the following: SEQUENCE { OBJECT(2a864886f70d01010b); NULL(); } This is an algorithm identifier plus an optional parameter. The modified DER can be passed to one of: keyctl padd asymmetric "" @s Tested-by: Marcel Holtmann Reviewed-by: David Woodhouse --- include/linux/asn1_ber_bytecode.h | 17 +++++++++++------ lib/asn1_decoder.c | 8 ++++++++ scripts/asn1_compiler.c | 3 ++- 3 files changed, 21 insertions(+), 7 deletions(-) (limited to 'include') diff --git a/include/linux/asn1_ber_bytecode.h b/include/linux/asn1_ber_bytecode.h index 27f35780aecf..ab3a6c002f7b 100644 --- a/include/linux/asn1_ber_bytecode.h +++ b/include/linux/asn1_ber_bytecode.h @@ -45,24 +45,27 @@ enum asn1_opcode { ASN1_OP_MATCH_JUMP = 0x04, ASN1_OP_MATCH_JUMP_OR_SKIP = 0x05, ASN1_OP_MATCH_ANY = 0x08, + ASN1_OP_MATCH_ANY_OR_SKIP = 0x09, ASN1_OP_MATCH_ANY_ACT = 0x0a, + ASN1_OP_MATCH_ANY_ACT_OR_SKIP = 0x0b, /* Everything before here matches unconditionally */ ASN1_OP_COND_MATCH_OR_SKIP = 0x11, ASN1_OP_COND_MATCH_ACT_OR_SKIP = 0x13, ASN1_OP_COND_MATCH_JUMP_OR_SKIP = 0x15, ASN1_OP_COND_MATCH_ANY = 0x18, + ASN1_OP_COND_MATCH_ANY_OR_SKIP = 0x19, ASN1_OP_COND_MATCH_ANY_ACT = 0x1a, + ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP = 0x1b, /* Everything before here will want a tag from the data */ -#define ASN1_OP__MATCHES_TAG ASN1_OP_COND_MATCH_ANY_ACT +#define ASN1_OP__MATCHES_TAG ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP /* These are here to help fill up space */ - ASN1_OP_COND_FAIL = 0x1b, - ASN1_OP_COMPLETE = 0x1c, - ASN1_OP_ACT = 0x1d, - ASN1_OP_MAYBE_ACT = 0x1e, - ASN1_OP_RETURN = 0x1f, + ASN1_OP_COND_FAIL = 0x1c, + ASN1_OP_COMPLETE = 0x1d, + ASN1_OP_ACT = 0x1e, + ASN1_OP_MAYBE_ACT = 0x1f, /* The following eight have bit 0 -> SET, 1 -> OF, 2 -> ACT */ ASN1_OP_END_SEQ = 0x20, @@ -77,6 +80,8 @@ enum asn1_opcode { #define ASN1_OP_END__OF 0x02 #define ASN1_OP_END__ACT 0x04 + ASN1_OP_RETURN = 0x28, + ASN1_OP__NR }; diff --git a/lib/asn1_decoder.c b/lib/asn1_decoder.c index 3f74dd3e2910..2b3f46c049d4 100644 --- a/lib/asn1_decoder.c +++ b/lib/asn1_decoder.c @@ -24,12 +24,16 @@ static const unsigned char asn1_op_lengths[ASN1_OP__NR] = { [ASN1_OP_MATCH_JUMP] = 1 + 1 + 1, [ASN1_OP_MATCH_JUMP_OR_SKIP] = 1 + 1 + 1, [ASN1_OP_MATCH_ANY] = 1, + [ASN1_OP_MATCH_ANY_OR_SKIP] = 1, [ASN1_OP_MATCH_ANY_ACT] = 1 + 1, + [ASN1_OP_MATCH_ANY_ACT_OR_SKIP] = 1 + 1, [ASN1_OP_COND_MATCH_OR_SKIP] = 1 + 1, [ASN1_OP_COND_MATCH_ACT_OR_SKIP] = 1 + 1 + 1, [ASN1_OP_COND_MATCH_JUMP_OR_SKIP] = 1 + 1 + 1, [ASN1_OP_COND_MATCH_ANY] = 1, + [ASN1_OP_COND_MATCH_ANY_OR_SKIP] = 1, [ASN1_OP_COND_MATCH_ANY_ACT] = 1 + 1, + [ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP] = 1 + 1, [ASN1_OP_COND_FAIL] = 1, [ASN1_OP_COMPLETE] = 1, [ASN1_OP_ACT] = 1 + 1, @@ -304,7 +308,9 @@ next_op: /* Decide how to handle the operation */ switch (op) { case ASN1_OP_MATCH_ANY_ACT: + case ASN1_OP_MATCH_ANY_ACT_OR_SKIP: case ASN1_OP_COND_MATCH_ANY_ACT: + case ASN1_OP_COND_MATCH_ANY_ACT_OR_SKIP: ret = actions[machine[pc + 1]](context, hdr, tag, data + dp, len); if (ret < 0) return ret; @@ -321,8 +327,10 @@ next_op: case ASN1_OP_MATCH: case ASN1_OP_MATCH_OR_SKIP: case ASN1_OP_MATCH_ANY: + case ASN1_OP_MATCH_ANY_OR_SKIP: case ASN1_OP_COND_MATCH_OR_SKIP: case ASN1_OP_COND_MATCH_ANY: + case ASN1_OP_COND_MATCH_ANY_OR_SKIP: skip_data: if (!(flags & FLAG_CONS)) { if (flags & FLAG_INDEFINITE_LENGTH) { diff --git a/scripts/asn1_compiler.c b/scripts/asn1_compiler.c index 0515bced929a..1c75e22b6385 100644 --- a/scripts/asn1_compiler.c +++ b/scripts/asn1_compiler.c @@ -1401,7 +1401,8 @@ static void render_element(FILE *out, struct element *e, struct element *tag) act = e->action ? "_ACT" : ""; switch (e->compound) { case ANY: - render_opcode(out, "ASN1_OP_%sMATCH_ANY%s,", cond, act); + render_opcode(out, "ASN1_OP_%sMATCH_ANY%s%s,", + cond, act, skippable ? "_OR_SKIP" : ""); if (e->name) render_more(out, "\t\t// %*.*s", (int)e->name->size, (int)e->name->size, -- cgit v1.2.3 From 4573b64a31cd8cb4cfeb1d1b95536cfe71980cf4 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 20 Jul 2015 21:16:26 +0100 Subject: X.509: Support X.509 lookup by Issuer+Serial form AuthorityKeyIdentifier If an X.509 certificate has an AuthorityKeyIdentifier extension that provides an issuer and serialNumber, then make it so that these are used in preference to the keyIdentifier field also held therein for searching for the signing certificate. If both the issuer+serialNumber and the keyIdentifier are supplied, then the certificate is looked up by the former but the latter is checked as well. If the latter doesn't match the subjectKeyIdentifier of the parent certificate, EKEYREJECTED is returned. This makes it possible to chain X.509 certificates based on the issuer and serialNumber fields rather than on subjectKeyIdentifier. This is necessary as we are having to deal with keys that are represented by X.509 certificates that lack a subjectKeyIdentifier. Signed-off-by: David Howells Tested-by: Vivek Goyal --- crypto/asymmetric_keys/pkcs7_trust.c | 10 ++-- crypto/asymmetric_keys/pkcs7_verify.c | 47 +++++++++++++----- crypto/asymmetric_keys/x509_public_key.c | 84 ++++++++++++++++++++++---------- include/crypto/public_key.h | 3 +- 4 files changed, 103 insertions(+), 41 deletions(-) (limited to 'include') diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c index 0f6463b6692b..90d6d47965b0 100644 --- a/crypto/asymmetric_keys/pkcs7_trust.c +++ b/crypto/asymmetric_keys/pkcs7_trust.c @@ -54,7 +54,8 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, /* Look to see if this certificate is present in the trusted * keys. */ - key = x509_request_asymmetric_key(trust_keyring, x509->id, + key = x509_request_asymmetric_key(trust_keyring, + x509->id, x509->skid, false); if (!IS_ERR(key)) { /* One of the X.509 certificates in the PKCS#7 message @@ -85,8 +86,10 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, /* No match - see if the root certificate has a signer amongst the * trusted keys. */ - if (last && last->akid_skid) { - key = x509_request_asymmetric_key(trust_keyring, last->akid_skid, + if (last && (last->akid_id || last->akid_skid)) { + key = x509_request_asymmetric_key(trust_keyring, + last->akid_id, + last->akid_skid, false); if (!IS_ERR(key)) { x509 = last; @@ -103,6 +106,7 @@ static int pkcs7_validate_trust_one(struct pkcs7_message *pkcs7, */ key = x509_request_asymmetric_key(trust_keyring, sinfo->signing_cert_id, + NULL, false); if (!IS_ERR(key)) { pr_devel("sinfo %u: Direct signer is key %x\n", diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index a4d083f7e9e1..42bfc9de0d79 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -170,6 +170,7 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, struct pkcs7_signed_info *sinfo) { struct x509_certificate *x509 = sinfo->signer, *p; + struct asymmetric_key_id *auth; int ret; kenter(""); @@ -187,11 +188,14 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, goto maybe_missing_crypto_in_x509; pr_debug("- issuer %s\n", x509->issuer); + if (x509->akid_id) + pr_debug("- authkeyid.id %*phN\n", + x509->akid_id->len, x509->akid_id->data); if (x509->akid_skid) - pr_debug("- authkeyid %*phN\n", + pr_debug("- authkeyid.skid %*phN\n", x509->akid_skid->len, x509->akid_skid->data); - if (!x509->akid_skid || + if ((!x509->akid_id && !x509->akid_skid) || strcmp(x509->subject, x509->issuer) == 0) { /* If there's no authority certificate specified, then * the certificate must be self-signed and is the root @@ -215,21 +219,42 @@ static int pkcs7_verify_sig_chain(struct pkcs7_message *pkcs7, /* Look through the X.509 certificates in the PKCS#7 message's * list to see if the next one is there. */ - pr_debug("- want %*phN\n", - x509->akid_skid->len, x509->akid_skid->data); - for (p = pkcs7->certs; p; p = p->next) { - if (!p->skid) - continue; - pr_debug("- cmp [%u] %*phN\n", - p->index, p->skid->len, p->skid->data); - if (asymmetric_key_id_same(p->skid, x509->akid_skid)) - goto found_issuer; + auth = x509->akid_id; + if (auth) { + pr_debug("- want %*phN\n", auth->len, auth->data); + for (p = pkcs7->certs; p; p = p->next) { + pr_debug("- cmp [%u] %*phN\n", + p->index, p->id->len, p->id->data); + if (asymmetric_key_id_same(p->id, auth)) + goto found_issuer_check_skid; + } + } else { + auth = x509->akid_skid; + pr_debug("- want %*phN\n", auth->len, auth->data); + for (p = pkcs7->certs; p; p = p->next) { + if (!p->skid) + continue; + pr_debug("- cmp [%u] %*phN\n", + p->index, p->skid->len, p->skid->data); + if (asymmetric_key_id_same(p->skid, auth)) + goto found_issuer; + } } /* We didn't find the root of this chain */ pr_debug("- top\n"); return 0; + found_issuer_check_skid: + /* We matched issuer + serialNumber, but if there's an + * authKeyId.keyId, that must match the CA subjKeyId also. + */ + if (x509->akid_skid && + !asymmetric_key_id_same(p->skid, x509->akid_skid)) { + pr_warn("Sig %u: X.509 chain contains auth-skid nonmatch (%u->%u)\n", + sinfo->index, x509->index, p->index); + return -EKEYREJECTED; + } found_issuer: pr_debug("- subject %s\n", p->subject); if (p->seen) { diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index bb55d6074d5f..6b060b290e77 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -65,23 +65,37 @@ __setup("ca_keys=", ca_keys_setup); /** * x509_request_asymmetric_key - Request a key by X.509 certificate params. * @keyring: The keys to search. - * @kid: The key ID. + * @id: The issuer & serialNumber to look for or NULL. + * @skid: The subjectKeyIdentifier to look for or NULL. * @partial: Use partial match if true, exact if false. * - * Find a key in the given keyring by subject name and key ID. These might, - * for instance, be the issuer name and the authority key ID of an X.509 - * certificate that needs to be verified. + * Find a key in the given keyring by identifier. The preferred identifier is + * the issuer + serialNumber and the fallback identifier is the + * subjectKeyIdentifier. If both are given, the lookup is by the former, but + * the latter must also match. */ struct key *x509_request_asymmetric_key(struct key *keyring, - const struct asymmetric_key_id *kid, + const struct asymmetric_key_id *id, + const struct asymmetric_key_id *skid, bool partial) { - key_ref_t key; - char *id, *p; - + struct key *key; + key_ref_t ref; + const char *lookup; + char *req, *p; + int len; + + if (id) { + lookup = id->data; + len = id->len; + } else { + lookup = skid->data; + len = skid->len; + } + /* Construct an identifier "id:". */ - p = id = kmalloc(2 + 1 + kid->len * 2 + 1, GFP_KERNEL); - if (!id) + p = req = kmalloc(2 + 1 + len * 2 + 1, GFP_KERNEL); + if (!req) return ERR_PTR(-ENOMEM); if (partial) { @@ -92,32 +106,48 @@ struct key *x509_request_asymmetric_key(struct key *keyring, *p++ = 'x'; } *p++ = ':'; - p = bin2hex(p, kid->data, kid->len); + p = bin2hex(p, lookup, len); *p = 0; - pr_debug("Look up: \"%s\"\n", id); + pr_debug("Look up: \"%s\"\n", req); - key = keyring_search(make_key_ref(keyring, 1), - &key_type_asymmetric, id); - if (IS_ERR(key)) - pr_debug("Request for key '%s' err %ld\n", id, PTR_ERR(key)); - kfree(id); + ref = keyring_search(make_key_ref(keyring, 1), + &key_type_asymmetric, req); + if (IS_ERR(ref)) + pr_debug("Request for key '%s' err %ld\n", req, PTR_ERR(ref)); + kfree(req); - if (IS_ERR(key)) { - switch (PTR_ERR(key)) { + if (IS_ERR(ref)) { + switch (PTR_ERR(ref)) { /* Hide some search errors */ case -EACCES: case -ENOTDIR: case -EAGAIN: return ERR_PTR(-ENOKEY); default: - return ERR_CAST(key); + return ERR_CAST(ref); + } + } + + key = key_ref_to_ptr(ref); + if (id && skid) { + const struct asymmetric_key_ids *kids = asymmetric_key_ids(key); + if (!kids->id[1]) { + pr_debug("issuer+serial match, but expected SKID missing\n"); + goto reject; + } + if (!asymmetric_key_id_same(skid, kids->id[1])) { + pr_debug("issuer+serial match, but SKID does not\n"); + goto reject; } } + + pr_devel("<==%s() = 0 [%x]\n", __func__, key_serial(key)); + return key; - pr_devel("<==%s() = 0 [%x]\n", __func__, - key_serial(key_ref_to_ptr(key))); - return key_ref_to_ptr(key); +reject: + key_put(key); + return ERR_PTR(-EKEYREJECTED); } EXPORT_SYMBOL_GPL(x509_request_asymmetric_key); @@ -230,7 +260,8 @@ static int x509_validate_trust(struct x509_certificate *cert, if (ca_keyid && !asymmetric_key_id_partial(cert->akid_skid, ca_keyid)) return -EPERM; - key = x509_request_asymmetric_key(trust_keyring, cert->akid_skid, + key = x509_request_asymmetric_key(trust_keyring, + cert->akid_id, cert->akid_skid, false); if (!IS_ERR(key)) { if (!use_builtin_keys @@ -287,8 +318,9 @@ static int x509_key_preparse(struct key_preparsed_payload *prep) cert->pub->id_type = PKEY_ID_X509; /* Check the signature on the key if it appears to be self-signed */ - if (!cert->akid_skid || - asymmetric_key_id_same(cert->skid, cert->akid_skid)) { + if ((!cert->akid_skid && !cert->akid_id) || + asymmetric_key_id_same(cert->skid, cert->akid_skid) || + asymmetric_key_id_same(cert->id, cert->akid_id)) { ret = x509_check_signature(cert->pub, cert); /* self-signed */ if (ret < 0) goto error_free_cert; diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index 54add2069901..b6f27a240856 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -101,7 +101,8 @@ extern int verify_signature(const struct key *key, struct asymmetric_key_id; extern struct key *x509_request_asymmetric_key(struct key *keyring, - const struct asymmetric_key_id *kid, + const struct asymmetric_key_id *id, + const struct asymmetric_key_id *skid, bool partial); #endif /* _LINUX_PUBLIC_KEY_H */ -- cgit v1.2.3 From 4ebdb76f7da662346267384440492bb9d87c2aa3 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 20 Jul 2015 21:16:26 +0100 Subject: PKCS#7: Allow detached data to be supplied for signature checking purposes It is possible for a PKCS#7 message to have detached data. However, to verify the signatures on a PKCS#7 message, we have to be able to digest the data. Provide a function to supply that data. An error is given if the PKCS#7 message included embedded data. This is used in a subsequent patch to supply the data to module signing where the signature is in the form of a PKCS#7 message with detached data, whereby the detached data is the module content that is signed. Signed-off-by: David Howells Tested-by: Vivek Goyal --- crypto/asymmetric_keys/pkcs7_verify.c | 25 +++++++++++++++++++++++++ include/crypto/pkcs7.h | 3 +++ 2 files changed, 28 insertions(+) (limited to 