Cumulative patch from commit 8b48e3200680f71ae083b84793e6bdc2099416d2 [DO NOT MERGE]
8b48e32 wpa_cli: Add MAC address randomization in scan
fb37588 ctrl_iface: Add MAC address randomization in scan processing
56c76fa scan: Add MAC address randomization in scan handling
86056fe nl80211: Handle MAC address randomization in scan/sched_scan
ff23ed2 driver: Add definitions for MAC address randomization in scan
7db53bb wpa_cli: Implement TDLS start/cancel channel switching commands
72b2605 nl80211: Pass TDLS channel-switch start/stop params to kernel
6b90dea TDLS: Propagate enable/disable channel-switch commands to driver
d9d3b78 TDLS: Track TDLS channel switch prohibition in BSS
4daa572 TDLS: Add channel-switch capability flag
ca16586 Sync with wireless-testing.git include/uapi/linux/nl80211.h
8c42b36 WMM AC: Reconfigure tspecs on reassociation to the same BSS
677e7a9 WMM AC: Do not fail on unknown IEs in Association Response
fecc2bb WMM AC: Delete tspecs on roaming
20fe745 WMM AC: Print user-priority in wmm_ac_status
730a0d1 nl80211: Always register management frames handler
...
209702d Add possibility to set the setband parameter
ee82e33 Do not trigger the scan during initialization on Android platforms
e69ae5f Reject new SCAN commands if there is a pending request
...
59d7148 nl80211: Provide subtype and reason code for AP SME drivers
9d4ff04 Add external EAPOL transmission option for testing purposes
61fc904 P2P: Handle improper WPS termination on GO during group formation
58b40fd P2P: Clear p2p_go_group_formation_completed on GO start
c155305 Complete sme-connect radio work when clearing connection state
debb2da P2P: Report group removal reason PSK_FAILURE in timeout case
51465a0 The master branch is now used for v2.4 development
Change-Id: I9b9cfa5c5cd4d26b2f3f5595f7c226ac60de6258
diff --git a/src/eap_peer/eap.c b/src/eap_peer/eap.c
index 9880d3b..31c1a29 100644
--- a/src/eap_peer/eap.c
+++ b/src/eap_peer/eap.c
@@ -23,6 +23,7 @@
#include "ext_password.h"
#include "crypto/crypto.h"
#include "crypto/tls.h"
+#include "crypto/sha256.h"
#include "common/wpa_ctrl.h"
#include "eap_common/eap_wsc_common.h"
#include "eap_i.h"
@@ -190,6 +191,8 @@
sm->num_rounds = 0;
sm->prev_failure = 0;
sm->expected_failure = 0;
+ sm->reauthInit = FALSE;
+ sm->erp_seq = (u32) -1;
}
@@ -353,6 +356,267 @@
}
+#ifdef CONFIG_ERP
+
+static char * eap_home_realm(struct eap_sm *sm)
+{
+ struct eap_peer_config *config = eap_get_config(sm);
+ char *realm;
+ size_t i, realm_len;
+
+ if (!config)
+ return NULL;
+
+ if (config->identity) {
+ for (i = 0; i < config->identity_len; i++) {
+ if (config->identity[i] == '@')
+ break;
+ }
