wpa_supplicant: Initial Revision 0.8.X

Based on:
commit 0725cc7b7efc434910e89865c42eda7ce61bbf08
Author: Jouni Malinen <j@w1.fi>
Date:   Thu Apr 21 20:41:01 2011 +0300

    Enable CONFIG_DRIVER_NL80211=y in the default configuration

    nl80211 should be preferred over WEXT with any recent Linux
    kernel version.

Change-Id: I26aec5afbbd4f4a1f5fd900912545b6f5050de64
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
diff --git a/src/tls/x509v3.c b/src/tls/x509v3.c
new file mode 100644
index 0000000..bc93df6
--- /dev/null
+++ b/src/tls/x509v3.c
@@ -0,0 +1,1985 @@
+/*
+ * X.509v3 certificate parsing and processing (RFC 3280 profile)
+ * Copyright (c) 2006-2007, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#include "includes.h"
+
+#include "common.h"
+#include "crypto/crypto.h"
+#include "asn1.h"
+#include "x509v3.h"
+
+
+static void x509_free_name(struct x509_name *name)
+{
+	size_t i;
+
+	for (i = 0; i < name->num_attr; i++) {
+		os_free(name->attr[i].value);
+		name->attr[i].value = NULL;
+		name->attr[i].type = X509_NAME_ATTR_NOT_USED;
+	}
+	name->num_attr = 0;
+	os_free(name->email);
+	name->email = NULL;
+
+	os_free(name->alt_email);
+	os_free(name->dns);
+	os_free(name->uri);
+	os_free(name->ip);
+	name->alt_email = name->dns = name->uri = NULL;
+	name->ip = NULL;
+	name->ip_len = 0;
+	os_memset(&name->rid, 0, sizeof(name->rid));
+}
+
+
+/**
+ * x509_certificate_free - Free an X.509 certificate
+ * @cert: Certificate to be freed
+ */
+void x509_certificate_free(struct x509_certificate *cert)
+{
+	if (cert == NULL)
+		return;
+	if (cert->next) {
+		wpa_printf(MSG_DEBUG, "X509: x509_certificate_free: cer=%p "
+			   "was still on a list (next=%p)\n",
+			   cert, cert->next);
+	}
+	x509_free_name(&cert->issuer);
+	x509_free_name(&cert->subject);
+	os_free(cert->public_key);
+	os_free(cert->sign_value);
+	os_free(cert);
+}
+
+
+/**
+ * x509_certificate_free - Free an X.509 certificate chain
+ * @cert: Pointer to the first certificate in the chain
+ */
+void x509_certificate_chain_free(struct x509_certificate *cert)
+{
+	struct x509_certificate *next;
+
+	while (cert) {
+		next = cert->next;
+		cert->next = NULL;
+		x509_certificate_free(cert);
+		cert = next;
+	}
+}
+
+
+static int x509_whitespace(char c)
+{
+	return c == ' ' || c == '\t';
+}
+
+
+static void x509_str_strip_whitespace(char *a)
+{
+	char *ipos, *opos;
+	int remove_whitespace = 1;
+
+	ipos = opos = a;
+
+	while (*ipos) {
+		if (remove_whitespace && x509_whitespace(*ipos))
+			ipos++;
+		else {
+			remove_whitespace = x509_whitespace(*ipos);
+			*opos++ = *ipos++;
+		}
+	}
+
+	*opos-- = '\0';
+	if (opos > a && x509_whitespace(*opos))
+		*opos = '\0';
+}
+
+
+static int x509_str_compare(const char *a, const char *b)
+{
+	char *aa, *bb;
+	int ret;
+
+	if (!a && b)
+		return -1;
+	if (a && !b)
+		return 1;
+	if (!a && !b)
+		return 0;
+
+	aa = os_strdup(a);
+	bb = os_strdup(b);
+
+	if (aa == NULL || bb == NULL) {
+		os_free(aa);
+		os_free(bb);
+		return os_strcasecmp(a, b);
+	}
+
+	x509_str_strip_whitespace(aa);
+	x509_str_strip_whitespace(bb);
+
+	ret = os_strcasecmp(aa, bb);
+
+	os_free(aa);
+	os_free(bb);
+
+	return ret;
+}
+
+
+/**
+ * x509_name_compare - Compare X.509 certificate names
+ * @a: Certificate name
+ * @b: Certificate name
+ * Returns: <0, 0, or >0 based on whether a is less than, equal to, or
+ * greater than b
+ */
+int x509_name_compare(struct x509_name *a, struct x509_name *b)
+{
+	int res;
+	size_t i;
+
+	if (!a && b)
+		return -1;
+	if (a && !b)
+		return 1;
+	if (!a && !b)
+		return 0;
+	if (a->num_attr < b->num_attr)
+		return -1;
+	if (a->num_attr > b->num_attr)
+		return 1;
+
+	for (i = 0; i < a->num_attr; i++) {
+		if (a->attr[i].type < b->attr[i].type)
+			return -1;
+		if (a->attr[i].type > b->attr[i].type)
+			return -1;
+		res = x509_str_compare(a->attr[i].value, b->attr[i].value);
+		if (res)
+			return res;
+	}
+	res = x509_str_compare(a->email, b->email);
+	if (res)
+		return res;
+
+	return 0;
+}
+
+
+static int x509_parse_algorithm_identifier(
+	const u8 *buf, size_t len,
+	struct x509_algorithm_identifier *id, const u8 **next)
+{
+	struct asn1_hdr hdr;
+	const u8 *pos, *end;
+
+	/*
+	 * AlgorithmIdentifier ::= SEQUENCE {
+	 *     algorithm            OBJECT IDENTIFIER,
+	 *     parameters           ANY DEFINED BY algorithm OPTIONAL
+	 * }
+	 */
+
+	if (asn1_get_next(buf, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE "
+			   "(AlgorithmIdentifier) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+	pos = hdr.payload;
+	end = pos + hdr.length;
+
+	if (end > buf + len)
+		return -1;
+
+	*next = end;
+
+	if (asn1_get_oid(pos, end - pos, &id->oid, &pos))
+		return -1;
+
+	/* TODO: optional parameters */
+
+	return 0;
+}
+
+
+static int x509_parse_public_key(const u8 *buf, size_t len,
+				 struct x509_certificate *cert,
+				 const u8 **next)
+{
+	struct asn1_hdr hdr;
+	const u8 *pos, *end;
+
+	/*
+	 * SubjectPublicKeyInfo ::= SEQUENCE {
+	 *     algorithm            AlgorithmIdentifier,
+	 *     subjectPublicKey     BIT STRING
+	 * }
+	 */
+
+	pos = buf;
+	end = buf + len;
+
+	if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE "
+			   "(SubjectPublicKeyInfo) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+	pos = hdr.payload;
+
+	if (pos + hdr.length > end)
+		return -1;
+	end = pos + hdr.length;
+	*next = end;
+
+	if (x509_parse_algorithm_identifier(pos, end - pos,
+					    &cert->public_key_alg, &pos))
+		return -1;
+
+	if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_BITSTRING) {
+		wpa_printf(MSG_DEBUG, "X509: Expected BITSTRING "
+			   "(subjectPublicKey) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+	if (hdr.length < 1)
+		return -1;
+	pos = hdr.payload;
+	if (*pos) {
+		wpa_printf(MSG_DEBUG, "X509: BITSTRING - %d unused bits",
+			   *pos);
+		/*
+		 * TODO: should this be rejected? X.509 certificates are
+		 * unlikely to use such a construction. Now we would end up
+		 * including the extra bits in the buffer which may also be
+		 * ok.
