linux-kernel - Re: [v2 1/1] i2c: dev: prevent ZERO_SIZE_PTR deref in i2cdev_ioctl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 27 Apr 2018 14:06:58 +0200
From:   Wolfram Sang <wsa@...-dreams.de>
To:     Alexander Popov <alex.popov@...ux.com>
Cc:     Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>, linux-i2c@...r.kernel.org,
        linux-kernel@...r.kernel.org, sil2review@...ts.osadl.org,
        Dmitry Vyukov <dvyukov@...gle.com>, syzkaller@...glegroups.com
Subject: Re: [v2 1/1] i2c: dev: prevent ZERO_SIZE_PTR deref in
 i2cdev_ioctl_rdwr()

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@...ux.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 for the debugging, Alexander!


Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)