SAE: Rename and move ECC/FFC functions to be next to each other

This makes it easier to see where there is separate implementation for
ECC and FFC groups.

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

diff --git a/src/common/sae.c b/src/common/sae.c
index 23588f2..2b29019 100644 (file)
--- a/src/common/sae.c
+++ b/src/common/sae.c
@@ -177,8 +177,8 @@ static void sae_pwd_seed_key(const u8 *addr1, const u8 *addr2, u8 *key)
 }
 
 
-static int sae_test_pwd_seed(struct sae_data *sae, const u8 *pwd_seed,
-                            struct crypto_ec_point *pwe)
+static int sae_test_pwd_seed_ecc(struct sae_data *sae, const u8 *pwd_seed,
+                                struct crypto_ec_point *pwe)
 {
        u8 pwd_value[SAE_MAX_ECC_PRIME_LEN], prime[SAE_MAX_ECC_PRIME_LEN];
        struct crypto_bignum *x;
@@ -221,135 +221,8 @@ static int sae_test_pwd_seed(struct sae_data *sae, const u8 *pwd_seed,
 }
 
 
-static int sae_derive_pwe(struct sae_data *sae, const u8 *addr1,
-                         const u8 *addr2, const u8 *password,
-                         size_t password_len)
-{
-       u8 counter, k = 4;
-       u8 addrs[2 * ETH_ALEN];
-       const u8 *addr[2];
-       size_t len[2];
-       int found = 0;
-       struct crypto_ec_point *pwe_tmp;
-
-       if (sae->pwe_ecc == NULL) {
-               sae->pwe_ecc = crypto_ec_point_init(sae->ec);
-               if (sae->pwe_ecc == NULL)
-                       return -1;
-       }
-       pwe_tmp = crypto_ec_point_init(sae->ec);
-       if (pwe_tmp == NULL)
-               return -1;
-
-       wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
-                             password, password_len);
-
-       /*
-        * H(salt, ikm) = HMAC-SHA256(salt, ikm)
-        * pwd-seed = H(MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC),
-        *              password || counter)
-        */
-       sae_pwd_seed_key(addr1, addr2, addrs);
-
-       addr[0] = password;
-       len[0] = password_len;
-       addr[1] = &counter;
-       len[1] = sizeof(counter);
-
-       /*
-        * Continue for at least k iterations to protect against side-channel
-        * attacks that attempt to determine the number of iterations required
-        * in the loop.
-        */
-       for (counter = 1; counter < k || !found; counter++) {
-               u8 pwd_seed[SHA256_MAC_LEN];
-               int res;
-
-               if (counter > 200) {
-                       /* This should not happen in practice */
-                       wpa_printf(MSG_DEBUG, "SAE: Failed to derive PWE");
-                       break;
-               }
-
-               wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter);
-               if (hmac_sha256_vector(addrs, sizeof(addrs), 2, addr, len,
-                                      pwd_seed) < 0)
-                       break;
-               res = sae_test_pwd_seed(sae, pwd_seed,
-                                       found ? pwe_tmp : sae->pwe_ecc);
-               if (res < 0)
-                       break;
-               if (res == 0)
-                       continue;
-               if (found) {
-                       wpa_printf(MSG_DEBUG, "SAE: Ignore this PWE (one was "
-                                  "already selected)");
-               } else {
-                       wpa_printf(MSG_DEBUG, "SAE: Use this PWE");
-                       found = 1;
-               }
-       }
-
-       crypto_ec_point_deinit(pwe_tmp, 1);
-
-       return found ? 0 : -1;
-}
-
-
-static int sae_derive_commit(struct sae_data *sae)
-{
-       struct crypto_bignum *mask;
-       int ret = -1;
-
-       mask = sae_get_rand_and_mask(sae);
-       if (mask == NULL) {
-               wpa_printf(MSG_DEBUG, "SAE: Could not get rand/mask");
-               return -1;
-       }
-
-       /* commit-scalar = (rand + mask) modulo r */
-       if (!sae->own_commit_scalar) {
-               sae->own_commit_scalar = crypto_bignum_init();
-               if (!sae->own_commit_scalar)
-                       goto fail;
-       }
-       crypto_bignum_add(sae->sae_rand, mask, sae->own_commit_scalar);
-       crypto_bignum_mod(sae->own_commit_scalar, sae->order,
-                         sae->own_commit_scalar);
-
-       /* COMMIT-ELEMENT = inverse(scalar-op(mask, PWE)) */
-       if (!sae->own_commit_element_ecc) {
-               sae->own_commit_element_ecc = crypto_ec_point_init(sae->ec);
-               if (!sae->own_commit_element_ecc)
-                       goto fail;
-       }
-       if (crypto_ec_point_mul(sae->ec, sae->pwe_ecc, mask,
-                               sae->own_commit_element_ecc) < 0 ||
-           crypto_ec_point_invert(sae->ec, sae->own_commit_element_ecc) < 0) {
-               wpa_printf(MSG_DEBUG, "SAE: Could not compute commit-element");
-               goto fail;
-       }
-
-       ret = 0;
-fail:
-       crypto_bignum_deinit(mask, 1);
-       return ret;
-}
-
-
-static int sae_prepare_commit_ec(const u8 *addr1, const u8 *addr2,
-                                const u8 *password, size_t password_len,
-                                struct sae_data *sae)
-{
-       if (sae_derive_pwe(sae, addr1, addr2, password, password_len) < 0 ||
-           sae_derive_commit(sae) < 0)
-               return -1;
-       return 0;
-}
-
-
-static int sae_test_pwd_seed_dh(struct sae_data *sae, const u8 *pwd_seed,
-                               struct crypto_bignum *pwe)
+static int sae_test_pwd_seed_ffc(struct sae_data *sae, const u8 *pwd_seed,
+                                struct crypto_bignum *pwe)
 {
        u8 pwd_value[SAE_MAX_PRIME_LEN], pwe_bin[SAE_MAX_PRIME_LEN];
        size_t bits = sae->prime_len * 8;
@@ -428,9 +301,84 @@ static int sae_test_pwd_seed_dh(struct sae_data *sae, const u8 *pwd_seed,
 }
 
