[PATCH][lucid/maverick] net: ipv4: relax AF_INET check in bind()

[Herton R. Krzesinski]

From: Eric Dumazet <eric.dumazet at gmail.com>

commit d0733d2e29b65 (Check for mistakenly passed in non-IPv4 address)
added regression on legacy apps that use bind() with AF_UNSPEC family.

Relax the check, but make sure the bind() is done on INADDR_ANY
addresses, as AF_UNSPEC has probably no sane meaning for other
addresses.

Bugzilla reference : https://bugzilla.kernel.org/show_bug.cgi?id=42012

Signed-off-by: Eric Dumazet <eric.dumazet at gmail.com>
Reported-and-bisected-by: Rene Meier <r_meier at freenet.de>
CC: Marcus Meissner <meissner at suse.de>
Signed-off-by: David S. Miller <davem at davemloft.net>
BugLink: https://bugs.launchpad.net/bugs/900396
(backported from commit 29c486df6a208432b370bd4be99ae1369ede28d8 upstream)
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski at canonical.com>
---
 net/ipv4/af_inet.c |   10 ++++++++--
 1 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 5c1bdde..fb9ed6e 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -464,8 +464,14 @@ int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 	if (addr_len < sizeof(struct sockaddr_in))
 		goto out;
 
-	if (addr->sin_family != AF_INET)
-		goto out;
+	if (addr->sin_family != AF_INET) {
+		/* Compatibility games : accept AF_UNSPEC (mapped to AF_INET)
+		 * only if s_addr is INADDR_ANY.
+		 */
+		if (addr->sin_family != AF_UNSPEC ||
+		    addr->sin_addr.s_addr != htonl(INADDR_ANY))
+			goto out;
+	}
 
 	chk_addr_ret = inet_addr_type(sock_net(sk), addr->sin_addr.s_addr);
 
-- 
1.7.5.4