+ if (i < config->identity_len) {
+ realm_len = config->identity_len - i - 1;
+ realm = os_malloc(realm_len + 1);
+ if (realm == NULL)
+ return NULL;
+ os_memcpy(realm, &config->identity[i + 1], realm_len);
+ realm[realm_len] = '\0';
+ return realm;
+ }
+ }
+
+ if (config->anonymous_identity) {
+ for (i = 0; i < config->anonymous_identity_len; i++) {
+ if (config->anonymous_identity[i] == '@')
+ break;
+ }
+ if (i < config->anonymous_identity_len) {
+ realm_len = config->anonymous_identity_len - i - 1;
+ realm = os_malloc(realm_len + 1);
+ if (realm == NULL)
+ return NULL;
+ os_memcpy(realm, &config->anonymous_identity[i + 1],
+ realm_len);
+ realm[realm_len] = '\0';
+ return realm;
+ }
+ }
+
+ return os_strdup("");
+}
+
+
+static struct eap_erp_key *
+eap_erp_get_key(struct eap_sm *sm, const char *realm)
+{
+ struct eap_erp_key *erp;
+
+ dl_list_for_each(erp, &sm->erp_keys, struct eap_erp_key, list) {
+ char *pos;
+
+ pos = os_strchr(erp->keyname_nai, '@');
+ if (!pos)
+ continue;
+ pos++;
+ if (os_strcmp(pos, realm) == 0)
+ return erp;
+ }
+
+ return NULL;
+}
+
+
+static struct eap_erp_key *
+eap_erp_get_key_nai(struct eap_sm *sm, const char *nai)
+{
+ struct eap_erp_key *erp;
+
+ dl_list_for_each(erp, &sm->erp_keys, struct eap_erp_key, list) {
+ if (os_strcmp(erp->keyname_nai, nai) == 0)
+ return erp;
+ }
+
+ return NULL;
+}
+
+
+static void eap_peer_erp_free_key(struct eap_erp_key *erp)
+{
+ dl_list_del(&erp->list);
+ bin_clear_free(erp, sizeof(*erp));
+}
+
+
+static void eap_erp_remove_keys_realm(struct eap_sm *sm, const char *realm)
+{
+ struct eap_erp_key *erp;
+
+ while ((erp = eap_erp_get_key(sm, realm)) != NULL) {
+ wpa_printf(MSG_DEBUG, "EAP: Delete old ERP key %s",
+ erp->keyname_nai);
+ eap_peer_erp_free_key(erp);
+ }
+}
+
+#endif /* CONFIG_ERP */
+
+
+void eap_peer_erp_free_keys(struct eap_sm *sm)
+{
+#ifdef CONFIG_ERP
+ struct eap_erp_key *erp, *tmp;
+
+ dl_list_for_each_safe(erp, tmp, &sm->erp_keys, struct eap_erp_key, list)
+ eap_peer_erp_free_key(erp);
+#endif /* CONFIG_ERP */
+}
+
+
+static void eap_peer_erp_init(struct eap_sm *sm)
+{
+#ifdef CONFIG_ERP
+ u8 *emsk = NULL;
+ size_t emsk_len = 0;
+ u8 EMSKname[EAP_EMSK_NAME_LEN];
+ u8 len[2];
+ char *realm;
+ size_t realm_len, nai_buf_len;
+ struct eap_erp_key *erp = NULL;
+ int pos;
+
+ realm = eap_home_realm(sm);
+ if (!realm)
+ return;
+ realm_len = os_strlen(realm);
+ wpa_printf(MSG_DEBUG, "EAP: Realm for ERP keyName-NAI: %s", realm);
+ eap_erp_remove_keys_realm(sm, realm);
+
+ nai_buf_len = 2 * EAP_EMSK_NAME_LEN + 1 + realm_len;
+ if (nai_buf_len > 253) {
+ /*
+ * keyName-NAI has a maximum length of 253 octet to fit in
+ * RADIUS attributes.
