On Thu, Apr 12, 2018 at 02:24:31PM +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.
>
> v1->v2:
> - define __sctp_v6_cmp_addr to do the common address comparison
> used for both pf and af v6 cmp_addr.
>
> Fixes: 40b4f0fd74e4 ("sctp: lack the check for ports in sctp_v6_cmp_addr")
> Reported-by: Jianwen Ji <jiji@xxxxxxxxxx>
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> ---
> net/sctp/ipv6.c | 60 ++++++++++++++++++++++++++++-----------------------------
> 1 file changed, 30 insertions(+), 30 deletions(-)
>
> diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
> index f1fc48e..09aba03 100644
> --- a/net/sctp/ipv6.c
> +++ b/net/sctp/ipv6.c
> @@ -521,46 +521,49 @@ static void sctp_v6_to_addr(union sctp_addr *addr, struct in6_addr *saddr,
> addr->v6.sin6_scope_id = 0;
> }
>
> -/* Compare addresses exactly.
> - * v4-mapped-v6 is also in consideration.
> - */
> -static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
> - const union sctp_addr *addr2)
> +static int __sctp_v6_cmp_addr(const union sctp_addr *addr1,
> + const union sctp_addr *addr2)
> {
> 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_port == addr1->v4.sin_port &&
> - addr2->v6.sin6_addr.s6_addr32[3] ==
> - addr1->v4.sin_addr.s_addr)
> - return 1;
> - }
> + ipv6_addr_v4mapped(&addr2->v6.sin6_addr) &&
> + 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_port == addr2->v4.sin_port &&
> - addr1->v6.sin6_addr.s6_addr32[3] ==
> - addr2->v4.sin_addr.s_addr)
> - return 1;
> - }
> + ipv6_addr_v4mapped(&addr1->v6.sin6_addr) &&
> + addr1->v6.sin6_addr.s6_addr32[3] ==
> + addr2->v4.sin_addr.s_addr)
> + return 1;
> +
> return 0;
> }
> - if (addr1->v6.sin6_port != addr2->v6.sin6_port)
> - return 0;
> +
> if (!ipv6_addr_equal(&addr1->v6.sin6_addr, &addr2->v6.sin6_addr))
> return 0;
> +
> /* If this is a linklocal address, compare the scope_id. */
> - if (ipv6_addr_type(&addr1->v6.sin6_addr) & IPV6_ADDR_LINKLOCAL) {
> - if (addr1->v6.sin6_scope_id && addr2->v6.sin6_scope_id &&
> - (addr1->v6.sin6_scope_id != addr2->v6.sin6_scope_id)) {
> - 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 1;
> }
>
> +/* Compare addresses exactly.
> + * v4-mapped-v6 is also in consideration.
> + */
> +static int sctp_v6_cmp_addr(const union sctp_addr *addr1,
> + const union sctp_addr *addr2)
> +{
> + return __sctp_v6_cmp_addr(addr1, addr2) &&
> + addr1->v6.sin6_port == addr2->v6.sin6_port;
> +}
> +
> /* Initialize addr struct to INADDR_ANY. */
> static void sctp_v6_inaddr_any(union sctp_addr *addr, __be16 port)
> {
> @@ -846,8 +849,8 @@ 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 +866,7 @@ 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)
> - return 0;
> -
> - return af1->cmp_addr(addr1, addr2);
> + return __sctp_v6_cmp_addr(addr1, addr2);
> }
>
> /* Verify that the provided sockaddr looks bindable. Common verification,
> --
> 2.1.0
>
> --
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>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
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