GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/trusted-firmware/trusted-firmware-a-2.8/drivers/auth/mbedtls/mbedtls_common.c

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2015-2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stddef.h>
+
+/* mbed TLS headers */
+#include <mbedtls/memory_buffer_alloc.h>
+#include <mbedtls/platform.h>
+
+#include <common/debug.h>
+#include <drivers/auth/mbedtls/mbedtls_common.h>
+#include MBEDTLS_CONFIG_FILE
+#include <plat/common/platform.h>
+
+static void cleanup(void)
+{
+	ERROR("EXIT from BL2\n");
+	panic();
+}
+
+/*
+ * mbed TLS initialization function
+ */
+void mbedtls_init(void)
+{
+	static int ready;
+	void *heap_addr;
+	size_t heap_size = 0;
+	int err;
+
+	if (!ready) {
+		if (atexit(cleanup))
+			panic();
+
+		err = plat_get_mbedtls_heap(&heap_addr, &heap_size);
+
+		/* Ensure heap setup is proper */
+		if (err < 0) {
+			ERROR("Mbed TLS failed to get a heap\n");
+			panic();
+		}
+		assert(heap_size >= TF_MBEDTLS_HEAP_SIZE);
+
+		/* Initialize the mbed TLS heap */
+		mbedtls_memory_buffer_alloc_init(heap_addr, heap_size);
+
+#ifdef MBEDTLS_PLATFORM_SNPRINTF_ALT
+		mbedtls_platform_set_snprintf(snprintf);
+#endif
+		ready = 1;
+	}
+}
+
+/*
+ * The following helper function simply returns the default allocated heap.
+ * It can be used by platforms for their plat_get_mbedtls_heap() implementation.
+ */
+int get_mbedtls_heap_helper(void **heap_addr, size_t *heap_size)
+{
+	static unsigned char heap[TF_MBEDTLS_HEAP_SIZE];
+
+	assert(heap_addr != NULL);
+	assert(heap_size != NULL);
+
+	*heap_addr = heap;
+	*heap_size = sizeof(heap);
+	return 0;
+}

source/trusted-firmware/trusted-firmware-a-2.8/drivers/auth/mbedtls/mbedtls_common.mk

@@ -0,0 +1,111 @@
+#
+# Copyright (c) 2015-2022, Arm Limited. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+ifneq (${MBEDTLS_COMMON_MK},1)
+MBEDTLS_COMMON_MK	:=	1
+
+# MBEDTLS_DIR must be set to the mbed TLS main directory (it must contain
+# the 'include' and 'library' subdirectories).
+ifeq (${MBEDTLS_DIR},)
+  $(error Error: MBEDTLS_DIR not set)
+endif
+
+MBEDTLS_INC		=	-I${MBEDTLS_DIR}/include
+
+# Specify mbed TLS configuration file
+MBEDTLS_CONFIG_FILE	?=	"<drivers/auth/mbedtls/mbedtls_config.h>"
+$(eval $(call add_define,MBEDTLS_CONFIG_FILE))
+
+MBEDTLS_SOURCES	+=		drivers/auth/mbedtls/mbedtls_common.c
+
+
+LIBMBEDTLS_SRCS		:= $(addprefix ${MBEDTLS_DIR}/library/,	\
+					aes.c 					\
+					asn1parse.c 				\
+					asn1write.c 				\
+					cipher.c 				\
+					cipher_wrap.c 				\
+					memory_buffer_alloc.c			\
+					oid.c 					\
+					platform.c 				\
+					platform_util.c				\
+					bignum.c				\
+					gcm.c 					\
+					md.c					\
+					pk.c 					\
+					pk_wrap.c 				\
+					pkparse.c 				\
+					pkwrite.c 				\
+					sha256.c            			\
+					sha512.c            			\
+					ecdsa.c					\
+					ecp_curves.c				\
+					ecp.c					\
+					rsa.c					\
+					rsa_internal.c				\
+					x509.c 					\
+					x509_crt.c 				\
+					constant_time.c 			\
+					)
+
+# The platform may define the variable 'TF_MBEDTLS_KEY_ALG' to select the key
+# algorithm to use. If the variable is not defined, select it based on
+# algorithm used for key generation `KEY_ALG`. If `KEY_ALG` is not defined,
+# then it is set to `rsa`.
