This is a note to let you know that I've just added the patch titled
media: dvb-usb-v2: af9035: Fix null-ptr-deref in af9035_i2c_master_xfer
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
media-dvb-usb-v2-af9035-fix-null-ptr-deref-in-af9035.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 39d6580085ee6fc9a5bd164f6e61742ece9d71be
Author: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
Date: Thu Jul 6 00:06:54 2023 +0800
media: dvb-usb-v2: af9035: Fix null-ptr-deref in af9035_i2c_master_xfer
[ Upstream commit 7bf744f2de0a848fb1d717f5831b03db96feae89 ]
In af9035_i2c_master_xfer, msg is controlled by user. When msg[i].buf
is null and msg[i].len is zero, former checks on msg[i].buf would be
passed. Malicious data finally reach af9035_i2c_master_xfer. If accessing
msg[i].buf[0] without sanity check, null ptr deref would happen.
We add check on msg[i].len to prevent crash.
Similar commit:
commit 0ed554fd769a
("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")
Signed-off-by: Zhang Shurong <zhang_shurong@xxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/media/usb/dvb-usb-v2/af9035.c b/drivers/media/usb/dvb-usb-v2/af9035.c
index 3afd18733614a..3a7e5f2f6e951 100644
--- a/drivers/media/usb/dvb-usb-v2/af9035.c
+++ b/drivers/media/usb/dvb-usb-v2/af9035.c
@@ -321,6 +321,8 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
ret = -EOPNOTSUPP;
} else if ((msg[0].addr == state->af9033_i2c_addr[0]) ||
(msg[0].addr == state->af9033_i2c_addr[1])) {
+ if (msg[0].len < 3 || msg[1].len < 1)
+ return -EOPNOTSUPP;
/* demod access via firmware interface */
u32 reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 |
msg[0].buf[2];
@@ -380,6 +382,8 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
ret = -EOPNOTSUPP;
} else if ((msg[0].addr == state->af9033_i2c_addr[0]) ||
(msg[0].addr == state->af9033_i2c_addr[1])) {
+ if (msg[0].len < 3)
+ return -EOPNOTSUPP;
/* demod access via firmware interface */
u32 reg = msg[0].buf[0] << 16 | msg[0].buf[1] << 8 |
msg[0].buf[2];
@@ -387,10 +391,7 @@ static int af9035_i2c_master_xfer(struct i2c_adapter *adap,
if (msg[0].addr == state->af9033_i2c_addr[1])
reg |= 0x100000;
- ret = (msg[0].len >= 3) ? af9035_wr_regs(d, reg,
- &msg[0].buf[3],
- msg[0].len - 3)
- : -EOPNOTSUPP;
+ ret = af9035_wr_regs(d, reg, &msg[0].buf[3], msg[0].len - 3);
} else {
/* I2C write */
u8 buf[MAX_XFER_SIZE];