'include') diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index 42bfc9de0d79..404f89a0f852 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -382,3 +382,28 @@ int pkcs7_verify(struct pkcs7_message *pkcs7) return enopkg; } EXPORT_SYMBOL_GPL(pkcs7_verify); + +/** + * pkcs7_supply_detached_data - Supply the data needed to verify a PKCS#7 message + * @pkcs7: The PKCS#7 message + * @data: The data to be verified + * @datalen: The amount of data + * + * Supply the detached data needed to verify a PKCS#7 message. Note that no + * attempt to retain/pin the data is made. That is left to the caller. The + * data will not be modified by pkcs7_verify() and will not be freed when the + * PKCS#7 message is freed. + * + * Returns -EINVAL if data is already supplied in the message, 0 otherwise. + */ +int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7, + const void *data, size_t datalen) +{ + if (pkcs7->data) { + pr_debug("Data already supplied\n"); + return -EINVAL; + } + pkcs7->data = data; + pkcs7->data_len = datalen; + return 0; +} diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h index 691c79172a26..e235ab4957ee 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -34,3 +34,6 @@ extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, * pkcs7_verify.c */ extern int pkcs7_verify(struct pkcs7_message *pkcs7); + +extern int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7, + const void *data, size_t datalen); -- cgit v1.2.3 From bc1c373dd2a5113800360f7152be729c9da996cc Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 20 Jul 2015 21:16:27 +0100 Subject: MODSIGN: Provide a utility to append a PKCS#7 signature to a module Provide a utility that: (1) Digests a module using the specified hash algorithm (typically sha256). [The digest can be dumped into a file by passing the '-d' flag] (2) Generates a PKCS#7 message that: (a) Has detached data (ie. the module content). (b) Is signed with the specified private key. (c) Refers to the specified X.509 certificate. (d) Has an empty X.509 certificate list. [The PKCS#7 message can be dumped into a file by passing the '-p' flag] (3) Generates a signed module by concatenating the old module, the PKCS#7 message, a descriptor and a magic string. The descriptor contains the size of the PKCS#7 message and indicates the id_type as PKEY_ID_PKCS7. (4) Either writes the signed module to the specified destination or renames it over the source module. This allows module signing to reuse the PKCS#7 handling code that was added for PE file parsing for signed kexec. Note that the utility is written in C and must be linked against the OpenSSL crypto library. Note further that I have temporarily dropped support for handling externally created signatures until we can work out the best way to do those. Hopefully, whoever creates the signature can give me a PKCS#7 certificate. Signed-off-by: David Howells Tested-by: Vivek Goyal --- include/crypto/public_key.h | 1 + scripts/sign-file.c | 205 ++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 206 insertions(+) create mode 100755 scripts/sign-file.c (limited to 'include') diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index b6f27a240856..fda097e079a4 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -33,6 +33,7 @@ extern const struct public_key_algorithm *pkey_algo[PKEY_ALGO__LAST]; enum pkey_id_type { PKEY_ID_PGP, /* OpenPGP generated key ID */ PKEY_ID_X509, /* X.509 arbitrary subjectKeyIdentifier */ + PKEY_ID_PKCS7, /* Signature in PKCS#7 message */ PKEY_ID_TYPE__LAST }; diff --git a/scripts/sign-file.c b/scripts/sign-file.c new file mode 100755 index 000000000000..5b8a6dda3235 --- /dev/null +++ b/scripts/sign-file.c @@ -0,0 +1,205 @@ +/* Sign a module file using the given key. + * + * Copyright (C) 2014 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +struct module_signature { + uint8_t algo; /* Public-key crypto algorithm [0] */ + uint8_t hash; /* Digest algorithm [0] */ + uint8_t id_type; /* Key identifier type [PKEY_ID_PKCS7] */ + uint8_t signer_len; /* Length of signer's name [0] */ + uint8_t key_id_len; /* Length of key identifier [0] */ + uint8_t __pad[3]; + uint32_t sig_len; /* Length of signature data */ +}; + +#define PKEY_ID_PKCS7 2 + +static char magic_number[] = "~Module signature appended~\n"; + +static __attribute__((noreturn)) +void format(void) +{ + fprintf(stderr, + "Usage: scripts/sign-file [-dp] []\n"); + exit(2); +} + +static void display_openssl_errors(int l) +{ + const char *file; + char buf[120]; + int e, line; + + if (ERR_peek_error() == 0) + return; + fprintf(stderr, "At main.c:%d:\n", l); + + while ((e = ERR_get_error_line(&file, &line))) { + ERR_error_string(e, buf); + fprintf(stderr, "- SSL %s: %s:%d\n", buf, file, line); + } +} + +static void drain_openssl_errors(void) +{ + const char *file; + int line; + + if (ERR_peek_error() == 0) + return; + while (ERR_get_error_line(&file, &line)) {} +} + +#define ERR(cond, fmt, ...) \ + do { \ + bool __cond = (cond); \ + display_openssl_errors(__LINE__); \ + if (__cond) { \ + err(1, fmt, ## __VA_ARGS__); \ + } \ + } while(0) + +int main(int argc, char **argv) +{ + struct module_signature sig_info = { .id_type = PKEY_ID_PKCS7 }; + char *hash_algo = NULL; + char *private_key_name, *x509_name, *module_name, *dest_name; + bool save_pkcs7 = false, replace_orig; + unsigned char buf[4096]; + unsigned long module_size, pkcs7_size; + const EVP_MD *digest_algo; + EVP_PKEY *private_key; + PKCS7 *pkcs7; + X509 *x509; + BIO *b, *bd, *bm; + int opt, n; + + ERR_load_crypto_strings(); + ERR_clear_error(); + + do { + opt = getopt(argc, argv, "dp"); + switch (opt) { + case 'p': save_pkcs7 = true; break; + case -1: break; + default: format(); + } + } while (opt != -1); + + argc -= optind; + argv += optind; + if (argc < 4 || argc > 5) + format(); + + hash_algo = argv[0]; + private_key_name = argv[1]; + x509_name = argv[2]; + module_name = argv[3]; + if (argc == 5) { + dest_name = argv[4]; + replace_orig = false; + } else { + ERR(asprintf(&dest_name, "%s.~signed~", module_name) < 0, + "asprintf"); + replace_orig = true; + } + + /* Read the private key and the X.509 cert the PKCS#7 message + * will point to. + */ + b = BIO_new_file(private_key_name, "rb"); + ERR(!b, "%s", private_key_name); + private_key = PEM_read_bio_PrivateKey(b, NULL, NULL, NULL); + BIO_free(b); + + b = BIO_new_file(x509_name, "rb"); + ERR(!b, "%s", x509_name); + x509 = d2i_X509_bio(b, NULL); /* Binary encoded X.509 */ + if (!x509) { + BIO_reset(b); + x509 = PEM_read_bio_X509(b, NULL, NULL, NULL); /* PEM encoded X.509 */ + if (x509) + drain_openssl_errors(); + } + BIO_free(b); + ERR(!x509, "%s", x509_name); + + /* Open the destination file now so that we can shovel the module data + * across as we read it. + */ + bd = BIO_new_file(dest_name, "wb"); + ERR(!bd, "%s", dest_name); + + /* Digest the module data. */ + OpenSSL_add_all_digests(); + display_openssl_errors(__LINE__); + digest_algo = EVP_get_digestbyname(hash_algo); + ERR(!digest_algo, "EVP_get_digestbyname"); + + bm = BIO_new_file(module_name, "rb"); + ERR(!bm, "%s", module_name); + + /* Load the PKCS#7 message from the digest buffer. */ + pkcs7 = PKCS7_sign(NULL, NULL, NULL, NULL, + PKCS7_NOCERTS | PKCS7_PARTIAL | PKCS7_BINARY | PKCS7_DETACHED | PKCS7_STREAM); + ERR(!pkcs7, "PKCS7_sign"); + + ERR(!PKCS7_sign_add_signer(pkcs7, x509, private_key, digest_algo, PKCS7_NOCERTS | PKCS7_BINARY), + "PKCS7_sign_add_signer"); + ERR(PKCS7_final(pkcs7, bm, PKCS7_NOCERTS | PKCS7_BINARY) < 0, + "PKCS7_final"); + + if (save_pkcs7) { + char *pkcs7_name; + + ERR(asprintf(&pkcs7_name, "%s.pkcs7", module_name) < 0, "asprintf"); + b = BIO_new_file(pkcs7_name, "wb"); + ERR(!b, "%s", pkcs7_name); + ERR(i2d_PKCS7_bio_stream(b, pkcs7, NULL, 0) < 0, "%s", pkcs7_name); + BIO_free(b); + } + + /* Append the marker and the PKCS#7 message to the destination file */ + ERR(BIO_reset(bm) < 0, "%s", module_name); + while ((n = BIO_read(bm, buf, sizeof(buf))), + n > 0) { + ERR(BIO_write(bd, buf, n) < 0, "%s", dest_name); + } + ERR(n < 0, "%s", module_name); + module_size = BIO_number_written(bd); + + ERR(i2d_PKCS7_bio_stream(bd, pkcs7, NULL, 0) < 0, "%s", dest_name); + pkcs7_size = BIO_number_written(bd) - module_size; + sig_info.sig_len = htonl(pkcs7_size); + ERR(BIO_write(bd, &sig_info, sizeof(sig_info)) < 0, "%s", dest_name); + ERR(BIO_write(bd, magic_number, sizeof(magic_number) - 1) < 0, "%s", dest_name); + + ERR(BIO_free(bd) < 0, "%s", dest_name); + + /* Finally, if we're signing in place, replace the original. */ + if (replace_orig) + ERR(rename(dest_name, module_name) < 0, "%s", dest_name); + + return 0; +} -- cgit v1.2.3 From 091f6e26eb326adbd718f406e440c838bed8ebb6 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 20 Jul 2015 21:16:28 +0100 Subject: MODSIGN: Extract the blob PKCS#7 signature verifier from module signing Extract the function that drives the PKCS#7 signature verification given a data blob and a PKCS#7 blob out from the module signing code and lump it with the system keyring code as it's generic. This makes it independent of module config options and opens it to use by the firmware loader. Signed-off-by: David Howells Cc: Luis R. Rodriguez Cc: Rusty Russell Cc: Ming Lei Cc: Seth Forshee Cc: Kyle McMartin --- include/keys/system_keyring.h | 5 +++++ init/Kconfig | 29 ++++++++++++++++--------- kernel/module_signing.c | 44 +------------------------------------ kernel/system_keyring.c | 50 +++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 75 insertions(+), 53 deletions(-) (limited to 'include') diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h index 72665eb80692..9791c907cdb7 100644 --- a/include/keys/system_keyring.h +++ b/include/keys/system_keyring.h @@ -28,4 +28,9 @@ static inline struct key *get_system_trusted_keyring(void) } #endif +#ifdef CONFIG_SYSTEM_DATA_VERIFICATION +extern int system_verify_data(const void *data, unsigned long len, + const void *raw_pkcs7, size_t pkcs7_len); +#endif + #endif /* _KEYS_SYSTEM_KEYRING_H */ diff --git a/init/Kconfig b/init/Kconfig index e16d9e587cee..14b3d8422502 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1752,6 +1752,24 @@ config SYSTEM_TRUSTED_KEYRING Keys in this keyring are used by module signature checking. +config SYSTEM_DATA_VERIFICATION + def_bool n + select SYSTEM_TRUSTED_KEYRING + select KEYS + select CRYPTO + select ASYMMETRIC_KEY_TYPE + select ASYMMETRIC_PUBLIC_KEY_SUBTYPE + select PUBLIC_KEY_ALGO_RSA + select ASN1 + select OID_REGISTRY + select X509_CERTIFICATE_PARSER + select PKCS7_MESSAGE_PARSER + help + Provide PKCS#7 message verification using the contents of the system + trusted keyring to provide public keys. This then can be used for + module verification, kexec image verification and firmware blob + verification. + config PROFILING bool "Profiling support" help @@ -1860,16 +1878,7 @@ config MODULE_SRCVERSION_ALL config MODULE_SIG bool "Module signature verification" depends on MODULES - select SYSTEM_TRUSTED_KEYRING - select KEYS - select CRYPTO - select ASYMMETRIC_KEY_TYPE - select ASYMMETRIC_PUBLIC_KEY_SUBTYPE - select PUBLIC_KEY_ALGO_RSA - select ASN1 - select OID_REGISTRY - select X509_CERTIFICATE_PARSER - select PKCS7_MESSAGE_PARSER + select SYSTEM_DATA_VERIFICATION help Check modules for valid signatures upon load: the signature is simply appended to the module. For more information see diff --git a/kernel/module_signing.c b/kernel/module_signing.c index 8eb20cc66b39..70ad463f6df0 100644 --- a/kernel/module_signing.c +++ b/kernel/module_signing.c @@ -10,10 +10,8 @@ */ #include -#include #include #include -#include #include "module-internal.h" /* @@ -36,46 +34,6 @@ struct module_signature { __be32 sig_len; /* Length of signature data */ }; -/* - * Verify a PKCS#7-based signature on a module. - */ -static int mod_verify_pkcs7(const void *mod, unsigned long modlen, - const void *raw_pkcs7, size_t pkcs7_len) -{ - struct pkcs7_message *pkcs7; - bool trusted; - int ret; - - pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); - if (IS_ERR(pkcs7)) - return PTR_ERR(pkcs7); - - /* The data should be detached - so we need to supply it. */ - if (pkcs7_supply_detached_data(pkcs7, mod, modlen) < 0) { - pr_err("PKCS#7 signature with non-detached data\n"); - ret = -EBADMSG; - goto error; - } - - ret = pkcs7_verify(pkcs7); - if (ret < 0) - goto error; - - ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted); - if (ret < 0) - goto error; - - if (!trusted) { - pr_err("PKCS#7 signature not signed with a trusted key\n"); - ret = -ENOKEY; - } - -error: - pkcs7_free_message(pkcs7); - pr_devel("<==%s() = %d\n", __func__, ret); - return ret; -} - /* * Verify the signature on a module. */ @@ -114,5 +72,5 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen) return -EBADMSG; } - return mod_verify_pkcs7(mod, modlen, mod + modlen, sig_len); + return system_verify_data(mod, modlen, mod + modlen, sig_len); } diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c index 4cda71ee51c7..95f2dcbc7616 100644 --- a/kernel/system_keyring.c +++ b/kernel/system_keyring.c @@ -16,6 +16,7 @@ #include #include #include +#include struct key *system_trusted_keyring; EXPORT_SYMBOL_GPL(system_trusted_keyring); @@ -103,3 +104,52 @@ dodgy_cert: return 0; } late_initcall(load_system_certificate_list); + +#ifdef CONFIG_SYSTEM_DATA_VERIFICATION + +/** + * Verify a PKCS#7-based signature on system data. + * @data: The data to be verified. + * @len: Size of @data. + * @raw_pkcs7: The PKCS#7 message that is the signature. + * @pkcs7_len: The size of @raw_pkcs7. + */ +int system_verify_data(const void *data, unsigned long len, + const void *raw_pkcs7, size_t pkcs7_len) +{ + struct pkcs7_message *pkcs7; + bool trusted; + int ret; + + pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len); + if (IS_ERR(pkcs7)) + return PTR_ERR(pkcs7); + + /* The data should be detached - so we need to supply it. */ + if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) { + pr_err("PKCS#7 signature with non-detached data\n"); + ret = -EBADMSG; + goto error; + } + + ret = pkcs7_verify(pkcs7); + if (ret < 0) + goto error; + + ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted); + if (ret < 0) + goto error; + + if (!trusted) { + pr_err("PKCS#7 signature not signed with a trusted key\n"); + ret = -ENOKEY; + } + +error: + pkcs7_free_message(pkcs7); + pr_devel("<==%s() = %d\n", __func__, ret); + return ret; +} +EXPORT_SYMBOL_GPL(system_verify_data); + +#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */ -- cgit v1.2.3 From 99db44350672c8a5ee9a7b0a6f4cd6ff10136065 Mon Sep 17 00:00:00 2001 From: David Howells Date: Wed, 5 Aug 2015 15:22:27 +0100 Subject: PKCS#7: Appropriately restrict authenticated attributes and content type A PKCS#7 or CMS message can have per-signature authenticated attributes that are digested as a lump and signed by the authorising key for that signature. If such attributes exist, the content digest isn't itself signed, but rather it is included in a special authattr which then contributes to the signature. Further, we already require the master message content type to be pkcs7_signedData - but there's also a separate content type for the data itself within the SignedData object and this must be repeated inside the authattrs for each signer [RFC2315 9.2, RFC5652 11.1]. We should really validate the authattrs if they exist or forbid them entirely as appropriate. To this end: (1) Alter the PKCS#7 parser to reject any message that has more than one signature where at least one signature has authattrs and at least one that does not. (2) Validate authattrs if they are present and strongly restrict them. Only the following authattrs are permitted and all others are rejected: (a) contentType. This is checked to be an OID that matches the content type in the SignedData object. (b) messageDigest. This must match the crypto digest of the data. (c) signingTime. If present, we check that this is a valid, parseable UTCTime or GeneralTime and that the date it encodes fits within the validity window of the matching X.509 cert. (d) S/MIME capabilities. We don't check the contents. (e) Authenticode SP Opus Info. We don't check the contents. (f) Authenticode Statement Type. We don't check the contents. The message is rejected if (a) or (b) are missing. If the message is an Authenticode type, the message is rejected if (e) is missing; if not Authenticode, the message is rejected if (d) - (f) are present. The S/MIME capabilities authattr (d) unfortunately has to be allowed to support kernels already signed by the pesign program. This only affects kexec. sign-file suppresses them (CMS_NOSMIMECAP). The message is also rejected if an authattr is given more than once or if it contains more than one element in its set of values. (3) Add a parameter to pkcs7_verify() to select one of the following restrictions and pass in the appropriate option from the callers: (*) VERIFYING_MODULE_SIGNATURE This requires that the SignedData content type be pkcs7-data and forbids authattrs. sign-file sets CMS_NOATTR. We could be more flexible and permit authattrs optionally, but only permit minimal content. (*) VERIFYING_FIRMWARE_SIGNATURE This requires that the SignedData content type be pkcs7-data and requires authattrs. In future, this will require an attribute holding the target firmware name in addition to the minimal set. (*) VERIFYING_UNSPECIFIED_SIGNATURE This requires that the SignedData content type be pkcs7-data but allows either no authattrs or only permits the minimal set. (*) VERIFYING_KEXEC_PE_SIGNATURE This only supports the Authenticode SPC_INDIRECT_DATA content type and requires at least an SpcSpOpusInfo authattr in addition to the minimal set. It also permits an SPC_STATEMENT_TYPE authattr (and an S/MIME capabilities authattr because the pesign program doesn't remove these). (*) VERIFYING_KEY_SIGNATURE (*) VERIFYING_KEY_SELF_SIGNATURE These are invalid in this context but are included for later use when limiting the use of X.509 certs. (4) The pkcs7_test key type is given a module parameter to select between the above options for testing purposes. For example: echo 1 >/sys/module/pkcs7_test_key/parameters/usage keyctl padd pkcs7_test foo @s Signed-off-by: David Howells Reviewed-by: Marcel Holtmann Reviewed-by: David Woodhouse --- arch/x86/kernel/kexec-bzimage64.c | 4 +- crypto/asymmetric_keys/asymmetric_type.c | 11 +++ crypto/asymmetric_keys/pkcs7.asn1 | 6 +- crypto/asymmetric_keys/pkcs7_key_type.c | 14 +++- crypto/asymmetric_keys/pkcs7_parser.c | 138 +++++++++++++++++++++++++++++-- crypto/asymmetric_keys/pkcs7_parser.h | 15 +++- crypto/asymmetric_keys/pkcs7_verify.c | 65 ++++++++++++++- crypto/asymmetric_keys/verify_pefile.c | 7 +- include/crypto/pkcs7.h | 10 ++- include/crypto/public_key.h | 14 ++++ include/keys/system_keyring.h | 4 +- include/linux/oid_registry.h | 4 +- include/linux/verify_pefile.h | 6 +- kernel/module_signing.c | 3 +- kernel/system_keyring.c | 6 +- scripts/sign-file.c | 5 +- 16 files changed, 285 insertions(+), 27 deletions(-) (limited to 'include') diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c index ca83f7ac388b..fab22e72808c 100644 --- a/arch/x86/kernel/kexec-bzimage64.c +++ b/arch/x86/kernel/kexec-bzimage64.c @@ -536,7 +536,9 @@ static int bzImage64_verify_sig(const char *kernel, unsigned long kernel_len) int ret; ret = verify_pefile_signature(kernel, kernel_len, - system_trusted_keyring, &trusted); + system_trusted_keyring, + VERIFYING_KEXEC_PE_SIGNATURE, + &trusted); if (ret < 0) return ret; if (!trusted) diff --git a/crypto/asymmetric_keys/asymmetric_type.c b/crypto/asymmetric_keys/asymmetric_type.c index b0e4ed23d668..1916680ad81b 100644 --- a/crypto/asymmetric_keys/asymmetric_type.c +++ b/crypto/asymmetric_keys/asymmetric_type.c @@ -12,6 +12,7 @@ */ #include #include +#include #include #include #include @@ -20,6 +21,16 @@ MODULE_LICENSE("GPL"); +const char *const key_being_used_for[NR__KEY_BEING_USED_FOR] = { + [VERIFYING_MODULE_SIGNATURE] = "mod sig", + [VERIFYING_FIRMWARE_SIGNATURE] = "firmware sig", + [VERIFYING_KEXEC_PE_SIGNATURE] = "kexec PE sig", + [VERIFYING_KEY_SIGNATURE] = "key sig", + [VERIFYING_KEY_SELF_SIGNATURE] = "key self sig", + [VERIFYING_UNSPECIFIED_SIGNATURE] = "unspec sig", +}; +EXPORT_SYMBOL_GPL(key_being_used_for); + static LIST_HEAD(asymmetric_key_parsers); static DECLARE_RWSEM(asymmetric_key_parsers_sem); diff --git a/crypto/asymmetric_keys/pkcs7.asn1 b/crypto/asymmetric_keys/pkcs7.asn1 index 6bf8ff4f7414..1eca740b816a 100644 --- a/crypto/asymmetric_keys/pkcs7.asn1 +++ b/crypto/asymmetric_keys/pkcs7.asn1 @@ -8,7 +8,7 @@ ContentType ::= OBJECT IDENTIFIER ({ pkcs7_note_OID }) SignedData ::= SEQUENCE { version INTEGER ({ pkcs7_note_signeddata_version }), digestAlgorithms DigestAlgorithmIdentifiers, - contentInfo ContentInfo, + contentInfo ContentInfo ({ pkcs7_note_content }), certificates CHOICE { certSet [0] IMPLICIT ExtendedCertificatesAndCertificates, certSequence [2] IMPLICIT Certificates @@ -21,7 +21,7 @@ SignedData ::= SEQUENCE { } ContentInfo ::= SEQUENCE { - contentType ContentType, + contentType ContentType ({ pkcs7_note_OID }), content [0] EXPLICIT Data OPTIONAL } @@ -111,7 +111,7 @@ AuthenticatedAttribute ::= SEQUENCE { } UnauthenticatedAttribute ::= SEQUENCE { - type OBJECT IDENTIFIER ({ pkcs7_note_OID }), + type OBJECT IDENTIFIER, values SET OF ANY } diff --git a/crypto/asymmetric_keys/pkcs7_key_type.c b/crypto/asymmetric_keys/pkcs7_key_type.c index 3d13b042da73..10d34dbd00b9 100644 --- a/crypto/asymmetric_keys/pkcs7_key_type.c +++ b/crypto/asymmetric_keys/pkcs7_key_type.c @@ -14,16 +14,23 @@ #include #include #include +#include #include #include #include #include "pkcs7_parser.h" +static unsigned