+ifeq (${TF_MBEDTLS_KEY_ALG},)
+    ifeq (${KEY_ALG}, ecdsa)
+        TF_MBEDTLS_KEY_ALG		:=	ecdsa
+    else
+        TF_MBEDTLS_KEY_ALG		:=	rsa
+    endif
+endif
+
+ifeq (${TF_MBEDTLS_KEY_SIZE},)
+    ifneq ($(findstring rsa,${TF_MBEDTLS_KEY_ALG}),)
+	ifeq (${KEY_SIZE},)
+            TF_MBEDTLS_KEY_SIZE		:=	2048
+	else
+            TF_MBEDTLS_KEY_SIZE		:=	${KEY_SIZE}
+	endif
+    endif
+endif
+
+ifeq (${HASH_ALG}, sha384)
+    TF_MBEDTLS_HASH_ALG_ID	:=	TF_MBEDTLS_SHA384
+else ifeq (${HASH_ALG}, sha512)
+    TF_MBEDTLS_HASH_ALG_ID	:=	TF_MBEDTLS_SHA512
+else
+    TF_MBEDTLS_HASH_ALG_ID	:=	TF_MBEDTLS_SHA256
+endif
+
+ifeq (${TF_MBEDTLS_KEY_ALG},ecdsa)
+    TF_MBEDTLS_KEY_ALG_ID	:=	TF_MBEDTLS_ECDSA
+else ifeq (${TF_MBEDTLS_KEY_ALG},rsa)
+    TF_MBEDTLS_KEY_ALG_ID	:=	TF_MBEDTLS_RSA
+else ifeq (${TF_MBEDTLS_KEY_ALG},rsa+ecdsa)
+    TF_MBEDTLS_KEY_ALG_ID	:=	TF_MBEDTLS_RSA_AND_ECDSA
+else
+    $(error "TF_MBEDTLS_KEY_ALG=${TF_MBEDTLS_KEY_ALG} not supported on mbed TLS")
+endif
+
+ifeq (${DECRYPTION_SUPPORT}, aes_gcm)
+    TF_MBEDTLS_USE_AES_GCM	:=	1
+else
+    TF_MBEDTLS_USE_AES_GCM	:=	0
+endif
+
+# Needs to be set to drive mbed TLS configuration correctly
+$(eval $(call add_defines,\
+    $(sort \
+        TF_MBEDTLS_KEY_ALG_ID \
+        TF_MBEDTLS_KEY_SIZE \
+        TF_MBEDTLS_HASH_ALG_ID \
+        TF_MBEDTLS_USE_AES_GCM \
+)))
+
+$(eval $(call MAKE_LIB,mbedtls))
+
+endif

source/trusted-firmware/trusted-firmware-a-2.8/drivers/auth/mbedtls/mbedtls_crypto.c

@@ -0,0 +1,394 @@
+/*
+ * Copyright (c) 2015-2022, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <stddef.h>
+#include <string.h>
+
+/* mbed TLS headers */
+#include <mbedtls/gcm.h>
+#include <mbedtls/md.h>
+#include <mbedtls/memory_buffer_alloc.h>
+#include <mbedtls/oid.h>
+#include <mbedtls/platform.h>
+#include <mbedtls/x509.h>
+
+#include <common/debug.h>
+#include <drivers/auth/crypto_mod.h>
+#include <drivers/auth/mbedtls/mbedtls_common.h>
+#include <drivers/auth/mbedtls/mbedtls_config.h>
+#include <plat/common/platform.h>
+
+#define LIB_NAME		"mbed TLS"
+
+#if CRYPTO_SUPPORT == CRYPTO_HASH_CALC_ONLY || \
+CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC
+/*
+ * CRYPTO_MD_MAX_SIZE value is as per current stronger algorithm available
+ * so make sure that mbed TLS MD maximum size must be lesser than this.
