/proc/pid/status: add "Seccomp" field (2f4b3bf6) · Commits · 戴 / test

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 <keescook@chromium.org> Reviewed-by:

Cyrill Gorcunov <gorcunov@openvz.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: James Morris <jmorris@namei.org> Acked-by:

Serge E. Hallyn <serge.hallyn@ubuntu.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/proc.txt

+2 −0

Original line number	Diff line number	Diff line
		@@ -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

fs/proc/array.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -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);

Admin message