sctp: do not check port in sctp_inet6_cmp_addr

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@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sctp/ipv6.c b/net/sctp/ipv6.c
index 31083b5035ecf6412abced7a939d8b1b8f53a302..2e3f7b75a8ece789fbbc722754200ad8505b5d64 100644 (file)
--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -556,46 +556,49 @@ 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)
 {
@@ -875,8 +878,8 @@ 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);
@@ -892,10 +895,7 @@ 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,