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path: root/drivers/auth/mbedtls/mbedtls_x509_parser.c
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Diffstat (limited to 'drivers/auth/mbedtls/mbedtls_x509_parser.c')
-rw-r--r--drivers/auth/mbedtls/mbedtls_x509_parser.c438
1 files changed, 438 insertions, 0 deletions
diff --git a/drivers/auth/mbedtls/mbedtls_x509_parser.c b/drivers/auth/mbedtls/mbedtls_x509_parser.c
new file mode 100644
index 00000000..a8605ce0
--- /dev/null
+++ b/drivers/auth/mbedtls/mbedtls_x509_parser.c
@@ -0,0 +1,438 @@
+/*
+ * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * X509 parser based on PolarSSL
+ *
+ * This module implements functions to check the integrity of a X509v3
+ * certificate ASN.1 structure and extract authentication parameters from the
+ * extensions field, such as an image hash or a public key.
+ */
+
+#include <assert.h>
+#include <img_parser_mod.h>
+#include <mbedtls_common.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+/* mbedTLS headers */
+#include <polarssl/asn1.h>
+#include <polarssl/oid.h>
+#include <polarssl/platform.h>
+
+/* Maximum OID string length ("a.b.c.d.e.f ...") */
+#define MAX_OID_STR_LEN 64
+
+#define LIB_NAME "mbedTLS X509v3"
+
+/* Temporary variables to speed up the authentication parameters search. These
+ * variables are assigned once during the integrity check and used any time an
+ * authentication parameter is requested, so we do not have to parse the image
+ * again */
+static asn1_buf tbs;
+static asn1_buf v3_ext;
+static asn1_buf pk;
+static asn1_buf sig_alg;
+static asn1_buf signature;
+
+/*
+ * Get X509v3 extension
+ *
+ * Global variable 'v3_ext' must point to the extensions region
+ * in the certificate. No need to check for errors since the image has passed
+ * the integrity check.
+ */
+static int get_ext(const char *oid, void **ext, unsigned int *ext_len)
+{
+ int oid_len;
+ size_t len;
+ unsigned char *end_ext_data, *end_ext_octet;
+ unsigned char *p;
+ const unsigned char *end;
+ char oid_str[MAX_OID_STR_LEN];
+ asn1_buf extn_oid;
+ int is_critical;
+
+ assert(oid != NULL);
+
+ p = v3_ext.p;
+ end = v3_ext.p + v3_ext.len;
+
+ asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+
+ while (p < end) {
+ memset(&extn_oid, 0x0, sizeof(extn_oid));
+ is_critical = 0; /* DEFAULT FALSE */
+
+ asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ end_ext_data = p + len;
+
+ /* Get extension ID */
+ extn_oid.tag = *p;
+ asn1_get_tag(&p, end, &extn_oid.len, ASN1_OID);
+ extn_oid.p = p;
+ p += extn_oid.len;
+
+ /* Get optional critical */
+ asn1_get_bool(&p, end_ext_data, &is_critical);
+
+ /* Extension data */
+ asn1_get_tag(&p, end_ext_data, &len, ASN1_OCTET_STRING);
+ end_ext_octet = p + len;
+
+ /* Detect requested extension */
+ oid_len = oid_get_numeric_string(oid_str,
+ MAX_OID_STR_LEN, &extn_oid);
+ if (oid_len == POLARSSL_ERR_OID_BUF_TOO_SMALL) {
+ return IMG_PARSER_ERR;
+ }
+ if ((oid_len == strlen(oid_str)) && !strcmp(oid, oid_str)) {
+ *ext = (void *)p;
+ *ext_len = (unsigned int)len;
+ return IMG_PARSER_OK;
+ }
+
+ /* Next */
+ p = end_ext_octet;
+ }
+
+ return IMG_PARSER_ERR_NOT_FOUND;
+}
+
+
+/*
+ * Check the integrity of the certificate ASN.1 structure.
+ * Extract the relevant data that will be used later during authentication.