+		 */
+	}
+	os_free(cert->public_key);
+	cert->public_key = os_malloc(hdr.length - 1);
+	if (cert->public_key == NULL) {
+		wpa_printf(MSG_DEBUG, "X509: Failed to allocate memory for "
+			   "public key");
+		return -1;
+	}
+	os_memcpy(cert->public_key, pos + 1, hdr.length - 1);
+	cert->public_key_len = hdr.length - 1;
+	wpa_hexdump(MSG_MSGDUMP, "X509: subjectPublicKey",
+		    cert->public_key, cert->public_key_len);
+
+	return 0;
+}
+
+
+static int x509_parse_name(const u8 *buf, size_t len, struct x509_name *name,
+			   const u8 **next)
+{
+	struct asn1_hdr hdr;
+	const u8 *pos, *end, *set_pos, *set_end, *seq_pos, *seq_end;
+	struct asn1_oid oid;
+	char *val;
+
+	/*
+	 * Name ::= CHOICE { RDNSequence }
+	 * RDNSequence ::= SEQUENCE OF RelativeDistinguishedName
+	 * RelativeDistinguishedName ::= SET OF AttributeTypeAndValue
+	 * AttributeTypeAndValue ::= SEQUENCE {
+	 *     type     AttributeType,
+	 *     value    AttributeValue
+	 * }
+	 * AttributeType ::= OBJECT IDENTIFIER
+	 * AttributeValue ::= ANY DEFINED BY AttributeType
+	 */
+
+	if (asn1_get_next(buf, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE "
+			   "(Name / RDNSequencer) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+	pos = hdr.payload;
+
+	if (pos + hdr.length > buf + len)
+		return -1;
+
+	end = *next = pos + hdr.length;
+
+	while (pos < end) {
+		enum x509_name_attr_type type;
+
+		if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+		    hdr.class != ASN1_CLASS_UNIVERSAL ||
+		    hdr.tag != ASN1_TAG_SET) {
+			wpa_printf(MSG_DEBUG, "X509: Expected SET "
+				   "(RelativeDistinguishedName) - found class "
+				   "%d tag 0x%x", hdr.class, hdr.tag);
+			x509_free_name(name);
+			return -1;
+		}
+
+		set_pos = hdr.payload;
+		pos = set_end = hdr.payload + hdr.length;
+
+		if (asn1_get_next(set_pos, set_end - set_pos, &hdr) < 0 ||
+		    hdr.class != ASN1_CLASS_UNIVERSAL ||
+		    hdr.tag != ASN1_TAG_SEQUENCE) {
+			wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE "
+				   "(AttributeTypeAndValue) - found class %d "
+				   "tag 0x%x", hdr.class, hdr.tag);
+			x509_free_name(name);
+			return -1;
+		}
+
+		seq_pos = hdr.payload;
+		seq_end = hdr.payload + hdr.length;
+
+		if (asn1_get_oid(seq_pos, seq_end - seq_pos, &oid, &seq_pos)) {
+			x509_free_name(name);
+			return -1;
+		}
+
+		if (asn1_get_next(seq_pos, seq_end - seq_pos, &hdr) < 0 ||
+		    hdr.class != ASN1_CLASS_UNIVERSAL) {
+			wpa_printf(MSG_DEBUG, "X509: Failed to parse "
+				   "AttributeValue");
+			x509_free_name(name);
+			return -1;
+		}
+
+		/* RFC 3280:
+		 * MUST: country, organization, organizational-unit,
+		 * distinguished name qualifier, state or province name,
+		 * common name, serial number.
+		 * SHOULD: locality, title, surname, given name, initials,
+		 * pseudonym, generation qualifier.
+		 * MUST: domainComponent (RFC 2247).
+		 */
+		type = X509_NAME_ATTR_NOT_USED;
+		if (oid.len == 4 &&
+		    oid.oid[0] == 2 && oid.oid[1] == 5 && oid.oid[2] == 4) {
+			/* id-at ::= 2.5.4 */
+			switch (oid.oid[3]) {
+			case 3:
+				/* commonName */
+				type = X509_NAME_ATTR_CN;
+				break;
+			case 6:
+				/*  countryName */
+				type = X509_NAME_ATTR_C;
+				break;
+			case 7:
+				/* localityName */
+				type = X509_NAME_ATTR_L;
+				break;
+			case 8:
+				/* stateOrProvinceName */
+				type = X509_NAME_ATTR_ST;
+				break;
+			case 10:
+				/* organizationName */
+				type = X509_NAME_ATTR_O;
+				break;
+			case 11:
+				/* organizationalUnitName */
+				type = X509_NAME_ATTR_OU;
+				break;
+			}
+		} else if (oid.len == 7 &&
+			   oid.oid[0] == 1 && oid.oid[1] == 2 &&
+			   oid.oid[2] == 840 && oid.oid[3] == 113549 &&
+			   oid.oid[4] == 1 && oid.oid[5] == 9 &&
+			   oid.oid[6] == 1) {
+			/* 1.2.840.113549.1.9.1 - e-mailAddress */
+			os_free(name->email);
+			name->email = os_malloc(hdr.length + 1);
+			if (name->email == NULL) {
+				x509_free_name(name);
+				return -1;
+			}
+			os_memcpy(name->email, hdr.payload, hdr.length);
+			name->email[hdr.length] = '\0';
+			continue;
+		} else if (oid.len == 7 &&
+			   oid.oid[0] == 0 && oid.oid[1] == 9 &&
+			   oid.oid[2] == 2342 && oid.oid[3] == 19200300 &&
+			   oid.oid[4] == 100 && oid.oid[5] == 1 &&
+			   oid.oid[6] == 25) {
+			/* 0.9.2342.19200300.100.1.25 - domainComponent */
+			type = X509_NAME_ATTR_DC;
+		}
+
+		if (type == X509_NAME_ATTR_NOT_USED) {
+			wpa_hexdump(MSG_DEBUG, "X509: Unrecognized OID",
+				    (u8 *) oid.oid,
+				    oid.len * sizeof(oid.oid[0]));
+			wpa_hexdump_ascii(MSG_MSGDUMP, "X509: Attribute Data",
+					  hdr.payload, hdr.length);
+			continue;
+		}
+
+		if (name->num_attr == X509_MAX_NAME_ATTRIBUTES) {
+			wpa_printf(MSG_INFO, "X509: Too many Name attributes");
+			x509_free_name(name);
+			return -1;
+		}
+
+		val = os_malloc(hdr.length + 1);
+		if (val == NULL) {
+			x509_free_name(name);
+			return -1;
+		}
+		os_memcpy(val, hdr.payload, hdr.length);
+		val[hdr.length] = '\0';
+		if (os_strlen(val) != hdr.length) {
+			wpa_printf(MSG_INFO, "X509: Reject certificate with "
+				   "embedded NUL byte in a string (%s[NUL])",
+				   val);
+			x509_free_name(name);
+			return -1;
+		}
+
+		name->attr[name->num_attr].type = type;
+		name->attr[name->num_attr].value = val;
+		name->num_attr++;
+	}
+
+	return 0;
+}
+
+
+static char * x509_name_attr_str(enum x509_name_attr_type type)
+{
+	switch (type) {
+	case X509_NAME_ATTR_NOT_USED:
+		return "[N/A]";
+	case X509_NAME_ATTR_DC:
+		return "DC";
+	case X509_NAME_ATTR_CN:
+		return "CN";
+	case X509_NAME_ATTR_C:
+		return "C";
+	case X509_NAME_ATTR_L:
+		return "L";
+	case X509_NAME_ATTR_ST:
+		return "ST";
+	case X509_NAME_ATTR_O:
+		return "O";
+	case X509_NAME_ATTR_OU:
+		return "OU";
+	}
+	return "?";
+}
+
+
+/**
+ * x509_name_string - Convert an X.509 certificate name into a string
+ * @name: Name to convert
+ * @buf: Buffer for the string
+ * @len: Maximum buffer length
+ */
+void x509_name_string(struct x509_name *name, char *buf, size_t len)
+{
+	char *pos, *end;
+	int ret;
+	size_t i;
+
+	if (len == 0)
+		return;
+
+	pos = buf;
+	end = buf + len;
+
+	for (i = 0; i < name->num_attr; i++) {
+		ret = os_snprintf(pos, end - pos, "%s=%s, ",
+				  x509_name_attr_str(name->attr[i].type),
+				  name->attr[i].value);
+		if (ret < 0 || ret >= end - pos)
+			goto done;
+		pos += ret;
+	}
+
+	if (pos > buf + 1 && pos[-1] == ' ' && pos[-2] == ',') {
+		pos--;
+		*pos = '\0';
+		pos--;
+		*pos = '\0';
+	}
+
+	if (name->email) {
+		ret = os_snprintf(pos, end - pos, "/emailAddress=%s",
+				  name->email);
