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SubjectRe: [PATCH] rds: Error on offset mismatch if not loopback
On Wed, Nov 13, 2013 at 6:55 PM, Honggang LI <> wrote:
> On 11/14/2013 01:40 AM, Josh Hunt wrote:
>> On Wed, Nov 13, 2013 at 9:16 AM, Venkat Venkatsubra
>> <> wrote:
>>> -----Original Message-----
>>> From: Josh Hunt []
>>> Sent: Tuesday, November 12, 2013 10:25 PM
>>> To: David Miller
>>> Cc:; LKML; Venkat Venkatsubra;
>>> Subject: Re: [PATCH] rds: Error on offset mismatch if not loopback
>>> On Tue, Nov 12, 2013 at 10:22 PM, Josh Hunt <> wrote:
>>>> On Sat, Sep 22, 2012 at 2:25 PM, David Miller <> wrote:
>>>>> From: John Jolly <>
>>>>> Date: Fri, 21 Sep 2012 15:32:40 -0600
>>>>>> Attempting an rds connection from the IP address of an IPoIB
>>>>>> interface to itself causes a kernel panic due to a BUG_ON() being triggered.
>>>>>> Making the test less strict allows rds-ping to work without
>>>>>> crashing the machine.
>>>>>> A local unprivileged user could use this flaw to crash the system.
>>>>>> Signed-off-by: John Jolly <>
>>>>> Besides the questions being asked of you by Venkat Venkatsubra, this
>>>>> patch has another issue.
>>>>> It has been completely corrupted by your email client, it has turned
>>>>> all TAB characters into spaces, making the patch useless.
>>>>> Please learn how to send a patch unmolested in the body of your
>>>>> email. Test it by emailing the patch to yourself, and verifying that
>>>>> you can in fact apply the patch you receive in that email.
>>>>> Then, and only then, should you consider making a new submission of
>>>>> this patch.
>>>>> Use Documentation/email-clients.txt for guidance.
>>>>> --
>>>>> To unsubscribe from this list: send the line "unsubscribe
>>>>> linux-kernel" in the body of a message to
>>>>> More majordomo info at
>>>>> Please read the FAQ at
>>>> I think this issue was lost in the shuffle. It appears that redhat,
>>>> ubuntu, and oracle are maintaining local patches to resolve this:
>>>> 2be130fa15fa8be10d4704e8
>>>> 88.html
>>>> Given that Oracle has applied it I'll make the assumption that
>>>> Venkat's question was answered at some point.
>>>> David - I can resubmit the patch with the proper signed-off-by and
>>>> formatting if you are willing to apply it unless John wants to try
>>>> again. I think it's time this got upstream.
>>>> --
>>>> Josh
>>> Ugh.. hopefully resending with all the html crap removed...
>>> --
>>> Josh
>>> Hi Josh,
>>> No, I still didn't get an answer for how "off" could be non-zero in case of rds-ping to hit BUG_ON(off % RDS_FRAG_SIZE).
>>> Because, rds-ping uses zero byte messages to ping.
>>> If you have a test case that reproduces the kernel panic I can try it out and see how that can happen.
>>> The Oracle's internal code I checked doesn't have that patch applied.
>>> Venkat
>> No I don't have a test case. I came across this CVE while doing an
>> audit and noticed it was patched in Ubuntu's kernel and other distros,
>> but was not in the upstream kernel yet. Quick googling of lkml showed
>> that there were at least two attempts to get this patch upstream, but
>> both had issues due to not following the proper submission process:
>> From my searching it appears the initial bug was found by someone at redhat:
>> I've added Li Honggang the reporter of this issue from Redhat to the
>> mail. Hopefully he can share his testcase.
> The test case is very simple:
> Steps to Reproduce:
> 1. yum install -y rds-tools
> 2. [root@rdma3 ~]# ifconfig ib0 | grep 'inet addr'
> inet addr: Bcast: Mask:
> 3. [root@rdma3 ~]# /usr/bin/rds-ping <<<< kernel panic (You
> may need to wait for a few seconds before the kernel panic.)
>> and possibly requires certain hardware as Jay writes in the first link above:
>> "...some Infiniband HCAs(QLogic, possibly others) the machine will panic..."
> This bug can be reproduced with Mellanox HCAs (mlx4_ib.ko and mthca.ko),
> QLogic HCA (ib_qib.ko). I did not test the QLogic HCA running "ib_ipath.ko".
> As I know the upstream code of RDS is broken. There are *many* RDS bugs.
> Best regards.
> Honggang

Thanks Honggang. I have resubmitted the patch for approval.


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