[PATCH] proc: show personality via /proc/pid/personality

Make process personality flags visible in /proc.  Since a process's
personality is potentially sensitive (e.g. READ_IMPLIES_EXEC), make this
file only readable by the process owner.

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

diff --git a/fs/proc/base.c b/fs/proc/base.c
index bb63fa1..c1332dd 100644 (file)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -2438,6 +2438,13 @@ static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
 }
 #endif /* CONFIG_TASK_IO_ACCOUNTING */
 
+static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
+                               struct pid *pid, struct task_struct *task)
+{
+       seq_printf(m, "%08x\n", task->personality);
+       return 0;
+}
+
 /*
  * Thread groups
  */
@@ -2454,6 +2461,7 @@ static const struct pid_entry tgid_base_stuff[] = {
        REG("environ",    S_IRUSR, environ),
        INF("auxv",       S_IRUSR, pid_auxv),
        ONE("status",     S_IRUGO, pid_status),
+       ONE("personality", S_IRUSR, pid_personality),
        INF("limits",     S_IRUSR, pid_limits),
 #ifdef CONFIG_SCHED_DEBUG
        REG("sched",      S_IRUGO|S_IWUSR, pid_sched),
@@ -2789,6 +2797,7 @@ static const struct pid_entry tid_base_stuff[] = {
        REG("environ",   S_IRUSR, environ),
        INF("auxv",      S_IRUSR, pid_auxv),
        ONE("status",    S_IRUGO, pid_status),
+       ONE("personality", S_IRUSR, pid_personality),
        INF("limits",    S_IRUSR, pid_limits),
 #ifdef CONFIG_SCHED_DEBUG
        REG("sched",     S_IRUGO|S_IWUSR, pid_sched),