Re: KASAN: stack-out-of-bounds Read in rds_sendmsg

[Santosh Shilimkar]

On 1/30/2018 6:16 PM, Eric Biggers wrote:
> On Thu, Dec 21, 2017 at 08:44:32AM -0800, Santosh Shilimkar wrote:
> > +Avinash
> >
> > On 12/21/2017 1:10 AM, syzbot wrote:
> > > syzkaller has found reproducer for the following crash on
> >
> > [..]
> >
> > > audit: type=1400 audit(1513847224.110:7): avc: denied { map } for
> > > pid=3157 comm="syzkaller455006" path="/root/syzkaller455006870"
> > > dev="sda1" ino=16481
> > > scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
> > > tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
> > > ==================================================================
> > > BUG: KASAN: stack-out-of-bounds in rds_rdma_bytes net/rds/send.c:1013
> > > [inline]
> >
> > Could you please post the discussed fix if you are ready with it ?
> > This new report is same as last one and cmesg length check should
> > address it.

[...]

> This crash seems to have stopped occurring.  I assume it was fixed by commit
> 14e138a86f63 (thanks Avinash!), so let's tell syzbot so that it can start
> reporting crashes in the same place again:
>
> #syz fix: RDS: Check cmsg_len before dereferencing CMSG_DATA
Thanks Eric for confirmation !!

Regards,
Santosh