Merge changes from topic "tbbr/fw_enc" into integration

* changes:
  docs: qemu: Add instructions to boot using FIP image
  docs: Update docs with firmware encryption feature
  qemu: Support optional encryption of BL31 and BL32 images
  qemu: Update flash address map to keep FIP in secure FLASH0
  Makefile: Add support to optionally encrypt BL31 and BL32
  tools: Add firmware authenticated encryption tool
  TBB: Add an IO abstraction layer to load encrypted firmwares
  drivers: crypto: Add authenticated decryption framework

5 files changed, 403 insertions, 4 deletions

diff --git a/drivers/auth/crypto_mod.c b/drivers/auth/crypto_mod.c
index 110c5045f..c63ff080f 100644
--- a/drivers/auth/crypto_mod.c
+++ b/drivers/auth/crypto_mod.c
@@ -124,3 +124,35 @@ int crypto_mod_calc_hash(unsigned int alg, void *data_ptr,
 	return crypto_lib_desc.calc_hash(alg, data_ptr, data_len, output);
 }
 #endif	/* MEASURED_BOOT */
+
+/*
+ * Authenticated decryption of data
+ *
+ * Parameters:
+ *
+ *   dec_algo: authenticated decryption algorithm
+ *   data_ptr, len: data to be decrypted (inout param)
+ *   key, key_len, key_flags: symmetric decryption key
+ *   iv, iv_len: initialization vector
+ *   tag, tag_len: authentication tag
+ */
+int crypto_mod_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)
+{
+	assert(crypto_lib_desc.auth_decrypt != NULL);
+	assert(data_ptr != NULL);
+	assert(len != 0U);
+	assert(key != NULL);
+	assert(key_len != 0U);
+	assert(iv != NULL);
+	assert((iv_len != 0U) && (iv_len <= CRYPTO_MAX_IV_SIZE));
+	assert(tag != NULL);
+	assert((tag_len != 0U) && (tag_len <= CRYPTO_MAX_TAG_SIZE));
+
+	return crypto_lib_desc.auth_decrypt(dec_algo, data_ptr, len, key,
+					    key_len, key_flags, iv, iv_len, tag,
+					    tag_len);
+}
diff --git a/drivers/auth/cryptocell/712/cryptocell_crypto.c b/drivers/auth/cryptocell/712/cryptocell_crypto.c
index 25eb6bcb6..cf4317534 100644
--- a/drivers/auth/cryptocell/712/cryptocell_crypto.c
+++ b/drivers/auth/cryptocell/712/cryptocell_crypto.c
@@ -301,5 +301,5 @@ static int verify_hash(void *data_ptr, unsigned int data_len,
 /*
  * Register crypto library descriptor
  */
-REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash);
+REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, NULL);
 
diff --git a/drivers/auth/mbedtls/mbedtls_common.mk b/drivers/auth/mbedtls/mbedtls_common.mk
index 4b8301541..044b368bc 100644
--- a/drivers/auth/mbedtls/mbedtls_common.mk
+++ b/drivers/auth/mbedtls/mbedtls_common.mk
@@ -23,13 +23,17 @@ 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					\
 					md_wrap.c				\
 					pk.c 					\
@@ -87,11 +91,17 @@ 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_define,TF_MBEDTLS_KEY_ALG_ID))
 $(eval $(call add_define,TF_MBEDTLS_KEY_SIZE))
 $(eval $(call add_define,TF_MBEDTLS_HASH_ALG_ID))
-
+$(eval $(call add_define,TF_MBEDTLS_USE_AES_GCM))
 
 $(eval $(call MAKE_LIB,mbedtls))
 
diff --git a/drivers/auth/mbedtls/mbedtls_crypto.c b/drivers/auth/mbedtls/mbedtls_crypto.c
index 04fbc648b..2a9801497 100644
--- a/drivers/auth/mbedtls/mbedtls_crypto.c
+++ b/drivers/auth/mbedtls/mbedtls_crypto.c
@@ -4,10 +4,12 @@
  * 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>
@@ -17,6 +19,7 @@
 #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"
 
