ALSA: usb-audio: Fix OOB access of mixer element list
commit 220345e98f
upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
parent
1cc2d29710
commit
25e1bb1e6c
|
@ -576,8 +576,9 @@ static int check_matrix_bitmap(unsigned char *bmap,
|
||||||
* if failed, give up and free the control instance.
|
* if failed, give up and free the control instance.
|
||||||
*/
|
*/
|
||||||
|
|
||||||
int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list,
|
int snd_usb_mixer_add_list(struct usb_mixer_elem_list *list,
|
||||||
struct snd_kcontrol *kctl)
|
struct snd_kcontrol *kctl,
|
||||||
|
bool is_std_info)
|
||||||
{
|
{
|
||||||
struct usb_mixer_interface *mixer = list->mixer;
|
struct usb_mixer_interface *mixer = list->mixer;
|
||||||
int err;
|
int err;
|
||||||
|
@ -591,6 +592,7 @@ int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list,
|
||||||
return err;
|
return err;
|
||||||
}
|
}
|
||||||
list->kctl = kctl;
|
list->kctl = kctl;
|
||||||
|
list->is_std_info = is_std_info;
|
||||||
list->next_id_elem = mixer->id_elems[list->id];
|
list->next_id_elem = mixer->id_elems[list->id];
|
||||||
mixer->id_elems[list->id] = list;
|
mixer->id_elems[list->id] = list;
|
||||||
return 0;
|
return 0;
|
||||||
|
@ -3213,8 +3215,11 @@ void snd_usb_mixer_notify_id(struct usb_mixer_interface *mixer, int unitid)
|
||||||
unitid = delegate_notify(mixer, unitid, NULL, NULL);
|
unitid = delegate_notify(mixer, unitid, NULL, NULL);
|
||||||
|
|
||||||
for_each_mixer_elem(list, mixer, unitid) {
|
for_each_mixer_elem(list, mixer, unitid) {
|
||||||
struct usb_mixer_elem_info *info =
|
struct usb_mixer_elem_info *info;
|
||||||
mixer_elem_list_to_info(list);
|
|
||||||
|
if (!list->is_std_info)
|
||||||
|
continue;
|
||||||
|
info = mixer_elem_list_to_info(list);
|
||||||
/* invalidate cache, so the value is read from the device */
|
/* invalidate cache, so the value is read from the device */
|
||||||
info->cached = 0;
|
info->cached = 0;
|
||||||
snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
|
snd_ctl_notify(mixer->chip->card, SNDRV_CTL_EVENT_MASK_VALUE,
|
||||||
|
@ -3294,6 +3299,8 @@ static void snd_usb_mixer_interrupt_v2(struct usb_mixer_interface *mixer,
|
||||||
|
|
||||||
if (!list->kctl)
|
if (!list->kctl)
|
||||||
continue;
|
continue;
|
||||||
|
if (!list->is_std_info)
|
||||||
|
continue;
|
||||||
|
|
||||||
info = mixer_elem_list_to_info(list);
|
info = mixer_elem_list_to_info(list);
|
||||||
if (count > 1 && info->control != control)
|
if (count > 1 && info->control != control)
|
||||||
|
|
|
@ -66,6 +66,7 @@ struct usb_mixer_elem_list {
|
||||||
struct usb_mixer_elem_list *next_id_elem; /* list of controls with same id */
|
struct usb_mixer_elem_list *next_id_elem; /* list of controls with same id */
|
||||||
struct snd_kcontrol *kctl;
|
struct snd_kcontrol *kctl;
|
||||||
unsigned int id;
|
unsigned int id;
|
||||||
|
bool is_std_info;
|
||||||
usb_mixer_elem_dump_func_t dump;
|
usb_mixer_elem_dump_func_t dump;
|
||||||
usb_mixer_elem_resume_func_t resume;
|
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 snd_usb_mixer_set_ctl_value(struct usb_mixer_elem_info *cval,
|
||||||
int request, int validx, int value_set);
|
int request, int validx, int value_set);
|
||||||
|
|
||||||
int snd_usb_mixer_add_control(struct usb_mixer_elem_list *list,
|
int snd_usb_mixer_add_list(struct usb_mixer_elem_list *list,
|
||||||
struct snd_kcontrol *kctl);
|
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,
|
void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
|
||||||
struct usb_mixer_interface *mixer,
|
struct usb_mixer_interface *mixer,
|
||||||
|
|
|
@ -157,7 +157,8 @@ static int add_single_ctl_with_resume(struct usb_mixer_interface *mixer,
|
||||||
return -ENOMEM;
|
return -ENOMEM;
|
||||||
}
|
}
|
||||||
kctl->private_free = snd_usb_mixer_elem_free;
|
kctl->private_free = snd_usb_mixer_elem_free;
|
||||||
return snd_usb_mixer_add_control(list, kctl);
|
/* don't use snd_usb_mixer_add_control() here, this is a special list element */
|
||||||
|
return snd_usb_mixer_add_list(list, kctl, false);
|
||||||
}
|
}
|
||||||
|
|
||||||
/*
|
/*
|
||||||
|
|
Loading…
Reference in New Issue