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 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> --- sound/core/pcm.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/sound/core/pcm.c b/sound/core/pcm.c index fdb9b92fc8d6..23141003a90d 100644 --- a/sound/core/pcm.c +++ b/sound/core/pcm.c @@ -32,6 +32,8 @@ #include <sound/control.h> #include <sound/info.h> +#include <linux/nospec.h> + #include "pcm_local.h" MODULE_AUTHOR("Jaroslav Kysela <perex@xxxxxxxx>, Abramo Bagnara <abramo@xxxxxxxxxxxxxxxx>"); @@ -129,6 +131,7 @@ 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); -- 2.17.1 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