pkcs7_usage; +module_param_named(usage, pkcs7_usage, uint, S_IWUSR | S_IRUGO); +MODULE_PARM_DESC(pkcs7_usage, + "Usage to specify when verifying the PKCS#7 message"); + /* * Preparse a PKCS#7 wrapped and validated data blob. */ static int pkcs7_preparse(struct key_preparsed_payload *prep) { + enum key_being_used_for usage = pkcs7_usage; struct pkcs7_message *pkcs7; const void *data, *saved_prep_data; size_t datalen, saved_prep_datalen; @@ -32,6 +39,11 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep) kenter(""); + if (usage >= NR__KEY_BEING_USED_FOR) { + pr_err("Invalid usage type %d\n", usage); + return -EINVAL; + } + saved_prep_data = prep->data; saved_prep_datalen = prep->datalen; pkcs7 = pkcs7_parse_message(saved_prep_data, saved_prep_datalen); @@ -40,7 +52,7 @@ static int pkcs7_preparse(struct key_preparsed_payload *prep) goto error; } - ret = pkcs7_verify(pkcs7); + ret = pkcs7_verify(pkcs7, usage); if (ret < 0) goto error_free; diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c index 826e2f3f507b..e6298b7a945a 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.c +++ b/crypto/asymmetric_keys/pkcs7_parser.c @@ -81,6 +81,30 @@ void pkcs7_free_message(struct pkcs7_message *pkcs7) } EXPORT_SYMBOL_GPL(pkcs7_free_message); +/* + * Check authenticatedAttributes are provided or not provided consistently. + */ +static int pkcs7_check_authattrs(struct pkcs7_message *msg) +{ + struct pkcs7_signed_info *sinfo; + bool want; + + sinfo = msg->signed_infos; + if (sinfo->authattrs) { + want = true; + msg->have_authattrs = true; + } + + for (sinfo = sinfo->next; sinfo; sinfo = sinfo->next) + if (!!sinfo->authattrs != want) + goto inconsistent; + return 0; + +inconsistent: + pr_warn("Inconsistently supplied authAttrs\n"); + return -EINVAL; +} + /** * pkcs7_parse_message - Parse a PKCS#7 message * @data: The raw binary ASN.1 encoded message to be parsed @@ -113,6 +137,10 @@ struct pkcs7_message *pkcs7_parse_message(const void *data, size_t datalen) goto out; } + ret = pkcs7_check_authattrs(ctx->msg); + if (ret < 0) + goto out; + msg = ctx->msg; ctx->msg = NULL; @@ -380,6 +408,25 @@ int pkcs7_note_certificate_list(void *context, size_t hdrlen, return 0; } +/* + * Note the content type. + */ +int pkcs7_note_content(void *context, size_t hdrlen, + unsigned char tag, + const void *value, size_t vlen) +{ + struct pkcs7_parse_context *ctx = context; + + if (ctx->last_oid != OID_data && + ctx->last_oid != OID_msIndirectData) { + pr_warn("Unsupported data type %d\n", ctx->last_oid); + return -EINVAL; + } + + ctx->msg->data_type = ctx->last_oid; + return 0; +} + /* * Extract the data from the message and store that and its content type OID in * the context. @@ -395,31 +442,90 @@ int pkcs7_note_data(void *context, size_t hdrlen, ctx->msg->data = value; ctx->msg->data_len = vlen; ctx->msg->data_hdrlen = hdrlen; - ctx->msg->data_type = ctx->last_oid; return 0; } /* - * Parse authenticated attributes + * Parse authenticated attributes. */ int pkcs7_sig_note_authenticated_attr(void *context, size_t hdrlen, unsigned char tag, const void *value, size_t vlen) { struct pkcs7_parse_context *ctx = context; + struct pkcs7_signed_info *sinfo = ctx->sinfo; + enum OID content_type; pr_devel("AuthAttr: %02x %zu [%*ph]\n", tag, vlen, (unsigned)vlen, value); switch (ctx->last_oid) { + case OID_contentType: + if (__test_and_set_bit(sinfo_has_content_type, &sinfo->aa_set)) + goto repeated; + content_type = look_up_OID(value, vlen); + if (content_type != ctx->msg->data_type) { + pr_warn("Mismatch between global data type (%d) and sinfo %u (%d)\n", + ctx->msg->data_type, sinfo->index, + content_type); + return -EBADMSG; + } + return 0; + + case OID_signingTime: + if (__test_and_set_bit(sinfo_has_signing_time, &sinfo->aa_set)) + goto repeated; + /* Should we check that the signing time is consistent + * with the signer's X.509 cert? + */ + return x509_decode_time(&sinfo->signing_time, + hdrlen, tag, value, vlen); + case OID_messageDigest: + if (__test_and_set_bit(sinfo_has_message_digest, &sinfo->aa_set)) + goto repeated; if (tag != ASN1_OTS) return -EBADMSG; - ctx->sinfo->msgdigest = value; - ctx->sinfo->msgdigest_len = vlen; + sinfo->msgdigest = value; + sinfo->msgdigest_len = vlen; + return 0; + + case OID_smimeCapabilites: + if (__test_and_set_bit(sinfo_has_smime_caps, &sinfo->aa_set)) + goto repeated; + if (ctx->msg->data_type != OID_msIndirectData) { + pr_warn("S/MIME Caps only allowed with Authenticode\n"); + return -EKEYREJECTED; + } + return 0; + + /* Microsoft SpOpusInfo seems to be contain cont[0] 16-bit BE + * char URLs and cont[1] 8-bit char URLs. + * + * Microsoft StatementType seems to contain a list of OIDs that + * are also used as extendedKeyUsage types in X.509 certs. + */ + case OID_msSpOpusInfo: + if (__test_and_set_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) + goto repeated; + goto authenticode_check; + case OID_msStatementType: + if (__test_and_set_bit(sinfo_has_ms_statement_type, &sinfo->aa_set)) + goto repeated; + authenticode_check: + if (ctx->msg->data_type != OID_msIndirectData) { + pr_warn("Authenticode AuthAttrs only allowed with Authenticode\n"); + return -EKEYREJECTED; + } + /* I'm not sure how to validate these */ return 0; default: return 0; } + +repeated: + /* We permit max one item per AuthenticatedAttribute and no repeats */ + pr_warn("Repeated/multivalue AuthAttrs not permitted\n"); + return -EKEYREJECTED; } /* @@ -430,10 +536,25 @@ int pkcs7_sig_note_set_of_authattrs(void *context, size_t hdrlen, const void *value, size_t vlen) { struct pkcs7_parse_context *ctx = context; + struct pkcs7_signed_info *sinfo = ctx->sinfo; + + if (!test_bit(sinfo_has_content_type, &sinfo->aa_set) || + !test_bit(sinfo_has_message_digest, &sinfo->aa_set) || + (ctx->msg->data_type == OID_msIndirectData && + !test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set))) { + pr_warn("Missing required AuthAttr\n"); + return -EBADMSG; + } + + if (ctx->msg->data_type != OID_msIndirectData && + test_bit(sinfo_has_ms_opus_info, &sinfo->aa_set)) { + pr_warn("Unexpected Authenticode AuthAttr\n"); + return -EBADMSG; + } /* We need to switch the 'CONT 0' to a 'SET OF' when we digest */ - ctx->sinfo->authattrs = value - (hdrlen - 1); - ctx->sinfo->authattrs_len = vlen + (hdrlen - 1); + sinfo->authattrs = value - (hdrlen - 1); + sinfo->authattrs_len = vlen + (hdrlen - 1); return 0; } @@ -511,6 +632,11 @@ int pkcs7_note_signed_info(void *context, size_t hdrlen, struct pkcs7_signed_info *sinfo = ctx->sinfo; struct asymmetric_key_id *kid; + if (ctx->msg->data_type == OID_msIndirectData && !sinfo->authattrs) { + pr_warn("Authenticode requires AuthAttrs\n"); + return -EBADMSG; + } + /* Generate cert issuer + serial number key ID */ if (!ctx->expect_skid) { kid = asymmetric_key_generate_id(ctx->raw_serial, diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h index 790dd7cec82c..a66b19ebcf47 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.h +++ b/crypto/asymmetric_keys/pkcs7_parser.h @@ -21,9 +21,9 @@ struct pkcs7_signed_info { struct pkcs7_signed_info *next; struct x509_certificate *signer; /* Signing certificate (in msg->certs) */ - unsigned index; - bool trusted; - bool unsupported_crypto; /* T if not usable due