Add support for signed images in single loader mode
Signed-off-by: Wouter Cappelle <wouter.cappelle@crodeon.com>
diff --git a/boot/zephyr/CMakeLists.txt b/boot/zephyr/CMakeLists.txt
index 0530a05..dde8c36 100644
--- a/boot/zephyr/CMakeLists.txt
+++ b/boot/zephyr/CMakeLists.txt
@@ -143,7 +143,7 @@
)
endif()
-if(CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256 OR CONFIG_BOOT_ENCRYPT_EC256)
+if(CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256 OR CONFIG_BOOT_ENCRYPT_EC256 OR CONFIG_BOOT_SERIAL_ENCRYPT_EC256)
zephyr_library_include_directories(
${MBEDTLS_ASN1_DIR}/include
)
@@ -158,6 +158,7 @@
${BOOT_DIR}/zephyr/include
${TINYCRYPT_DIR}/include
)
+ zephyr_include_directories(${TINYCRYPT_DIR}/include)
zephyr_library_sources(
${TINYCRYPT_DIR}/source/ecc.c
@@ -231,7 +232,7 @@
)
endif()
-if(CONFIG_BOOT_ENCRYPT_EC256 OR CONFIG_BOOT_ENCRYPT_X25519)
+if(CONFIG_BOOT_ENCRYPT_EC256 OR CONFIG_BOOT_ENCRYPT_X25519 OR CONFIG_BOOT_SERIAL_ENCRYPT_EC256)
zephyr_library_sources(
${TINYCRYPT_DIR}/source/aes_encrypt.c
${TINYCRYPT_DIR}/source/aes_decrypt.c
@@ -304,6 +305,47 @@
zephyr_library_sources(${GENERATED_PUBKEY})
endif()
+# CONF_FILE points to the KConfig configuration files of the bootloader.
+unset(CONF_DIR)
+foreach(filepath ${CONF_FILE})
+ file(READ ${filepath} temp_text)
+ string(FIND "${temp_text}" ${CONFIG_BOOT_ENCRYPTION_KEY_FILE} match)
+ if(${match} GREATER_EQUAL 0)
+ if(NOT DEFINED CONF_DIR)
+ get_filename_component(CONF_DIR ${filepath} DIRECTORY)
+ else()
+ message(FATAL_ERROR "Encryption key file defined in multiple conf files")
+ endif()
+ endif()
+endforeach()
+
+
+if(NOT CONFIG_BOOT_ENCRYPTION_KEY_FILE STREQUAL "")
+ if(IS_ABSOLUTE ${CONFIG_BOOT_ENCRYPTION_KEY_FILE})
+ set(KEY_FILE ${CONFIG_BOOT_ENCRYPTION_KEY_FILE})
+ elseif((DEFINED CONF_DIR) AND
+ (EXISTS ${CONF_DIR}/${CONFIG_BOOT_ENCRYPTION_KEY_FILE}))
+ set(KEY_FILE ${CONF_DIR}/${CONFIG_BOOT_ENCRYPTION_KEY_FILE})
+ else()
+ set(KEY_FILE ${MCUBOOT_DIR}/${CONFIG_BOOT_ENCRYPTION_KEY_FILE})
+ endif()
+ message("MCUBoot bootloader key file: ${KEY_FILE}")
+
+ set(GENERATED_ENCKEY ${ZEPHYR_BINARY_DIR}/autogen-enckey.c)
+ add_custom_command(
+ OUTPUT ${GENERATED_ENCKEY}
+ COMMAND
+ ${PYTHON_EXECUTABLE}
+ ${MCUBOOT_DIR}/scripts/imgtool.py
+ getpriv
+ -k
+ ${KEY_FILE}
+ > ${GENERATED_ENCKEY}
+ DEPENDS ${KEY_FILE}
+ )
+ zephyr_library_sources(${GENERATED_ENCKEY})
+endif()
+
if(CONFIG_MCUBOOT_CLEANUP_ARM_CORE)
zephyr_library_sources(
${BOOT_DIR}/zephyr/arm_cleanup.c
diff --git a/boot/zephyr/Kconfig b/boot/zephyr/Kconfig
index 2c585b9..1d16b03 100644
--- a/boot/zephyr/Kconfig
+++ b/boot/zephyr/Kconfig
@@ -292,6 +292,21 @@
described under "ECIES-X25519 encryption" in docs/encrypted_images.md.
endif # !SINGLE_APPLICATION_SLOT
+config BOOT_ENCRYPTION_KEY_FILE
+ string "encryption key file"
+ depends on BOOT_ENCRYPT_EC256 || BOOT_SERIAL_ENCRYPT_EC256
+ default "enc-ec256-priv.pem" if BOOT_SIGNATURE_TYPE_ECDSA_P256
+ default ""
+ help
+ You can use either absolute or relative path.
