Subject: Re: Bug in SCTP with SCTP_BINDX_REM_ADDR

From: Paolo Galtieri <[email-masked]>
Date: Thu, 05 Apr 2007 14:08:41 -0700

Oops, the patch I sent previously was for an older 2.6 kernel.  I'm 
testing on a 2.6.10+ SCTP patches up to 2.6.17.  Here is a revised patch 
for 2.6.21:

Paolo

Signed-off-by: Paolo Galtieri <[email-masked]>

--- linux-2.6.21/net/sctp/socket.c      2007-03-26 06:58:14.000000000 -0700
+++ linux-2.6.21build/net/sctp/socket.c 2007-04-05 14:04:51.000000000 -0700
@@ -627,6 +627,12 @@ int sctp_bindx_rem(struct sock *sk, stru
                        retval = -EINVAL;
                        goto err_bindx_rem;
                }
+
+               if (!af->addr_valid(sa_addr, sp, NULL)) {
+                       retval = -EADDRNOTAVAIL;
+                       goto err_bindx_rem;
+               }
+
                if (sa_addr->v4.sin_port != htons(bp->port)) {
                        retval = -EINVAL;
                        goto err_bindx_rem;

Paolo Galtieri wrote:
> Here's the revises patch
>
> Paolo
>
> Signed-off-by: Paolo Galtieri <[email-masked]>
>
> --- net/sctp/socket.c.orig      2007-04-05 12:59:15.000000000 -0700
> +++ net/sctp/socket.c   2007-04-05 13:11:37.000000000 -0700
> @@ -627,6 +627,12 @@ int sctp_bindx_rem(struct sock *sk, stru
>                        retval = -EINVAL;
>                        goto err_bindx_rem;
>                }
> +
> +               if (!af->addr_valid(&saveaddr, sp)) {
> +                       retval = -EADDRNOTAVAIL;
> +                       goto err_bindx_rem;
> +               }
> +
>                if (sa_addr->v4.sin_port != htons(bp->port)) {
>                        retval = -EINVAL;
>                        goto err_bindx_rem;
>
>
> Vlad Yasevich wrote:
>> Hi Paolo
>>
>> Paolo Galtieri wrote:
>>> What is happening is that the check for IPV6_ADDR_MAPPED that occurs
>>> during the add is missing when you do the remove and hence the IPv6
>>> address is never mapped to the IPv4 address causing the lookup to
>>> fail.  Below is the patch to add the necessary checks to do the
>>> mapping.  This patch is against 2.6.21-rc5
>>>
>>> Does this make sense?  Any comments are appreciated.
>>>
>>
>> Yes, it makes perfect sense; however, I think you can just use
>> af->addr_valid() instead of adding a special case below.
>>
>> If that works, can you regenerate the patch and provide a
>> Signed-off-by line so I can incorporate that.
>>
>> Thanks
>> -vlad
>>
>>> Thank you,
>>> Paolo
>>>
>>> I've attached the test program - compile as gcc -o bindx-test-ipv6 
>>> bindx-test-ipv6.c -lsctp
>>> ================================ >8 
>>> ==========================================
>>> --- net/sctp/socket.c.orig      2007-04-04 13:22:59.000000000 -0700
>>> +++ net/sctp/socket.c   2007-04-04 13:25:35.000000000 -0700
>>> @@ -627,6 +627,27 @@ int sctp_bindx_rem(struct sock *sk, stru
>>>                        retval = -EINVAL;
>>>                        goto err_bindx_rem;
>>>                }
>>> +               /*
>>> +                * It's possible that we mapped an IPV6 addr to an 
>>> IPV4 addr
>>> +                * during the sctp_bindx_add() operation.  This will 
>>> happen if
>>> +                * the IPV6 address we assigned to an interface is a 
>>> mapped
>>> +                * address, e.g. ::ffff:192.0.2.128.  If we have 
>>> mapped an IPV6
>>> +                * address to an IPV4 address during the add we need 
>>> to make
>>> +                * sure we do the same thing during the remove, 
>>> otherwise we
>>> +                * wont find a match on the address_list.
>>> +                */
>>> +
>>> +               if (af->sa_family == AF_INET6) {
>>> +                       struct in6_addr *in6;
>>> +                       int type;
>>> +
>>> +                       in6 = (struct in6_addr 
>>> *)&sa_addr->v6.sin6_addr;
>>> +                       type = ipv6_addr_type(in6);
>>> +
>>> +                       if (type == IPV6_ADDR_MAPPED)
>>> +                               sctp_v6_map_v4(sa_addr);
>>> +               }
>>> +
>>>                if (sa_addr->v4.sin_port != htons(bp->port)) {
>>>                        retval = -EINVAL;
>>>                        goto err_bindx_rem;
>>>
>>>
>>
>>
> -
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