This is a note to let you know that I've just added the patch titled
i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr()
to the 4.14-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:
i2c-dev-prevent-zero_size_ptr-deref-in-i2cdev_ioctl_rdwr.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 23a27722b5292ef0b27403c87a109feea8296a5c Mon Sep 17 00:00:00 2001
From: Alexander Popov <alex.popov@xxxxxxxxx>
Date: Thu, 19 Apr 2018 15:29:22 +0300
Subject: i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr()
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From: Alexander Popov <alex.popov@xxxxxxxxx>
commit 23a27722b5292ef0b27403c87a109feea8296a5c upstream.
i2cdev_ioctl_rdwr() allocates i2c_msg.buf using memdup_user(), which
returns ZERO_SIZE_PTR if i2c_msg.len is zero.
Currently i2cdev_ioctl_rdwr() always dereferences the buf pointer in case
of I2C_M_RD | I2C_M_RECV_LEN transfer. That causes a kernel oops in
case of zero len.
Let's check the len against zero before dereferencing buf pointer.
This issue was triggered by syzkaller.
Signed-off-by: Alexander Popov <alex.popov@xxxxxxxxx>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
[wsa: use '< 1' instead of '!' for easier readability]
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
[Harshit: backport to 4.14.y, use rdwr_pa[i].len instead of msgs[i].len
as the 4.14.y code uses rdwr_pa.]
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/i2c-dev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/i2c/i2c-dev.c
+++ b/drivers/i2c/i2c-dev.c
@@ -297,7 +297,7 @@ static noinline int i2cdev_ioctl_rdwr(st
*/
if (rdwr_pa[i].flags & I2C_M_RECV_LEN) {
if (!(rdwr_pa[i].flags & I2C_M_RD) ||
- rdwr_pa[i].buf[0] < 1 ||
+ rdwr_pa[i].len < 1 || rdwr_pa[i].buf[0] < 1 ||
rdwr_pa[i].len < rdwr_pa[i].buf[0] +
I2C_SMBUS_BLOCK_MAX) {
i++;
Patches currently in stable-queue which might be from alex.popov@xxxxxxxxx are
queue-4.14/i2c-dev-prevent-zero_size_ptr-deref-in-i2cdev_ioctl_rdwr.patch