+ In case relative path is used, the build system assumes that it starts
+ from the directory where the MCUBoot KConfig configuration file is
+ located. If the key file is not there, the build system uses relative
+ path that starts from the MCUBoot repository root directory.
+ The key file will be parsed by imgtool's getpriv command and a .c source
+ with the public key information will be written in a format expected by
+ MCUboot.
+
config BOOT_MAX_IMG_SECTORS
int "Maximum number of sectors per image slot"
default 128
@@ -581,6 +596,16 @@
statuses (custom property) for all images.
endif # ENABLE_MGMT_PERUSER
+
+config BOOT_SERIAL_ENCRYPT_EC256
+ bool "Support for encrypted upgrade images using ECIES-P256 in serial recovery upload"
+ default n
+ help
+ If y, uploaded images via serial recovery can be decrypted
+ on the fly when upgrading to the primary slot. The
+ encryption mechanism used in this case is ECIES using primitives
+ described under "ECIES-P256 encryption" in docs/encrypted_images.md.
+
endif # MCUBOOT_SERIAL
config BOOT_INTR_VEC_RELOC
diff --git a/boot/zephyr/include/mcuboot-mbedtls-cfg.h b/boot/zephyr/include/mcuboot-mbedtls-cfg.h
index 2bab537..02bf0b0 100644
--- a/boot/zephyr/include/mcuboot-mbedtls-cfg.h
+++ b/boot/zephyr/include/mcuboot-mbedtls-cfg.h
@@ -25,6 +25,7 @@
#include "config-rsa.h"
#elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ECDSA_P256) || \
defined(CONFIG_BOOT_ENCRYPT_EC256) || \
+ defined(CONFIG_BOOT_SERIAL_ENCRYPT_EC256) || \
(defined(CONFIG_BOOT_ENCRYPT_X25519) && !defined(CONFIG_BOOT_SIGNATURE_TYPE_ED25519))
#include "config-asn1.h"
#elif defined(CONFIG_BOOT_SIGNATURE_TYPE_ED25519)
diff --git a/boot/zephyr/include/mcuboot_config/mcuboot_config.h b/boot/zephyr/include/mcuboot_config/mcuboot_config.h
index 6d043c4..a737a17 100644
--- a/boot/zephyr/include/mcuboot_config/mcuboot_config.h
+++ b/boot/zephyr/include/mcuboot_config/mcuboot_config.h
@@ -109,6 +109,11 @@
#define MCUBOOT_ENCRYPT_EC256
#endif
+#ifdef CONFIG_BOOT_SERIAL_ENCRYPT_EC256
+#define MCUBOOT_ENC_IMAGES
+#define MCUBOOT_ENCRYPT_EC256
+#endif
+
#ifdef CONFIG_BOOT_ENCRYPT_X25519
#define MCUBOOT_ENC_IMAGES
#define MCUBOOT_ENCRYPT_X25519
diff --git a/boot/zephyr/include/single_loader.h b/boot/zephyr/include/single_loader.h
new file mode 100644
index 0000000..e762d15
--- /dev/null
+++ b/boot/zephyr/include/single_loader.h
@@ -0,0 +1,20 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2021-2021 Crodeon Technologies
+ *
+ */
+
+#ifndef H_SINGLE_LOADER_
+#define H_SINGLE_LOADER_
+#include "bootutil/fault_injection_hardening.h"
+
+/**
+ * Handle an encrypted firmware in the main flash.