 
-static int sae_derive_pwe_dh(struct sae_data *sae, const u8 *addr1,
-                            const u8 *addr2, const u8 *password,
-                            size_t password_len)
+static int sae_derive_pwe_ecc(struct sae_data *sae, const u8 *addr1,
+                             const u8 *addr2, const u8 *password,
+                             size_t password_len)
+{
+       u8 counter, k = 4;
+       u8 addrs[2 * ETH_ALEN];
+       const u8 *addr[2];
+       size_t len[2];
+       int found = 0;
+       struct crypto_ec_point *pwe_tmp;
+
+       if (sae->pwe_ecc == NULL) {
+               sae->pwe_ecc = crypto_ec_point_init(sae->ec);
+               if (sae->pwe_ecc == NULL)
+                       return -1;
+       }
+       pwe_tmp = crypto_ec_point_init(sae->ec);
+       if (pwe_tmp == NULL)
+               return -1;
+
+       wpa_hexdump_ascii_key(MSG_DEBUG, "SAE: password",
+                             password, password_len);
+
+       /*
+        * H(salt, ikm) = HMAC-SHA256(salt, ikm)
+        * pwd-seed = H(MAX(STA-A-MAC, STA-B-MAC) || MIN(STA-A-MAC, STA-B-MAC),
+        *              password || counter)
+        */
+       sae_pwd_seed_key(addr1, addr2, addrs);
+
+       addr[0] = password;
+       len[0] = password_len;
+       addr[1] = &counter;
+       len[1] = sizeof(counter);
+
+       /*
+        * Continue for at least k iterations to protect against side-channel
+        * attacks that attempt to determine the number of iterations required
+        * in the loop.
+        */
+       for (counter = 1; counter < k || !found; counter++) {
+               u8 pwd_seed[SHA256_MAC_LEN];
+               int res;
+
+               if (counter > 200) {
+                       /* This should not happen in practice */
+                       wpa_printf(MSG_DEBUG, "SAE: Failed to derive PWE");
+                       break;
+               }
+
+               wpa_printf(MSG_DEBUG, "SAE: counter = %u", counter);
+               if (hmac_sha256_vector(addrs, sizeof(addrs), 2, addr, len,
+                                      pwd_seed) < 0)
+                       break;
+               res = sae_test_pwd_seed_ecc(sae, pwd_seed,
+                                           found ? pwe_tmp : sae->pwe_ecc);
+               if (res < 0)
+                       break;
+               if (res == 0)
+                       continue;
+               if (found) {
+                       wpa_printf(MSG_DEBUG, "SAE: Ignore this PWE (one was "
+                                  "already selected)");
+               } else {
+                       wpa_printf(MSG_DEBUG, "SAE: Use this PWE");
+                       found = 1;
+               }
+       }
+
+       crypto_ec_point_deinit(pwe_tmp, 1);
+
+       return found ? 0 : -1;
+}
+
+
+static int sae_derive_pwe_ffc(struct sae_data *sae, const u8 *addr1,
+                             const u8 *addr2, const u8 *password,
+                             size_t password_len)
 {
        u8 counter;
        u8 addrs[2 * ETH_ALEN];
@@ -473,7 +421,7 @@ static int sae_derive_pwe_dh(struct sae_data *sae, const u8 *addr1,
                if (hmac_sha256_vector(addrs, sizeof(addrs), 2, addr, len,
                                       pwd_seed) < 0)
                        break;
-               res = sae_test_pwd_seed_dh(sae, pwd_seed, sae->pwe_ffc);
+               res = sae_test_pwd_seed_ffc(sae, pwd_seed, sae->pwe_ffc);
                if (res < 0)
                        break;
                if (res > 0) {
@@ -486,7 +434,48 @@ static int sae_derive_pwe_dh(struct sae_data *sae, const u8 *addr1,
 }
 