+ */
+ wpa_printf(MSG_DEBUG,
+ "EAP: Too long realm for ERP keyName-NAI maximum length");
+ goto fail;
+ }
+ nai_buf_len++; /* null termination */
+ erp = os_zalloc(sizeof(*erp) + nai_buf_len);
+ if (erp == NULL)
+ goto fail;
+
+ emsk = sm->m->get_emsk(sm, sm->eap_method_priv, &emsk_len);
+ if (!emsk || emsk_len == 0 || emsk_len > ERP_MAX_KEY_LEN) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: No suitable EMSK available for ERP");
+ goto fail;
+ }
+
+ wpa_hexdump_key(MSG_DEBUG, "EAP: EMSK", emsk, emsk_len);
+
+ WPA_PUT_BE16(len, 8);
+ if (hmac_sha256_kdf(sm->eapSessionId, sm->eapSessionIdLen, "EMSK",
+ len, sizeof(len),
+ EMSKname, EAP_EMSK_NAME_LEN) < 0) {
+ wpa_printf(MSG_DEBUG, "EAP: Could not derive EMSKname");
+ goto fail;
+ }
+ wpa_hexdump(MSG_DEBUG, "EAP: EMSKname", EMSKname, EAP_EMSK_NAME_LEN);
+
+ pos = wpa_snprintf_hex(erp->keyname_nai, nai_buf_len,
+ EMSKname, EAP_EMSK_NAME_LEN);
+ erp->keyname_nai[pos] = '@';
+ os_memcpy(&erp->keyname_nai[pos + 1], realm, realm_len);
+
+ WPA_PUT_BE16(len, emsk_len);
+ if (hmac_sha256_kdf(emsk, emsk_len,
+ "EAP Re-authentication Root Key@ietf.org",
+ len, sizeof(len), erp->rRK, emsk_len) < 0) {
+ wpa_printf(MSG_DEBUG, "EAP: Could not derive rRK for ERP");
+ goto fail;
+ }
+ erp->rRK_len = emsk_len;
+ wpa_hexdump_key(MSG_DEBUG, "EAP: ERP rRK", erp->rRK, erp->rRK_len);
+
+ if (hmac_sha256_kdf(erp->rRK, erp->rRK_len,
+ "EAP Re-authentication Integrity Key@ietf.org",
+ len, sizeof(len), erp->rIK, erp->rRK_len) < 0) {
+ wpa_printf(MSG_DEBUG, "EAP: Could not derive rIK for ERP");
+ goto fail;
+ }
+ erp->rIK_len = erp->rRK_len;
+ wpa_hexdump_key(MSG_DEBUG, "EAP: ERP rIK", erp->rIK, erp->rIK_len);
+
+ wpa_printf(MSG_DEBUG, "EAP: Stored ERP keys %s", erp->keyname_nai);
+ dl_list_add(&sm->erp_keys, &erp->list);
+ erp = NULL;
+fail:
+ bin_clear_free(emsk, emsk_len);
+ bin_clear_free(erp, sizeof(*erp));
+ os_free(realm);
+#endif /* CONFIG_ERP */
+}
+
+
+#ifdef CONFIG_ERP
+static int eap_peer_erp_reauth_start(struct eap_sm *sm,
+ const struct eap_hdr *hdr, size_t len)
+{
+ char *realm;
+ struct eap_erp_key *erp;
+ struct wpabuf *msg;
+ u8 hash[SHA256_MAC_LEN];
+
+ realm = eap_home_realm(sm);
+ if (!realm)
+ return -1;
+
+ erp = eap_erp_get_key(sm, realm);
+ os_free(realm);
+ realm = NULL;
+ if (!erp)
+ return -1;
+
+ if (erp->next_seq >= 65536)
+ return -1; /* SEQ has range of 0..65535 */
+
+ /* TODO: check rRK lifetime expiration */
+
+ wpa_printf(MSG_DEBUG, "EAP: Valid ERP key found %s (SEQ=%u)",
+ erp->keyname_nai, erp->next_seq);
+
+ msg = eap_msg_alloc(EAP_VENDOR_IETF, EAP_ERP_TYPE_REAUTH,
+ 1 + 2 + 2 + os_strlen(erp->keyname_nai) + 1 + 16,
+ EAP_CODE_INITIATE, hdr->identifier);
+ if (msg == NULL)
+ return -1;
+
+ wpabuf_put_u8(msg, 0x20); /* Flags: R=0 B=0 L=1 */
+ wpabuf_put_be16(msg, erp->next_seq);
+
+ wpabuf_put_u8(msg, EAP_ERP_TLV_KEYNAME_NAI);
+ wpabuf_put_u8(msg, os_strlen(erp->keyname_nai));
+ wpabuf_put_str(msg, erp->keyname_nai);
+
+ wpabuf_put_u8(msg, EAP_ERP_CS_HMAC_SHA256_128); /* Cryptosuite */
+
+ if (hmac_sha256(erp->rIK, erp->rIK_len,
+ wpabuf_head(msg), wpabuf_len(msg), hash) < 0) {
+ wpabuf_free(msg);
+ return -1;
+ }
+ wpabuf_put_data(msg, hash, 16);
+
+ wpa_printf(MSG_DEBUG, "EAP: Sending EAP-Initiate/Re-auth");
+ sm->erp_seq = erp->next_seq;
+ erp->next_seq++;
+ wpabuf_free(sm->eapRespData);
+ sm->eapRespData = msg;
+ sm->reauthInit = TRUE;
+ return 0;
+}
+#endif /* CONFIG_ERP */
+
+
/*
* The method processing happens here. The request from the authenticator is
* processed, and an appropriate response packet is built.
