From 24dc1e2a2c4737a45d3670253327aa535d48292e Mon Sep 17 00:00:00 2001 From: Jouni Malinen Date: Sun, 6 Jan 2013 17:03:09 +0200 Subject: [PATCH] SAE: Split sae_parse_commit() into helper functions Signed-hostap: Jouni Malinen --- src/common/sae.c | 96 +++++++++++++++++++++++++++++++++++------------- 1 file changed, 70 insertions(+), 26 deletions(-) diff --git a/src/common/sae.c b/src/common/sae.c index de5dedd6c..ad5955f7c 100644 --- a/src/common/sae.c +++ b/src/common/sae.c @@ -758,23 +758,9 @@ void sae_write_commit(struct sae_data *sae, struct wpabuf *buf, } -u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len, - const u8 **token, size_t *token_len, int *allowed_groups) +static u16 sae_group_allowed(struct sae_data *sae, int *allowed_groups, + u16 group) { - const u8 *pos = data, *end = data + len; - u16 group; - struct crypto_bignum *peer_scalar; - - wpa_hexdump(MSG_DEBUG, "SAE: Commit fields", data, len); - if (token) - *token = NULL; - if (token_len) - *token_len = 0; - - /* Check Finite Cyclic Group */ - if (pos + 2 > end) - return WLAN_STATUS_UNSPECIFIED_FAILURE; - group = WPA_GET_LE16(pos); if (allowed_groups) { int i; for (i = 0; allowed_groups[i] >= 0; i++) { @@ -788,38 +774,60 @@ u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len, return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; } } + if (sae->state == SAE_COMMITTED && group != sae->group) { wpa_printf(MSG_DEBUG, "SAE: Do not allow group to be changed"); return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; } + if (group != sae->group && sae_set_group(sae, group) < 0) { wpa_printf(MSG_DEBUG, "SAE: Unsupported Finite Cyclic Group %u", group); return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; } + if (sae->dh && !allowed_groups) { wpa_printf(MSG_DEBUG, "SAE: Do not allow FFC group %u without " "explicit configuration enabling it", group); return WLAN_STATUS_FINITE_CYCLIC_GROUP_NOT_SUPPORTED; } - pos += 2; - if (pos + (sae->ec ? 3 : 2) * sae->prime_len < end) { - size_t tlen = end - (pos + (sae->ec ? 3 : 2) * sae->prime_len); - wpa_hexdump(MSG_DEBUG, "SAE: Anti-Clogging Token", pos, tlen); + return WLAN_STATUS_SUCCESS; +} + + +static void sae_parse_commit_token(struct sae_data *sae, const u8 **pos, + const u8 *end, const u8 **token, + size_t *token_len) +{ + if (*pos + (sae->ec ? 3 : 2) * sae->prime_len < end) { + size_t tlen = end - (*pos + (sae->ec ? 3 : 2) * sae->prime_len); + wpa_hexdump(MSG_DEBUG, "SAE: Anti-Clogging Token", *pos, tlen); if (token) - *token = pos; + *token = *pos; if (token_len) *token_len = tlen; - pos += tlen; + *pos += tlen; + } else { + if (token) + *token = NULL; + if (token_len) + *token_len = 0; } +} - if (pos + sae->prime_len > end) { + +static u16 sae_parse_commit_scalar(struct sae_data *sae, const u8 **pos, + const u8 *end) +{ + struct crypto_bignum *peer_scalar; + + if (*pos + sae->prime_len > end) { wpa_printf(MSG_DEBUG, "SAE: Not enough data for scalar"); return WLAN_STATUS_UNSPECIFIED_FAILURE; } - peer_scalar = crypto_bignum_init_set(pos, sae->prime_len); + peer_scalar = crypto_bignum_init_set(*pos, sae->prime_len); if (peer_scalar == NULL) return WLAN_STATUS_UNSPECIFIED_FAILURE; @@ -839,9 +847,16 @@ u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len, crypto_bignum_deinit(sae->peer_commit_scalar, 0); sae->peer_commit_scalar = peer_scalar; - wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-scalar", pos, sae->prime_len); - pos += sae->prime_len; + wpa_hexdump(MSG_DEBUG, "SAE: Peer commit-scalar", *pos, sae->prime_len); + *pos += sae->prime_len; + return WLAN_STATUS_SUCCESS; +} + + +static u16 sae_parse_commit_element(struct sae_data *sae, const u8 *pos, + const u8 *end) +{ if (sae->dh) { if (pos + sae->prime_len > end) { wpa_printf(MSG_DEBUG, "SAE: Not enough data for " @@ -870,6 +885,35 @@ u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len, } +u16 sae_parse_commit(struct sae_data *sae, const u8 *data, size_t len, + const u8 **token, size_t *token_len, int *allowed_groups) +{ + const u8 *pos = data, *end = data + len; + u16 res; + + wpa_hexdump(MSG_DEBUG, "SAE: Commit fields", data, len); + + /* Check Finite Cyclic Group */ + if (pos + 2 > end) + return WLAN_STATUS_UNSPECIFIED_FAILURE; + res = sae_group_allowed(sae, allowed_groups, WPA_GET_LE16(pos)); + if (res != WLAN_STATUS_SUCCESS) + return res; + pos += 2; + + /* Optional Anti-Clogging Token */ + sae_parse_commit_token(sae, &pos, end, token, token_len); + + /* commit-scalar */ + res = sae_parse_commit_scalar(sae, &pos, end); + if (res != WLAN_STATUS_SUCCESS) + return res; + + /* commit-element */ + return sae_parse_commit_element(sae, pos, end); +} + + static void sae_cn_confirm(struct sae_data *sae, const u8 *sc, const struct crypto_bignum *scalar1, const u8 *element1,