lkml.org 
[lkml]   [2009]   [Sep]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 1/2] ipv4: fix do_ip_setsockopt optlen check for IP_MULTICAST_IF
David Miller wrote, at 09/23/2009 04:38 AM:
> From: Shan Wei <shanwei@cn.fujitsu.com>
> Date: Thu, 17 Sep 2009 17:15:22 +0800
>
>> Xiaotian Feng wrote, at 09/17/2009 01:19 PM:
>>> Due to man page of setsockopt, if optlen is not valid, kernel should return
>>> -EINVAL. But a simple testcase as following, errno is 0, which means setsockopt
>>> is successful.
>>>
>>> addr.s_addr = inet_addr("192.1.2.3");
>>> setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &addr, 1);
>>> printf("errno is %d\n", errno);
>>>
>>> This patch fixes the optlen check part, with the patch, we got errno EINVAL.
>>>
>> I also think it's a bug, the freebsd also does the optlen check.
>> But the style should be coincident with other option: firstly check the
>> availability of optlen, then copy option value from user and deal with it.
>>
>> How about this one:
>
> This definitely is better and cleaner, but please don't post such
> things without proper signoffs and commit messages because now
> I have to ask you to do that instead of me just applying your
> patch :-/
>

I'm so sorry about that. The whole patch is below.

[PATCH BUGFIX] ipv4: check optlen for IP_MULTICAST_IF option

Due to man page of setsockopt, if optlen is not valid, kernel should return
-EINVAL. But a simple testcase as following, errno is 0, which means setsockopt
is successful.
addr.s_addr = inet_addr("192.1.2.3");
setsockopt(s, IPPROTO_IP, IP_MULTICAST_IF, &addr, 1);
printf("errno is %d\n", errno);

Xiaotian Feng(dfeng@redhat.com) caught the bug. We fix it firstly checking
the availability of optlen and then dealing with the logic like other options.


Reported-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Acked-by: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
---
net/ipv4/ip_sockglue.c | 3 +++
1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index fc7993e..5a06935 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -611,6 +611,9 @@ static int do_ip_setsockopt(struct sock *sk, int level,
* Check the arguments are allowable
*/

+ if (optlen < sizeof(struct in_addr))
+ goto e_inval;
+
err = -EFAULT;
if (optlen >= sizeof(struct ip_mreqn)) {
if (copy_from_user(&mreq, optval, sizeof(mreq)))
--
1.6.0.4

\
 
 \ /
  Last update: 2009-09-23 03:43    [W:0.044 / U:0.136 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site