Messages in this thread Patch in this message | | | Date | Thu, 17 Sep 2009 17:15:22 +0800 | From | Shan Wei <> | Subject | Re: [PATCH 1/2] ipv4: fix do_ip_setsockopt optlen check for IP_MULTICAST_IF |
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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:
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)))
Best Regards ----- Shan Wei
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