+		if (ret < 0 || ret >= end - pos)
+			goto done;
+		pos += ret;
+	}
+
+done:
+	end[-1] = '\0';
+}
+
+
+static int x509_parse_time(const u8 *buf, size_t len, u8 asn1_tag,
+			   os_time_t *val)
+{
+	const char *pos;
+	int year, month, day, hour, min, sec;
+
+	/*
+	 * Time ::= CHOICE {
+	 *     utcTime        UTCTime,
+	 *     generalTime    GeneralizedTime
+	 * }
+	 *
+	 * UTCTime: YYMMDDHHMMSSZ
+	 * GeneralizedTime: YYYYMMDDHHMMSSZ
+	 */
+
+	pos = (const char *) buf;
+
+	switch (asn1_tag) {
+	case ASN1_TAG_UTCTIME:
+		if (len != 13 || buf[12] != 'Z') {
+			wpa_hexdump_ascii(MSG_DEBUG, "X509: Unrecognized "
+					  "UTCTime format", buf, len);
+			return -1;
+		}
+		if (sscanf(pos, "%02d", &year) != 1) {
+			wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse "
+					  "UTCTime year", buf, len);
+			return -1;
+		}
+		if (year < 50)
+			year += 2000;
+		else
+			year += 1900;
+		pos += 2;
+		break;
+	case ASN1_TAG_GENERALIZEDTIME:
+		if (len != 15 || buf[14] != 'Z') {
+			wpa_hexdump_ascii(MSG_DEBUG, "X509: Unrecognized "
+					  "GeneralizedTime format", buf, len);
+			return -1;
+		}
+		if (sscanf(pos, "%04d", &year) != 1) {
+			wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse "
+					  "GeneralizedTime year", buf, len);
+			return -1;
+		}
+		pos += 4;
+		break;
+	default:
+		wpa_printf(MSG_DEBUG, "X509: Expected UTCTime or "
+			   "GeneralizedTime - found tag 0x%x", asn1_tag);
+		return -1;
+	}
+
+	if (sscanf(pos, "%02d", &month) != 1) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse Time "
+				  "(month)", buf, len);
+		return -1;
+	}
+	pos += 2;
+
+	if (sscanf(pos, "%02d", &day) != 1) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse Time "
+				  "(day)", buf, len);
+		return -1;
+	}
+	pos += 2;
+
+	if (sscanf(pos, "%02d", &hour) != 1) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse Time "
+				  "(hour)", buf, len);
+		return -1;
+	}
+	pos += 2;
+
+	if (sscanf(pos, "%02d", &min) != 1) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse Time "
+				  "(min)", buf, len);
+		return -1;
+	}
+	pos += 2;
+
+	if (sscanf(pos, "%02d", &sec) != 1) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse Time "
+				  "(sec)", buf, len);
+		return -1;
+	}
+
+	if (os_mktime(year, month, day, hour, min, sec, val) < 0) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to convert Time",
+				  buf, len);
+		if (year < 1970) {
+			/*
+			 * At least some test certificates have been configured
+			 * to use dates prior to 1970. Set the date to
+			 * beginning of 1970 to handle these case.
+			 */
+			wpa_printf(MSG_DEBUG, "X509: Year=%d before epoch - "
+				   "assume epoch as the time", year);
+			*val = 0;
+			return 0;
+		}
+		return -1;
+	}
+
+	return 0;
+}
+
+
+static int x509_parse_validity(const u8 *buf, size_t len,
+			       struct x509_certificate *cert, const u8 **next)
+{
+	struct asn1_hdr hdr;
+	const u8 *pos;
+	size_t plen;
+
+	/*
+	 * Validity ::= SEQUENCE {
+	 *     notBefore      Time,
+	 *     notAfter       Time
+	 * }
+	 *
+	 * RFC 3280, 4.1.2.5:
+	 * CAs conforming to this profile MUST always encode certificate
+	 * validity dates through the year 2049 as UTCTime; certificate
+	 * validity dates in 2050 or later MUST be encoded as GeneralizedTime.
+	 */
+
+	if (asn1_get_next(buf, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE "
+			   "(Validity) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+	pos = hdr.payload;
+	plen = hdr.length;
+
+	if (pos + plen > buf + len)
+		return -1;
+
+	*next = pos + plen;
+
+	if (asn1_get_next(pos, plen, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    x509_parse_time(hdr.payload, hdr.length, hdr.tag,
+			    &cert->not_before) < 0) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse notBefore "
+				  "Time", hdr.payload, hdr.length);
+		return -1;
+	}
+
+	pos = hdr.payload + hdr.length;
+	plen = *next - pos;
+
+	if (asn1_get_next(pos, plen, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    x509_parse_time(hdr.payload, hdr.length, hdr.tag,
+			    &cert->not_after) < 0) {
+		wpa_hexdump_ascii(MSG_DEBUG, "X509: Failed to parse notAfter "
+				  "Time", hdr.payload, hdr.length);
+		return -1;
+	}
+
+	wpa_printf(MSG_MSGDUMP, "X509: Validity: notBefore: %lu notAfter: %lu",
+		   (unsigned long) cert->not_before,
+		   (unsigned long) cert->not_after);
+
+	return 0;
+}
+
+
+static int x509_id_ce_oid(struct asn1_oid *oid)
+{
+	/* id-ce arc from X.509 for standard X.509v3 extensions */
+	return oid->len >= 4 &&
+		oid->oid[0] == 2 /* joint-iso-ccitt */ &&
+		oid->oid[1] == 5 /* ds */ &&
+		oid->oid[2] == 29 /* id-ce */;
+}
+
+
+static int x509_parse_ext_key_usage(struct x509_certificate *cert,
+				    const u8 *pos, size_t len)
+{
+	struct asn1_hdr hdr;
+
+	/*
+	 * KeyUsage ::= BIT STRING {
+	 *     digitalSignature        (0),
+	 *     nonRepudiation          (1),
+	 *     keyEncipherment         (2),
+	 *     dataEncipherment        (3),
+	 *     keyAgreement            (4),
+	 *     keyCertSign             (5),
+	 *     cRLSign                 (6),
+	 *     encipherOnly            (7),
+	 *     decipherOnly            (8) }
+	 */
+
+	if (asn1_get_next(pos, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_BITSTRING ||
+	    hdr.length < 1) {
+		wpa_printf(MSG_DEBUG, "X509: Expected BIT STRING in "
+			   "KeyUsage; found %d tag 0x%x len %d",
+			   hdr.class, hdr.tag, hdr.length);
+		return -1;
+	}
+
+	cert->extensions_present |= X509_EXT_KEY_USAGE;
+	cert->key_usage = asn1_bit_string_to_long(hdr.payload, hdr.length);
+
+	wpa_printf(MSG_DEBUG, "X509: KeyUsage 0x%lx", cert->key_usage);
+
+	return 0;
+}
+
+
+static int x509_parse_ext_basic_constraints(struct x509_certificate *cert,
+					    const u8 *pos, size_t len)
+{
+	struct asn1_hdr hdr;
+	unsigned long value;
+	size_t left;
+
+	/*
+	 * BasicConstraints ::= SEQUENCE {
+	 * cA                      BOOLEAN DEFAULT FALSE,
+	 * pathLenConstraint       INTEGER (0..MAX) OPTIONAL }
+	 */
+
+	if (asn1_get_next(pos, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE in "
+			   "BasicConstraints; found %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+
+	cert->extensions_present |= X509_EXT_BASIC_CONSTRAINTS;
+
+	if (hdr.length == 0)
+		return 0;
+
+	if (asn1_get_next(hdr.payload, hdr.length, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL) {
+		wpa_printf(MSG_DEBUG, "X509: Failed to parse "
+			   "BasicConstraints");
+		return -1;
+	}
+
+	if (hdr.tag == ASN1_TAG_BOOLEAN) {
+		if (hdr.length != 1) {
+			wpa_printf(MSG_DEBUG, "X509: Unexpected "
+				   "Boolean length (%u) in BasicConstraints",
