diff options
| author | Eric Caruso <ejcaruso@google.com> | 2016-06-08 16:08:59 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-22 10:38:16 +0200 |
| commit | c520dfc66f8bad5cd8534aeb3cf60178d3bb525d (patch) | |
| tree | d935dd18fe717350146c9e6a5b37758185f40e92 | |
| parent | 47127fcd287c91397d11bcf697d12c79169528f2 (diff) | |
timerfd: Reject ALARM timerfds without CAP_WAKE_ALARM
commit 2895a5e5b3ae78d9923a91fce405d4a2f32c4309 upstream.
timerfd gives processes a way to set wake alarms, but unlike timers made using
timer_create, timerfds don't check whether the process has CAP_WAKE_ALARM
before setting alarm-time timers. CAP_WAKE_ALARM is supposed to gate this
behavior and so it makes sense that we should deny permission to create such
timerfds if the process doesn't have this capability.
Signed-off-by: Eric Caruso <ejcaruso@google.com>
Cc: Todd Poynor <toddpoynor@google.com>
Link: http://lkml.kernel.org/r/1465427339-96209-1-git-send-email-ejcaruso@chromium.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Kasper Zwijsen <Kasper.Zwijsen@UGent.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/timerfd.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/timerfd.c b/fs/timerfd.c index 1327a02ec778..ab8dd1538381 100644 --- a/fs/timerfd.c +++ b/fs/timerfd.c @@ -400,6 +400,11 @@ SYSCALL_DEFINE2(timerfd_create, int, clockid, int, flags) clockid != CLOCK_BOOTTIME_ALARM)) return -EINVAL; + if (!capable(CAP_WAKE_ALARM) && + (clockid == CLOCK_REALTIME_ALARM || + clockid == CLOCK_BOOTTIME_ALARM)) + return -EPERM; + ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return -ENOMEM; @@ -444,6 +449,11 @@ static int do_timerfd_settime(int ufd, int flags, return ret; ctx = f.file->private_data; + if (!capable(CAP_WAKE_ALARM) && isalarm(ctx)) { + fdput(f); + return -EPERM; + } + timerfd_setup_cancel(ctx, flags); /* |