diff options
| author | Jann Horn <jannh@google.com> | 2019-03-30 03:12:32 +0100 |
|---|---|---|
| committer | Bruno Martins <bgcngm@gmail.com> | 2022-10-28 15:57:23 +0100 |
| commit | 229e1bdd624eb6e2a4b946ae938485a05b37438a (patch) | |
| tree | 839761cf5ba16218ed7a9395ed387fc592e8189a /kernel/signal.c | |
| parent | ada02e996b52d9389d76b72213e01ffcdd648e96 (diff) | |
UPSTREAM: signal: don't silently convert SI_USER signals to non-current pidfd
The current sys_pidfd_send_signal() silently turns signals with explicit
SI_USER context that are sent to non-current tasks into signals with
kernel-generated siginfo.
This is unlike do_rt_sigqueueinfo(), which returns -EPERM in this case.
If a user actually wants to send a signal with kernel-provided siginfo,
they can do that with pidfd_send_signal(pidfd, sig, NULL, 0); so allowing
this case is unnecessary.
Instead of silently replacing the siginfo, just bail out with an error;
this is consistent with other interfaces and avoids special-casing behavior
based on security checks.
Fixes: 3eb39f47934f ("signal: add pidfd_send_signal() syscall")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Christian Brauner <christian@brauner.io>
(cherry picked from commit 556a888a14afe27164191955618990fb3ccc9aad)
Bug: 135608568
Test: test program using syscall(__NR_pidfd_send_signal,..) to send SIGKILL
Change-Id: I493af671b82c43bff1425ee24550d2fb9aa6d961
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 6f97979faec5..3c06e9a2a117 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -3039,16 +3039,11 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig, if (unlikely(sig != kinfo.si_signo)) goto err; + /* Only allow sending arbitrary signals to yourself. */ + ret = -EPERM; if ((task_pid(current) != pid) && - (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) { - /* Only allow sending arbitrary signals to yourself. */ - ret = -EPERM; - if (kinfo.si_code != SI_USER) - goto err; - - /* Turn this into a regular kill signal. */ - prepare_kill_siginfo(sig, &kinfo); - } + (kinfo.si_code >= 0 || kinfo.si_code == SI_TKILL)) + goto err; } else { prepare_kill_siginfo(sig, &kinfo); } |