EAP-IKEv2: Make proposal_len validation clearer

Some static analyzers seem to have issues understanding "pos +
proposal_len > end" style validation, so convert this to "proposal_len >
end - pos" to make this more obvious to be bounds checking for
proposal_len. (CID 62874)

Signed-off-by: Jouni Malinen <j@w1.fi>

diff --git a/src/eap_peer/ikev2.c b/src/eap_peer/ikev2.c
index 8186afb53e299d05263aa524832fd9ea2f86e732..e6a173ec14394755231bd0776ad46e464d72354f 100644 (file)
--- a/src/eap_peer/ikev2.c
+++ b/src/eap_peer/ikev2.c
@@ -213,7 +213,7 @@ static int ikev2_parse_proposal(struct ikev2_proposal_data *prop,
 
        p = (const struct ikev2_proposal *) pos;
        proposal_len = WPA_GET_BE16(p->proposal_length);
-       if (proposal_len < (int) sizeof(*p) || pos + proposal_len > end) {
+       if (proposal_len < (int) sizeof(*p) || proposal_len > end - pos) {
                wpa_printf(MSG_INFO, "IKEV2: Invalid proposal length %d",
                           proposal_len);
                return -1;