[PATCH] proc: add "personality" to process status file

Kees Cook
2008-10-02T21:51:42Z

There is no sane way to query the personality flags of arbitrary process
from userspace. This adds the flags to the /proc/$pid/status file.
For example, to detect READ_IMPLIES_EXEC:

$ ./32bit-sleeper &
[1] 6732
$ grep ^Pers /proc/6732/status
Personality: 00000000
$ execstack -s 32bit-sleeper
$ ./32bit-slepper &
[2] 6735
$ grep ^Pers /proc/6735/status
Personality: 00040000

Signed-off-by: Kees Cook <kees.cook@canonical.com>
---
fs/proc/array.c | 6 ++++--
include/linux/sched.h | 3 +--
2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/proc/array.c b/fs/proc/array.c
index 71c9be5..1235fab 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -182,13 +182,15 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
"PPid:\t%d\n"
"TracerPid:\t%d\n"
"Uid:\t%d\t%d\t%d\t%d\n"
- "Gid:\t%d\t%d\t%d\t%d\n",
+ "Gid:\t%d\t%d\t%d\t%d\n"
+ "Personality:\t%08x\n",
get_task_state(p),
task_tgid_nr_ns(p, ns),
pid_nr_ns(pid, ns),
ppid, tpid,
p->uid, p->euid, p->suid, p->fsuid,
- p->gid, p->egid, p->sgid, p->fsgid);
+ p->gid, p->egid, p->sgid, p->fsgid,
+ p->personality);

task_lock(p);
if (p->files)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 3d9120c..f2fc441 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1085,8 +1085,7 @@ struct task_struct {
int exit_state;
int exit_code, exit_signal;
int pdeath_signal; /* The signal sent when the parent dies */
- /* ??? */
- unsigned int personality;
+ unsigned int personality; /* Special-case bits (linux/personality.h) */
unsigned did_exec:1;
pid_t pid;
pid_t tgid;
--
1.5.6.3

--
Kees Cook
Ubuntu Security Team