Messages in this thread |  | | Date | Wed, 18 Apr 2018 09:07:04 +0200 | From | Uwe Kleine-König <> | Subject | Re: [PATCH 1/1] i2c: dev: check i2c_msg len before memdup_user() to prevent ZERO_SIZE_PTR deref |
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Hello,
On Wed, Apr 18, 2018 at 03:16:45AM +0300, Alexander Popov wrote: > Currently i2cdev_ioctl_rdwr() doesn't check i2c_msg len against zero > before calling memdup_user(). If this len is zero memdup_user() returns > ZERO_SIZE_PTR, which is later considered as valid since > IS_ERR(ZERO_SIZE_PTR) is false. That causes ZERO_SIZE_PTR deref oops.
You're saying that
memdup_user(ptr, 0)
reads from *ptr? I'd say this is a bug in memdup_user, not its user.
If however the problem only happens later in
if (msgs[i].flags & I2C_M_RECV_LEN) { if (!(msgs[i].flags & I2C_M_RD) || msgs[i].buf[0] < 1 || ...)
Your commit log is wrong (and I think the patch, too).
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
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