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-rw-r--r--main/hostapd/0013-EAP-pwd-Check-element-x-y-coordinates-explicitly.patch331
1 files changed, 331 insertions, 0 deletions
diff --git a/main/hostapd/0013-EAP-pwd-Check-element-x-y-coordinates-explicitly.patch b/main/hostapd/0013-EAP-pwd-Check-element-x-y-coordinates-explicitly.patch
new file mode 100644
index 0000000000..daea13e21a
--- /dev/null
+++ b/main/hostapd/0013-EAP-pwd-Check-element-x-y-coordinates-explicitly.patch
@@ -0,0 +1,331 @@
+From 16d4f1069118aa19bfce013493e1ac5783f92f1d Mon Sep 17 00:00:00 2001
+From: Jouni Malinen <jouni@codeaurora.org>
+Date: Fri, 5 Apr 2019 02:12:50 +0300
+Subject: [PATCH] EAP-pwd: Check element x,y coordinates explicitly
+
+This adds an explicit check for 0 < x,y < prime based on RFC 5931,
+2.8.5.2.2 requirement. The earlier checks might have covered this
+implicitly, but it is safer to avoid any dependency on implicit checks
+and specific crypto library behavior. (CVE-2019-9498 and CVE-2019-9499)
+
+Furthermore, this moves the EAP-pwd element and scalar parsing and
+validation steps into shared helper functions so that there is no need
+to maintain two separate copies of this common functionality between the
+server and peer implementations.
+
+Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
+---
+ src/eap_common/eap_pwd_common.c | 106 ++++++++++++++++++++++++++++++++
+ src/eap_common/eap_pwd_common.h | 3 +
+ src/eap_peer/eap_pwd.c | 45 ++------------
+ src/eap_server/eap_server_pwd.c | 45 ++------------
+ 4 files changed, 117 insertions(+), 82 deletions(-)
+
+diff --git a/src/eap_common/eap_pwd_common.c b/src/eap_common/eap_pwd_common.c
+index e49aaf8c7..c28b56d62 100644
+--- a/src/eap_common/eap_pwd_common.c
++++ b/src/eap_common/eap_pwd_common.c
+@@ -428,3 +428,109 @@ int compute_keys(EAP_PWD_group *grp, const struct crypto_bignum *k,
+
+ return 1;
+ }
++
++
++static int eap_pwd_element_coord_ok(const struct crypto_bignum *prime,
++ const u8 *buf, size_t len)
++{
++ struct crypto_bignum *val;
++ int ok = 1;
++
++ val = crypto_bignum_init_set(buf, len);
++ if (!val || crypto_bignum_is_zero(val) ||
++ crypto_bignum_cmp(val, prime) >= 0)
++ ok = 0;
++ crypto_bignum_deinit(val, 0);
++ return ok;
++}
++
++
++struct crypto_ec_point * eap_pwd_get_element(EAP_PWD_group *group,
++ const u8 *buf)
++{
++ struct crypto_ec_point *element;
++ const struct crypto_bignum *prime;
++ size_t prime_len;
++ struct crypto_bignum *cofactor = NULL;
++
++ prime = crypto_ec_get_prime(group->group);
++ prime_len = crypto_ec_prime_len(group->group);
++
++ /* RFC 5931, 2.8.5.2.2: 0 < x,y < p */
++ if (!eap_pwd_element_coord_ok(prime, buf, prime_len) ||
++ !eap_pwd_element_coord_ok(prime, buf + prime_len, prime_len)) {
++ wpa_printf(MSG_INFO, "EAP-pwd: Invalid coordinate in element");
++ return NULL;
++ }
++
++ element = crypto_ec_point_from_bin(group->group, buf);
++ if (!element) {
++ wpa_printf(MSG_INFO, "EAP-pwd: EC point from element failed");
++ return NULL;
++ }
++
++ /* RFC 5931, 2.8.5.2.2: on curve and not the point at infinity */
++ if (!crypto_ec_point_is_on_curve(group->group, element) ||
++ crypto_ec_point_is_at_infinity(group->group, element)) {
++ wpa_printf(MSG_INFO, "EAP-pwd: Invalid element");
++ goto fail;
++ }
++
++ cofactor = crypto_bignum_init();
++ if (!cofactor || crypto_ec_cofactor(group->group, cofactor) < 0) {
++ wpa_printf(MSG_INFO,
++ "EAP-pwd: Unable to get cofactor for curve");
++ goto fail;
++ }
++
++ if (!crypto_bignum_is_one(cofactor)) {
++ struct crypto_ec_point *point;
++ int ok = 1;
++
++ /* check to ensure peer's element is not in a small sub-group */
++ point = crypto_ec_point_init(group->group);
++ if (!point ||
++ crypto_ec_point_mul(group->group, element,
++ cofactor, point) != 0 ||
++ crypto_ec_point_is_at_infinity(group->group, point))
++ ok = 0;
