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authorLv Yunlong <lyl2019@mail.ustc.edu.cn>2021-04-26 06:11:29 -0700
committerTakashi Iwai <tiwai@suse.de>2021-04-26 16:23:41 +0200
commit1c98f574403dbcf2eb832d5535a10d967333ef2d (patch)
tree554d0fa0bd9914a852e5289120a93c8f49307720 /sound/isa
parent9bbb94e57df135ef61bef075d9c99b8d9e89e246 (diff)
ALSA: emu8000: Fix a use after free in snd_emu8000_create_mixer
Our code analyzer reported a uaf. In snd_emu8000_create_mixer, the callee snd_ctl_add(..,emu->controls[i]) calls snd_ctl_add_replace(.., kcontrol,..). Inside snd_ctl_add_replace(), if error happens, kcontrol will be freed by snd_ctl_free_one(kcontrol). Then emu->controls[i] points to a freed memory, and the execution comes to __error branch of snd_emu8000_create_mixer. The freed emu->controls[i] is used in snd_ctl_remove(card, emu->controls[i]). My patch set emu->controls[i] to NULL if snd_ctl_add() failed to avoid the uaf. Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20210426131129.4796-1-lyl2019@mail.ustc.edu.cn Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/isa')
-rw-r--r--sound/isa/sb/emu8000.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/sound/isa/sb/emu8000.c b/sound/isa/sb/emu8000.c
index 0aa545ac6e60..1c90421a88dc 100644
--- a/sound/isa/sb/emu8000.c
+++ b/sound/isa/sb/emu8000.c
@@ -1029,8 +1029,10 @@ snd_emu8000_create_mixer(struct snd_card *card, struct snd_emu8000 *emu)
memset(emu->controls, 0, sizeof(emu->controls));
for (i = 0; i < EMU8000_NUM_CONTROLS; i++) {
- if ((err = snd_ctl_add(card, emu->controls[i] = snd_ctl_new1(mixer_defs[i], emu))) < 0)
+ if ((err = snd_ctl_add(card, emu->controls[i] = snd_ctl_new1(mixer_defs[i], emu))) < 0) {
+ emu->controls[i] = NULL;
goto __error;
+ }
}
return 0;