Messages in this thread | | | Date | Mon, 30 Apr 2018 09:13:10 +0200 | From | Uwe Kleine-König <> | Subject | Re: [v2 1/1] i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl_rdwr() |
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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@linux.com> > > 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/ |
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