+				   hdr.length);
+			return -1;
+		}
+		cert->ca = hdr.payload[0];
+
+		if (hdr.payload + hdr.length == pos + len) {
+			wpa_printf(MSG_DEBUG, "X509: BasicConstraints - cA=%d",
+				   cert->ca);
+			return 0;
+		}
+
+		if (asn1_get_next(hdr.payload + hdr.length, len - hdr.length,
+				  &hdr) < 0 ||
+		    hdr.class != ASN1_CLASS_UNIVERSAL) {
+			wpa_printf(MSG_DEBUG, "X509: Failed to parse "
+				   "BasicConstraints");
+			return -1;
+		}
+	}
+
+	if (hdr.tag != ASN1_TAG_INTEGER) {
+		wpa_printf(MSG_DEBUG, "X509: Expected INTEGER in "
+			   "BasicConstraints; found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+
+	pos = hdr.payload;
+	left = hdr.length;
+	value = 0;
+	while (left) {
+		value <<= 8;
+		value |= *pos++;
+		left--;
+	}
+
+	cert->path_len_constraint = value;
+	cert->extensions_present |= X509_EXT_PATH_LEN_CONSTRAINT;
+
+	wpa_printf(MSG_DEBUG, "X509: BasicConstraints - cA=%d "
+		   "pathLenConstraint=%lu",
+		   cert->ca, cert->path_len_constraint);
+
+	return 0;
+}
+
+
+static int x509_parse_alt_name_rfc8222(struct x509_name *name,
+				       const u8 *pos, size_t len)
+{
+	/* rfc822Name IA5String */
+	wpa_hexdump_ascii(MSG_MSGDUMP, "X509: altName - rfc822Name", pos, len);
+	os_free(name->alt_email);
+	name->alt_email = os_zalloc(len + 1);
+	if (name->alt_email == NULL)
+		return -1;
+	os_memcpy(name->alt_email, pos, len);
+	if (os_strlen(name->alt_email) != len) {
+		wpa_printf(MSG_INFO, "X509: Reject certificate with "
+			   "embedded NUL byte in rfc822Name (%s[NUL])",
+			   name->alt_email);
+		os_free(name->alt_email);
+		name->alt_email = NULL;
+		return -1;
+	}
+	return 0;
+}
+
+
+static int x509_parse_alt_name_dns(struct x509_name *name,
+				   const u8 *pos, size_t len)
+{
+	/* dNSName IA5String */
+	wpa_hexdump_ascii(MSG_MSGDUMP, "X509: altName - dNSName", pos, len);
+	os_free(name->dns);
+	name->dns = os_zalloc(len + 1);
+	if (name->dns == NULL)
+		return -1;
+	os_memcpy(name->dns, pos, len);
+	if (os_strlen(name->dns) != len) {
+		wpa_printf(MSG_INFO, "X509: Reject certificate with "
+			   "embedded NUL byte in dNSName (%s[NUL])",
+			   name->dns);
+		os_free(name->dns);
+		name->dns = NULL;
+		return -1;
+	}
+	return 0;
+}
+
+
+static int x509_parse_alt_name_uri(struct x509_name *name,
+				   const u8 *pos, size_t len)
+{
+	/* uniformResourceIdentifier IA5String */
+	wpa_hexdump_ascii(MSG_MSGDUMP,
+			  "X509: altName - uniformResourceIdentifier",
+			  pos, len);
+	os_free(name->uri);
+	name->uri = os_zalloc(len + 1);
+	if (name->uri == NULL)
+		return -1;
+	os_memcpy(name->uri, pos, len);
+	if (os_strlen(name->uri) != len) {
+		wpa_printf(MSG_INFO, "X509: Reject certificate with "
+			   "embedded NUL byte in uniformResourceIdentifier "
+			   "(%s[NUL])", name->uri);
+		os_free(name->uri);
+		name->uri = NULL;
+		return -1;
+	}
+	return 0;
+}
+
+
+static int x509_parse_alt_name_ip(struct x509_name *name,
+				       const u8 *pos, size_t len)
+{
+	/* iPAddress OCTET STRING */
+	wpa_hexdump(MSG_MSGDUMP, "X509: altName - iPAddress", pos, len);
+	os_free(name->ip);
+	name->ip = os_malloc(len);
+	if (name->ip == NULL)
+		return -1;
+	os_memcpy(name->ip, pos, len);
+	name->ip_len = len;
+	return 0;
+}
+
+
+static int x509_parse_alt_name_rid(struct x509_name *name,
+				   const u8 *pos, size_t len)
+{
+	char buf[80];
+
+	/* registeredID OBJECT IDENTIFIER */
+	if (asn1_parse_oid(pos, len, &name->rid) < 0)
+		return -1;
+
+	asn1_oid_to_str(&name->rid, buf, sizeof(buf));
+	wpa_printf(MSG_MSGDUMP, "X509: altName - registeredID: %s", buf);
+
+	return 0;
+}
+
+
+static int x509_parse_ext_alt_name(struct x509_name *name,
+				   const u8 *pos, size_t len)
+{
+	struct asn1_hdr hdr;
+	const u8 *p, *end;
+
+	/*
+	 * GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName
+	 *
+	 * GeneralName ::= CHOICE {
+	 *     otherName                       [0]     OtherName,
+	 *     rfc822Name                      [1]     IA5String,
+	 *     dNSName                         [2]     IA5String,
+	 *     x400Address                     [3]     ORAddress,
+	 *     directoryName                   [4]     Name,
+	 *     ediPartyName                    [5]     EDIPartyName,
+	 *     uniformResourceIdentifier       [6]     IA5String,
+	 *     iPAddress                       [7]     OCTET STRING,
+	 *     registeredID                    [8]     OBJECT IDENTIFIER }
+	 *
+	 * OtherName ::= SEQUENCE {
+	 *     type-id    OBJECT IDENTIFIER,
+	 *     value      [0] EXPLICIT ANY DEFINED BY type-id }
+	 *
+	 * EDIPartyName ::= SEQUENCE {
+	 *     nameAssigner            [0]     DirectoryString OPTIONAL,
+	 *     partyName               [1]     DirectoryString }
+	 */
+
+	for (p = pos, end = pos + len; p < end; p = hdr.payload + hdr.length) {
+		int res;
+
+		if (asn1_get_next(p, end - p, &hdr) < 0) {
+			wpa_printf(MSG_DEBUG, "X509: Failed to parse "
+				   "SubjectAltName item");
+			return -1;
+		}
+
+		if (hdr.class != ASN1_CLASS_CONTEXT_SPECIFIC)
+			continue;
+
+		switch (hdr.tag) {
+		case 1:
+			res = x509_parse_alt_name_rfc8222(name, hdr.payload,
+							  hdr.length);
+			break;
+		case 2:
+			res = x509_parse_alt_name_dns(name, hdr.payload,
+						      hdr.length);
+			break;
+		case 6:
+			res = x509_parse_alt_name_uri(name, hdr.payload,
+						      hdr.length);
+			break;
+		case 7:
+			res = x509_parse_alt_name_ip(name, hdr.payload,
+						     hdr.length);
+			break;
+		case 8:
+			res = x509_parse_alt_name_rid(name, hdr.payload,
+						      hdr.length);
+			break;
+		case 0: /* TODO: otherName */
+		case 3: /* TODO: x500Address */
+		case 4: /* TODO: directoryName */
+		case 5: /* TODO: ediPartyName */
+		default:
+			res = 0;
+			break;
+		}
+		if (res < 0)
+			return res;
+	}
+
+	return 0;
+}
+
+
+static int x509_parse_ext_subject_alt_name(struct x509_certificate *cert,
+					   const u8 *pos, size_t len)
+{
+	struct asn1_hdr hdr;
+
+	/* SubjectAltName ::= GeneralNames */
+
+	if (asn1_get_next(pos, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE in "
+			   "SubjectAltName; found %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+
+	wpa_printf(MSG_DEBUG, "X509: SubjectAltName");
+	cert->extensions_present |= X509_EXT_SUBJECT_ALT_NAME;
+
+	if (hdr.length == 0)
+		return 0;
+
+	return x509_parse_ext_alt_name(&cert->subject, hdr.payload,
+				       hdr.length);
+}
+
+
+static int x509_parse_ext_issuer_alt_name(struct x509_certificate *cert,
+					  const u8 *pos, size_t len)
+{
+	struct asn1_hdr hdr;
+
+	/* IssuerAltName ::= GeneralNames */
+
