diff options
| author | Dan Rosenberg <drosenberg@vsecurity.com> | 2010-09-28 14:18:20 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-10-28 21:04:14 -0700 |
| commit | 56b40aa2ea3788e9b8f8411868f0f35a6f8a14cf (patch) | |
| tree | bec88e5901763f40cb5e1dc7245924f800faa4a5 | |
| parent | 7b1178dc25f59d6f61dc87853d164e8ec87eba25 (diff) | |
ALSA: prevent heap corruption in snd_ctl_new()
commit 5591bf07225523600450edd9e6ad258bb877b779 upstream.
The snd_ctl_new() function in sound/core/control.c allocates space for a
snd_kcontrol struct by performing arithmetic operations on a
user-provided size without checking for integer overflow. If a user
provides a large enough size, an overflow will occur, the allocated
chunk will be too small, and a second user-influenced value will be
written repeatedly past the bounds of this chunk. This code is
reachable by unprivileged users who have permission to open
a /dev/snd/controlC* device (on many distros, this is group "audio") via
the SNDRV_CTL_IOCTL_ELEM_ADD and SNDRV_CTL_IOCTL_ELEM_REPLACE ioctls.
Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | sound/core/control.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sound/core/control.c b/sound/core/control.c index 236bbb15b250..a708b0bb20d6 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -31,6 +31,7 @@ /* max number of user-defined controls */ #define MAX_USER_CONTROLS 32 +#define MAX_CONTROL_COUNT 1028 struct snd_kctl_ioctl { struct list_head list; /* list of all ioctls */ @@ -190,6 +191,8 @@ static struct snd_kcontrol *snd_ctl_new(struct snd_kcontrol *control, snd_assert(control != NULL, return NULL); snd_assert(control->count > 0, return NULL); + if (control->count > MAX_CONTROL_COUNT) + return NULL; kctl = kzalloc(sizeof(*kctl) + sizeof(struct snd_kcontrol_volatile) * control->count, GFP_KERNEL); if (kctl == NULL) { snd_printk(KERN_ERR "Cannot allocate control instance\n"); |