+ */
+CASSERT(CRYPTO_MD_MAX_SIZE >= MBEDTLS_MD_MAX_SIZE,
+	assert_mbedtls_md_size_overflow);
+
+#endif /* CRYPTO_SUPPORT == CRYPTO_HASH_CALC_ONLY || \
+	  CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC */
+
+/*
+ * AlgorithmIdentifier  ::=  SEQUENCE  {
+ *     algorithm               OBJECT IDENTIFIER,
+ *     parameters              ANY DEFINED BY algorithm OPTIONAL
+ * }
+ *
+ * SubjectPublicKeyInfo  ::=  SEQUENCE  {
+ *     algorithm            AlgorithmIdentifier,
+ *     subjectPublicKey     BIT STRING
+ * }
+ *
+ * DigestInfo ::= SEQUENCE {
+ *     digestAlgorithm AlgorithmIdentifier,
+ *     digest OCTET STRING
+ * }
+ */
+
+/*
+ * Initialize the library and export the descriptor
+ */
+static void init(void)
+{
+	/* Initialize mbed TLS */
+	mbedtls_init();
+}
+
+#if CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_ONLY || \
+CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC
+/*
+ * Verify a signature.
+ *
+ * Parameters are passed using the DER encoding format following the ASN.1
+ * structures detailed above.
+ */
+static int verify_signature(void *data_ptr, unsigned int data_len,
+			    void *sig_ptr, unsigned int sig_len,
+			    void *sig_alg, unsigned int sig_alg_len,
+			    void *pk_ptr, unsigned int pk_len)
+{
+	mbedtls_asn1_buf sig_oid, sig_params;
+	mbedtls_asn1_buf signature;
+	mbedtls_md_type_t md_alg;
+	mbedtls_pk_type_t pk_alg;
+	mbedtls_pk_context pk = {0};
+	int rc;
+	void *sig_opts = NULL;
+	const mbedtls_md_info_t *md_info;
+	unsigned char *p, *end;
+	unsigned char hash[MBEDTLS_MD_MAX_SIZE];
+
+	/* Get pointers to signature OID and parameters */
+	p = (unsigned char *)sig_alg;
+	end = (unsigned char *)(p + sig_alg_len);
+	rc = mbedtls_asn1_get_alg(&p, end, &sig_oid, &sig_params);
+	if (rc != 0) {
+		return CRYPTO_ERR_SIGNATURE;
+	}
+
+	/* Get the actual signature algorithm (MD + PK) */
+	rc = mbedtls_x509_get_sig_alg(&sig_oid, &sig_params, &md_alg, &pk_alg, &sig_opts);
+	if (rc != 0) {
+		return CRYPTO_ERR_SIGNATURE;
+	}
+
+	/* Parse the public key */
+	mbedtls_pk_init(&pk);
+	p = (unsigned char *)pk_ptr;
+	end = (unsigned char *)(p + pk_len);
+	rc = mbedtls_pk_parse_subpubkey(&p, end, &pk);
+	if (rc != 0) {
+		rc = CRYPTO_ERR_SIGNATURE;
+		goto end2;
+	}
+
+	/* Get the signature (bitstring) */
+	p = (unsigned char *)sig_ptr;
+	end = (unsigned char *)(p + sig_len);
+	signature.tag = *p;
+	rc = mbedtls_asn1_get_bitstring_null(&p, end, &signature.len);
+	if (rc != 0) {
+		rc = CRYPTO_ERR_SIGNATURE;
+		goto end1;
+	}
+	signature.p = p;
+
+	/* Calculate the hash of the data */
+	md_info = mbedtls_md_info_from_type(md_alg);
+	if (md_info == NULL) {
+		rc = CRYPTO_ERR_SIGNATURE;
+		goto end1;
+	}
+	p = (unsigned char *)data_ptr;
+	rc = mbedtls_md(md_info, p, data_len, hash);
+	if (rc != 0) {
+		rc = CRYPTO_ERR_SIGNATURE;
+		goto end1;
+	}
+
+	/* Verify the signature */
+	rc = mbedtls_pk_verify_ext(pk_alg, sig_opts, &pk, md_alg, hash,
+			mbedtls_md_get_size(md_info),
+			signature.p, signature.len);
+	if (rc != 0) {
+		rc = CRYPTO_ERR_SIGNATURE;
+		goto end1;
+	}
+
+	/* Signature verification success */
+	rc = CRYPTO_SUCCESS;
+
+end1:
+	mbedtls_pk_free(&pk);
+end2:
+	mbedtls_free(sig_opts);
+	return rc;
+}
+
+/*
+ * Match a hash
+ *
+ * Digest info is passed in DER format following the ASN.1 structure detailed
+ * above.