+	if (asn1_get_next(pos, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE in "
+			   "IssuerAltName; found %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+
+	wpa_printf(MSG_DEBUG, "X509: IssuerAltName");
+	cert->extensions_present |= X509_EXT_ISSUER_ALT_NAME;
+
+	if (hdr.length == 0)
+		return 0;
+
+	return x509_parse_ext_alt_name(&cert->issuer, hdr.payload,
+				       hdr.length);
+}
+
+
+static int x509_parse_extension_data(struct x509_certificate *cert,
+				     struct asn1_oid *oid,
+				     const u8 *pos, size_t len)
+{
+	if (!x509_id_ce_oid(oid))
+		return 1;
+
+	/* TODO: add other extensions required by RFC 3280, Ch 4.2:
+	 * certificate policies (section 4.2.1.5)
+	 * name constraints (section 4.2.1.11)
+	 * policy constraints (section 4.2.1.12)
+	 * extended key usage (section 4.2.1.13)
+	 * inhibit any-policy (section 4.2.1.15)
+	 */
+	switch (oid->oid[3]) {
+	case 15: /* id-ce-keyUsage */
+		return x509_parse_ext_key_usage(cert, pos, len);
+	case 17: /* id-ce-subjectAltName */
+		return x509_parse_ext_subject_alt_name(cert, pos, len);
+	case 18: /* id-ce-issuerAltName */
+		return x509_parse_ext_issuer_alt_name(cert, pos, len);
+	case 19: /* id-ce-basicConstraints */
+		return x509_parse_ext_basic_constraints(cert, pos, len);
+	default:
+		return 1;
+	}
+}
+
+
+static int x509_parse_extension(struct x509_certificate *cert,
+				const u8 *pos, size_t len, const u8 **next)
+{
+	const u8 *end;
+	struct asn1_hdr hdr;
+	struct asn1_oid oid;
+	int critical_ext = 0, res;
+	char buf[80];
+
+	/*
+	 * Extension  ::=  SEQUENCE  {
+	 *     extnID      OBJECT IDENTIFIER,
+	 *     critical    BOOLEAN DEFAULT FALSE,
+	 *     extnValue   OCTET STRING
+	 * }
+	 */
+
+	if (asn1_get_next(pos, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Unexpected ASN.1 header in "
+			   "Extensions: class %d tag 0x%x; expected SEQUENCE",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+	pos = hdr.payload;
+	*next = end = pos + hdr.length;
+
+	if (asn1_get_oid(pos, end - pos, &oid, &pos) < 0) {
+		wpa_printf(MSG_DEBUG, "X509: Unexpected ASN.1 data for "
+			   "Extension (expected OID)");
+		return -1;
+	}
+
+	if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    (hdr.tag != ASN1_TAG_BOOLEAN &&
+	     hdr.tag != ASN1_TAG_OCTETSTRING)) {
+		wpa_printf(MSG_DEBUG, "X509: Unexpected ASN.1 header in "
+			   "Extensions: class %d tag 0x%x; expected BOOLEAN "
+			   "or OCTET STRING", hdr.class, hdr.tag);
+		return -1;
+	}
+
+	if (hdr.tag == ASN1_TAG_BOOLEAN) {
+		if (hdr.length != 1) {
+			wpa_printf(MSG_DEBUG, "X509: Unexpected "
+				   "Boolean length (%u)", hdr.length);
+			return -1;
+		}
+		critical_ext = hdr.payload[0];
+		pos = hdr.payload;
+		if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+		    (hdr.class != ASN1_CLASS_UNIVERSAL &&
+		     hdr.class != ASN1_CLASS_PRIVATE) ||
+		    hdr.tag != ASN1_TAG_OCTETSTRING) {
+			wpa_printf(MSG_DEBUG, "X509: Unexpected ASN.1 header "
+				   "in Extensions: class %d tag 0x%x; "
+				   "expected OCTET STRING",
+				   hdr.class, hdr.tag);
+			return -1;
+		}
+	}
+
+	asn1_oid_to_str(&oid, buf, sizeof(buf));
+	wpa_printf(MSG_DEBUG, "X509: Extension: extnID=%s critical=%d",
+		   buf, critical_ext);
+	wpa_hexdump(MSG_MSGDUMP, "X509: extnValue", hdr.payload, hdr.length);
+
+	res = x509_parse_extension_data(cert, &oid, hdr.payload, hdr.length);
+	if (res < 0)
+		return res;
+	if (res == 1 && critical_ext) {
+		wpa_printf(MSG_INFO, "X509: Unknown critical extension %s",
+			   buf);
+		return -1;
+	}
+
+	return 0;
+}
+
+
+static int x509_parse_extensions(struct x509_certificate *cert,
+				 const u8 *pos, size_t len)
+{
+	const u8 *end;
+	struct asn1_hdr hdr;
+
+	/* Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension */
+
+	if (asn1_get_next(pos, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Unexpected ASN.1 data "
+			   "for Extensions: class %d tag 0x%x; "
+			   "expected SEQUENCE", hdr.class, hdr.tag);
+		return -1;
+	}
+
+	pos = hdr.payload;
+	end = pos + hdr.length;
+
+	while (pos < end) {
+		if (x509_parse_extension(cert, pos, end - pos, &pos)
+		    < 0)
+			return -1;
+	}
+
+	return 0;
+}
+
+
+static int x509_parse_tbs_certificate(const u8 *buf, size_t len,
+				      struct x509_certificate *cert,
+				      const u8 **next)
+{
+	struct asn1_hdr hdr;
+	const u8 *pos, *end;
+	size_t left;
+	char sbuf[128];
+	unsigned long value;
+
+	/* tbsCertificate TBSCertificate ::= SEQUENCE */
+	if (asn1_get_next(buf, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: tbsCertificate did not start "
+			   "with a valid SEQUENCE - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+	pos = hdr.payload;
+	end = *next = pos + hdr.length;
+
+	/*
+	 * version [0]  EXPLICIT Version DEFAULT v1
+	 * Version  ::=  INTEGER  {  v1(0), v2(1), v3(2)  }
+	 */
+	if (asn1_get_next(pos, end - pos, &hdr) < 0)
+		return -1;
+	pos = hdr.payload;
+
+	if (hdr.class == ASN1_CLASS_CONTEXT_SPECIFIC) {
+		if (asn1_get_next(pos, end - pos, &hdr) < 0)
+			return -1;
+
+		if (hdr.class != ASN1_CLASS_UNIVERSAL ||
+		    hdr.tag != ASN1_TAG_INTEGER) {
+			wpa_printf(MSG_DEBUG, "X509: No INTEGER tag found for "
+				   "version field - found class %d tag 0x%x",
+				   hdr.class, hdr.tag);
+			return -1;
+		}
+		if (hdr.length != 1) {
+			wpa_printf(MSG_DEBUG, "X509: Unexpected version field "
+				   "length %u (expected 1)", hdr.length);
+			return -1;
+		}
+		pos = hdr.payload;
+		left = hdr.length;
+		value = 0;
+		while (left) {
+			value <<= 8;
+			value |= *pos++;
+			left--;
+		}
+
+		cert->version = value;
+		if (cert->version != X509_CERT_V1 &&
+		    cert->version != X509_CERT_V2 &&
+		    cert->version != X509_CERT_V3) {
+			wpa_printf(MSG_DEBUG, "X509: Unsupported version %d",
+				   cert->version + 1);
+			return -1;
+		}
+
+		if (asn1_get_next(pos, end - pos, &hdr) < 0)
+			return -1;
+	} else
+		cert->version = X509_CERT_V1;
+	wpa_printf(MSG_MSGDUMP, "X509: Version X.509v%d", cert->version + 1);
+
+	/* serialNumber CertificateSerialNumber ::= INTEGER */
+	if (hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_INTEGER) {
+		wpa_printf(MSG_DEBUG, "X509: No INTEGER tag found for "
+			   "serialNumber; class=%d tag=0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+
+	pos = hdr.payload;
+	left = hdr.length;
+	while (left) {
+		cert->serial_number <<= 8;
+		cert->serial_number |= *pos++;
+		left--;
+	}
+	wpa_printf(MSG_MSGDUMP, "X509: serialNumber %lu", cert->serial_number);
+
+	/* signature AlgorithmIdentifier */
+	if (x509_parse_algorithm_identifier(pos, end - pos, &cert->signature,
+					    &pos))
