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| author | Takashi Iwai <tiwai@suse.de> | 2020-06-24 15:23:40 +0300 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2020-06-24 15:24:29 +0300 |
| commit | 220345e98f1cdc768eeb6e3364a0fa7ab9647fe7 (patch) | |
| tree | c3fd3927a037edc80b7ec782cd15e390089168fd /sound/usb/mixer.h | |
| parent | a32a1fc99807244d920d274adc46ba04b538cc8a (diff) | |
| download | linux-220345e98f1cdc768eeb6e3364a0fa7ab9647fe7.tar.xz | |
ALSA: usb-audio: Fix OOB access of mixer element list
The USB-audio mixer code holds a linked list of usb_mixer_elem_list,
and several operations are performed for each mixer element. A few of
them (snd_usb_mixer_notify_id() and snd_usb_mixer_interrupt_v2())
assume each mixer element being a usb_mixer_elem_info object that is a
subclass of usb_mixer_elem_list, cast via container_of() and access it
members. This may result in an out-of-bound access when a
non-standard list element has been added, as spotted by syzkaller
recently.
This patch adds a new field, is_std_info, in usb_mixer_elem_list to
indicate that the element is the usb_mixer_elem_info type or not, and
skip the access to such an element if needed.
Reported-by: syzbot+fb14314433463ad51625@syzkaller.appspotmail.com
Reported-by: syzbot+2405ca3401e943c538b5@syzkaller.appspotmail.com
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200624122340.9615-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/mixer.h')
| -rw-r--r-- | sound/usb/mixer.h | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/sound/usb/mixer.h b/sound/usb/mixer.h index 41ec9dc4139b..c29e27ac43a7 100644 --- a/sound/usb/mixer.h +++ b/sound/usb/mixer.h @@ -66,6 +66,7 @@ struct usb_mixer_elem_list { struct usb_mixer_elem_list *next_id_elem; /* list of controls with same id */ struct snd_kcontrol *kctl; unsigned int id; + bool is_std_info; usb_mixer_elem_dump_func_t dump; usb_mixer_elem_resume_func_t resume; }; @@ -103,8 +104,12 @@ void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid); int snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval, int request, int validx, int value_set); -int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list, - struct snd_kcontrol *kctl); +int snd_usb_mixer_add_list(struct usb_mixer_elem_list *list, + struct snd_kcontrol *kctl, + bool is_std_info); + +#define snd_usb_mixer_add_control(list, kctl) \ + snd_usb_mixer_add_list(list, kctl, true) void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list, struct usb_mixer_interface *mixer, |