lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Wed, 9 Mar 2016 15:13:19 -0800 From: Kamal Mostafa <kamal@...onical.com> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org, kernel-team@...ts.ubuntu.com Cc: Takashi Iwai <tiwai@...e.de>, Kamal Mostafa <kamal@...onical.com> Subject: [PATCH 3.13.y-ckt 072/138] ALSA: timer: Fix race between stop and interrupt 3.13.11-ckt36 -stable review patch. If anyone has any objections, please let me know. ---8<------------------------------------------------------------ From: Takashi Iwai <tiwai@...e.de> commit ed8b1d6d2c741ab26d60d499d7fbb7ac801f0f51 upstream. A slave timer element also unlinks at snd_timer_stop() but it takes only slave_active_lock. When a slave is assigned to a master, however, this may become a race against the master's interrupt handling, eventually resulting in a list corruption. The actual bug could be seen with a syzkaller fuzzer test case in BugLink below. As a fix, we need to take timeri->timer->lock when timer isn't NULL, i.e. assigned to a master, while the assignment to a master itself is protected by slave_active_lock. BugLink: http://lkml.kernel.org/r/CACT4Y+Y_Bm+7epAb=8Wi=AaWd+DYS7qawX52qxdCfOfY49vozQ@mail.gmail.com Signed-off-by: Takashi Iwai <tiwai@...e.de> [ kamal: backport to 3.13-stable: context ] Signed-off-by: Kamal Mostafa <kamal@...onical.com> --- sound/core/timer.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/core/timer.c b/sound/core/timer.c index 44cbdde..cbb127b 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -511,9 +511,13 @@ static int _snd_timer_stop(struct snd_timer_instance * timeri, spin_unlock_irqrestore(&slave_active_lock, flags); return -EBUSY; } + if (timeri->timer) + spin_lock(&timeri->timer->lock); timeri->flags &= ~SNDRV_TIMER_IFLG_RUNNING; list_del_init(&timeri->ack_list); list_del_init(&timeri->active_list); + if (timeri->timer) + spin_unlock(&timeri->timer->lock); spin_unlock_irqrestore(&slave_active_lock, flags); } goto __end; -- 2.7.0
Powered by blists - more mailing lists