+		return -1;
+
+	/* issuer Name */
+	if (x509_parse_name(pos, end - pos, &cert->issuer, &pos))
+		return -1;
+	x509_name_string(&cert->issuer, sbuf, sizeof(sbuf));
+	wpa_printf(MSG_MSGDUMP, "X509: issuer %s", sbuf);
+
+	/* validity Validity */
+	if (x509_parse_validity(pos, end - pos, cert, &pos))
+		return -1;
+
+	/* subject Name */
+	if (x509_parse_name(pos, end - pos, &cert->subject, &pos))
+		return -1;
+	x509_name_string(&cert->subject, sbuf, sizeof(sbuf));
+	wpa_printf(MSG_MSGDUMP, "X509: subject %s", sbuf);
+
+	/* subjectPublicKeyInfo SubjectPublicKeyInfo */
+	if (x509_parse_public_key(pos, end - pos, cert, &pos))
+		return -1;
+
+	if (pos == end)
+		return 0;
+
+	if (cert->version == X509_CERT_V1)
+		return 0;
+
+	if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_CONTEXT_SPECIFIC) {
+		wpa_printf(MSG_DEBUG, "X509: Expected Context-Specific"
+			   " tag to parse optional tbsCertificate "
+			   "field(s); parsed class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		return -1;
+	}
+
+	if (hdr.tag == 1) {
+		/* issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL */
+		wpa_printf(MSG_DEBUG, "X509: issuerUniqueID");
+		/* TODO: parse UniqueIdentifier ::= BIT STRING */
+
+		if (hdr.payload + hdr.length == end)
+			return 0;
+
+		if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+		    hdr.class != ASN1_CLASS_CONTEXT_SPECIFIC) {
+			wpa_printf(MSG_DEBUG, "X509: Expected Context-Specific"
+				   " tag to parse optional tbsCertificate "
+				   "field(s); parsed class %d tag 0x%x",
+				   hdr.class, hdr.tag);
+			return -1;
+		}
+	}
+
+	if (hdr.tag == 2) {
+		/* subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL */
+		wpa_printf(MSG_DEBUG, "X509: subjectUniqueID");
+		/* TODO: parse UniqueIdentifier ::= BIT STRING */
+
+		if (hdr.payload + hdr.length == end)
+			return 0;
+
+		if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+		    hdr.class != ASN1_CLASS_CONTEXT_SPECIFIC) {
+			wpa_printf(MSG_DEBUG, "X509: Expected Context-Specific"
+				   " tag to parse optional tbsCertificate "
+				   "field(s); parsed class %d tag 0x%x",
+				   hdr.class, hdr.tag);
+			return -1;
+		}
+	}
+
+	if (hdr.tag != 3) {
+		wpa_printf(MSG_DEBUG, "X509: Ignored unexpected "
+			   "Context-Specific tag %d in optional "
+			   "tbsCertificate fields", hdr.tag);
+		return 0;
+	}
+
+	/* extensions      [3]  EXPLICIT Extensions OPTIONAL */
+
+	if (cert->version != X509_CERT_V3) {
+		wpa_printf(MSG_DEBUG, "X509: X.509%d certificate and "
+			   "Extensions data which are only allowed for "
+			   "version 3", cert->version + 1);
+		return -1;
+	}
+
+	if (x509_parse_extensions(cert, hdr.payload, hdr.length) < 0)
+		return -1;
+
+	pos = hdr.payload + hdr.length;
+	if (pos < end) {
+		wpa_hexdump(MSG_DEBUG,
+			    "X509: Ignored extra tbsCertificate data",
+			    pos, end - pos);
+	}
+
+	return 0;
+}
+
+
+static int x509_rsadsi_oid(struct asn1_oid *oid)
+{
+	return oid->len >= 4 &&
+		oid->oid[0] == 1 /* iso */ &&
+		oid->oid[1] == 2 /* member-body */ &&
+		oid->oid[2] == 840 /* us */ &&
+		oid->oid[3] == 113549 /* rsadsi */;
+}
+
+
+static int x509_pkcs_oid(struct asn1_oid *oid)
+{
+	return oid->len >= 5 &&
+		x509_rsadsi_oid(oid) &&
+		oid->oid[4] == 1 /* pkcs */;
+}
+
+
+static int x509_digest_oid(struct asn1_oid *oid)
+{
+	return oid->len >= 5 &&
+		x509_rsadsi_oid(oid) &&
+		oid->oid[4] == 2 /* digestAlgorithm */;
+}
+
+
+static int x509_sha1_oid(struct asn1_oid *oid)
+{
+	return oid->len == 6 &&
+		oid->oid[0] == 1 /* iso */ &&
+		oid->oid[1] == 3 /* identified-organization */ &&
+		oid->oid[2] == 14 /* oiw */ &&
+		oid->oid[3] == 3 /* secsig */ &&
+		oid->oid[4] == 2 /* algorithms */ &&
+		oid->oid[5] == 26 /* id-sha1 */;
+}
+
+
+static int x509_sha256_oid(struct asn1_oid *oid)
+{
+	return oid->len == 9 &&
+		oid->oid[0] == 2 /* joint-iso-itu-t */ &&
+		oid->oid[1] == 16 /* country */ &&
+		oid->oid[2] == 840 /* us */ &&
+		oid->oid[3] == 1 /* organization */ &&
+		oid->oid[4] == 101 /* gov */ &&
+		oid->oid[5] == 3 /* csor */ &&
+		oid->oid[6] == 4 /* nistAlgorithm */ &&
+		oid->oid[7] == 2 /* hashAlgs */ &&
+		oid->oid[8] == 1 /* sha256 */;
+}
+
+
+/**
+ * x509_certificate_parse - Parse a X.509 certificate in DER format
+ * @buf: Pointer to the X.509 certificate in DER format
+ * @len: Buffer length
+ * Returns: Pointer to the parsed certificate or %NULL on failure
+ *
+ * Caller is responsible for freeing the returned certificate by calling
+ * x509_certificate_free().
+ */
+struct x509_certificate * x509_certificate_parse(const u8 *buf, size_t len)
+{
+	struct asn1_hdr hdr;
+	const u8 *pos, *end, *hash_start;
+	struct x509_certificate *cert;
+
+	cert = os_zalloc(sizeof(*cert) + len);
+	if (cert == NULL)
+		return NULL;
+	os_memcpy(cert + 1, buf, len);
+	cert->cert_start = (u8 *) (cert + 1);
+	cert->cert_len = len;
+
+	pos = buf;
+	end = buf + len;
+
+	/* RFC 3280 - X.509 v3 certificate / ASN.1 DER */
+
+	/* Certificate ::= SEQUENCE */
+	if (asn1_get_next(pos, len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Certificate did not start with "
+			   "a valid SEQUENCE - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		x509_certificate_free(cert);
+		return NULL;
+	}
+	pos = hdr.payload;
+
+	if (pos + hdr.length > end) {
+		x509_certificate_free(cert);
+		return NULL;
+	}
+
+	if (pos + hdr.length < end) {
+		wpa_hexdump(MSG_MSGDUMP, "X509: Ignoring extra data after DER "
+			    "encoded certificate",
+			    pos + hdr.length, end - pos + hdr.length);
+		end = pos + hdr.length;
+	}
+
+	hash_start = pos;
+	cert->tbs_cert_start = cert->cert_start + (hash_start - buf);
+	if (x509_parse_tbs_certificate(pos, end - pos, cert, &pos)) {
+		x509_certificate_free(cert);
+		return NULL;
+	}
+	cert->tbs_cert_len = pos - hash_start;
+
+	/* signatureAlgorithm AlgorithmIdentifier */
+	if (x509_parse_algorithm_identifier(pos, end - pos,
+					    &cert->signature_alg, &pos)) {
+		x509_certificate_free(cert);
+		return NULL;
+	}
+
+	/* signatureValue BIT STRING */
+	if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_BITSTRING) {
+		wpa_printf(MSG_DEBUG, "X509: Expected BITSTRING "
+			   "(signatureValue) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		x509_certificate_free(cert);
+		return NULL;
+	}
+	if (hdr.length < 1) {
+		x509_certificate_free(cert);
+		return NULL;
+	}
+	pos = hdr.payload;
+	if (*pos) {
+		wpa_printf(MSG_DEBUG, "X509: BITSTRING - %d unused bits",
+			   *pos);
+		/* PKCS #1 v1.5 10.2.1:
+		 * It is an error if the length in bits of the signature S is
+		 * not a multiple of eight.
