[PATCH 3.16 143/366] sctp: do not check port in sctp_inet6_cmp_addr

Ben Hutchings
2018-10-14T23:23:31Z

From: Xin Long <lucien.xin@gmail.com>

commit 1071ec9d453a38023579714b64a951a2fb982071 upstream.

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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
net/sctp/ipv6.c | 60 ++++++++++++++++++++++++-------------------------
1 file changed, 30 insertions(+), 30 deletions(-)

--- a/net/sctp/ipv6.c
+++ b/net/sctp/ipv6.c
@@ -496,46 +496,49 @@ static void sctp_v6_to_addr(union sctp_a
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)
{
@@ -820,8 +823,8 @@ static int sctp_inet6_cmp_addr(const uni
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);
@@ -837,10 +840,7 @@ static int sctp_inet6_cmp_addr(const uni
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,