++ crypto_ec_point_deinit(point, 0);
++
++ if (!ok) {
++ wpa_printf(MSG_INFO,
++ "EAP-pwd: Small sub-group check on peer element failed");
++ goto fail;
++ }
++ }
++
++out:
++ crypto_bignum_deinit(cofactor, 0);
++ return element;
++fail:
++ crypto_ec_point_deinit(element, 0);
++ element = NULL;
++ goto out;
++}
++
++
++struct crypto_bignum * eap_pwd_get_scalar(EAP_PWD_group *group, const u8 *buf)
++{
++ struct crypto_bignum *scalar;
++ const struct crypto_bignum *order;
++ size_t order_len;
++
++ order = crypto_ec_get_order(group->group);
++ order_len = crypto_ec_order_len(group->group);
++
++ /* RFC 5931, 2.8.5.2: 1 < scalar < r */
++ scalar = crypto_bignum_init_set(buf, order_len);
++ if (!scalar || crypto_bignum_is_zero(scalar) ||
++ crypto_bignum_is_one(scalar) ||
++ crypto_bignum_cmp(scalar, order) >= 0) {
++ wpa_printf(MSG_INFO, "EAP-pwd: received scalar is invalid");
++ crypto_bignum_deinit(scalar, 0);
++ scalar = NULL;
++ }
++
++ return scalar;
++}
+diff --git a/src/eap_common/eap_pwd_common.h b/src/eap_common/eap_pwd_common.h
+index 6b07cf8f7..2387e59a2 100644
+--- a/src/eap_common/eap_pwd_common.h
++++ b/src/eap_common/eap_pwd_common.h
+@@ -67,5 +67,8 @@ int compute_keys(EAP_PWD_group *grp, const struct crypto_bignum *k,
+ struct crypto_hash * eap_pwd_h_init(void);
+ void eap_pwd_h_update(struct crypto_hash *hash, const u8 *data, size_t len);
+ void eap_pwd_h_final(struct crypto_hash *hash, u8 *digest);
++struct crypto_ec_point * eap_pwd_get_element(EAP_PWD_group *group,
++ const u8 *buf);
++struct crypto_bignum * eap_pwd_get_scalar(EAP_PWD_group *group, const u8 *buf);
+
+ #endif /* EAP_PWD_COMMON_H */
+diff --git a/src/eap_peer/eap_pwd.c b/src/eap_peer/eap_pwd.c
+index 5a05e5432..f37b974eb 100644
+--- a/src/eap_peer/eap_pwd.c
++++ b/src/eap_peer/eap_pwd.c
+@@ -308,7 +308,7 @@ eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
+ const struct wpabuf *reqData,
+ const u8 *payload, size_t payload_len)
+ {
+- struct crypto_ec_point *K = NULL, *point = NULL;
++ struct crypto_ec_point *K = NULL;
+ struct crypto_bignum *mask = NULL, *cofactor = NULL;
+ const u8 *ptr = payload;
+ u8 *scalar = NULL, *element = NULL;
+@@ -572,63 +572,27 @@ eap_pwd_perform_commit_exchange(struct eap_sm *sm, struct eap_pwd_data *data,
+ /* process the request */
+ data->k = crypto_bignum_init();
+ K = crypto_ec_point_init(data->grp->group);
+- point = crypto_ec_point_init(data->grp->group);
+- if (!data->k || !K || !point) {
++ if (!data->k || !K) {
+ wpa_printf(MSG_INFO, "EAP-PWD (peer): peer data allocation "
+ "fail");
+ goto fin;
+ }
+
+ /* element, x then y, followed by scalar */
+- data->server_element = crypto_ec_point_from_bin(data->grp->group, ptr);
++ data->server_element = eap_pwd_get_element(data->grp, ptr);
+ if (!data->server_element) {
+ wpa_printf(MSG_INFO, "EAP-PWD (peer): setting peer element "
+ "fail");
+ goto fin;
+ }
+ ptr += prime_len * 2;
+- data->server_scalar = crypto_bignum_init_set(ptr, order_len);
++ data->server_scalar = eap_pwd_get_scalar(data->grp, ptr);
+ if (!data->server_scalar) {
+ wpa_printf(MSG_INFO,
+ "EAP-PWD (peer): setting peer scalar fail");
+ goto fin;
+ }
+
+- /* verify received scalar */
+- if (crypto_bignum_is_zero(data->server_scalar) ||
+- crypto_bignum_is_one(data->server_scalar) ||
+- crypto_bignum_cmp(data->server_scalar,
+- crypto_ec_get_order(data->grp->group)) >= 0) {
+- wpa_printf(MSG_INFO,
+- "EAP-PWD (peer): received scalar is invalid");
+- goto fin;
+- }
+-
+- /* verify received element */
+- if (!crypto_ec_point_is_on_curve(data->grp->group,
+- data->server_element) ||
+- crypto_ec_point_is_at_infinity(data->grp->group,
+- data->server_element)) {
+- wpa_printf(MSG_INFO,
+- "EAP-PWD (peer): received element is invalid");
+- goto fin;
+- }
+-
+- /* check to ensure server's element is not in a small sub-group */
+- if (!crypto_bignum_is_one(cofactor)) {
