From 2f4b3bf6b2318cfaa177ec5a802f4d8d6afbd816 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 17 Dec 2012 16:03:14 -0800 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 Acked-by: Serge E. Hallyn Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 74cb394e6888..12665ee7094a 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 377a37366dde..077235ffb38b 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);