to missing crypto */ + unsigned index; + bool trusted; + bool unsupported_crypto; /* T if not usable due to missing crypto */ /* Message digest - the digest of the Content Data (or NULL) */ const void *msgdigest; @@ -32,6 +32,14 @@ struct pkcs7_signed_info { /* Authenticated Attribute data (or NULL) */ unsigned authattrs_len; const void *authattrs; + unsigned long aa_set; +#define sinfo_has_content_type 0 +#define sinfo_has_signing_time 1 +#define sinfo_has_message_digest 2 +#define sinfo_has_smime_caps 3 +#define sinfo_has_ms_opus_info 4 +#define sinfo_has_ms_statement_type 5 + time64_t signing_time; /* Issuing cert serial number and issuer's name [PKCS#7 or CMS ver 1] * or issuing cert's SKID [CMS ver 3]. @@ -53,6 +61,7 @@ struct pkcs7_message { struct x509_certificate *crl; /* Revocation list */ struct pkcs7_signed_info *signed_infos; u8 version; /* Version of cert (1 -> PKCS#7 or CMS; 3 -> CMS) */ + bool have_authattrs; /* T if have authattrs */ /* Content Data (or NULL) */ enum OID data_type; /* Type of Data */ diff --git a/crypto/asymmetric_keys/pkcs7_verify.c b/crypto/asymmetric_keys/pkcs7_verify.c index 404f89a0f852..d20c0b4b880e 100644 --- a/crypto/asymmetric_keys/pkcs7_verify.c +++ b/crypto/asymmetric_keys/pkcs7_verify.c @@ -70,9 +70,15 @@ static int pkcs7_digest(struct pkcs7_message *pkcs7, * message digest attribute amongst them which corresponds to the * digest we just calculated. */ - if (sinfo->msgdigest) { + if (sinfo->authattrs) { u8 tag; + if (!sinfo->msgdigest) { + pr_warn("Sig %u: No messageDigest\n", sinfo->index); + ret = -EKEYREJECTED; + goto error; + } + if (sinfo->msgdigest_len != sinfo->sig.digest_size) { pr_debug("Sig %u: Invalid digest size (%u)\n", sinfo->index, sinfo->msgdigest_len); @@ -314,6 +320,18 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7, pr_devel("Using X.509[%u] for sig %u\n", sinfo->signer->index, sinfo->index); + /* Check that the PKCS#7 signing time is valid according to the X.509 + * certificate. We can't, however, check against the system clock + * since that may not have been set yet and may be wrong. + */ + if (test_bit(sinfo_has_signing_time, &sinfo->aa_set)) { + if (sinfo->signing_time < sinfo->signer->valid_from || + sinfo->signing_time > sinfo->signer->valid_to) { + pr_warn("Message signed outside of X.509 validity window\n"); + return -EKEYREJECTED; + } + } + /* Verify the PKCS#7 binary against the key */ ret = public_key_verify_signature(sinfo->signer->pub, &sinfo->sig); if (ret < 0) @@ -328,6 +346,7 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7, /** * pkcs7_verify - Verify a PKCS#7 message * @pkcs7: The PKCS#7 message to be verified + * @usage: The use to which the key is being put * * Verify a PKCS#7 message is internally consistent - that is, the data digest * matches the digest in the AuthAttrs and any signature in the message or one @@ -339,6 +358,9 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7, * * Returns, in order of descending priority: * + * (*) -EKEYREJECTED if a key was selected that had a usage restriction at + * odds with the specified usage, or: + * * (*) -EKEYREJECTED if a signature failed to match for which we found an * appropriate X.509 certificate, or: * @@ -350,7 +372,8 @@ static int pkcs7_verify_one(struct pkcs7_message *pkcs7, * (*) 0 if all the signature chains that don't incur -ENOPKG can be verified * (note that a signature chain may be of zero length), or: */ -int pkcs7_verify(struct pkcs7_message *pkcs7) +int pkcs7_verify(struct pkcs7_message *pkcs7, + enum key_being_used_for usage) { struct pkcs7_signed_info *sinfo; struct x509_certificate *x509; @@ -359,6 +382,44 @@ int pkcs7_verify(struct pkcs7_message *pkcs7) kenter(""); + switch (usage) { + case VERIFYING_MODULE_SIGNATURE: + if (pkcs7->data_type != OID_data) { + pr_warn("Invalid module sig (not pkcs7-data)\n"); + return -EKEYREJECTED; + } + if (pkcs7->have_authattrs) { + pr_warn("Invalid module sig (has authattrs)\n"); + return -EKEYREJECTED; + } + break; + case VERIFYING_FIRMWARE_SIGNATURE: + if (pkcs7->data_type != OID_data) { + pr_warn("Invalid firmware sig (not pkcs7-data)\n"); + return -EKEYREJECTED; + } + if (!pkcs7->have_authattrs) { + pr_warn("Invalid firmware sig (missing authattrs)\n"); + return -EKEYREJECTED; + } + break; + case VERIFYING_KEXEC_PE_SIGNATURE: + if (pkcs7->data_type != OID_msIndirectData) { + pr_warn("Invalid kexec sig (not Authenticode)\n"); + return -EKEYREJECTED; + } + /* Authattr presence checked in parser */ + break; + case VERIFYING_UNSPECIFIED_SIGNATURE: + if (pkcs7->data_type != OID_data) { + pr_warn("Invalid unspecified sig (not pkcs7-data)\n"); + return -EKEYREJECTED; + } + break; + default: + return -EINVAL; + } + for (n = 0, x509 = pkcs7->certs; x509; x509 = x509->next, n++) { ret = x509_get_sig_params(x509); if (ret < 0) diff --git a/crypto/asymmetric_keys/verify_pefile.c b/crypto/asymmetric_keys/verify_pefile.c index 2421f46184ce..897b734dabf9 100644 --- a/crypto/asymmetric_keys/verify_pefile.c +++ b/crypto/asymmetric_keys/verify_pefile.c @@ -393,6 +393,7 @@ error_no_desc: * @pebuf: Buffer containing the PE binary image * @pelen: Length of the binary image * @trust_keyring: Signing certificates to use as starting points + * @usage: The use to which the key is being put. * @_trusted: Set to true if trustworth, false otherwise * * Validate that the certificate chain inside the PKCS#7 message inside the PE @@ -417,7 +418,9 @@ error_no_desc: * May also return -ENOMEM. */ int verify_pefile_signature(const void *pebuf, unsigned pelen, - struct key *trusted_keyring, bool *_trusted) + struct key *trusted_keyring, + enum key_being_used_for usage, + bool *_trusted) { struct pkcs7_message *pkcs7; struct pefile_context ctx; @@ -462,7 +465,7 @@ int verify_pefile_signature(const void *pebuf, unsigned pelen, if (ret < 0) goto error; - ret = pkcs7_verify(pkcs7); + ret = pkcs7_verify(pkcs7, usage); if (ret < 0) goto error; diff --git a/include/crypto/pkcs7.h b/include/crypto/pkcs7.h index e235ab4957ee..441aff9b5aa7 100644 --- a/include/crypto/pkcs7.h +++ b/include/crypto/pkcs7.h @@ -9,6 +9,11 @@ * 2 of the Licence, or (at your option) any later version. */ +#ifndef _CRYPTO_PKCS7_H +#define _CRYPTO_PKCS7_H + +#include + struct key; struct pkcs7_message; @@ -33,7 +38,10 @@ extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7, /* * pkcs7_verify.c */ -extern int pkcs7_verify(struct pkcs7_message *pkcs7); +extern int pkcs7_verify(struct pkcs7_message *pkcs7, + enum key_being_used_for usage); extern int pkcs7_supply_detached_data(struct pkcs7_message *pkcs7, const void *data, size_t datalen); + +#endif /* _CRYPTO_PKCS7_H */ diff --git a/include/crypto/public_key.h b/include/crypto/public_key.h index fda097e079a4..067c242b1e15 100644 --- a/include/crypto/public_key.h +++ b/include/crypto/public_key.h @@ -39,6 +39,20 @@ enum pkey_id_type { extern const char *const pkey_id_type_name[PKEY_ID_TYPE__LAST]; +/* + * The use to which an asymmetric key is being put. + */ +enum key_being_used_for { + VERIFYING_MODULE_SIGNATURE, + VERIFYING_FIRMWARE_SIGNATURE, + VERIFYING_KEXEC_PE_SIGNATURE, + VERIFYING_KEY_SIGNATURE, + VERIFYING_KEY_SELF_SIGNATURE, + VERIFYING_UNSPECIFIED_SIGNATURE, + NR__KEY_BEING_USED_FOR +}; +extern