Re: [PATCH v1 net 1/2] tcp: Fix bind() conflict check for dual-stack wildcard address.

[Martin KaFai Lau <martin.lau@linux.dev>]

On 3/11/23 7:19 PM, Kuniyuki Iwashima wrote:
> Paul Holzinger reported [0] that commit 5456262d2baa ("net: Fix
> incorrect address comparison when searching for a bind2 bucket")
> introduced a bind() regression.  Paul also gave a nice repro that
> calls two types of bind() on the same port, both of which now
> succeed, but the second call should fail:
> 
>    bind(fd1, ::, port) + bind(fd2, 127.0.0.1, port)
> 
> The cited commit added address family tests in three functions to
> fix the uninit-value KMSAN report. [1]  However, the test added to
> inet_bind2_bucket_match_addr_any() removed a necessary conflict
> check; the dual-stack wildcard address no longer conflicts with
> an IPv4 non-wildcard address.
> 
> If tb->family is AF_INET6 and sk->sk_family is AF_INET in
> inet_bind2_bucket_match_addr_any(), we still need to check
> if tb has the dual-stack wildcard address.
> 
> Note that the IPv4 wildcard address does not conflict with
> IPv6 non-wildcard addresses.
> 
> [0]: https://lore.kernel.org/netdev/e21bf153-80b0-9ec0-15ba-e04a4ad42c34@redhat.com/
> [1]: https://lore.kernel.org/netdev/CAG_fn=Ud3zSW7AZWXc+asfMhZVL5ETnvuY44Pmyv4NPv-ijN-A@mail.gmail.com/
> 
> Fixes: 5456262d2baa ("net: Fix incorrect address comparison when searching for a bind2 bucket")
> Reported-by: Paul Holzinger <pholzing@redhat.com>
> Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>

Thanks for the fix.

Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>