[PATCH 132/139] sock_diag: Fix out-of-bounds access to sock_diag_handlers[]

[Luis Henriques]

3.5.7.7 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mathias Krause <minipli@xxxxxxxxxxxxxx>

commit 6e601a53566d84e1ffd25e7b6fe0b6894ffd79c0 upstream.

Userland can send a netlink message requesting SOCK_DIAG_BY_FAMILY
with a family greater or equal then AF_MAX -- the array size of
sock_diag_handlers[]. The current code does not test for this
condition therefore is vulnerable to an out-of-bound access opening
doors for a privilege escalation.

Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 net/core/sock_diag.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/sock_diag.c b/net/core/sock_diag.c
index 5fd1467..964a92c 100644
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
@@ -126,6 +126,9 @@ static int __sock_diag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 	if (nlmsg_len(nlh) < sizeof(*req))
 		return -EINVAL;
 
+	if (req->sdiag_family >= AF_MAX)
+		return -EINVAL;
+
 	hndl = sock_diag_lock_handler(req->sdiag_family);
 	if (hndl == NULL)
 		err = -ENOENT;
-- 
1.8.1.2

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