+ */
+static int verify_hash(void *data_ptr, unsigned int data_len,
+		       void *digest_info_ptr, unsigned int digest_info_len)
+{
+	mbedtls_asn1_buf hash_oid, params;
+	mbedtls_md_type_t md_alg;
+	const mbedtls_md_info_t *md_info;
+	unsigned char *p, *end, *hash;
+	unsigned char data_hash[MBEDTLS_MD_MAX_SIZE];
+	size_t len;
+	int rc;
+
+	/* Digest info should be an MBEDTLS_ASN1_SEQUENCE */
+	p = (unsigned char *)digest_info_ptr;
+	end = p + digest_info_len;
+	rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				  MBEDTLS_ASN1_SEQUENCE);
+	if (rc != 0) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	/* Get the hash algorithm */
+	rc = mbedtls_asn1_get_alg(&p, end, &hash_oid, &params);
+	if (rc != 0) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	rc = mbedtls_oid_get_md_alg(&hash_oid, &md_alg);
+	if (rc != 0) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	md_info = mbedtls_md_info_from_type(md_alg);
+	if (md_info == NULL) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	/* Hash should be octet string type */
+	rc = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
+	if (rc != 0) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	/* Length of hash must match the algorithm's size */
+	if (len != mbedtls_md_get_size(md_info)) {
+		return CRYPTO_ERR_HASH;
+	}
+	hash = p;
+
+	/* Calculate the hash of the data */
+	p = (unsigned char *)data_ptr;
+	rc = mbedtls_md(md_info, p, data_len, data_hash);
+	if (rc != 0) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	/* Compare values */
+	rc = memcmp(data_hash, hash, mbedtls_md_get_size(md_info));
+	if (rc != 0) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	return CRYPTO_SUCCESS;
+}
+#endif /* CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_ONLY || \
+	  CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC */
+
+#if CRYPTO_SUPPORT == CRYPTO_HASH_CALC_ONLY || \
+CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC
+/*
+ * Map a generic crypto message digest algorithm to the corresponding macro used
+ * by Mbed TLS.
+ */
+static inline mbedtls_md_type_t md_type(enum crypto_md_algo algo)
+{
+	switch (algo) {
+	case CRYPTO_MD_SHA512:
+		return MBEDTLS_MD_SHA512;
+	case CRYPTO_MD_SHA384:
+		return MBEDTLS_MD_SHA384;
+	case CRYPTO_MD_SHA256:
+		return MBEDTLS_MD_SHA256;
+	default:
+		/* Invalid hash algorithm. */
+		return MBEDTLS_MD_NONE;
+	}
+}
+
+/*
+ * Calculate a hash
+ *
+ * output points to the computed hash
+ */
+static int calc_hash(enum crypto_md_algo md_algo, void *data_ptr,
+		     unsigned int data_len,
+		     unsigned char output[CRYPTO_MD_MAX_SIZE])
+{
+	const mbedtls_md_info_t *md_info;
+
+	md_info = mbedtls_md_info_from_type(md_type(md_algo));
+	if (md_info == NULL) {
+		return CRYPTO_ERR_HASH;
+	}
+
+	/*
+	 * Calculate the hash of the data, it is safe to pass the
+	 * 'output' hash buffer pointer considering its size is always
+	 * bigger than or equal to MBEDTLS_MD_MAX_SIZE.