@@ -226,11 +229,121 @@ int calc_hash(unsigned int alg, void *data_ptr,
 }
 #endif /* MEASURED_BOOT */
 
+#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 MEASURED_BOOT
-REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, calc_hash);
+#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
+#else /* MEASURED_BOOT */
+#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);
+REGISTER_CRYPTO_LIB(LIB_NAME, init, verify_signature, verify_hash, NULL);
+#endif
 #endif /* MEASURED_BOOT */
diff --git a/drivers/io/io_encrypted.c b/drivers/io/io_encrypted.c
new file mode 100644
index 000000000..744ca8356
--- /dev/null
+++ b/drivers/io/io_encrypted.c
@@ -0,0 +1,244 @@
+/*
+ * Copyright (c) 2020, Linaro Limited. All rights reserved.
+ * Author: Sumit Garg <sumit.garg@linaro.org>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <platform_def.h>
+
+#include <common/bl_common.h>
+#include <common/debug.h>
+#include <drivers/auth/crypto_mod.h>
+#include <drivers/io/io_driver.h>
+#include <drivers/io/io_encrypted.h>
+#include <drivers/io/io_storage.h>
+#include <lib/utils.h>
+#include <plat/common/platform.h>
+#include <tools_share/firmware_encrypted.h>
+#include <tools_share/uuid.h>
+
+static uintptr_t backend_dev_handle;
+static uintptr_t backend_dev_spec;
+static uintptr_t backend_handle;
+static uintptr_t backend_image_spec;
+
+static io_dev_info_t enc_dev_info;
+
+/* Encrypted firmware driver functions */
+static int enc_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info);
+static int enc_file_open(io_dev_info_t *dev_info, const uintptr_t spec,
+			  io_entity_t *entity);
+static int enc_file_len(io_entity_t *entity, size_t *length);
+static int enc_file_read(io_entity_t *entity, uintptr_t buffer, size_t length,
+			  size_t *length_read);
+static int enc_file_close(io_entity_t *entity);
+static int enc_dev_init(io_dev_info_t *dev_info, const uintptr_t init_params);
+static int enc_dev_close(io_dev_info_t *dev_info);
+
+static inline int is_valid_header(struct fw_enc_hdr *header)
+{
+	if (header->magic == ENC_HEADER_MAGIC)
+		return 1;
+	else
+		return 0;
+}
+
+static io_type_t device_type_enc(void)
+{
+	return IO_TYPE_ENCRYPTED;
+}
+
+static const io_dev_connector_t enc_dev_connector = {
+	.dev_open = enc_dev_open
+};
+
+static const io_dev_funcs_t enc_dev_funcs = {
+	.type = device_type_enc,
+	.open = enc_file_open,
+	.seek = NULL,
+	.size = enc_file_len,
+	.read = enc_file_read,
+	.write = NULL,
+	.close = enc_file_close,
+	.dev_init = enc_dev_init,
+	.dev_close = enc_dev_close,
+};
+
+static int enc_dev_open(const uintptr_t dev_spec, io_dev_info_t **dev_info)
+{
+	assert(dev_info != NULL);
+
+	enc_dev_info.funcs = &enc_dev_funcs;
+	*dev_info = &enc_dev_info;
+
+	return 0;
+}
+
+static int enc_dev_init(io_dev_info_t *dev_info, const uintptr_t init_params)
+{
+	int result;
+	unsigned int image_id = (unsigned int)init_params;
+
+	/* Obtain a reference to the image by querying the platform layer */
+	result = plat_get_image_source(image_id, &backend_dev_handle,
+				       &backend_dev_spec);
+	if (result != 0) {
+		WARN("Failed to obtain reference to image id=%u (%i)\n",
+			image_id, result);
+		return -ENOENT;
+	}
+
+	return result;
+}
+
+static int enc_dev_close(io_dev_info_t *dev_info)
+{
+	backend_dev_handle = (uintptr_t)NULL;