@@ -414,6 +678,8 @@
if (sm->m->isKeyAvailable && sm->m->getKey &&
sm->m->isKeyAvailable(sm, sm->eap_method_priv)) {
+ struct eap_peer_config *config = eap_get_config(sm);
+
eap_sm_free_key(sm);
sm->eapKeyData = sm->m->getKey(sm, sm->eap_method_priv,
&sm->eapKeyDataLen);
@@ -426,6 +692,8 @@
wpa_hexdump(MSG_DEBUG, "EAP: Session-Id",
sm->eapSessionId, sm->eapSessionIdLen);
}
+ if (config->erp && sm->m->get_emsk && sm->eapSessionId)
+ eap_peer_erp_init(sm);
}
}
@@ -450,6 +718,7 @@
}
eapol_set_bool(sm, EAPOL_eapReq, FALSE);
eapol_set_int(sm, EAPOL_idleWhile, sm->ClientTimeout);
+ sm->reauthInit = FALSE;
}
@@ -709,6 +978,8 @@
else if (sm->selectedMethod == EAP_TYPE_LEAP &&
(sm->rxSuccess || sm->rxResp))
SM_ENTER(EAP, METHOD);
+ else if (sm->reauthInit)
+ SM_ENTER(EAP, SEND_RESPONSE);
else
SM_ENTER(EAP, DISCARD);
}
@@ -1231,6 +1502,219 @@
}
+static void eap_peer_initiate(struct eap_sm *sm, const struct eap_hdr *hdr,
+ size_t len)
+{
+#ifdef CONFIG_ERP
+ const u8 *pos = (const u8 *) (hdr + 1);
+ const u8 *end = ((const u8 *) hdr) + len;
+ struct erp_tlvs parse;
+
+ if (len < sizeof(*hdr) + 1) {
+ wpa_printf(MSG_DEBUG, "EAP: Ignored too short EAP-Initiate");
+ return;
+ }
+
+ if (*pos != EAP_ERP_TYPE_REAUTH_START) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Ignored unexpected EAP-Initiate Type=%u",
+ *pos);
+ return;
+ }
+
+ pos++;
+ if (pos >= end) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Too short EAP-Initiate/Re-auth-Start");
+ return;
+ }
+ pos++; /* Reserved */
+ wpa_hexdump(MSG_DEBUG, "EAP: EAP-Initiate/Re-auth-Start TVs/TLVs",
+ pos, end - pos);
+
+ if (erp_parse_tlvs(pos, end, &parse, 0) < 0)
+ goto invalid;
+
+ if (parse.domain) {
+ wpa_hexdump_ascii(MSG_DEBUG,
+ "EAP: EAP-Initiate/Re-auth-Start - Domain name",
+ parse.domain, parse.domain_len);
+ /* TODO: Derivation of domain specific keys for local ER */
+ }
+
+ if (eap_peer_erp_reauth_start(sm, hdr, len) == 0)
+ return;
+
+invalid:
+#endif /* CONFIG_ERP */
+ wpa_printf(MSG_DEBUG,
+ "EAP: EAP-Initiate/Re-auth-Start - No suitable ERP keys available - try to start full EAP authentication");
+ eapol_set_bool(sm, EAPOL_eapTriggerStart, TRUE);
+}
+
+
+static void eap_peer_finish(struct eap_sm *sm, const struct eap_hdr *hdr,
+ size_t len)
+{
+#ifdef CONFIG_ERP
+ const u8 *pos = (const u8 *) (hdr + 1);
+ const u8 *end = ((const u8 *) hdr) + len;
+ const u8 *start;
+ struct erp_tlvs parse;
+ u8 flags;
+ u16 seq;
+ u8 hash[SHA256_MAC_LEN];
+ size_t hash_len;
+ struct eap_erp_key *erp;
+ int max_len;
+ char nai[254];
+ u8 seed[4];
+ int auth_tag_ok = 0;
+
+ if (len < sizeof(*hdr) + 1) {
+ wpa_printf(MSG_DEBUG, "EAP: Ignored too short EAP-Finish");
+ return;
+ }
+
+ if (*pos != EAP_ERP_TYPE_REAUTH) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Ignored unexpected EAP-Finish Type=%u", *pos);
+ return;
+ }
+
+ if (len < sizeof(*hdr) + 4) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Ignored too short EAP-Finish/Re-auth");
+ return;
+ }
+
+ pos++;
+ flags = *pos++;
+ seq = WPA_GET_BE16(pos);
+ pos += 2;
+ wpa_printf(MSG_DEBUG, "EAP: Flags=0x%x SEQ=%u", flags, seq);
+
+ if (seq != sm->erp_seq) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Unexpected EAP-Finish/Re-auth SEQ=%u", seq);
+ return;
+ }
+
+ /*
+ * Parse TVs/TLVs. Since we do not yet know the length of the
+ * Authentication Tag, stop parsing if an unknown TV/TLV is seen and
+ * just try to find the keyName-NAI first so that we can check the
+ * Authentication Tag.
