From e89d77b2ba590f62e382543f9bbf550866fa25b9 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Sat, 3 Nov 2012 11:43:02 +1100 Subject: [PATCH] /proc/pid/status: add "Seccomp" field It is currently impossible to examine the state of seccomp for a given process. While attaching with gdb and attempting "call prctl(PR_GET_SECCOMP,...)" will work with some situations, it is not reliable. If the process is in seccomp mode 1, this query will kill the process (prctl not allowed), if the process is in mode 2 with prctl not allowed, it will similarly be killed, and in weird cases, if prctl is filtered to return errno 0, it can look like seccomp is disabled. When reviewing the state of running processes, there should be a way to externally examine the seccomp mode. ("Did this build of Chrome end up using seccomp?" "Did my distro ship ssh with seccomp enabled?") This adds the "Seccomp" line to /proc/$pid/status. Signed-off-by: Kees Cook Reviewed-by: Cyrill Gorcunov Cc: Andrea Arcangeli Cc: James Morris Signed-off-by: Andrew Morton --- Documentation/filesystems/proc.txt | 2 ++ fs/proc/array.c | 8 ++++++++ 2 files changed, 10 insertions(+) diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index c97b8321b14d..55381fe77cc6 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -181,6 +181,7 @@ read the file /proc/PID/status: CapPrm: 0000000000000000 CapEff: 0000000000000000 CapBnd: ffffffffffffffff + Seccomp: 0 voluntary_ctxt_switches: 0 nonvoluntary_ctxt_switches: 1 @@ -237,6 +238,7 @@ Table 1-2: Contents of the status files (as of 2.6.30-rc7) CapPrm bitmap of permitted capabilities CapEff bitmap of effective capabilities CapBnd bitmap of capabilities bounding set + Seccomp seccomp mode, like prctl(PR_GET_SECCOMP, ...) Cpus_allowed mask of CPUs on which this process may run Cpus_allowed_list Same as previous, but in "list format" Mems_allowed mask of memory nodes allowed to this process diff --git a/fs/proc/array.c b/fs/proc/array.c index d4efc333b132..fb10c6ce5c31 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -336,6 +336,13 @@ static inline void task_cap(struct seq_file *m, struct task_struct *p) render_cap_t(m, "CapBnd:\t", &cap_bset); } +static inline void task_seccomp(struct seq_file *m, struct task_struct *p) +{ +#ifdef CONFIG_SECCOMP + seq_printf(m, "Seccomp:\t%d\n", p->seccomp.mode); +#endif +} + static inline void task_context_switch_counts(struct seq_file *m, struct task_struct *p) { @@ -369,6 +376,7 @@ int proc_pid_status(struct seq_file *m, struct pid_namespace *ns, } task_sig(m, task); task_cap(m, task); + task_seccomp(m, task); task_cpus_allowed(m, task); cpuset_task_status_allowed(m, task); task_context_switch_counts(m, task); -- 2.39.5