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Message-ID: <41aa904c-6707-4c74-ae72-96e401c68e13@default>
Date: Thu, 14 Nov 2013 05:43:28 -0800 (PST)
From: Venkat Venkatsubra <venkat.x.venkatsubra@...cle.com>
To: Honggang LI <honli@...hat.com>, Josh Hunt <joshhunt00@...il.com>
Cc: David Miller <davem@...emloft.net>, jjolly@...e.com,
LKML <linux-kernel@...r.kernel.org>, netdev@...r.kernel.org
Subject: RE: [PATCH] rds: Error on offset mismatch if not loopback
-----Original Message-----
From: Honggang LI [mailto:honli@...hat.com]
Sent: Wednesday, November 13, 2013 6:56 PM
To: Josh Hunt; Venkat Venkatsubra
Cc: David Miller; jjolly@...e.com; LKML; netdev@...r.kernel.org
Subject: Re: [PATCH] rds: Error on offset mismatch if not loopback
On 11/14/2013 01:40 AM, Josh Hunt wrote:
> On Wed, Nov 13, 2013 at 9:16 AM, Venkat Venkatsubra
> <venkat.x.venkatsubra@...cle.com> wrote:
>>
>> -----Original Message-----
>> From: Josh Hunt [mailto:joshhunt00@...il.com]
>> Sent: Tuesday, November 12, 2013 10:25 PM
>> To: David Miller
>> Cc: jjolly@...e.com; LKML; Venkat Venkatsubra; netdev@...r.kernel.org
>> Subject: Re: [PATCH] rds: Error on offset mismatch if not loopback
>>
>> On Tue, Nov 12, 2013 at 10:22 PM, Josh Hunt <joshhunt00@...il.com> wrote:
>>> On Sat, Sep 22, 2012 at 2:25 PM, David Miller <davem@...emloft.net> wrote:
>>>> From: John Jolly <jjolly@...e.com>
>>>> 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 <jjolly@...e.com>
>>>> 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 majordomo@...r.kernel.org
>>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>>> Please read the FAQ at http://www.tux.org/lkml/
>>>
>>> I think this issue was lost in the shuffle. It appears that redhat,
>>> ubuntu, and oracle are maintaining local patches to resolve this:
>>>
>>> https://oss.oracle.com/git/?p=redpatch.git;a=commit;h=c7b6a0a1d8d636
>>> 85
>>> 2be130fa15fa8be10d4704e8
>>> https://bugzilla.redhat.com/show_bug.cgi?id=822754
>>> http://ubuntu.5.x6.nabble.com/CVE-2012-2372-RDS-local-ping-DOS-td498
>>> 53
>>> 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:
>
> https://lkml.org/lkml/2012/10/22/433
> https://lkml.org/lkml/2012/9/21/505
>
> From my searching it appears the initial bug was found by someone at redhat:
> https://bugzilla.redhat.com/show_bug.cgi?id=822754
>
> 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@...a3 ~]# ifconfig ib0 | grep 'inet addr'
inet addr:172.31.0.3 Bcast:172.31.0.255 Mask:255.255.255.0
3. [root@...a3 ~]# /usr/bin/rds-ping 172.31.0.3 <<<< 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
>
> I was referring to this oracle commit:
> https://oss.oracle.com/git/?p=redpatch.git;a=commit;h=c7b6a0a1d8d63685
> 2be130fa15fa8be10d4704e8
>
> I have no experience with this code. There were a few comments around
> the reset and xmit fns about making sure the caller did certain things
> if not they were racy, but I have no idea if that's coming into play
> here.
>
Hi Honggang,
I ran rds-ping over local interface for 30 minutes. I stopped it after that.
It didn't hit any panic.
# ip addr show dev ib0
6: ib0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 2044 qdisc pfifo_fast qlen 1024
link/infiniband 80:00:00:48:fe:80:00:00:00:00:00:00:00:21:28:00:01:cf:63:db brd 00:ff:ff:ff:ff:12:40:1b:ff:ff:00:00:00:00:00:00:ff:ff:ff:ff
inet 10.196.4.125/30 brd 10.196.4.127 scope global ib0
inet6 fe80::221:2800:1cf:63db/64 scope link
valid_lft forever preferred_lft forever
#
# rds-ping 10.196.4.125
1: 170 usec
2: 171 usec
....
....
....
1860: 173 usec
1861: 171 usec
1862: 177 usec
1863: 168 usec
1864: 171 usec
1865: 175 usec
^C#
I tested with Oracle UEK2 which is based on 2.6.39 kernel. Mellanox IB adaptor.
19:00.0 InfiniBand: Mellanox Technologies MT26428 [ConnectX VPI PCIe 2.0 5GT/s - IB QDR / 10GigE] (rev b0)
There is something about your setup that must be causing it for you.
Can I work with you offline if you are available ?
The panic you are hitting is not making sense to me.
Venkat
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