Subject: Re: [PATCH net-next] rtnetlink: Fix null-ptr-deref in rtnl_newlink

From: Ido Schimmel <[email-masked]>
Date: Fri, 1 Jun 2018 16:03:18 +0300

On Fri, Jun 01, 2018 at 05:16:58PM +0900, Prashant Bhole wrote:
> In rtnl_newlink(), NULL check is performed on m_ops however member of
> ops is accessed. Fixed by accessing member of m_ops instead of ops.
> 
> [  345.432629] BUG: KASAN: null-ptr-deref in rtnl_newlink+0x400/0x1110
> [  345.432629] Read of size 4 at addr 0000000000000088 by task ip/986
> [  345.432629]
> [  345.432629] CPU: 1 PID: 986 Comm: ip Not tainted 4.17.0-rc6+ #9
> [  345.432629] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
> [  345.432629] Call Trace:
> [  345.432629]  dump_stack+0xc6/0x150
> [  345.432629]  ? dump_stack_print_info.cold.0+0x1b/0x1b
> [  345.432629]  ? kasan_report+0xb4/0x410
> [  345.432629]  kasan_report.cold.4+0x8f/0x91
> [  345.432629]  ? rtnl_newlink+0x400/0x1110
> [  345.432629]  rtnl_newlink+0x400/0x1110
> [...]
> 
> Fixes: ccf8dbcd062a ("rtnetlink: Remove VLA usage")
> Signed-off-by: Prashant Bhole <[email-masked]>

My machine crashed while running regression tests. Thanks for fixing!

Tested-by: Ido Schimmel <[email-masked]>