 
-static int sae_derive_commit_dh(struct sae_data *sae)
+static int sae_derive_commit_ecc(struct sae_data *sae)
+{
+       struct crypto_bignum *mask;
+       int ret = -1;
+
+       mask = sae_get_rand_and_mask(sae);
+       if (mask == NULL) {
+               wpa_printf(MSG_DEBUG, "SAE: Could not get rand/mask");
+               return -1;
+       }
+
+       /* commit-scalar = (rand + mask) modulo r */
+       if (!sae->own_commit_scalar) {
+               sae->own_commit_scalar = crypto_bignum_init();
+               if (!sae->own_commit_scalar)
+                       goto fail;
+       }
+       crypto_bignum_add(sae->sae_rand, mask, sae->own_commit_scalar);
+       crypto_bignum_mod(sae->own_commit_scalar, sae->order,
+                         sae->own_commit_scalar);
+
+       /* COMMIT-ELEMENT = inverse(scalar-op(mask, PWE)) */
+       if (!sae->own_commit_element_ecc) {
+               sae->own_commit_element_ecc = crypto_ec_point_init(sae->ec);
+               if (!sae->own_commit_element_ecc)
+                       goto fail;
+       }
+       if (crypto_ec_point_mul(sae->ec, sae->pwe_ecc, mask,
+                               sae->own_commit_element_ecc) < 0 ||
+           crypto_ec_point_invert(sae->ec, sae->own_commit_element_ecc) < 0) {
+               wpa_printf(MSG_DEBUG, "SAE: Could not compute commit-element");
+               goto fail;
+       }
+
+       ret = 0;
+fail:
+       crypto_bignum_deinit(mask, 1);
+       return ret;
+}
+
+
+static int sae_derive_commit_ffc(struct sae_data *sae)
 {
        struct crypto_bignum *mask;
        int ret = -1;
@@ -528,36 +517,31 @@ fail:
 }
 
 
-static int sae_prepare_commit_dh(const u8 *addr1, const u8 *addr2,
-                                const u8 *password, size_t password_len,
-                                struct sae_data *sae)
-{
-       if (sae_derive_pwe_dh(sae, addr1, addr2, password, password_len) < 0 ||
-           sae_derive_commit_dh(sae) < 0)
-               return -1;
-       return 0;
-}
-
-
 int sae_prepare_commit(const u8 *addr1, const u8 *addr2,
                       const u8 *password, size_t password_len,
                       struct sae_data *sae)
 {
        if (sae->ec) {
-               return sae_prepare_commit_ec(addr1, addr2, password,
-                                            password_len, sae);
+               if (sae_derive_pwe_ecc(sae, addr1, addr2, password,
+                                      password_len) < 0 ||
+                   sae_derive_commit_ecc(sae) < 0)
+                       return -1;
+               return 0;
        }
 
        if (sae->dh) {
-               return sae_prepare_commit_dh(addr1, addr2, password,
-                                            password_len, sae);
+               if (sae_derive_pwe_ffc(sae, addr1, addr2, password,
+                                      password_len) < 0 ||
+                   sae_derive_commit_ffc(sae) < 0)
+                       return -1;
+               return 0;
        }
 
        return -1;
 }
 
 
-static int sae_derive_k_ec(struct sae_data *sae, u8 *k)
+static int sae_derive_k_ecc(struct sae_data *sae, u8 *k)
 {
        struct crypto_ec_point *K;
        int ret = -1;
@@ -599,7 +583,7 @@ fail:
 }
 
