x25: add a sanity check parsing X.25 facilities

This was found with a manual audit and I don't have a reproducer. We limit ->calling_len and ->called_len when we get them from copy_from_user() in x25_ioctl() so when they come from skb->data then we should cap them there as well. Signed-off-by: Dan Carpenter <[email protected]> Signed-off-by: David S. Miller <[email protected]>
TechNexion · Sep 4, 2013 · 80aa4e1 · 80aa4e1
1 parent cab6ce9
commit 80aa4e1
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c
@@ -156,13 +156,17 @@ int x25_parse_facilities(struct sk_buff *skb, struct x25_facilities *facilities,
 			case X25_FAC_CALLING_AE:
 				if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
 					return -1;
+				if (p[2] > X25_MAX_AE_LEN)
+					return -1;
 				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 || p[1] <= 1)
 					return -1;
+				if (p[2] > X25_MAX_AE_LEN)
+					return -1;
 				dte_facs->called_len = p[2];
 				memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
 				*vc_fac_mask |= X25_MASK_CALLED_AE;