On Wed, Apr 11, 2018 at 08:58:05PM +0800, Xin Long wrote:
> pf->cmp_addr() is called before binding a v6 address to the sock. It
> should not check ports, like in sctp_inet_cmp_addr.
>
> But sctp_inet6_cmp_addr checks the addr by invoking af(6)->cmp_addr,
> sctp_v6_cmp_addr where it also compares the ports.
>
> This would cause that setsockopt(SCTP_SOCKOPT_BINDX_ADD) could bind
> multiple duplicated IPv6 addresses after Commit 40b4f0fd74e4 ("sctp:
> lack the check for ports in sctp_v6_cmp_addr").
>
> This patch is to remove af->cmp_addr called in sctp_inet6_cmp_addr,
> but do the proper check for both v6 addrs and v4mapped addrs.
>
> Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in sctp_v6_cmp_addr")
> Reported-by: Jianwen Ji <j...@redhat.com>
> Signed-off-by: Xin Long <lucien....@gmail.com>
> ---
> net/sctp/ipv6.c | 27 ++++++++++++++++++++++++---
> 1 file changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index f1fc48e..be4b72c 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -846,8 +846,8 @@ static int sctp_inet6_cmp_addr(const union sctp_addr
> *addr1,
> const union sctp_addr *addr2,
> struct sctp_sock *opt)
> {
> - struct sctp_af *af1, *af2;
> struct sock *sk = sctp_opt2sk(opt);
> + struct sctp_af *af1, *af2;
>
> af1 = sctp_get_af_specific(addr1->sa.sa_family);
> af2 = sctp_get_af_specific(addr2->sa.sa_family);
> @@ -863,10 +863,31 @@ static int sctp_inet6_cmp_addr(const union sctp_addr
> *addr1,
> if (sctp_is_any(sk, addr1) || sctp_is_any(sk, addr2))
> return 1;
>
> - if (addr1->sa.sa_family != addr2->sa.sa_family)
> + if (addr1->sa.sa_family != addr2->sa.sa_family) {
> + if (addr1->sa.sa_family == AF_INET &&
> + addr2->sa.sa_family == AF_INET6 &&
> + ipv6_addr_v4mapped(&addr2->v6.sin6_addr))
> + if (addr2->v6.sin6_addr.s6_addr32[3] ==
> + addr1->v4.sin_addr.s_addr)
> + return 1;
> + if (addr2->sa.sa_family == AF_INET &&
> + addr1->sa.sa_family == AF_INET6 &&
> + ipv6_addr_v4mapped(&addr1->v6.sin6_addr))
> + if (addr1->v6.sin6_addr.s6_addr32[3] ==
> + addr2->v4.sin_addr.s_addr)
> + return 1;
> + return 0;
> + }
> +
> + if (!ipv6_addr_equal(&addr1->v6.sin6_addr, &addr2->v6.sin6_addr))
> + return 0;
> +
> + if ((ipv6_addr_type(&addr1->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) &&
> + addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
> + addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)
> return 0;
>
> - return af1->cmp_addr(addr1, addr2);
> + return 1;
> }
>
> /* Verify that the provided sockaddr looks bindable. Common verification,
> --
> 2.1.0
>
This looks correct to me, but is it worth duplicating the comparison code like
this from the cmp_addr function? It might be more worthwhile to add a flag to
the cmp_addr method to direct weather it needs to check port values or not.
That way you could continue to use the cmp_addr function here.
Neil
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