1 files changed, 67 insertions, 0 deletions
diff --git a/src/libcharon/encoding/payloads/ke_payload.c b/src/libcharon/encoding/payloads/ke_payload.c
index 4f552d6ac..644b5b6f9 100644
--- a/src/libcharon/encoding/payloads/ke_payload.c
+++ b/src/libcharon/encoding/payloads/ke_payload.c
@@ -142,6 +142,73 @@ static encoding_rule_t encodings_v1[] = {
 METHOD(payload_t, verify, status_t,
 	private_ke_payload_t *this)
 {
+	diffie_hellman_params_t *params;
+	diffie_hellman_group_t g = this->dh_group_number;
+	bool valid = TRUE;
+
+	switch (g)
+	{
+		case MODP_NONE:
+			valid = FALSE;
+			break;
+		case MODP_768_BIT:
+		case MODP_1024_BIT:
+		case MODP_1536_BIT:
+		case MODP_2048_BIT:
+		case MODP_3072_BIT:
+		case MODP_4096_BIT:
+		case MODP_6144_BIT:
+		case MODP_8192_BIT:
+		case MODP_1024_160:
+		case MODP_2048_224:
+		case MODP_2048_256:
+			params = diffie_hellman_get_params(g);
+			if (params)
+			{
+				valid = this->key_exchange_data.len == params->prime.len;
+			}
+			break;
+		case ECP_192_BIT:
+			valid = this->key_exchange_data.len == 48;
+			break;
+		case ECP_224_BIT:
+		case ECP_224_BP:
+			valid = this->key_exchange_data.len == 56;
+			break;
+		case ECP_256_BIT:
+		case ECP_256_BP:
+			valid = this->key_exchange_data.len == 64;
+			break;
+		case ECP_384_BIT:
+		case ECP_384_BP:
+			valid = this->key_exchange_data.len == 96;
+			break;
+		case ECP_512_BP:
+			valid = this->key_exchange_data.len == 128;
+			break;
+		case ECP_521_BIT:
+			valid = this->key_exchange_data.len == 132;
+			break;
+		case NTRU_112_BIT:
+		case NTRU_128_BIT:
+		case NTRU_192_BIT:
+		case NTRU_256_BIT:
+			/* NTRU public key size depends on the parameter set, but is
+			 * at least 512 bytes */
+			valid = this->key_exchange_data.len > 512;
+			break;
+		case MODP_NULL:
+		case MODP_CUSTOM:
+			break;
+		/* compile-warn unhandled groups, but accept them so we can negotiate
+		 * a different group that we support. */
+	}
+	if (!valid)
+	{
+		DBG1(DBG_ENC, "invalid KE data size (%zu bytes) for %N",
+			 this->key_exchange_data.len, diffie_hellman_group_names, g);
+		return FAILED;
+	}
 	return SUCCESS;
 }