+ */
+ if (erp_parse_tlvs(pos, end, &parse, 1) < 0)
+ return;
+
+ if (!parse.keyname) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: No keyName-NAI in EAP-Finish/Re-auth Packet");
+ return;
+ }
+
+ wpa_hexdump_ascii(MSG_DEBUG, "EAP: EAP-Finish/Re-auth - keyName-NAI",
+ parse.keyname, parse.keyname_len);
+ if (parse.keyname_len > 253) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Too long keyName-NAI in EAP-Finish/Re-auth");
+ return;
+ }
+ os_memcpy(nai, parse.keyname, parse.keyname_len);
+ nai[parse.keyname_len] = '\0';
+
+ erp = eap_erp_get_key_nai(sm, nai);
+ if (!erp) {
+ wpa_printf(MSG_DEBUG, "EAP: No matching ERP key found for %s",
+ nai);
+ return;
+ }
+
+ /* Is there enough room for Cryptosuite and Authentication Tag? */
+ start = parse.keyname + parse.keyname_len;
+ max_len = end - start;
+ hash_len = 16;
+ if (max_len < 1 + (int) hash_len) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Not enough room for Authentication Tag");
+ if (flags & 0x80)
+ goto no_auth_tag;
+ return;
+ }
+ if (end[-17] != EAP_ERP_CS_HMAC_SHA256_128) {
+ wpa_printf(MSG_DEBUG, "EAP: Different Cryptosuite used");
+ if (flags & 0x80)
+ goto no_auth_tag;
+ return;
+ }
+
+ if (hmac_sha256(erp->rIK, erp->rIK_len, (const u8 *) hdr,
+ end - ((const u8 *) hdr) - hash_len, hash) < 0)
+ return;
+ if (os_memcmp(end - hash_len, hash, hash_len) != 0) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: Authentication Tag mismatch");
+ return;
+ }
+ auth_tag_ok = 1;
+ end -= 1 + hash_len;
+
+no_auth_tag:
+ /*
+ * Parse TVs/TLVs again now that we know the exact part of the buffer
+ * that contains them.
