[PATCH v5 04/13] seccomp_filter: add process state reporting

From: Will Drewry
Date: Fri Jun 03 2011 - 17:48:18 EST


Adds seccomp and seccomp_filter status reporting to proc.
/proc/<pid>/seccomp_filter provides the current seccomp mode
and the list of allowed or dynamically filtered system calls.

v5: fix typos when mailing the wrong patch series
v4: move from rcu guard to mutex guard
v3: changed to using filters directly.
v2: removed status entry, added seccomp file.
(requested by kosaki.motohiro@xxxxxxxxxxxxxx)
allowed S_IRUGO reading of entries
(requested by viro@xxxxxxxxxxxxxxxxxx)
added flags
got rid of the seccomp_t type
dropped seccomp file

Signed-off-by: Will Drewry <wad@xxxxxxxxxxxx>
---
fs/proc/base.c | 29 +++++++++++++++++++++++++++++
1 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/fs/proc/base.c b/fs/proc/base.c
index dfa5327..8673064 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -73,6 +73,7 @@
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/tracehook.h>
+#include <linux/seccomp.h>
#include <linux/cgroup.h>
#include <linux/cpuset.h>
#include <linux/audit.h>
@@ -579,6 +580,28 @@ static int proc_pid_syscall(struct task_struct *task, char *buffer)
}
#endif /* CONFIG_HAVE_ARCH_TRACEHOOK */

+/*
+ * Print out the current seccomp filter set for the task.
+ */
+#ifdef CONFIG_SECCOMP_FILTER
+int proc_pid_seccomp_filter_show(struct seq_file *m, struct pid_namespace *ns,
+ struct pid *pid, struct task_struct *task)
+{
+ struct seccomp_filters *filters;
+ /* Avoid allowing other processes to incur too much added contention by
+ * only acquiring a reference under the task-wide mutex.
+ */
+ if (mutex_lock_killable(&task->seccomp.filters_guard))
+ return -1;
+ filters = get_seccomp_filters(task->seccomp.filters);
+ mutex_unlock(&task->seccomp.filters_guard);
+
+ seccomp_show_filters(filters, m);
+ put_seccomp_filters(filters);
+ return 0;
+}
+#endif /* CONFIG_SECCOMP_FILTER */
+
/************************************************************************/
/* Here the fs part begins */
/************************************************************************/
@@ -2838,6 +2861,9 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
INF("syscall", S_IRUGO, proc_pid_syscall),
#endif
+#ifdef CONFIG_SECCOMP_FILTER
+ ONE("seccomp_filter", S_IRUGO, proc_pid_seccomp_filter_show),
+#endif
INF("cmdline", S_IRUGO, proc_pid_cmdline),
ONE("stat", S_IRUGO, proc_tgid_stat),
ONE("statm", S_IRUGO, proc_pid_statm),
@@ -3180,6 +3206,9 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
INF("syscall", S_IRUGO, proc_pid_syscall),
#endif
+#ifdef CONFIG_SECCOMP_FILTER
+ ONE("seccomp_filter", S_IRUGO, proc_pid_seccomp_filter_show),
+#endif
INF("cmdline", S_IRUGO, proc_pid_cmdline),
ONE("stat", S_IRUGO, proc_tid_stat),
ONE("statm", S_IRUGO, proc_pid_statm),
--
1.7.0.4

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