Messages in this thread Patch in this message | | | Date | Wed, 23 Sep 2009 09:41:10 +0800 | From | Shan Wei <> | Subject | Re: [PATCH 1/2] ipv4: fix do_ip_setsockopt optlen check for IP_MULTICAST_IF |
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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
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