+ * This will decrypt the image inplace
+ */
+int boot_handle_enc_fw();
+
+fih_int boot_image_validate(const struct flash_area *fa_p,
+ struct image_header *hdr);
+#endif
diff --git a/boot/zephyr/keys.c b/boot/zephyr/keys.c
index 7214748..b7a9edf 100644
--- a/boot/zephyr/keys.c
+++ b/boot/zephyr/keys.c
@@ -186,15 +186,8 @@
.len = &enc_priv_key_len,
};
#elif defined(MCUBOOT_ENCRYPT_EC256)
-unsigned char enc_priv_key[] = {
- 0x30, 0x81, 0x43, 0x02, 0x01, 0x00, 0x30, 0x13, 0x06, 0x07, 0x2a, 0x86,
- 0x48, 0xce, 0x3d, 0x02, 0x01, 0x06, 0x08, 0x2a, 0x86, 0x48, 0xce, 0x3d,
- 0x03, 0x01, 0x07, 0x04, 0x29, 0x30, 0x27, 0x02, 0x01, 0x01, 0x04, 0x20,
- 0xf6, 0x1e, 0x51, 0x9d, 0xf8, 0xfa, 0xdd, 0xa1, 0xb7, 0xd9, 0xa9, 0x64,
- 0x64, 0x3b, 0x54, 0xd0, 0x3d, 0xd0, 0x1f, 0xe5, 0x78, 0xd9, 0x17, 0x98,
- 0xa5, 0x28, 0xca, 0xcc, 0x6b, 0x67, 0x9e, 0x06, 0xa1, 0x44,
-};
-static unsigned int enc_priv_key_len = 70;
+extern const unsigned char enc_priv_key[];
+extern unsigned int enc_priv_key_len;
const struct bootutil_key bootutil_enc_key = {
.key = enc_priv_key,
.len = &enc_priv_key_len,
diff --git a/boot/zephyr/single_loader.c b/boot/zephyr/single_loader.c
index af2d398..24032e1 100644
--- a/boot/zephyr/single_loader.c
+++ b/boot/zephyr/single_loader.c
@@ -19,7 +19,7 @@
static const struct flash_area *_fa_p;
static struct image_header _hdr = { 0 };
-#ifdef MCUBOOT_VALIDATE_PRIMARY_SLOT
+#if defined(MCUBOOT_VALIDATE_PRIMARY_SLOT) || defined(MCUBOOT_VALIDATE_PRIMARY_SLOT_ONCE)
/**
* Validate hash of a primary boot image.
*
@@ -28,7 +28,7 @@
*
* @return FIH_SUCCESS on success, error code otherwise
*/
-inline static fih_int
+fih_int
boot_image_validate(const struct flash_area *fa_p,
struct image_header *hdr)
{
@@ -41,12 +41,21 @@
* the pointer from compilation.
*/
/* Validate hash */
+ if (hdr->ih_flags & IMAGE_F_ENCRYPTED)
+ {
+ /* Clear the encrypted flag we didn't supply a key
+ * This flag could be set if there was a decryption in place
+ * was performed. We will try to validate the image, and if still
+ * encrypted the validation will fail, and go in panic mode
+ */
+ hdr->ih_flags &= ~IMAGE_F_ENCRYPTED;
+ }
FIH_CALL(bootutil_img_validate, fih_rc, NULL, 0, hdr, fa_p, tmpbuf,
BOOT_TMPBUF_SZ, NULL, 0, NULL);
FIH_RET(fih_rc);
}
-#endif /* MCUBOOT_VALIDATE_PRIMARY_SLOT */
+#endif /* MCUBOOT_VALIDATE_PRIMARY_SLOT || MCUBOOT_VALIDATE_PRIMARY_SLOT_ONCE*/
/**
@@ -90,6 +99,302 @@
return 0;
}
+#ifdef MCUBOOT_ENC_IMAGES
+
+/**
+ * Validate hash of a primary boot image doing on the fly decryption as well
+ *
+ * @param[in] fa_p flash area pointer
+ * @param[in] hdr boot image header pointer
+ *
+ * @return FIH_SUCCESS on success, error code otherwise
+ */
+inline static fih_int
+boot_image_validate_encrypted(const struct flash_area *fa_p,
+ struct image_header *hdr)
+{
+ static uint8_t tmpbuf[BOOT_TMPBUF_SZ];
+ fih_int fih_rc = FIH_FAILURE;
+
+ struct boot_loader_state boot_data;
+ struct boot_loader_state *state = &boot_data;
+ struct boot_status _bs;
+ struct boot_status *bs = &_bs;
+ uint8_t image_index;
+ int rc;
+
+ memset(&boot_data, 0, sizeof(struct boot_loader_state));
+ image_index = BOOT_CURR_IMG(state);
+ if (MUST_DECRYPT(fa_p, image_index, hdr)) {
+ rc = boot_enc_load(BOOT_CURR_ENC(state), image_index, hdr, fa_p, bs);
+ if (rc < 0) {
+ FIH_RET(fih_rc);
+ }
+ if (rc == 0 && boot_enc_set_key(BOOT_CURR_ENC(state), 0, bs)) {
+ FIH_RET(fih_rc);
+ }
+ }
+ FIH_CALL(bootutil_img_validate, fih_rc, BOOT_CURR_ENC(state), image_index,
+ hdr, fa_p, tmpbuf, BOOT_TMPBUF_SZ, NULL, 0, NULL);
+
+ FIH_RET(fih_rc);
+}
+
+/*
+ * Compute the total size of the given image. Includes the size of
+ * the TLVs.