+	backend_dev_spec = (uintptr_t)NULL;
+
+	return 0;
+}
+
+static int enc_file_open(io_dev_info_t *dev_info, const uintptr_t spec,
+			 io_entity_t *entity)
+{
+	int result;
+
+	assert(spec != 0);
+	assert(entity != NULL);
+
+	backend_image_spec = spec;
+
+	result = io_open(backend_dev_handle, backend_image_spec,
+			 &backend_handle);
+	if (result != 0) {
+		WARN("Failed to open backend device (%i)\n", result);
+		result = -ENOENT;
+	}
+
+	return result;
+}
+
+static int enc_file_len(io_entity_t *entity, size_t *length)
+{
+	int result;
+
+	assert(entity != NULL);
+	assert(length != NULL);
+
+	result = io_size(backend_handle, length);
+	if (result != 0) {
+		WARN("Failed to read blob length (%i)\n", result);
+		return -ENOENT;
+	}
+
+	/*
+	 * Encryption header is attached at the beginning of the encrypted file
+	 * and is not considered a part of the payload.
+	 */
+	if (*length < sizeof(struct fw_enc_hdr))
+		return -EIO;
+
+	*length -= sizeof(struct fw_enc_hdr);
+
+	return result;
+}
+
+static int enc_file_read(io_entity_t *entity, uintptr_t buffer, size_t length,
+			 size_t *length_read)
+{
+	int result;
+	struct fw_enc_hdr header;
+	enum fw_enc_status_t fw_enc_status;
+	size_t bytes_read;
+	uint8_t key[ENC_MAX_KEY_SIZE];
+	size_t key_len = sizeof(key);
+	unsigned int key_flags = 0;
+	const io_uuid_spec_t *uuid_spec = (io_uuid_spec_t *)backend_image_spec;
+
+	assert(entity != NULL);
+	assert(length_read != NULL);
+
+	result = io_read(backend_handle, (uintptr_t)&header, sizeof(header),
+			 &bytes_read);
+	if (result != 0) {
+		WARN("Failed to read encryption header (%i)\n", result);
+		return -ENOENT;
+	}
+
+	if (!is_valid_header(&header)) {
+		WARN("Encryption header check failed.\n");
+		return -ENOENT;
+	}
+
+	VERBOSE("Encryption header looks OK.\n");
+	fw_enc_status = header.flags & FW_ENC_STATUS_FLAG_MASK;
+
+	if ((header.iv_len > ENC_MAX_IV_SIZE) ||
+	    (header.tag_len > ENC_MAX_TAG_SIZE)) {
+		WARN("Incorrect IV or tag length\n");
+		return -ENOENT;
+	}
+
+	result = io_read(backend_handle, buffer, length, &bytes_read);
+	if (result != 0) {
+		WARN("Failed to read encrypted payload (%i)\n", result);
+		return -ENOENT;
+	}
+
+	*length_read = bytes_read;
+
+	result = plat_get_enc_key_info(fw_enc_status, key, &key_len, &key_flags,
+				       (uint8_t *)&uuid_spec->uuid,
+				       sizeof(uuid_t));
+	if (result != 0) {
+		WARN("Failed to obtain encryption key (%i)\n", result);
+		return -ENOENT;
+	}
+
+	result = crypto_mod_auth_decrypt(header.dec_algo,
+					 (void *)buffer, *length_read, key,
+					 key_len, key_flags, header.iv,
+					 header.iv_len, header.tag,
+					 header.tag_len);
+	memset(key, 0, key_len);
+
+	if (result != 0) {
+		ERROR("File decryption failed (%i)\n", result);
+		return -ENOENT;
+	}
+
+	return result;
+}
+
+static int enc_file_close(io_entity_t *entity)
+{
+	io_close(backend_handle);
+
+	backend_image_spec = (uintptr_t)NULL;
+	entity->info = 0;
+
+	return 0;
+}
+
+/* Exported functions */
+
+/* Register the Encrypted Firmware driver with the IO abstraction */
+int register_io_dev_enc(const io_dev_connector_t **dev_con)
+{
+	int result;
+
+	assert(dev_con != NULL);
+
+	result = io_register_device(&enc_dev_info);
+	if (result == 0)
+		*dev_con = &enc_dev_connector;
+
+	return result;
+}