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 for the debugging, Alexander!
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