+		 */
+		x509_certificate_free(cert);
+		return NULL;
+	}
+	os_free(cert->sign_value);
+	cert->sign_value = os_malloc(hdr.length - 1);
+	if (cert->sign_value == NULL) {
+		wpa_printf(MSG_DEBUG, "X509: Failed to allocate memory for "
+			   "signatureValue");
+		x509_certificate_free(cert);
+		return NULL;
+	}
+	os_memcpy(cert->sign_value, pos + 1, hdr.length - 1);
+	cert->sign_value_len = hdr.length - 1;
+	wpa_hexdump(MSG_MSGDUMP, "X509: signature",
+		    cert->sign_value, cert->sign_value_len);
+
+	return cert;
+}
+
+
+/**
+ * x509_certificate_check_signature - Verify certificate signature
+ * @issuer: Issuer certificate
+ * @cert: Certificate to be verified
+ * Returns: 0 if cert has a valid signature that was signed by the issuer,
+ * -1 if not
+ */
+int x509_certificate_check_signature(struct x509_certificate *issuer,
+				     struct x509_certificate *cert)
+{
+	struct crypto_public_key *pk;
+	u8 *data;
+	const u8 *pos, *end, *next, *da_end;
+	size_t data_len;
+	struct asn1_hdr hdr;
+	struct asn1_oid oid;
+	u8 hash[32];
+	size_t hash_len;
+
+	if (!x509_pkcs_oid(&cert->signature.oid) ||
+	    cert->signature.oid.len != 7 ||
+	    cert->signature.oid.oid[5] != 1 /* pkcs-1 */) {
+		wpa_printf(MSG_DEBUG, "X509: Unrecognized signature "
+			   "algorithm");
+		return -1;
+	}
+
+	pk = crypto_public_key_import(issuer->public_key,
+				      issuer->public_key_len);
+	if (pk == NULL)
+		return -1;
+
+	data_len = cert->sign_value_len;
+	data = os_malloc(data_len);
+	if (data == NULL) {
+		crypto_public_key_free(pk);
+		return -1;
+	}
+
+	if (crypto_public_key_decrypt_pkcs1(pk, cert->sign_value,
+					    cert->sign_value_len, data,
+					    &data_len) < 0) {
+		wpa_printf(MSG_DEBUG, "X509: Failed to decrypt signature");
+		crypto_public_key_free(pk);
+		os_free(data);
+		return -1;
+	}
+	crypto_public_key_free(pk);
+
+	wpa_hexdump(MSG_MSGDUMP, "X509: Signature data D", data, data_len);
+
+	/*
+	 * PKCS #1 v1.5, 10.1.2:
+	 *
+	 * DigestInfo ::= SEQUENCE {
+	 *     digestAlgorithm DigestAlgorithmIdentifier,
+	 *     digest Digest
+	 * }
+	 *
+	 * DigestAlgorithmIdentifier ::= AlgorithmIdentifier
+	 *
+	 * Digest ::= OCTET STRING
+	 *
+	 */
+	if (asn1_get_next(data, data_len, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE "
+			   "(DigestInfo) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		os_free(data);
+		return -1;
+	}
+
+	pos = hdr.payload;
+	end = pos + hdr.length;
+
+	/*
+	 * X.509:
+	 * AlgorithmIdentifier ::= SEQUENCE {
+	 *     algorithm            OBJECT IDENTIFIER,
+	 *     parameters           ANY DEFINED BY algorithm OPTIONAL
+	 * }
+	 */
+
+	if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_SEQUENCE) {
+		wpa_printf(MSG_DEBUG, "X509: Expected SEQUENCE "
+			   "(AlgorithmIdentifier) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		os_free(data);
+		return -1;
+	}
+	da_end = hdr.payload + hdr.length;
+
+	if (asn1_get_oid(hdr.payload, hdr.length, &oid, &next)) {
+		wpa_printf(MSG_DEBUG, "X509: Failed to parse digestAlgorithm");
+		os_free(data);
+		return -1;
+	}
+
+	if (x509_sha1_oid(&oid)) {
+		if (cert->signature.oid.oid[6] !=
+		    5 /* sha-1WithRSAEncryption */) {
+			wpa_printf(MSG_DEBUG, "X509: digestAlgorithm SHA1 "
+				   "does not match with certificate "
+				   "signatureAlgorithm (%lu)",
+				   cert->signature.oid.oid[6]);
+			os_free(data);
+			return -1;
+		}
+		goto skip_digest_oid;
+	}
+
+	if (x509_sha256_oid(&oid)) {
+		if (cert->signature.oid.oid[6] !=
+		    11 /* sha2561WithRSAEncryption */) {
+			wpa_printf(MSG_DEBUG, "X509: digestAlgorithm SHA256 "
+				   "does not match with certificate "
+				   "signatureAlgorithm (%lu)",
+				   cert->signature.oid.oid[6]);
+			os_free(data);
+			return -1;
+		}
+		goto skip_digest_oid;
+	}
+
+	if (!x509_digest_oid(&oid)) {
+		wpa_printf(MSG_DEBUG, "X509: Unrecognized digestAlgorithm");
+		os_free(data);
+		return -1;
+	}
+	switch (oid.oid[5]) {
+	case 5: /* md5 */
+		if (cert->signature.oid.oid[6] != 4 /* md5WithRSAEncryption */)
+		{
+			wpa_printf(MSG_DEBUG, "X509: digestAlgorithm MD5 does "
+				   "not match with certificate "
+				   "signatureAlgorithm (%lu)",
+				   cert->signature.oid.oid[6]);
+			os_free(data);
+			return -1;
+		}
+		break;
+	case 2: /* md2 */
+	case 4: /* md4 */
+	default:
+		wpa_printf(MSG_DEBUG, "X509: Unsupported digestAlgorithm "
+			   "(%lu)", oid.oid[5]);
+		os_free(data);
+		return -1;
+	}
+
+skip_digest_oid:
+	/* Digest ::= OCTET STRING */
+	pos = da_end;
+	end = data + data_len;
+
+	if (asn1_get_next(pos, end - pos, &hdr) < 0 ||
+	    hdr.class != ASN1_CLASS_UNIVERSAL ||
+	    hdr.tag != ASN1_TAG_OCTETSTRING) {
+		wpa_printf(MSG_DEBUG, "X509: Expected OCTETSTRING "
+			   "(Digest) - found class %d tag 0x%x",
+			   hdr.class, hdr.tag);
+		os_free(data);
+		return -1;
+	}
+	wpa_hexdump(MSG_MSGDUMP, "X509: Decrypted Digest",
+		    hdr.payload, hdr.length);
+
+	switch (cert->signature.oid.oid[6]) {
+	case 4: /* md5WithRSAEncryption */
+		md5_vector(1, &cert->tbs_cert_start, &cert->tbs_cert_len,
+			   hash);
+		hash_len = 16;
+		wpa_hexdump(MSG_MSGDUMP, "X509: Certificate hash (MD5)",
+			    hash, hash_len);
+		break;
+	case 5: /* sha-1WithRSAEncryption */
+		sha1_vector(1, &cert->tbs_cert_start, &cert->tbs_cert_len,
+			    hash);
+		hash_len = 20;
+		wpa_hexdump(MSG_MSGDUMP, "X509: Certificate hash (SHA1)",
+			    hash, hash_len);
+		break;
+	case 11: /* sha256WithRSAEncryption */
+		sha256_vector(1, &cert->tbs_cert_start, &cert->tbs_cert_len,
+			      hash);
+		hash_len = 32;
+		wpa_hexdump(MSG_MSGDUMP, "X509: Certificate hash (SHA256)",
+			    hash, hash_len);
+		break;
+	case 2: /* md2WithRSAEncryption */
+	case 12: /* sha384WithRSAEncryption */
+	case 13: /* sha512WithRSAEncryption */
+	default:
+		wpa_printf(MSG_INFO, "X509: Unsupported certificate signature "