+	 */
+	return mbedtls_md(md_info, data_ptr, data_len, output);
+}
+#endif /* CRYPTO_SUPPORT == CRYPTO_HASH_CALC_ONLY || \
+	  CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC */
+
+#if TF_MBEDTLS_USE_AES_GCM
+/*
+ * Stack based buffer allocation for decryption operation. It could
+ * be configured to balance stack usage vs execution speed.
+ */
+#define DEC_OP_BUF_SIZE		128
+
+static int aes_gcm_decrypt(void *data_ptr, size_t len, const void *key,
+			   unsigned int key_len, const void *iv,
+			   unsigned int iv_len, const void *tag,
+			   unsigned int tag_len)
+{
+	mbedtls_gcm_context ctx;
+	mbedtls_cipher_id_t cipher = MBEDTLS_CIPHER_ID_AES;
+	unsigned char buf[DEC_OP_BUF_SIZE];
+	unsigned char tag_buf[CRYPTO_MAX_TAG_SIZE];
+	unsigned char *pt = data_ptr;
+	size_t dec_len;
+	int diff, i, rc;
+
+	mbedtls_gcm_init(&ctx);
+
+	rc = mbedtls_gcm_setkey(&ctx, cipher, key, key_len * 8);
+	if (rc != 0) {
+		rc = CRYPTO_ERR_DECRYPTION;
+		goto exit_gcm;
+	}
+
+	rc = mbedtls_gcm_starts(&ctx, MBEDTLS_GCM_DECRYPT, iv, iv_len, NULL, 0);
+	if (rc != 0) {
+		rc = CRYPTO_ERR_DECRYPTION;
+		goto exit_gcm;
+	}
+
+	while (len > 0) {
+		dec_len = MIN(sizeof(buf), len);
+
+		rc = mbedtls_gcm_update(&ctx, dec_len, pt, buf);
+		if (rc != 0) {
+			rc = CRYPTO_ERR_DECRYPTION;
+			goto exit_gcm;
+		}
+
+		memcpy(pt, buf, dec_len);
+		pt += dec_len;
+		len -= dec_len;
+	}
+
+	rc = mbedtls_gcm_finish(&ctx, tag_buf, sizeof(tag_buf));
+	if (rc != 0) {
+		rc = CRYPTO_ERR_DECRYPTION;
+		goto exit_gcm;
+	}
+
+	/* Check tag in "constant-time" */
+	for (diff = 0, i = 0; i < tag_len; i++)
+		diff |= ((const unsigned char *)tag)[i] ^ tag_buf[i];
+
+	if (diff != 0) {
+		rc = CRYPTO_ERR_DECRYPTION;
+		goto exit_gcm;
+	}
+
+	/* GCM decryption success */
+	rc = CRYPTO_SUCCESS;
+
+exit_gcm:
+	mbedtls_gcm_free(&ctx);
+	return rc;
+}
+
+/*
+ * Authenticated decryption of an image
+ */
+static int auth_decrypt(enum crypto_dec_algo dec_algo, void *data_ptr,
+			size_t len, const void *key, unsigned int key_len,
+			unsigned int key_flags, const void *iv,
+			unsigned int iv_len, const void *tag,
+			unsigned int tag_len)
+{
+	int rc;
+
+	assert((key_flags & ENC_KEY_IS_IDENTIFIER) == 0);
+
+	switch (dec_algo) {
+	case CRYPTO_GCM_DECRYPT:
+		rc = aes_gcm_decrypt(data_ptr, len, key, key_len, iv, iv_len,
+				     tag, tag_len);
+		if (rc != 0)
+			return rc;
+		break;
