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iwd
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eap-mschapv2: Memzero copies of secrets

This commit is contained in:
Andrew Zaborowski 2019-03-21 03:54:14 +01:00 committed by Denis Kenzior
parent 881fbd1d80
commit 94043d6bcb
1 changed files with 24 additions and 12 deletions
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36
src/eap-mschapv2.c
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@ -305,7 +305,7 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
state->user, nt_response); state->user, nt_response);
if (!ret) if (!ret)
goto err; goto done;
ret = mschapv2_generate_authenticator_response(password_hash_hash, ret = mschapv2_generate_authenticator_response(password_hash_hash,
nt_response, nt_response,
@ -315,19 +315,19 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
authenticator_resp); authenticator_resp);
if (!ret) if (!ret)
goto err; goto done;
/* /*
* For iwd timing attacks are unlikly because media access will * For iwd timing attacks are unlikely because media access will
* influence timing. If this code is ever taken out of iwd, memcmp * influence timing. If this code is ever taken out of iwd, memcmp
* should be replaced by a constant time memcmp * should be replaced by a constant time memcmp
*/ */
if (len < 42 || memcmp(authenticator_resp, pkt, 42)) { if (len < 42 || memcmp(authenticator_resp, pkt, 42)) {
l_warn("Authenticator response didn't match"); l_warn("Authenticator response didn't match");
goto err; ret = false;
goto done;
} }
ret = mschapv2_get_master_key(password_hash_hash, nt_response, ret = mschapv2_get_master_key(password_hash_hash, nt_response,
master_key); master_key);
ret &= mschapv2_get_asymmetric_start_key(master_key, session_key, ret &= mschapv2_get_asymmetric_start_key(master_key, session_key,
@ -336,7 +336,7 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
16, false, false); 16, false, false);
if (!ret) if (!ret)
goto err; goto done;
eap_method_success(eap); eap_method_success(eap);
@ -346,10 +346,13 @@ static void eap_mschapv2_handle_success(struct eap_state *eap,
/* The eapol set_key_material only needs msk, and that's all we got */ /* The eapol set_key_material only needs msk, and that's all we got */
eap_set_key_material(eap, session_key, 32, NULL, 0, NULL, 0); eap_set_key_material(eap, session_key, 32, NULL, 0, NULL, 0);
return; done:
if (!ret)
eap_method_error(eap);
err: explicit_bzero(master_key, sizeof(master_key));
eap_method_error(eap); explicit_bzero(session_key, sizeof(session_key));
explicit_bzero(password_hash_hash, sizeof(password_hash_hash));
} }
static void eap_mschapv2_handle_failure(struct eap_state *eap, static void eap_mschapv2_handle_failure(struct eap_state *eap,
@ -426,6 +429,7 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
const struct eap_secret_info *secret; const struct eap_secret_info *secret;
char setting[64], setting2[64]; char setting[64], setting2[64];
uint8_t hash[16]; uint8_t hash[16];
int r = 0;
snprintf(setting, sizeof(setting), "%sIdentity", prefix); snprintf(setting, sizeof(setting), "%sIdentity", prefix);
identity = l_settings_get_string(settings, "Security", setting); identity = l_settings_get_string(settings, "Security", setting);
@ -457,7 +461,8 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
if (password && password_hash) { if (password && password_hash) {
l_error("Exactly one of (%s, %s) must be present", l_error("Exactly one of (%s, %s) must be present",
setting, setting2); setting, setting2);
return -EEXIST; r = -EEXIST;
goto cleanup;
} }
if (password_hash) { if (password_hash) {
@ -465,6 +470,9 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
size_t len; size_t len;
tmp = l_util_from_hexstring(password_hash, &len); tmp = l_util_from_hexstring(password_hash, &len);
if (tmp)
explicit_bzero(tmp, len);
l_free(tmp); l_free(tmp);
if (!tmp || len != 16) { if (!tmp || len != 16) {
@ -489,9 +497,11 @@ static int eap_mschapv2_check_settings(struct l_settings *settings,
validate: validate:
if (!mschap_nt_password_hash(password, hash)) if (!mschap_nt_password_hash(password, hash))
return -EINVAL; r = -EINVAL;
return 0; cleanup:
explicit_bzero(password, strlen(password));
return r;
} }
static bool eap_mschapv2_load_settings(struct eap_state *eap, static bool eap_mschapv2_load_settings(struct eap_state *eap,
@ -517,6 +527,7 @@ static bool eap_mschapv2_load_settings(struct eap_state *eap,
if (password) { if (password) {
set_password_from_string(state, password); set_password_from_string(state, password);
explicit_bzero(password, strlen(password));
} else { } else {
unsigned char *tmp; unsigned char *tmp;
size_t len; size_t len;
@ -529,6 +540,7 @@ static bool eap_mschapv2_load_settings(struct eap_state *eap,
tmp = l_util_from_hexstring(hash_str, &len); tmp = l_util_from_hexstring(hash_str, &len);
memcpy(state->password_hash, tmp, 16); memcpy(state->password_hash, tmp, 16);
explicit_bzero(tmp, len);
l_free(tmp); l_free(tmp);
} }