From db54db11aec763b6fc74715c36e0f9de0d65e206 Mon Sep 17 00:00:00 2001
From: Jouni Malinen <jouni@codeaurora.org>
Date: Mon, 8 Apr 2019 18:01:07 +0300
Subject: SAE: Reject unsuitable groups based on REVmd changes

The rules defining which DH groups are suitable for SAE use were
accepted into IEEE 802.11 REVmd based on this document:
https://mentor.ieee.org/802.11/dcn/19/11-19-0387-02-000m-addressing-some-sae-comments.docx

Enforce those rules in production builds of wpa_supplicant and hostapd.
CONFIG_TESTING_OPTIONS=y builds can still be used to select any o the
implemented groups to maintain testing coverage.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>

---
 src/common/sae.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/common/sae.c b/src/common/sae.c
index e155a71..91b6b41 100644
--- a/src/common/sae.c
+++ b/src/common/sae.c
@@ -17,11 +17,32 @@
 #include "ieee802_11_defs.h"
 #include "sae.h"
 
+static int sae_suitable_group(int group)
+{
+#ifdef CONFIG_TESTING_OPTIONS
+	/* Allow all groups for testing purposes in non-production builds. */
+	return 1;
+#else /* CONFIG_TESTING_OPTIONS */
+	/* Enforce REVmd rules on which SAE groups are suitable for production
+	 * purposes: FFC groups whose prime is >= 3072 bits and ECC groups
+	 * defined over a prime field whose prime is >= 256 bits. Furthermore,
+	 * ECC groups defined over a characteristic 2 finite field and ECC
+	 * groups with a co-factor greater than 1 are not suitable. */
+	return group == 19 || group == 20 || group == 21 ||
+		group == 28 || group == 29 || group == 30 ||
+		group == 15 || group == 16 || group == 17 || group == 18;
+#endif /* CONFIG_TESTING_OPTIONS */
+}
 
 int sae_set_group(struct sae_data *sae, int group)
 {
 	struct sae_temporary_data *tmp;
 
+	if (!sae_suitable_group(group)) {
+		wpa_printf(MSG_DEBUG, "SAE: Reject unsuitable group %d", group);
+		return -1;
+	}
+
 	sae_clear_data(sae);
 	tmp = sae->tmp = os_zalloc(sizeof(*tmp));
 	if (tmp == NULL)
-- 
2.23.0

