diff options
| author | Takashi Iwai <tiwai@suse.de> | 2018-04-24 07:45:56 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2018-04-25 10:37:46 +0200 |
| commit | 088e861edffb84879cf0c0d1b02eda078c3a0ffe (patch) | |
| tree | 90999b564bf855bf817623802810b90a47831f5c | |
| parent | 8d218dd8116695ecda7164f97631c069938aa22e (diff) | |
ALSA: control: Hardening for potential Spectre v1
As recently Smatch suggested, a few places in ALSA control core codes
may expand the array directly from the user-space value with
speculation:
sound/core/control.c:1003 snd_ctl_elem_lock() warn: potential spectre issue 'kctl->vd'
sound/core/control.c:1031 snd_ctl_elem_unlock() warn: potential spectre issue 'kctl->vd'
sound/core/control.c:844 snd_ctl_elem_info() warn: potential spectre issue 'kctl->vd'
sound/core/control.c:891 snd_ctl_elem_read() warn: potential spectre issue 'kctl->vd'
sound/core/control.c:939 snd_ctl_elem_write() warn: potential spectre issue 'kctl->vd'
Although all these seem doing only the first load without further
reference, we may want to stay in a safer side, so hardening with
array_index_nospec() would still make sense.
In this patch, we put array_index_nospec() to the common
snd_ctl_get_ioff*() helpers instead of each caller. These helpers are
also referred from some drivers, too, and basically all usages are to
calculate the array index from the user-space value, hence it's better
to cover there.
BugLink: https://marc.info/?l=linux-kernel&m=152411496503418&w=2
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
| -rw-r--r-- | include/sound/control.h | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/include/sound/control.h b/include/sound/control.h index ca13a44ae9d4..6011a58d3e20 100644 --- a/include/sound/control.h +++ b/include/sound/control.h @@ -23,6 +23,7 @@ */ #include <linux/wait.h> +#include <linux/nospec.h> #include <sound/asound.h> #define snd_kcontrol_chip(kcontrol) ((kcontrol)->private_data) @@ -148,12 +149,14 @@ int snd_ctl_get_preferred_subdevice(struct snd_card *card, int type); static inline unsigned int snd_ctl_get_ioffnum(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id) { - return id->numid - kctl->id.numid; + unsigned int ioff = id->numid - kctl->id.numid; + return array_index_nospec(ioff, kctl->count); } static inline unsigned int snd_ctl_get_ioffidx(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id) { - return id->index - kctl->id.index; + unsigned int ioff = id->index - kctl->id.index; + return array_index_nospec(ioff, kctl->count); } static inline unsigned int snd_ctl_get_ioff(struct snd_kcontrol *kctl, struct snd_ctl_elem_id *id) |