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authorDan Rosenberg <drosenberg@vsecurity.com>2010-12-25 16:23:40 -0500
committerGreg Kroah-Hartman <gregkh@suse.de>2011-01-07 14:43:16 -0800
commit815fc814077615de661c902b0dab82c3609373f1 (patch)
treeae7dca90a622caf7462df66f43f415bf66c817fb
parente3220459813fb6395809bbdb12f87cace16e315f (diff)
downloadlinux-linaro-stable-815fc814077615de661c902b0dab82c3609373f1.tar.gz
sound: Prevent buffer overflow in OSS load_mixer_volumes
commit d81a12bc29ae4038770e05dce4ab7f26fd5880fb upstream. 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> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-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 61aaedae6b7e..31ee7866dc10 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;