+ */
+static int cert_parse(void *img, unsigned int img_len)
+{
+ int ret, is_critical;
+ size_t len;
+ unsigned char *p, *end, *crt_end;
+ asn1_buf sig_alg1, sig_alg2;
+
+ p = (unsigned char *)img;
+ len = img_len;
+ end = p + len;
+
+ /*
+ * Certificate ::= SEQUENCE {
+ * tbsCertificate TBSCertificate,
+ * signatureAlgorithm AlgorithmIdentifier,
+ * signatureValue BIT STRING }
+ */
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+
+ if (len > (size_t)(end - p)) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ crt_end = p + len;
+
+ /*
+ * TBSCertificate ::= SEQUENCE {
+ */
+ tbs.p = p;
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ end = p + len;
+ tbs.len = end - tbs.p;
+
+ /*
+ * Version ::= INTEGER { v1(0), v2(1), v3(2) }
+ */
+ ret = asn1_get_tag(&p, end, &len,
+ ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 0);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ p += len;
+
+ /*
+ * CertificateSerialNumber ::= INTEGER
+ */
+ ret = asn1_get_tag(&p, end, &len, ASN1_INTEGER);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ p += len;
+
+ /*
+ * signature AlgorithmIdentifier
+ */
+ sig_alg1.p = p;
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ if ((end - p) < 1) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ sig_alg1.len = (p + len) - sig_alg1.p;
+ p += len;
+
+ /*
+ * issuer Name
+ */
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ p += len;
+
+ /*
+ * Validity ::= SEQUENCE {
+ * notBefore Time,
+ * notAfter Time }
+ *
+ */
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ p += len;
+
+ /*
+ * subject Name
+ */
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ p += len;
+
+ /*
+ * SubjectPublicKeyInfo
+ */
+ pk.p = p;
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ pk.len = (p + len) - pk.p;
+ p += len;
+
+ /*
+ * issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL,
+ */
+ ret = asn1_get_tag(&p, end, &len,
+ ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 1);
+ if (ret != 0) {
+ if (ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ } else {
+ p += len;
+ }
+
+ /*
+ * subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL,
+ */
+ ret = asn1_get_tag(&p, end, &len,
+ ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 2);
+ if (ret != 0) {
+ if (ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ } else {
+ p += len;
+ }
+
+ /*
+ * extensions [3] EXPLICIT Extensions OPTIONAL
+ */
+ ret = asn1_get_tag(&p, end, &len,
+ ASN1_CONTEXT_SPECIFIC | ASN1_CONSTRUCTED | 3);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+
+ /*
+ * Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension
+ */
+ v3_ext.p = p;
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ v3_ext.len = (p + len) - v3_ext.p;
+
+ /*
+ * Check extensions integrity
+ */
+ while (p < end) {
+ ret = asn1_get_tag(&p, end, &len,
+ ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+
+ /* Get extension ID */
+ ret = asn1_get_tag(&p, end, &len, ASN1_OID);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ p += len;
+
+ /* Get optional critical */
+ ret = asn1_get_bool(&p, end, &is_critical);
+ if ((ret != 0) && (ret != POLARSSL_ERR_ASN1_UNEXPECTED_TAG)) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+
+ /* Data should be octet string type */
+ ret = asn1_get_tag(&p, end, &len, ASN1_OCTET_STRING);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ p += len;
+ }
+
+ if (p != end) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+
+ end = crt_end;
+
+ /*
+ * }
+ * -- end of TBSCertificate
+ *
+ * signatureAlgorithm AlgorithmIdentifier
+ */
+ sig_alg2.p = p;
+ ret = asn1_get_tag(&p, end, &len, ASN1_CONSTRUCTED | ASN1_SEQUENCE);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ if ((end - p) < 1) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ sig_alg2.len = (p + len) - sig_alg2.p;
+ p += len;
+
+ /* Compare both signature algorithms */
+ if (sig_alg1.len != sig_alg2.len) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ if (0 != memcmp(sig_alg1.p, sig_alg2.p, sig_alg1.len)) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ memcpy(&sig_alg, &sig_alg1, sizeof(sig_alg));
+
+ /*
+ * signatureValue BIT STRING
+ */
+ signature.p = p;
+ ret = asn1_get_tag(&p, end, &len, ASN1_BIT_STRING);
+ if (ret != 0) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+ signature.len = (p + len) - signature.p;
+ p += len;
+
+ /* Check certificate length */
+ if (p != end) {
+ return IMG_PARSER_ERR_FORMAT;
+ }
+
+ return IMG_PARSER_OK;
+}
+
+
+/* Exported functions */
+
+static void init(void)
+{
+ mbedtls_init();
+}
+
+static int check_integrity(void *img, unsigned int img_len)
+{
+ return cert_parse(img, img_len);
+}
+
+/*
+ * Extract an authentication parameter from an X509v3 certificate
+ */
+static int get_auth_param(const auth_param_type_desc_t *type_desc,
+ void *img, unsigned int img_len,
+ void **param, unsigned int *param_len)
+{
+ int rc = IMG_PARSER_OK;
+
+ /* We do not use img because the check_integrity function has already
+ * extracted the relevant data (v3_ext, pk, sig_alg, etc) */
+
+ switch (type_desc->type) {
+ case AUTH_PARAM_RAW_DATA:
+ /* Data to be signed */
+ *param = (void *)tbs.p;
+ *param_len = (unsigned int)tbs.len;
+ break;
+ case AUTH_PARAM_HASH:
+ /* All these parameters are included as X509v3 extensions */
+ rc = get_ext(type_desc->cookie, param, param_len);
+ break;
+ case AUTH_PARAM_PUB_KEY:
+ if (type_desc->cookie != 0) {
+ /* Get public key from extension */
+ rc = get_ext(type_desc->cookie, param, param_len);
+ } else {
+ /* Get the subject public key */
+ *param = (void *)pk.p;
+ *param_len = (unsigned int)pk.len;
+ }
+ break;
+ case AUTH_PARAM_SIG_ALG:
+ /* Get the certificate signature algorithm */
+ *param = (void *)sig_alg.p;
+ *param_len = (unsigned int)sig_alg.len;
+ break;
+ case AUTH_PARAM_SIG:
+ /* Get the certificate signature */
+ *param = (void *)signature.p;
+ *param_len = (unsigned int)signature.len;
+ break;
+ default:
+ rc = IMG_PARSER_ERR_NOT_FOUND;
+ break;
+ }
+
+ return rc;
+}
+
+REGISTER_IMG_PARSER_LIB(IMG_CERT, LIB_NAME, init, \
+ check_integrity, get_auth_param);
generated by cgit (git 2.34.1) at 2025-07-16 14:00:14 +0000