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authorDan Rosenberg <drosenberg@vsecurity.com>2010-12-25 16:23:40 -0500
committerTakashi Iwai <tiwai@suse.de>2010-12-30 13:20:55 +0100
commitd81a12bc29ae4038770e05dce4ab7f26fd5880fb (patch)
tree69b5439b49368704465f797ff7ae147e3d81d451 /sound/oss
parentMerge branch 'fix/hda' into for-linus (diff)
downloadlinux-dev-d81a12bc29ae4038770e05dce4ab7f26fd5880fb.tar.xz
linux-dev-d81a12bc29ae4038770e05dce4ab7f26fd5880fb.zip
sound: Prevent buffer overflow in OSS load_mixer_volumes
The load_mixer_volumes() function, which can be triggered by unprivileged users via the SOUND_MIXER_SETLEVELS ioctl, is vulnerable to a buffer overflow. Because the provided "name" argument isn't guaranteed to be NULL terminated at the expected 32 bytes, it's possible to overflow past the end of the last element in the mixer_vols array. Further exploitation can result in an arbitrary kernel write (via subsequent calls to load_mixer_volumes()) leading to privilege escalation, or arbitrary kernel reads via get_mixer_levels(). In addition, the strcmp() may leak bytes beyond the mixer_vols array. Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com> Cc: stable <stable@kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/oss')
-rw-r--r--sound/oss/soundcard.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/sound/oss/soundcard.c b/sound/oss/soundcard.c
index 46c0d03dbecc..fcb14a099822 100644
--- a/sound/oss/soundcard.c
+++ b/sound/oss/soundcard.c
@@ -87,7 +87,7 @@ int *load_mixer_volumes(char *name, int *levels, int present)
int i, n;
for (i = 0; i < num_mixer_volumes; i++) {
- if (strcmp(name, mixer_vols[i].name) == 0) {
+ if (strncmp(name, mixer_vols[i].name, 32) == 0) {
if (present)
mixer_vols[i].num = i;
return mixer_vols[i].levels;
@@ -99,7 +99,7 @@ int *load_mixer_volumes(char *name, int *levels, int present)
}
n = num_mixer_volumes++;
- strcpy(mixer_vols[n].name, name);
+ strncpy(mixer_vols[n].name, name, 32);
if (present)
mixer_vols[n].num = n;