 
-static int sae_derive_k_dh(struct sae_data *sae, u8 *k)
+static int sae_derive_k_ffc(struct sae_data *sae, u8 *k)
 {
        struct crypto_bignum *K;
        int ret = -1;
@@ -638,8 +622,8 @@ fail:
 static int sae_derive_k(struct sae_data *sae, u8 *k)
 {
        if (sae->ec)
-               return sae_derive_k_ec(sae, k);
-       return sae_derive_k_dh(sae, k);
+               return sae_derive_k_ecc(sae, k);
+       return sae_derive_k_ffc(sae, k);
 }
 
 
@@ -826,35 +810,6 @@ static u16 sae_parse_commit_scalar(struct sae_data *sae, const u8 **pos,
 }
 
 
-static u16 sae_parse_commit_element_ffc(struct sae_data *sae, const u8 *pos,
-                                       const u8 *end)
-{
-       if (pos + sae->prime_len > end) {
-               wpa_printf(MSG_DEBUG, "SAE: Not enough data for "
-                          "commit-element");
-               return WLAN_STATUS_UNSPECIFIED_FAILURE;
-       }
-       wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element", pos, sae->prime_len);
-
-       if (val_zero_or_one(pos, sae->prime_len)) {
-               wpa_printf(MSG_DEBUG, "SAE: Invalid peer element");
-               return WLAN_STATUS_UNSPECIFIED_FAILURE;
-       }
-
-       crypto_bignum_deinit(sae->peer_commit_element_ffc, 0);
-       sae->peer_commit_element_ffc = crypto_bignum_init_set(pos,
-                                                             sae->prime_len);
-       if (sae->peer_commit_element_ffc == NULL)
-               return WLAN_STATUS_UNSPECIFIED_FAILURE;
-       if (crypto_bignum_cmp(sae->peer_commit_element_ffc, sae->prime) >= 0) {
-               wpa_printf(MSG_DEBUG, "SAE: Invalid peer element");
-               return WLAN_STATUS_UNSPECIFIED_FAILURE;
-       }
-
-       return WLAN_STATUS_SUCCESS;
-}
-
-
 static u16 sae_parse_commit_element_ecc(struct sae_data *sae, const u8 *pos,
                                        const u8 *end)
 {
@@ -893,6 +848,35 @@ static u16 sae_parse_commit_element_ecc(struct sae_data *sae, const u8 *pos,
 }
 
 
+static u16 sae_parse_commit_element_ffc(struct sae_data *sae, const u8 *pos,
+                                       const u8 *end)
+{
+       if (pos + sae->prime_len > end) {
+               wpa_printf(MSG_DEBUG, "SAE: Not enough data for "
+                          "commit-element");
+               return WLAN_STATUS_UNSPECIFIED_FAILURE;
+       }
+       wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-element", pos, sae->prime_len);
+
+       if (val_zero_or_one(pos, sae->prime_len)) {
+               wpa_printf(MSG_DEBUG, "SAE: Invalid peer element");
+               return WLAN_STATUS_UNSPECIFIED_FAILURE;
+       }
+
+       crypto_bignum_deinit(sae->peer_commit_element_ffc, 0);
+       sae->peer_commit_element_ffc = crypto_bignum_init_set(pos,
+                                                             sae->prime_len);
+       if (sae->peer_commit_element_ffc == NULL)
+               return WLAN_STATUS_UNSPECIFIED_FAILURE;
+       if (crypto_bignum_cmp(sae->peer_commit_element_ffc, sae->prime) >= 0) {
+               wpa_printf(MSG_DEBUG, "SAE: Invalid peer element");
+               return WLAN_STATUS_UNSPECIFIED_FAILURE;
+       }
+
+       return WLAN_STATUS_SUCCESS;
+}
+
+
 static u16 sae_parse_commit_element(struct sae_data *sae, const u8 *pos,
                                    const u8 *end)
 {