+- if (crypto_ec_point_mul(data->grp->group, data->server_element,
+- cofactor, point) < 0) {
+- wpa_printf(MSG_INFO, "EAP-PWD (peer): cannot multiply "
+- "server element by order!\n");
+- goto fin;
+- }
+- if (crypto_ec_point_is_at_infinity(data->grp->group, point)) {
+- wpa_printf(MSG_INFO, "EAP-PWD (peer): server element "
+- "is at infinity!\n");
+- goto fin;
+- }
+- }
+-
+ /* compute the shared key, k */
+ if (crypto_ec_point_mul(data->grp->group, data->grp->pwe,
+ data->server_scalar, K) < 0 ||
+@@ -702,7 +666,6 @@ fin:
+ crypto_bignum_deinit(mask, 1);
+ crypto_bignum_deinit(cofactor, 1);
+ crypto_ec_point_deinit(K, 1);
+- crypto_ec_point_deinit(point, 1);
+ if (data->outbuf == NULL)
+ eap_pwd_state(data, FAILURE);
+ else
+diff --git a/src/eap_server/eap_server_pwd.c b/src/eap_server/eap_server_pwd.c
+index 16057e94f..f6c75cf80 100644
+--- a/src/eap_server/eap_server_pwd.c
++++ b/src/eap_server/eap_server_pwd.c
+@@ -669,7 +669,7 @@ eap_pwd_process_commit_resp(struct eap_sm *sm, struct eap_pwd_data *data,
+ {
+ const u8 *ptr;
+ struct crypto_bignum *cofactor = NULL;
+- struct crypto_ec_point *K = NULL, *point = NULL;
++ struct crypto_ec_point *K = NULL;
+ int res = 0;
+ size_t prime_len, order_len;
+
+@@ -688,9 +688,8 @@ eap_pwd_process_commit_resp(struct eap_sm *sm, struct eap_pwd_data *data,
+
+ data->k = crypto_bignum_init();
+ cofactor = crypto_bignum_init();
+- point = crypto_ec_point_init(data->grp->group);
+ K = crypto_ec_point_init(data->grp->group);
+- if (!data->k || !cofactor || !point || !K) {
++ if (!data->k || !cofactor || !K) {
+ wpa_printf(MSG_INFO, "EAP-PWD (server): peer data allocation "
+ "fail");
+ goto fin;
+@@ -704,55 +703,20 @@ eap_pwd_process_commit_resp(struct eap_sm *sm, struct eap_pwd_data *data,
+
+ /* element, x then y, followed by scalar */
+ ptr = payload;
+- data->peer_element = crypto_ec_point_from_bin(data->grp->group, ptr);
++ data->peer_element = eap_pwd_get_element(data->grp, ptr);
+ if (!data->peer_element) {
+ wpa_printf(MSG_INFO, "EAP-PWD (server): setting peer element "
+ "fail");
+ goto fin;
+ }
+ ptr += prime_len * 2;
+- data->peer_scalar = crypto_bignum_init_set(ptr, order_len);
++ data->peer_scalar = eap_pwd_get_scalar(data->grp, ptr);
+ if (!data->peer_scalar) {
+ wpa_printf(MSG_INFO, "EAP-PWD (server): peer data allocation "
+ "fail");
+ goto fin;
+ }
+
+- /* verify received scalar */
+- if (crypto_bignum_is_zero(data->peer_scalar) ||
+- crypto_bignum_is_one(data->peer_scalar) ||
+- crypto_bignum_cmp(data->peer_scalar,
+- crypto_ec_get_order(data->grp->group)) >= 0) {
+- wpa_printf(MSG_INFO,
+- "EAP-PWD (server): received scalar is invalid");
+- goto fin;
+- }
+-
+- /* verify received element */
+- if (!crypto_ec_point_is_on_curve(data->grp->group,
+- data->peer_element) ||
+- crypto_ec_point_is_at_infinity(data->grp->group,
+- data->peer_element)) {
+- wpa_printf(MSG_INFO,
+- "EAP-PWD (server): received element is invalid");
+- goto fin;
+- }
+-
+- /* check to ensure peer's element is not in a small sub-group */
+- if (!crypto_bignum_is_one(cofactor)) {
+- if (crypto_ec_point_mul(data->grp->group, data->peer_element,
+- cofactor, point) != 0) {
+- wpa_printf(MSG_INFO, "EAP-PWD (server): cannot "
+- "multiply peer element by order");
+- goto fin;
+- }
+- if (crypto_ec_point_is_at_infinity(data->grp->group, point)) {
+- wpa_printf(MSG_INFO, "EAP-PWD (server): peer element "
+- "is at infinity!\n");
+- goto fin;
+- }
+- }
+-
+ /* detect reflection attacks */
+ if (crypto_bignum_cmp(data->my_scalar, data->peer_scalar) == 0 ||
+ crypto_ec_point_cmp(data->grp->group, data->my_element,
+@@ -804,7 +768,6 @@ eap_pwd_process_commit_resp(struct eap_sm *sm, struct eap_pwd_data *data,
+
+ fin:
+ crypto_ec_point_deinit(K, 1);
+- crypto_ec_point_deinit(point, 1);
+ crypto_bignum_deinit(cofactor, 1);
+
+ if (res)
+--
+2.21.0
+