[patch 13/16] sctp: add verification checks to SCTP_AUTH_KEY option

[Greg KH <gregkh@suse.de>]

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2.6.25-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Vlad Yasevich <vladislav.yasevich@hp.com>

[ Upstream commit 30c2235cbc477d4629983d440cdc4f496fec9246 ]

The structure used for SCTP_AUTH_KEY option contains a
length that needs to be verfied to prevent buffer overflow
conditions.  Spoted by Eugene Teo <eteo@redhat.com>.

Signed-off-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
 net/sctp/auth.c   |    4 ++++
 net/sctp/socket.c |    5 +++++
 2 files changed, 9 insertions(+)

--- a/net/sctp/auth.c
+++ b/net/sctp/auth.c
@@ -80,6 +80,10 @@ static struct sctp_auth_bytes *sctp_auth
 {
 	struct sctp_auth_bytes *key;
 
+	/* Verify that we are not going to overflow INT_MAX */
+	if ((INT_MAX - key_len) < sizeof(struct sctp_auth_bytes))
+		return NULL;
+
 	/* Allocate the shared key */
 	key = kmalloc(sizeof(struct sctp_auth_bytes) + key_len, gfp);
 	if (!key)
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -3072,6 +3072,11 @@ static int sctp_setsockopt_auth_key(stru
 		goto out;
 	}
 
+	if (authkey->sca_keylength > optlen) {
+		ret = -EINVAL;
+		goto out;
+	}
+
 	asoc = sctp_id2assoc(sk, authkey->sca_assoc_id);
 	if (!asoc && authkey->sca_assoc_id && sctp_style(sk, UDP)) {
 		ret = -EINVAL;

--