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| author |   Alexander Popov <alex.popov@linux.com> | 2018-04-19 15:29:22 +0300 |
|---|---|---|
| committer |   Wolfram Sang <wsa@the-dreams.de> | 2018-04-27 14:04:10 +0200 |
| commit | 23a27722b5292ef0b27403c87a109feea8296a5c (patch) | |
| tree | 3516ceaf2c36581588bcb11db81b669f4e45bba3 /drivers/i2c | |
| parent | Documentation/i2c: adopt kernel commenting style in examples (diff) | |
| download | linux-dev-23a27722b5292ef0b27403c87a109feea8296a5c.tar.xz linux-dev-23a27722b5292ef0b27403c87a109feea8296a5c.zip | |
i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr()
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>
Diffstat (limited to 'drivers/i2c')
| -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 036a03f0d0a6..1667b6e7674f 100644 --- a/drivers/i2c/i2c-dev.c +++ b/drivers/i2c/i2c-dev.c @@ -280,7 +280,7 @@ static noinline int i2cdev_ioctl_rdwr(struct i2c_client *client, */ if (msgs[i].flags & I2C_M_RECV_LEN) { if (!(msgs[i].flags & I2C_M_RD) || - msgs[i].buf[0] < 1 || + msgs[i].len < 1 || msgs[i].buf[0] < 1 || msgs[i].len < msgs[i].buf[0] + I2C_SMBUS_BLOCK_MAX) { res = -EINVAL; |