+	default:
+		return CRYPTO_ERR_DECRYPTION;
+	}
+
+	return CRYPTO_SUCCESS;
+}
+#endif /* TF_MBEDTLS_USE_AES_GCM */
+
+/*
+ * Register crypto library descriptor
+ */
+#if CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC
+#if TF_MBEDTLS_USE_AES_GCM
+REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash,
+		    auth_decrypt);
+#else
+REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash,
+		    NULL);
+#endif
+#elif CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_ONLY
+#if TF_MBEDTLS_USE_AES_GCM
+REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash,
+		    auth_decrypt);
+#else
+REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, NULL);
+#endif
+#elif CRYPTO_SUPPORT == CRYPTO_HASH_CALC_ONLY
+REGISTER_CRYPTO_LIB(LIB_NAME, init, calc_hash);
+#endif /* CRYPTO_SUPPORT == CRYPTO_AUTH_VERIFY_AND_HASH_CALC */

source/trusted-firmware/trusted-firmware-a-2.8/drivers/auth/mbedtls/mbedtls_crypto.mk

@@ -0,0 +1,11 @@
+#
+# Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+include drivers/auth/mbedtls/mbedtls_common.mk
+
+MBEDTLS_SOURCES	+=		drivers/auth/mbedtls/mbedtls_crypto.c
+
+

source/trusted-firmware/trusted-firmware-a-2.8/drivers/auth/mbedtls/mbedtls_x509.mk

@@ -0,0 +1,9 @@
+#
+# Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+
+include drivers/auth/mbedtls/mbedtls_common.mk
+
+MBEDTLS_SOURCES	+=	drivers/auth/mbedtls/mbedtls_x509_parser.c

source/trusted-firmware/trusted-firmware-a-2.8/drivers/auth/mbedtls/mbedtls_x509_parser.c

@@ -0,0 +1,500 @@
+/*
+ * Copyright (c) 2015-2022, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/*
+ * X509 parser based on mbed TLS
+ *
+ * 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 <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+/* mbed TLS headers */
+#include <mbedtls/asn1.h>
+#include <mbedtls/oid.h>
+#include <mbedtls/platform.h>
+
+#include <arch_helpers.h>
+#include <drivers/auth/img_parser_mod.h>
+#include <drivers/auth/mbedtls/mbedtls_common.h>
+#include <lib/utils.h>
+
+/* Maximum OID string length ("a.b.c.d.e.f ...") */
+#define MAX_OID_STR_LEN			64
+
+#define LIB_NAME	"mbed TLS 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 mbedtls_asn1_buf tbs;
+static mbedtls_asn1_buf v3_ext;
+static mbedtls_asn1_buf pk;
+static mbedtls_asn1_buf sig_alg;
+static mbedtls_asn1_buf signature;
+
+/*
+ * Clear all static temporary variables.
