diff options
| author | Andy Lutomirski <luto@kernel.org> | 2016-09-30 10:58:56 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-10-20 09:21:41 +0200 |
| commit | 0a1eb2d474edfe75466be6b4677ad84e5e8ca3f5 (patch) | |
| tree | 3966a6309145b8e7982d32e4903c64654118d697 | |
| parent | 137baabe351e0554d06c6d5c84059fe343e2791e (diff) | |
fs/proc: Stop reporting eip and esp in /proc/PID/stat
Reporting these fields on a non-current task is dangerous. If the
task is in any state other than normal kernel code, they may contain
garbage or even kernel addresses on some architectures. (x86_64
used to do this. I bet lots of architectures still do.) With
CONFIG_THREAD_INFO_IN_TASK=y, it can OOPS, too.
As far as I know, there are no use programs that make any material
use of these fields, so just get rid of them.
Reported-by: Jann Horn <jann@thejh.net>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux API <linux-api@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Tycho Andersen <tycho.andersen@canonical.com>
Link: http://lkml.kernel.org/r/a5fed4c3f4e33ed25d4bb03567e329bc5a712bcc.1475257877.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | fs/proc/array.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index 89600fd5963d..81818adb8e9e 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -412,10 +412,11 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns, mm = get_task_mm(task); if (mm) { vsize = task_vsize(mm); - if (permitted) { - eip = KSTK_EIP(task); - esp = KSTK_ESP(task); - } + /* + * esp and eip are intentionally zeroed out. There is no + * non-racy way to read them without freezing the task. + * Programs that need reliable values can use ptrace(2). + */ } get_task_comm(tcomm, task); |