const char *const key_being_used_for[NR__KEY_BEING_USED_FOR]; + /* * Cryptographic data for the public-key subtype of the asymmetric key type. * diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h index 9791c907cdb7..b20cd885c1fd 100644 --- a/include/keys/system_keyring.h +++ b/include/keys/system_keyring.h @@ -15,6 +15,7 @@ #ifdef CONFIG_SYSTEM_TRUSTED_KEYRING #include +#include extern struct key *system_trusted_keyring; static inline struct key *get_system_trusted_keyring(void) @@ -30,7 +31,8 @@ static inline struct key *get_system_trusted_keyring(void) #ifdef CONFIG_SYSTEM_DATA_VERIFICATION extern int system_verify_data(const void *data, unsigned long len, - const void *raw_pkcs7, size_t pkcs7_len); + const void *raw_pkcs7, size_t pkcs7_len, + enum key_being_used_for usage); #endif #endif /* _KEYS_SYSTEM_KEYRING_H */ diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h index c2bbf672b84e..93e0ff92fb9b 100644 --- a/include/linux/oid_registry.h +++ b/include/linux/oid_registry.h @@ -41,7 +41,7 @@ enum OID { OID_signed_data, /* 1.2.840.113549.1.7.2 */ /* PKCS#9 {iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9)} */ OID_email_address, /* 1.2.840.113549.1.9.1 */ - OID_content_type, /* 1.2.840.113549.1.9.3 */ + OID_contentType, /* 1.2.840.113549.1.9.3 */ OID_messageDigest, /* 1.2.840.113549.1.9.4 */ OID_signingTime, /* 1.2.840.113549.1.9.5 */ OID_smimeCapabilites, /* 1.2.840.113549.1.9.15 */ @@ -54,6 +54,8 @@ enum OID { /* Microsoft Authenticode & Software Publishing */ OID_msIndirectData, /* 1.3.6.1.4.1.311.2.1.4 */ + OID_msStatementType, /* 1.3.6.1.4.1.311.2.1.11 */ + OID_msSpOpusInfo, /* 1.3.6.1.4.1.311.2.1.12 */ OID_msPeImageDataObjId, /* 1.3.6.1.4.1.311.2.1.15 */ OID_msIndividualSPKeyPurpose, /* 1.3.6.1.4.1.311.2.1.21 */ OID_msOutlookExpress, /* 1.3.6.1.4.1.311.16.4 */ diff --git a/include/linux/verify_pefile.h b/include/linux/verify_pefile.h index ac34819214f9..da2049b5161c 100644 --- a/include/linux/verify_pefile.h +++ b/include/linux/verify_pefile.h @@ -12,7 +12,11 @@ #ifndef _LINUX_VERIFY_PEFILE_H #define _LINUX_VERIFY_PEFILE_H +#include + extern int verify_pefile_signature(const void *pebuf, unsigned pelen, - struct key *trusted_keyring, bool *_trusted); + struct key *trusted_keyring, + enum key_being_used_for usage, + bool *_trusted); #endif /* _LINUX_VERIFY_PEFILE_H */ diff --git a/kernel/module_signing.c b/kernel/module_signing.c index 70ad463f6df0..bd62f5cda746 100644 --- a/kernel/module_signing.c +++ b/kernel/module_signing.c @@ -72,5 +72,6 @@ int mod_verify_sig(const void *mod, unsigned long *_modlen) return -EBADMSG; } - return system_verify_data(mod, modlen, mod + modlen, sig_len); + return system_verify_data(mod, modlen, mod + modlen, sig_len, + VERIFYING_MODULE_SIGNATURE); } diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c index 95f2dcbc7616..2570598b784d 100644 --- a/kernel/system_keyring.c +++ b/kernel/system_keyring.c @@ -113,9 +113,11 @@ late_initcall(load_system_certificate_list); * @len: Size of @data. * @raw_pkcs7: The PKCS#7 message that is the signature. * @pkcs7_len: The size of @raw_pkcs7. + * @usage: The use to which the key is being put. */ int system_verify_data(const void *data, unsigned long len, - const void *raw_pkcs7, size_t pkcs7_len) + const void *raw_pkcs7, size_t pkcs7_len, + enum key_being_used_for usage) { struct pkcs7_message *pkcs7; bool trusted; @@ -132,7 +134,7 @@ int system_verify_data(const void *data, unsigned long len, goto error; } - ret = pkcs7_verify(pkcs7); + ret = pkcs7_verify(pkcs7, usage); if (ret < 0) goto error; diff --git a/scripts/sign-file.c b/scripts/sign-file.c index de213e5c0cd3..e9741e879bbd 100755 --- a/scripts/sign-file.c +++ b/scripts/sign-file.c @@ -111,7 +111,7 @@ int main(int argc, char **argv) bool sign_only = false; unsigned char buf[4096]; unsigned long module_size, cms_size; - unsigned int use_keyid = 0; + unsigned int use_keyid = 0, use_signed_attrs = CMS_NOATTR; const EVP_MD *digest_algo; EVP_PKEY *private_key; CMS_ContentInfo *cms; @@ -216,7 +216,8 @@ int main(int argc, char **argv) ERR(!cms, "CMS_sign"); ERR(!CMS_add1_signer(cms, x509, private_key, digest_algo, - CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | use_keyid), + CMS_NOCERTS | CMS_BINARY | CMS_NOSMIMECAP | + use_keyid | use_signed_attrs), "CMS_sign_add_signer"); ERR(CMS_final(cms, bm, NULL, CMS_NOCERTS | CMS_BINARY) < 0, "CMS_final"); -- cgit v1.2.3 From 07f081fb5057b2ea98baeca3a47bf0eb33e94aa1 Mon Sep 17 00:00:00 2001 From: David Howells Date: Sun, 30 Aug 2015 16:59:57 +0100 Subject: PKCS#7: Add OIDs for sha224, sha284 and sha512 hash algos and use them Add OIDs for sha224, sha284 and sha512 hash algos and use them to select the hashing algorithm. Without this, something like the following error might get written to dmesg: [ 31.829322] PKCS7: Unknown OID: [32] 2.16.840.1.101.3.4.2.3 [ 31.829328] PKCS7: Unknown OID: [180] 2.16.840.1.101.3.4.2.3 [ 31.829330] Unsupported digest algo: 55 Where the 55 on the third line is OID__NR indicating an unknown OID. Reported-by: Valdis Kletnieks Signed-off-by: David Howells Tested-By: Valdis Kletnieks Signed-off-by: James Morris --- crypto/asymmetric_keys/mscode_parser.c | 9 +++++++++ crypto/asymmetric_keys/pkcs7_parser.c | 8 ++++++++ include/linux/oid_registry.h | 3 +++ 3 files changed, 20 insertions(+) (limited to 'include') diff --git a/crypto/asymmetric_keys/mscode_parser.c b/crypto/asymmetric_keys/mscode_parser.c index 214a992123cd..adcef59eec0b 100644 --- a/crypto/asymmetric_keys/mscode_parser.c +++ b/crypto/asymmetric_keys/mscode_parser.c @@ -97,6 +97,15 @@ int mscode_note_digest_algo(void *context, size_t hdrlen, case OID_sha256: ctx->digest_algo = HASH_ALGO_SHA256; break; + case OID_sha384: + ctx->digest_algo = HASH_ALGO_SHA384; + break; + case OID_sha512: + ctx->digest_algo = HASH_ALGO_SHA512; + break; + case OID_sha224: + ctx->digest_algo = HASH_ALGO_SHA224; + break; case OID__NR: sprint_oid(value, vlen, buffer, sizeof(buffer)); diff --git a/crypto/asymmetric_keys/pkcs7_parser.c b/crypto/asymmetric_keys/pkcs7_parser.c index e6298b7a945a..758acabf2d81 100644 --- a/crypto/asymmetric_keys/pkcs7_parser.c +++ b/crypto/asymmetric_keys/pkcs7_parser.c @@ -229,6 +229,14 @@ int pkcs7_sig_note_digest_algo(void *context, size_t hdrlen, case OID_sha256: ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA256; break; + case OID_sha384: + ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA384; + break; + case OID_sha512: + ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA512; + break; + case OID_sha224: + ctx->sinfo->sig.pkey_hash_algo = HASH_ALGO_SHA224; default: printk("Unsupported digest algo: %u\n", ctx->last_oid); return -ENOPKG; diff --git a/include/linux/oid_registry.h b/include/linux/oid_registry.h index 93e0ff92fb9b..d2fa9ca42e9a 100644 --- a/include/linux/oid_registry.h +++ b/include/linux/oid_registry.h @@ -63,6 +63,9 @@ enum OID { OID_certAuthInfoAccess, /* 1.3.6.1.5.5.7.1.1 */ OID_sha1, /* 1.3.14.3.2.26 */ OID_sha256, /* 2.16.840.1.101.3.4.2.1 */ + OID_sha384, /* 2.16.840.1.101.3.4.2.2 */ + OID_sha512, /* 2.16.840.1.101.3.4.2.3 */ + OID_sha224, /* 2.16.840.1.101.3.4.2.4 */ /* Distinguished Name attribute IDs [RFC 2256] */ OID_commonName, /* 2.5.4.3 */ -- cgit v1.2.3