memory corruption in X.25 facilities parsing

commit a6331d6f upstream.
Signed-of-by: Andrew Hendry <andrew.hendry@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

net/x25/x25_facilities.c

@@ -134,15 +134,15 @@ int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
 		case X25_FAC_CLASS_D:
 			switch (*p) {
 			case X25_FAC_CALLING_AE:
-				if (p[1] > X25_MAX_DTE_FACIL_LEN)
-					break;
+				if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
+					return 0;
 				dte_facs->calling_len = p[2];
 				memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
 				*vc_fac_mask |= X25_MASK_CALLING_AE;
 				break;
 			case X25_FAC_CALLED_AE:
-				if (p[1] > X25_MAX_DTE_FACIL_LEN)
-					break;
+				if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
+					return 0;
 				dte_facs->called_len = p[2];
 				memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
 				*vc_fac_mask |= X25_MASK_CALLED_AE;

net/x25/x25_in.c

@@ -118,6 +118,8 @@ static int x25_state1_machine(struct sock *sk, struct sk_buff *skb, int frametyp
 						&x25->vc_facil_mask);
 			if (len > 0)
 				skb_pull(skb, len);
+			else
+				return -1;
 			/*
 			 *	Copy any Call User Data.
 			 */