+ */
+static void clear_temp_vars(void)
+{
+#define ZERO_AND_CLEAN(x)					\
+	do {							\
+		zeromem(&x, sizeof(x));				\
+		clean_dcache_range((uintptr_t)&x, sizeof(x));	\
+	} while (0);
+
+	ZERO_AND_CLEAN(tbs)
+	ZERO_AND_CLEAN(v3_ext);
+	ZERO_AND_CLEAN(pk);
+	ZERO_AND_CLEAN(sig_alg);
+	ZERO_AND_CLEAN(signature);
+
+#undef ZERO_AND_CLEAN
+}
+
+/*
+ * 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];
+	mbedtls_asn1_buf extn_oid;
+	int is_critical;
+
+	assert(oid != NULL);
+
+	p = v3_ext.p;
+	end = v3_ext.p + v3_ext.len;
+
+	mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+			     MBEDTLS_ASN1_SEQUENCE);
+
+	while (p < end) {
+		zeromem(&extn_oid, sizeof(extn_oid));
+		is_critical = 0; /* DEFAULT FALSE */
+
+		mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				     MBEDTLS_ASN1_SEQUENCE);
+		end_ext_data = p + len;
+
+		/* Get extension ID */
+		extn_oid.tag = *p;
+		mbedtls_asn1_get_tag(&p, end, &extn_oid.len, MBEDTLS_ASN1_OID);
+		extn_oid.p = p;
+		p += extn_oid.len;
+
+		/* Get optional critical */
+		mbedtls_asn1_get_bool(&p, end_ext_data, &is_critical);
+
+		/* Extension data */
+		mbedtls_asn1_get_tag(&p, end_ext_data, &len,
+				     MBEDTLS_ASN1_OCTET_STRING);
+		end_ext_octet = p + len;
+
+		/* Detect requested extension */
+		oid_len = mbedtls_oid_get_numeric_string(oid_str,
+							 MAX_OID_STR_LEN,
+							 &extn_oid);
+		if ((oid_len == MBEDTLS_ERR_OID_BUF_TOO_SMALL) || (oid_len < 0)) {
+			return IMG_PARSER_ERR;
+		}
+		if (((size_t)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.
+ *
+ * This function doesn't clear the static variables located on the top of this
+ * file in case of an error. It is only called from check_integrity(), which
+ * performs the cleanup if necessary.
+ */
+static int cert_parse(void *img, unsigned int img_len)
+{
+	int ret, is_critical;
+	size_t len;
+	unsigned char *p, *end, *crt_end;
+	mbedtls_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 = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_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 = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_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 = mbedtls_asn1_get_tag(&p, end, &len,
+				   MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+				   MBEDTLS_ASN1_CONSTRUCTED | 0);
+	if (ret != 0) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+	p += len;
+
+	/*
+	 * CertificateSerialNumber  ::=  INTEGER
+	 */
+	ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER);
+	if (ret != 0) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+	p += len;
+
+	/*
+	 * signature            AlgorithmIdentifier
+	 */
+	sig_alg1.p = p;
+	ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_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 = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_ASN1_SEQUENCE);
+	if (ret != 0) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+	p += len;
+
+	/*
+	 * Validity ::= SEQUENCE {
+	 *      notBefore      Time,
+	 *      notAfter       Time }
+	 *
+	 */
+	ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_ASN1_SEQUENCE);
+	if (ret != 0) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+	p += len;
+
+	/*
+	 * subject              Name
+	 */
+	ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_ASN1_SEQUENCE);
+	if (ret != 0) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+	p += len;
+
+	/*
+	 * SubjectPublicKeyInfo
+	 */
+	pk.p = p;
+	ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_ASN1_SEQUENCE);
+	if (ret != 0) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+	pk.len = (p + len) - pk.p;
+	p += len;
+
+	/*
+	 * issuerUniqueID  [1]  IMPLICIT UniqueIdentifier OPTIONAL,
+	 */
+	ret = mbedtls_asn1_get_tag(&p, end, &len,
+				   MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+				   MBEDTLS_ASN1_CONSTRUCTED | 1);
+	if (ret != 0) {
+		if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
+			return IMG_PARSER_ERR_FORMAT;
+		}
+	} else {
+		p += len;
+	}
+
+	/*
+	 * subjectUniqueID [2]  IMPLICIT UniqueIdentifier OPTIONAL,
+	 */
+	ret = mbedtls_asn1_get_tag(&p, end, &len,
+				   MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+				   MBEDTLS_ASN1_CONSTRUCTED | 2);
+	if (ret != 0) {
+		if (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG) {
+			return IMG_PARSER_ERR_FORMAT;
+		}
+	} else {
+		p += len;
+	}
+
+	/*
+	 * extensions      [3]  EXPLICIT Extensions OPTIONAL
+	 * }
+	 *
+	 * X.509 and RFC5280 allow omitting the extensions entirely.
