[v2,03/10] ap: add profile settings PairwiseCiphers/GroupCipher

Commit Message

James Prestwood Nov. 2, 2022, 8:53 p.m. UTC

These can now be optionally provided in an AP profile and provide a
way to limit what ciphers can be chosen. This still is dependent on
what the hardware supports.
---
 src/ap.c | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 83 insertions(+), 6 deletions(-)

Patch

diff --git a/src/ap.c b/src/ap.c
index ba827728..341a1662 100644
--- a/src/ap.c
+++ b/src/ap.c
@@ -3132,12 +3132,38 @@  static bool ap_load_psk(struct ap_state *ap, const struct l_settings *config)
 	return true;
 }
 
+/*
+ * Note: only PTK/GTK ciphers are supported here since this is all these are
+ *       used for.
+ */
+static enum ie_rsn_cipher_suite ap_string_to_cipher(const char *str)
+{
+	if (!strcmp(str, "UseGroupCipher"))
+		return IE_RSN_CIPHER_SUITE_USE_GROUP_CIPHER;
+	else if (!strcmp(str, "TKIP"))
+		return IE_RSN_CIPHER_SUITE_TKIP;
+	else if (!strcmp(str, "CCMP-128") || !strcmp(str, "CCMP"))
+		return IE_RSN_CIPHER_SUITE_CCMP;
+	else if (!strcmp(str, "GCMP-128") || !strcmp(str, "GCMP"))
+		return IE_RSN_CIPHER_SUITE_GCMP;
+	else if (!strcmp(str, "GCMP-256"))
+		return IE_RSN_CIPHER_SUITE_GCMP_256;
+	else if (!strcmp(str, "CCMP-256"))
+		return IE_RSN_CIPHER_SUITE_CCMP_256;
+	else
+		return 0;
+}
+
 static int ap_load_config(struct ap_state *ap, const struct l_settings *config,
 				bool *out_cck_rates)
 {
+	struct wiphy *wiphy = netdev_get_wiphy(ap->netdev);
 	size_t len;
 	L_AUTO_FREE_VAR(char *, strval) = NULL;
+	_auto_(l_strv_free) char **ciphers_str;
+	uint16_t cipher_mask;
 	int err;
+	int i;
 
 	strval = l_settings_get_string(config, "General", "SSID");
 	if (L_WARN_ON(!strval))
@@ -3212,6 +3238,8 @@  static int ap_load_config(struct ap_state *ap, const struct l_settings *config,
 			l_error("AP [WSC].PrimaryDeviceType format unknown");
 			return -EINVAL;
 		}
+
+		l_free(l_steal_ptr(strval));
 	} else {
 		/* Make ourselves a WFA standard PC by default */
 		ap->wsc_primary_device_type.category = 1;
@@ -3260,6 +3288,61 @@  static int ap_load_config(struct ap_state *ap, const struct l_settings *config,
 	} else
 		*out_cck_rates = true;
 
+	cipher_mask = wiphy_get_supported_ciphers(wiphy, IE_GROUP_CIPHERS);
+
+	/* If the config sets a group cipher use that directly */
+	strval = l_settings_get_string(config, "Security", "GroupCipher");
+	if (strval) {
+		enum ie_rsn_cipher_suite cipher = ap_string_to_cipher(strval);
+
+		if (!cipher || !(cipher & cipher_mask)) {
+			l_error("Unsupported or unknown group cipher %s",
+					strval);
+			return -ENOTSUP;
+		}
+
+		ap->group_cipher = cipher;
+		l_free(l_steal_ptr(strval));
+	} else {
+		/* No config override, use CCMP (or TKIP if not supported) */
+		if (cipher_mask & IE_RSN_CIPHER_SUITE_CCMP)
+			ap->group_cipher = IE_RSN_CIPHER_SUITE_CCMP;
+		else
+			ap->group_cipher = IE_RSN_CIPHER_SUITE_TKIP;
+	}
+
+	cipher_mask = wiphy_get_supported_ciphers(wiphy, IE_PAIRWISE_CIPHERS);
+
+	ciphers_str = l_settings_get_string_list(config, "Security",
+						"PairwiseCiphers", ',');
+	for (i = 0; ciphers_str && ciphers_str[i]; i++) {
+		enum ie_rsn_cipher_suite cipher =
+					ap_string_to_cipher(ciphers_str[i]);
+
+		/*
+		 * Constrain list to only values in both supported ciphers and
+		 * the cipher list provided.
+		 */
+		if (!cipher || !(cipher & cipher_mask)) {
+			l_error("Unsupported or unknown pairwise cipher %s",
+					ciphers_str[i]);
+			return -ENOTSUP;
+		}
+
+		ap->ciphers |= cipher;
+	}
+
+	if (!ap->ciphers) {
+		/*
+		 * Default behavior if no ciphers are specified, disable TKIP
+		 * for security if CCMP is available
+		 */
+		if (cipher_mask & IE_RSN_CIPHER_SUITE_CCMP)
+			cipher_mask &= ~IE_RSN_CIPHER_SUITE_TKIP;
+
+		ap->ciphers = cipher_mask;
+	}
+
 	return 0;
 }
 
@@ -3302,12 +3385,6 @@  struct ap_state *ap_start(struct netdev *netdev, struct l_settings *config,
 
 	err = -EINVAL;
 
-	/* TODO: Add all ciphers supported by wiphy */
-	ap->ciphers = wiphy_select_cipher(wiphy, IE_RSN_CIPHER_SUITE_TKIP |
-						IE_RSN_CIPHER_SUITE_CCMP);
-	ap->group_cipher = wiphy_select_cipher(wiphy,
-						IE_RSN_CIPHER_SUITE_TKIP |
-						IE_RSN_CIPHER_SUITE_CCMP);
 	ap->beacon_interval = 100;
 	ap->networks = l_queue_new();