From 94ffb030b6d31ec840bb811be455dd2e26a4f43e Mon Sep 17 00:00:00 2001 From: "Gustavo A. R. Silva" Date: Wed, 12 Dec 2018 15:36:28 -0600 Subject: ALSA: pcm: Fix potential Spectre v1 vulnerability stream is indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: sound/core/pcm.c:140 snd_pcm_control_ioctl() warn: potential spectre issue 'pcm->streams' [r] (local cap) Fix this by sanitizing stream before using it to index pcm->streams Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Signed-off-by: Gustavo A. R. Silva Cc: stable@vger.kernel.org Signed-off-by: Takashi Iwai --- sound/core/pcm.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'sound/core/pcm.c') diff --git a/sound/core/pcm.c b/sound/core/pcm.c index fdb9b92fc8d6..01b9d62eef14 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include #include @@ -129,6 +130,7 @@ static int snd_pcm_control_ioctl(struct snd_card *card, return -EFAULT; if (stream < 0 || stream > 1) return -EINVAL; + stream = array_index_nospec(stream, 2); if (get_user(subdevice, &info->subdevice)) return -EFAULT; mutex_lock(®ister_mutex); -- cgit v1.2.3-59-g8ed1b