diff options
| author | Kees Cook <keescook@chromium.org> | 2020-05-13 14:11:26 -0700 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2020-07-10 16:01:51 -0700 |
| commit | c818c03b661cd769e035e41673d5543ba2ebda64 (patch) | |
| tree | ceb9cf9666ce0e0e3964c1ff1a0a5949de471cf6 | |
| parent | e4d05028a07f505a08802a6d1b11674c149df2b3 (diff) | |
seccomp: Report number of loaded filters in /proc/$pid/status
A common question asked when debugging seccomp filters is "how many
filters are attached to your process?" Provide a way to easily answer
this question through /proc/$pid/status with a "Seccomp_filters" line.
Signed-off-by: Kees Cook <keescook@chromium.org>
| -rw-r--r-- | fs/proc/array.c | 2 | ||||
| -rw-r--r-- | include/linux/seccomp.h | 2 | ||||
| -rw-r--r-- | init/init_task.c | 3 | ||||
| -rw-r--r-- | kernel/seccomp.c | 3 |
4 files changed, 10 insertions, 0 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 55ecbeb3a721..65ec2029fa80 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -341,6 +341,8 @@ static inline void task_seccomp(struct seq_file *m, struct task_struct *p) seq_put_decimal_ull(m, "NoNewPrivs:\t", task_no_new_privs(p)); #ifdef CONFIG_SECCOMP seq_put_decimal_ull(m, "\nSeccomp:\t", p->seccomp.mode); + seq_put_decimal_ull(m, "\nSeccomp_filters:\t", + atomic_read(&p->seccomp.filter_count)); #endif seq_puts(m, "\nSpeculation_Store_Bypass:\t"); switch (arch_prctl_spec_ctrl_get(p, PR_SPEC_STORE_BYPASS)) { diff --git a/include/linux/seccomp.h b/include/linux/seccomp.h index 4192369b8418..2ec2720f83cc 100644 --- a/include/linux/seccomp.h +++ b/include/linux/seccomp.h @@ -13,6 +13,7 @@ #ifdef CONFIG_SECCOMP #include <linux/thread_info.h> +#include <linux/atomic.h> #include <asm/seccomp.h> struct seccomp_filter; @@ -29,6 +30,7 @@ struct seccomp_filter; */ struct seccomp { int mode; + atomic_t filter_count; struct seccomp_filter *filter; }; diff --git a/init/init_task.c b/init/init_task.c index 15089d15010a..a3eb3847e1f4 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -204,6 +204,9 @@ struct task_struct init_task #ifdef CONFIG_SECURITY .security = NULL, #endif +#ifdef CONFIG_SECCOMP + .seccomp = { .filter_count = ATOMIC_INIT(0) }, +#endif }; EXPORT_SYMBOL(init_task); diff --git a/kernel/seccomp.c b/kernel/seccomp.c index d653d8426de9..f387e5004c29 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -398,6 +398,8 @@ static inline void seccomp_sync_threads(unsigned long flags) put_seccomp_filter(thread); smp_store_release(&thread->seccomp.filter, caller->seccomp.filter); + atomic_set(&thread->seccomp.filter_count, + atomic_read(&thread->seccomp.filter_count)); /* * Don't let an unprivileged task work around @@ -544,6 +546,7 @@ static long seccomp_attach_filter(unsigned int flags, */ filter->prev = current->seccomp.filter; current->seccomp.filter = filter; + atomic_inc(¤t->seccomp.filter_count); /* Now that the new filter is in place, synchronize to all threads. */ if (flags & SECCOMP_FILTER_FLAG_TSYNC) |