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: NAlexander Popov <alex.popov@linux.com> Reviewed-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de> [wsa: use '< 1' instead of '!' for easier readability] Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Showing
想要评论请 注册 或 登录