diff options
| author | Alexander Popov <alex.popov@linux.com> | 2018-04-19 15:29:22 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-10-26 14:16:51 +0300 |
| commit | dc76815698d63016284aef22b69aefb006489418 (patch) | |
| tree | b8d4fbd6277834383ebd8aee53dba561a8f65224 | |
| parent | c8da52294dec4ff622a4dfa7fef3df6e94549b87 (diff) | |
| download | linux-dc76815698d63016284aef22b69aefb006489418.tar.xz | |
i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr()
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@linux.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[wsa: use '< 1' instead of '!' for easier readability]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
[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@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/i2c/i2c-dev.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/i2c/i2c-dev.c b/drivers/i2c/i2c-dev.c index b7f9fb00f695..08aff5ebc99a 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -297,7 +297,7 @@ static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client, */ 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++; |