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Subject: Re: KASAN: stack-out-of-bounds Read in rds_sendmsg
To:     Eric Biggers <ebiggers3@gmail.com>
Cc:     syzkaller-bugs@googlegroups.com,
        Avinash Repaka <avinash.repaka@oracle.com>,
        syzbot 
        <bot+9461c9b9d340854a404b46c42cbfc91ded1232d8@syzkaller.appspotmail.com>,
        davem@davemloft.net, linux-kernel@vger.kernel.org,
        linux-rdma@vger.kernel.org, netdev@vger.kernel.org,
        rds-devel@oss.oracle.com
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 <20180131021638.6h5fukvzzakzu5g2@gmail.com>
From:   Santosh Shilimkar <santosh.shilimkar@oracle.com>
Organization: Oracle Corporation
Message-ID: <5db55967-3608-d9cc-768a-e75dc61ed311@oracle.com>
Date:   Tue, 30 Jan 2018 18:55:32 -0800
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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