+			   "algorithm (%lu)", cert->signature.oid.oid[6]);
+		os_free(data);
+		return -1;
+	}
+
+	if (hdr.length != hash_len ||
+	    os_memcmp(hdr.payload, hash, hdr.length) != 0) {
+		wpa_printf(MSG_INFO, "X509: Certificate Digest does not match "
+			   "with calculated tbsCertificate hash");
+		os_free(data);
+		return -1;
+	}
+
+	os_free(data);
+
+	wpa_printf(MSG_DEBUG, "X509: Certificate Digest matches with "
+		   "calculated tbsCertificate hash");
+
+	return 0;
+}
+
+
+static int x509_valid_issuer(const struct x509_certificate *cert)
+{
+	if ((cert->extensions_present & X509_EXT_BASIC_CONSTRAINTS) &&
+	    !cert->ca) {
+		wpa_printf(MSG_DEBUG, "X509: Non-CA certificate used as an "
+			   "issuer");
+		return -1;
+	}
+
+	if (cert->version == X509_CERT_V3 &&
+	    !(cert->extensions_present & X509_EXT_BASIC_CONSTRAINTS)) {
+		wpa_printf(MSG_DEBUG, "X509: v3 CA certificate did not "
+			   "include BasicConstraints extension");
+		return -1;
+	}
+
+	if ((cert->extensions_present & X509_EXT_KEY_USAGE) &&
+	    !(cert->key_usage & X509_KEY_USAGE_KEY_CERT_SIGN)) {
+		wpa_printf(MSG_DEBUG, "X509: Issuer certificate did not have "
+			   "keyCertSign bit in Key Usage");
+		return -1;
+	}
+
+	return 0;
+}
+
+
+/**
+ * x509_certificate_chain_validate - Validate X.509 certificate chain
+ * @trusted: List of trusted certificates
+ * @chain: Certificate chain to be validated (first chain must be issued by
+ * signed by the second certificate in the chain and so on)
+ * @reason: Buffer for returning failure reason (X509_VALIDATE_*)
+ * Returns: 0 if chain is valid, -1 if not
+ */
+int x509_certificate_chain_validate(struct x509_certificate *trusted,
+				    struct x509_certificate *chain,
+				    int *reason)
+{
+	long unsigned idx;
+	int chain_trusted = 0;
+	struct x509_certificate *cert, *trust;
+	char buf[128];
+	struct os_time now;
+
+	*reason = X509_VALIDATE_OK;
+
+	wpa_printf(MSG_DEBUG, "X509: Validate certificate chain");
+	os_get_time(&now);
+
+	for (cert = chain, idx = 0; cert; cert = cert->next, idx++) {
+		x509_name_string(&cert->subject, buf, sizeof(buf)); 
+		wpa_printf(MSG_DEBUG, "X509: %lu: %s", idx, buf);
+
+		if (chain_trusted)
+			continue;
+
+		if ((unsigned long) now.sec <
+		    (unsigned long) cert->not_before ||
+		    (unsigned long) now.sec >
+		    (unsigned long) cert->not_after) {
+			wpa_printf(MSG_INFO, "X509: Certificate not valid "
+				   "(now=%lu not_before=%lu not_after=%lu)",
+				   now.sec, cert->not_before, cert->not_after);
+			*reason = X509_VALIDATE_CERTIFICATE_EXPIRED;
+			return -1;
+		}
+
+		if (cert->next) {
+			if (x509_name_compare(&cert->issuer,
+					      &cert->next->subject) != 0) {
+				wpa_printf(MSG_DEBUG, "X509: Certificate "
+					   "chain issuer name mismatch");
+				x509_name_string(&cert->issuer, buf,
+						 sizeof(buf)); 
+				wpa_printf(MSG_DEBUG, "X509: cert issuer: %s",
+					   buf);
+				x509_name_string(&cert->next->subject, buf,
+						 sizeof(buf)); 
+				wpa_printf(MSG_DEBUG, "X509: next cert "
+					   "subject: %s", buf);
+				*reason = X509_VALIDATE_CERTIFICATE_UNKNOWN;
+				return -1;
+			}
+
+			if (x509_valid_issuer(cert->next) < 0) {
+				*reason = X509_VALIDATE_BAD_CERTIFICATE;
+				return -1;
+			}
+
+			if ((cert->next->extensions_present &
+			     X509_EXT_PATH_LEN_CONSTRAINT) &&
+			    idx > cert->next->path_len_constraint) {
+				wpa_printf(MSG_DEBUG, "X509: pathLenConstraint"
+					   " not met (idx=%lu issuer "
+					   "pathLenConstraint=%lu)", idx,
+					   cert->next->path_len_constraint);
+				*reason = X509_VALIDATE_BAD_CERTIFICATE;
+				return -1;
+			}
+
+			if (x509_certificate_check_signature(cert->next, cert)
+			    < 0) {
+				wpa_printf(MSG_DEBUG, "X509: Invalid "
+					   "certificate signature within "
+					   "chain");
+				*reason = X509_VALIDATE_BAD_CERTIFICATE;
+				return -1;
+			}
+		}
+
+		for (trust = trusted; trust; trust = trust->next) {
+			if (x509_name_compare(&cert->issuer, &trust->subject)
+			    == 0)
+				break;
+		}
+
+		if (trust) {
+			wpa_printf(MSG_DEBUG, "X509: Found issuer from the "
+				   "list of trusted certificates");
+			if (x509_valid_issuer(trust) < 0) {
+				*reason = X509_VALIDATE_BAD_CERTIFICATE;
+				return -1;
+			}
+
+			if (x509_certificate_check_signature(trust, cert) < 0)
+			{
+				wpa_printf(MSG_DEBUG, "X509: Invalid "
+					   "certificate signature");
+				*reason = X509_VALIDATE_BAD_CERTIFICATE;
+				return -1;
+			}
+
+			wpa_printf(MSG_DEBUG, "X509: Trusted certificate "
+				   "found to complete the chain");
+			chain_trusted = 1;
+		}
+	}
+
+	if (!chain_trusted) {
+		wpa_printf(MSG_DEBUG, "X509: Did not find any of the issuers "
+			   "from the list of trusted certificates");
+		if (trusted) {
+			*reason = X509_VALIDATE_UNKNOWN_CA;
+			return -1;
+		}
+		wpa_printf(MSG_DEBUG, "X509: Certificate chain validation "
+			   "disabled - ignore unknown CA issue");
+	}
+
+	wpa_printf(MSG_DEBUG, "X509: Certificate chain valid");
+
+	return 0;
+}
+
+
+/**
+ * x509_certificate_get_subject - Get a certificate based on Subject name
+ * @chain: Certificate chain to search through
+ * @name: Subject name to search for
+ * Returns: Pointer to the certificate with the given Subject name or
+ * %NULL on failure
+ */
+struct x509_certificate *
+x509_certificate_get_subject(struct x509_certificate *chain,
+			     struct x509_name *name)
+{
+	struct x509_certificate *cert;
+
+	for (cert = chain; cert; cert = cert->next) {
+		if (x509_name_compare(&cert->subject, name) == 0)
+			return cert;
+	}
+	return NULL;
+}
+
+
+/**
+ * x509_certificate_self_signed - Is the certificate self-signed?
+ * @cert: Certificate
+ * Returns: 1 if certificate is self-signed, 0 if not
+ */
+int x509_certificate_self_signed(struct x509_certificate *cert)
+{
+	return x509_name_compare(&cert->issuer, &cert->subject) == 0;
+}