From: Hui Peng <benquike@gmail.com>
To: security@kernel.org
Cc: Hui Peng <benquike@gmail.com>,
Mathias Payer <mathias.payer@nebelwelt.net>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
Thomas Gleixner <tglx@linutronix.de>,
Allison Randal <allison@lohutok.net>,
YueHaibing <yuehaibing@huawei.com>,
Wenwen Wang <wang6495@umn.edu>,
alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Subject: [PATCH] Fix an OOB bug in parse_audio_mixer_unit
Date: Tue, 13 Aug 2019 22:36:24 -0400 [thread overview]
Message-ID: <20190814023625.21683-1-benquike@gmail.com> (raw)
The `uac_mixer_unit_descriptor` shown as below is read from the
device side. In `parse_audio_mixer_unit`, `baSourceID` field is
accessed from index 0 to `bNrInPins` - 1, the current implementation
assumes that descriptor is always valid (the length of descriptor
is no shorter than 5 + `bNrInPins`). If a descriptor read from
the device side is invalid, it may trigger out-of-bound memory
access.
```
struct uac_mixer_unit_descriptor {
__u8 bLength;
__u8 bDescriptorType;
__u8 bDescriptorSubtype;
__u8 bUnitID;
__u8 bNrInPins;
__u8 baSourceID[];
}
```
This patch fixes the bug by add a sanity check on the length of
the descriptor.
Signed-off-by: Hui Peng <benquike@gmail.com>
Reported-by: Hui Peng <benquike@gmail.com>
Reported-by: Mathias Payer <mathias.payer@nebelwelt.net>
---
sound/usb/mixer.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 7498b5191b68..38202ce67237 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2091,6 +2091,15 @@ static int parse_audio_mixer_unit(struct mixer_build *state, int unitid,
struct usb_audio_term iterm;
int input_pins, num_ins, num_outs;
int pin, ich, err;
+ int desc_len = (int) ((unsigned long) state->buffer +
+ state->buflen - (unsigned long) raw_desc);
+
+ if (desc_len < sizeof(*desc) + desc->bNrInPins) {
+ usb_audio_err(state->chip,
+ "descriptor %d too short\n",
+ unitid);
+ return -EINVAL;
+ }
err = uac_mixer_unit_get_channels(state, desc);
if (err < 0) {
--
2.22.1
next reply other threads:[~2019-08-14 2:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 2:36 Hui Peng [this message]
2019-08-14 6:36 ` [PATCH] Fix an OOB bug in parse_audio_mixer_unit Takashi Iwai
2019-08-14 9:09 ` Dan Carpenter
2019-08-14 15:14 ` Takashi Iwai
[not found] ` <CAKpmkkUv=arsdJiexaM-UVhXEwfGN=zreny9P_kDNhQUij8=FQ@mail.gmail.com>
2019-08-14 16:33 ` Takashi Iwai
[not found] ` <CAKpmkkVzT5H0RTAu_Fa=9_gjf5v7k3qzPnnJvPpBp3BaP7G0ag@mail.gmail.com>
2019-08-14 18:21 ` Takashi Iwai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190814023625.21683-1-benquike@gmail.com \
--to=benquike@gmail.com \
--cc=allison@lohutok.net \
--cc=alsa-devel@alsa-project.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mathias.payer@nebelwelt.net \
--cc=perex@perex.cz \
--cc=security@kernel.org \
--cc=tglx@linutronix.de \
--cc=tiwai@suse.com \
--cc=wang6495@umn.edu \
--cc=yuehaibing@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).