Re: [PATCH v2] audit: create explicit AUDIT_SECCOMP event type

The seccomp path was using AUDIT_ANOM_ABEND from when seccomp mode 1 could only kill a process. While we still want to make sure an audit record is forced on a kill, this should use a separate record type since seccomp mode 2 introduces other behaviors. In the case of "handled" behaviors (process wasn't killed), only emit a record if the process is under inspection. This change also fixes userspace examination of seccomp audit events, since it was considered malformed due to missing fields of the AUDIT_ANOM_ABEND event type. Cc: Julien Tinnes <jln(a)google.com&gt; Cc: Will Drewry <wad(a)google.com&gt; Cc: stable(a)vger.kernel.org Signed-off-by: Kees Cook <keescook(a)chromium.org&gt; Acked-by: Steve Grubb <sgrubb(a)redhat.com&gt; --- v2: - update commit message and add Cc to stable, suggested by Steve Grubb --- include/linux/audit.h | 3 ++- include/uapi/linux/audit.h | 1 + kernel/auditsc.c | 14 +++++++++++--- 3 files changed, 14 insertions(+), 4 deletions(-) diff --git a/include/linux/audit.h b/include/linux/audit.h index bce729a..9d5104d 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -157,7 +157,8 @@ void audit_core_dumps(long signr); static inline void audit_seccomp(unsigned long syscall, long signr, int code) { - if (unlikely(!audit_dummy_context())) + /* Force a record to be reported if a signal was delivered. */ + if (signr || unlikely(!audit_dummy_context())) __audit_seccomp(syscall, signr, code); } diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 76352ac..09a2d94 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -106,6 +106,7 @@ #define AUDIT_MMAP 1323 /* Record showing descriptor and flags in mmap */ #define AUDIT_NETFILTER_PKT 1324 /* Packets traversing netfilter chains */ #define AUDIT_NETFILTER_CFG 1325 /* Netfilter chain modifications */ +#define AUDIT_SECCOMP 1326 /* Secure Computing event */ #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */ #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */ diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 2f186ed..157e989 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2735,7 +2735,7 @@ void __audit_mmap_fd(int fd, int flags) context->type = AUDIT_MMAP; } -static void audit_log_abend(struct audit_buffer *ab, char *reason, long signr) +static void audit_log_task(struct audit_buffer *ab) { kuid_t auid, uid; kgid_t gid; @@ -2753,6 +2753,11 @@ static void audit_log_abend(struct audit_buffer *ab, char *reason, long signr) audit_log_task_context(ab); audit_log_format(ab, " pid=%d comm=", current->pid); audit_log_untrustedstring(ab, current->comm); +} + +static void audit_log_abend(struct audit_buffer *ab, char *reason, long signr) +{ + audit_log_task(ab); audit_log_format(ab, " reason="); audit_log_string(ab, reason); audit_log_format(ab, " sig=%ld", signr); @@ -2783,8 +2788,11 @@ void __audit_seccomp(unsigned long syscall, long signr, int code) { struct audit_buffer *ab; - ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_ANOM_ABEND); - audit_log_abend(ab, "seccomp", signr); + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_SECCOMP); + if (unlikely(!ab)) + return; + audit_log_task(ab); + audit_log_format(ab, " sig=%ld", signr); audit_log_format(ab, " syscall=%ld", syscall); audit_log_format(ab, " compat=%d", is_compat_task()); audit_log_format(ab, " ip=0x%lx", KSTK_EIP(current)); -- 1.7.9.5 -- Kees Cook Chrome OS Security