+ */
+ wpa_hexdump(MSG_DEBUG, "EAP: EAP-Finish/Re-Auth TVs/TLVs",
+ pos, end - pos);
+ if (erp_parse_tlvs(pos, end, &parse, 0) < 0)
+ return;
+
+ if (flags & 0x80 || !auth_tag_ok) {
+ wpa_printf(MSG_DEBUG,
+ "EAP: EAP-Finish/Re-auth indicated failure");
+ eapol_set_bool(sm, EAPOL_eapFail, TRUE);
+ eapol_set_bool(sm, EAPOL_eapReq, FALSE);
+ eapol_set_bool(sm, EAPOL_eapNoResp, TRUE);
+ wpa_msg(sm->msg_ctx, MSG_INFO, WPA_EVENT_EAP_FAILURE
+ "EAP authentication failed");
+ sm->prev_failure = 1;
+ wpa_printf(MSG_DEBUG,
+ "EAP: Drop ERP key to try full authentication on next attempt");
+ eap_peer_erp_free_key(erp);
+ return;
+ }
+
+ eap_sm_free_key(sm);
+ sm->eapKeyDataLen = 0;
+ sm->eapKeyData = os_malloc(erp->rRK_len);
+ if (!sm->eapKeyData)
+ return;
+ sm->eapKeyDataLen = erp->rRK_len;
+
+ WPA_PUT_BE16(seed, seq);
+ WPA_PUT_BE16(&seed[2], erp->rRK_len);
+ if (hmac_sha256_kdf(erp->rRK, erp->rRK_len,
+ "Re-authentication Master Session Key@ietf.org",
+ seed, sizeof(seed),
+ sm->eapKeyData, erp->rRK_len) < 0) {
+ wpa_printf(MSG_DEBUG, "EAP: Could not derive rMSK for ERP");
+ eap_sm_free_key(sm);
+ return;
+ }
+ wpa_hexdump_key(MSG_DEBUG, "EAP: ERP rMSK",
+ sm->eapKeyData, sm->eapKeyDataLen);
+ sm->eapKeyAvailable = TRUE;
+ eapol_set_bool(sm, EAPOL_eapSuccess, TRUE);
+ eapol_set_bool(sm, EAPOL_eapReq, FALSE);
+ eapol_set_bool(sm, EAPOL_eapNoResp, TRUE);
+ wpa_msg(sm->msg_ctx, MSG_INFO, WPA_EVENT_EAP_SUCCESS
+ "EAP re-authentication completed successfully");
+#endif /* CONFIG_ERP */
+}
+
+
static void eap_sm_parseEapReq(struct eap_sm *sm, const struct wpabuf *req)
{
const struct eap_hdr *hdr;
@@ -1322,6 +1806,12 @@
eap_notify_status(sm, "completion", "failure");
sm->rxFailure = TRUE;
break;
+ case EAP_CODE_INITIATE:
+ eap_peer_initiate(sm, hdr, plen);
+ break;
+ case EAP_CODE_FINISH:
+ eap_peer_finish(sm, hdr, plen);
+ break;
default:
wpa_printf(MSG_DEBUG, "EAP: Ignored EAP-Packet with unknown "
"code %d", hdr->code);
@@ -1413,11 +1903,13 @@
sm->msg_ctx = msg_ctx;
sm->ClientTimeout = EAP_CLIENT_TIMEOUT_DEFAULT;
sm->wps = conf->wps;
+ dl_list_init(&sm->erp_keys);
os_memset(&tlsconf, 0, sizeof(tlsconf));
tlsconf.opensc_engine_path = conf->opensc_engine_path;
tlsconf.pkcs11_engine_path = conf->pkcs11_engine_path;
tlsconf.pkcs11_module_path = conf->pkcs11_module_path;
+ tlsconf.openssl_ciphers = conf->openssl_ciphers;
#ifdef CONFIG_FIPS
tlsconf.fips_mode = 1;
#endif /* CONFIG_FIPS */
@@ -1459,6 +1951,7 @@
if (sm->ssl_ctx2)
tls_deinit(sm->ssl_ctx2);
tls_deinit(sm->ssl_ctx);
+ eap_peer_erp_free_keys(sm);
os_free(sm);
}
@@ -1607,7 +2100,7 @@
len = os_snprintf(buf, buflen,
"EAP state=%s\n",
eap_sm_state_txt(sm->EAP_state));
- if (len < 0 || (size_t) len >= buflen)
+ if (os_snprintf_error(buflen, len))
return 0;
if (sm->selectedMethod != EAP_TYPE_NONE) {
@@ -1626,7 +2119,7 @@
ret = os_snprintf(buf + len, buflen - len,
"selectedMethod=%d (EAP-%s)\n",
sm->selectedMethod, name);
- if (ret < 0 || (size_t) ret >= buflen - len)
+ if (os_snprintf_error(buflen - len, ret))
return len;
len += ret;
@@ -1647,7 +2140,7 @@
eap_sm_method_state_txt(sm->methodState),
eap_sm_decision_txt(sm->decision),
sm->ClientTimeout);
- if (ret < 0 || (size_t) ret >= buflen - len)
+ if (os_snprintf_error(buflen - len, ret))
return len;
len += ret;
}