On Fri, Apr 27, 2018 at 02:06:58PM +0200, Wolfram Sang wrote: > On Thu, Apr 19, 2018 at 03:29:22PM +0300, Alexander Popov wrote: > > 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> > > Applied to for-current with the arithmetic expression changed to '< 1' > to keep in sync with the previous one. Will push out soon, so you can > double check if you are interested. Thanks, I like it. An added bonus is also that you don't need to think about the type of msgs[i].len and what happens if it is negative. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
