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DPP2: Derive a separate key for enveloped data

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Derive a new key from bk to be used as the password for PBKDF2 instead
of using ke for this.

Signed-off-by: Jouni Malinen <jouni@codeaurora.org>
This commit is contained in:
Jouni Malinen 2020-05-29 21:42:33 +03:00 committed by Jouni Malinen
parent 32d3360f33
commit d10a57f6e9
1 changed files with 13 additions and 8 deletions
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21
src/common/dpp_backup.c
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@ -275,18 +275,21 @@ dpp_build_pw_recipient_info(struct dpp_authentication *auth, size_t hash_len,
struct wpabuf *pwri = NULL, *enc_key = NULL, *key_der_alg = NULL,
*key_enc_alg = NULL, *salt;
u8 kek[DPP_MAX_HASH_LEN];
const u8 *key;
u8 key[DPP_MAX_HASH_LEN];
size_t key_len;
int res;
salt = wpabuf_alloc(64);
if (!salt || os_get_random(wpabuf_put(salt, 64), 64) < 0)
goto fail;
wpa_hexdump_buf(MSG_DEBUG, "DPP: PBKDF2 salt", salt);
/* TODO: For initial testing, use ke as the key. Replace this with a
* new key once that has been defined. */
key = auth->ke;
key_len = auth->curve->hash_len;
/* password = HKDF-Expand(bk, "Enveloped Data Password", length) */
res = dpp_hkdf_expand(key_len, auth->bk, key_len,
"Enveloped Data Password", key, key_len);
if (res < 0)
goto fail;
wpa_hexdump_key(MSG_DEBUG, "DPP: PBKDF2 key", key, key_len);
if (dpp_pbkdf2(hash_len, key, key_len, wpabuf_head(salt), 64, 1000,
@ -1151,7 +1154,7 @@ dpp_parse_dpp_asymmetric_key_package(const u8 *key_pkg, size_t key_pkg_len)
int dpp_conf_resp_env_data(struct dpp_authentication *auth,
const u8 *env_data, size_t env_data_len)
{
const u8 *key;
u8 key[DPP_MAX_HASH_LEN];
size_t key_len;
u8 kek[DPP_MAX_HASH_LEN];
u8 cont_encr_key[DPP_MAX_HASH_LEN];
@ -1167,10 +1170,12 @@ int dpp_conf_resp_env_data(struct dpp_authentication *auth,
if (dpp_parse_enveloped_data(env_data, env_data_len, &data) < 0)
return -1;
/* TODO: For initial testing, use ke as the key. Replace this with a
* new key once that has been defined. */
key = auth->ke;
key_len = auth->curve->hash_len;
/* password = HKDF-Expand(bk, "Enveloped Data Password", length) */
res = dpp_hkdf_expand(key_len, auth->bk, key_len,
"Enveloped Data Password", key, key_len);
if (res < 0)
return -1;
wpa_hexdump_key(MSG_DEBUG, "DPP: PBKDF2 key", key, key_len);
if (dpp_pbkdf2(data.prf_hash_len, key, key_len, data.salt, 64, 1000,