+	 * However, in TF-A, a certificate with no extensions would
+	 * always fail later on, as the extensions contain the
+	 * information needed to authenticate the next stage in the
+	 * boot chain.  Furthermore, get_ext() assumes that the
+	 * extensions have been parsed into v3_ext, and allowing
+	 * there to be no extensions would pointlessly complicate
+	 * the code.  Therefore, just reject certificates without
+	 * extensions.  This is also why version 1 and 2 certificates
+	 * are rejected above.
+	 */
+	ret = mbedtls_asn1_get_tag(&p, end, &len,
+				   MBEDTLS_ASN1_CONTEXT_SPECIFIC |
+				   MBEDTLS_ASN1_CONSTRUCTED | 3);
+	if ((ret != 0) || (len != (size_t)(end - p))) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+
+	/*
+	 * Extensions  ::=  SEQUENCE SIZE (1..MAX) OF Extension
+	 * -- must use all remaining bytes in TBSCertificate
+	 */
+	v3_ext.p = p;
+	ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_ASN1_SEQUENCE);
+	if ((ret != 0) || (len != (size_t)(end - p))) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+	v3_ext.len = end - v3_ext.p;
+
+	/*
+	 * Check extensions integrity.  At least one extension is
+	 * required: the ASN.1 specifies a minimum size of 1, and at
+	 * least one extension is needed to authenticate the next stage
+	 * in the boot chain.
+	 */
+	do {
+		unsigned char *end_ext_data;
+
+		ret = mbedtls_asn1_get_tag(&p, end, &len,
+					   MBEDTLS_ASN1_CONSTRUCTED |
+					   MBEDTLS_ASN1_SEQUENCE);
+		if (ret != 0) {
+			return IMG_PARSER_ERR_FORMAT;
+		}
+		end_ext_data = p + len;
+
+		/* Get extension ID */
+		ret = mbedtls_asn1_get_tag(&p, end_ext_data, &len, MBEDTLS_ASN1_OID);
+		if (ret != 0) {
+			return IMG_PARSER_ERR_FORMAT;
+		}
+		p += len;
+
+		/* Get optional critical */
+		ret = mbedtls_asn1_get_bool(&p, end_ext_data, &is_critical);
+		if ((ret != 0) && (ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG)) {
+			return IMG_PARSER_ERR_FORMAT;
+		}
+
+		/*
+		 * Data should be octet string type and must use all bytes in
+		 * the Extension.
+		 */
+		ret = mbedtls_asn1_get_tag(&p, end_ext_data, &len,
+					   MBEDTLS_ASN1_OCTET_STRING);
+		if ((ret != 0) || ((p + len) != end_ext_data)) {
+			return IMG_PARSER_ERR_FORMAT;
+		}
+		p = end_ext_data;
+	} while (p < end);
+
+	if (p != end) {
+		return IMG_PARSER_ERR_FORMAT;
+	}
+
+	end = crt_end;
+
+	/*
+	 *  }
+	 *  -- end of TBSCertificate
+	 *
+	 *  signatureAlgorithm   AlgorithmIdentifier
+	 */
+	sig_alg2.p = p;
+	ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED |
+				   MBEDTLS_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 = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_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();
+}
+
+/*
+ * Wrapper for cert_parse() that clears the static variables used by it in case
+ * of an error.
+ */
+static int check_integrity(void *img, unsigned int img_len)
+{
+	int rc = cert_parse(img, img_len);
+
+	if (rc != IMG_PARSER_OK)
+		clear_temp_vars();
+
+	return rc;
+}
+
+/*
+ * Extract an authentication parameter from an X509v3 certificate
+ *
+ * This function returns a pointer to the extracted data and its length.
+ * Depending on the type of parameter, a pointer to the data stored in the
+ * certificate may be returned (i.e. an octet string containing a hash). Other
+ * data may need to be copied and formatted (i.e. integers). In the later case,
+ * a buffer of the correct type needs to be statically allocated, filled and
+ * returned.
+ */
+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:
+	case AUTH_PARAM_NV_CTR:
+		/* 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);