+ */
+static int
+read_image_size(const struct flash_area *fa_p,
+ struct image_header *hdr,
+ uint32_t *size)
+{
+ struct image_tlv_info info;
+ uint32_t off;
+ uint32_t protect_tlv_size;
+ int rc;
+
+ off = BOOT_TLV_OFF(hdr);
+
+ if (flash_area_read(fa_p, off, &info, sizeof(info))) {
+ rc = BOOT_EFLASH;
+ goto done;
+ }
+
+ protect_tlv_size = hdr->ih_protect_tlv_size;
+ if (info.it_magic == IMAGE_TLV_PROT_INFO_MAGIC) {
+ if (protect_tlv_size != info.it_tlv_tot) {
+ rc = BOOT_EBADIMAGE;
+ goto done;
+ }
+
+ if (flash_area_read(fa_p, off + info.it_tlv_tot, &info, sizeof(info))) {
+ rc = BOOT_EFLASH;
+ goto done;
+ }
+ } else if (protect_tlv_size != 0) {
+ rc = BOOT_EBADIMAGE;
+ goto done;
+ }
+
+ if (info.it_magic != IMAGE_TLV_INFO_MAGIC) {
+ rc = BOOT_EBADIMAGE;
+ goto done;
+ }
+
+ *size = off + protect_tlv_size + info.it_tlv_tot;
+ rc = 0;
+
+done:
+ return rc;
+}
+
+
+/**
+ * reads, decrypts in memory & write back the decrypted image in the same region
+ * This function is NOT power failsafe since the image is decrypted in ram (stack)
+ *
+ * @param flash_area The ID of the source flash area.
+ * @param off_src The offset within the flash area to
+ * copy from.
+ * @param sz The number of bytes to copy. should match erase sector
+ *
+ * @return 0 on success; nonzero on failure.
+ */
+int
+decrypt_region_inplace(struct boot_loader_state *state,
+ const struct flash_area *fap,
+ struct image_header *hdr,
+ uint32_t off, uint32_t sz)
+{
+ uint32_t bytes_copied;
+ int chunk_sz;
+ int rc;
+ uint32_t tlv_off;
+ size_t blk_off;
+ uint16_t idx;
+ uint32_t blk_sz;
+ uint8_t image_index;
+
+ static uint8_t buf[1024] __attribute__((aligned));
+ assert(sz <= sizeof buf);
+
+ bytes_copied = 0;
+ while (bytes_copied < sz) {
+ if (sz - bytes_copied > sizeof buf) {
+ chunk_sz = sizeof buf;
+ } else {
+ chunk_sz = sz - bytes_copied;
+ }
+
+ rc = flash_area_read(fap, off + bytes_copied, buf, chunk_sz);
+ if (rc != 0) {
+ return BOOT_EFLASH;
+ }
+
+ image_index = BOOT_CURR_IMG(state);
+ if (IS_ENCRYPTED(hdr)) {
+ blk_sz = chunk_sz;
+ idx = 0;
+ if (off + bytes_copied < hdr->ih_hdr_size) {
+ /* do not decrypt header */
+ if (hdr->ih_hdr_size > (off + bytes_copied + chunk_sz)) {
+ /* all bytes in header, skip decryption */
+ blk_sz = 0;
+ }
+ else {
+ blk_sz = off + bytes_copied + chunk_sz - hdr->ih_hdr_size;
+ }
+
+ blk_off = 0;
+ idx = hdr->ih_hdr_size;
+ } else {
+ blk_off = ((off + bytes_copied) - hdr->ih_hdr_size) & 0xf;
+ }
+ tlv_off = BOOT_TLV_OFF(hdr);
+ if (off + bytes_copied + chunk_sz > tlv_off) {
+ /* do not decrypt TLVs */
+ if (off + bytes_copied >= tlv_off) {
+ blk_sz = 0;
+ } else {
+ blk_sz = tlv_off - (off + bytes_copied);
+ }
+ }
+ boot_encrypt(BOOT_CURR_ENC(state), image_index, fap,
+ (off + bytes_copied + idx) - hdr->ih_hdr_size, blk_sz,
+ blk_off, &buf[idx]);
+ }
+ rc = flash_area_erase(fap, off + bytes_copied, chunk_sz);
+ if (rc != 0) {
+ return BOOT_EFLASH;
+ }
+ rc = flash_area_write(fap, off + bytes_copied, buf, chunk_sz);
+ if (rc != 0) {
+ return BOOT_EFLASH;
+ }
+
+ bytes_copied += chunk_sz;
+
+ MCUBOOT_WATCHDOG_FEED();
+ }
+
+ return 0;
+}
+
+/**
+ * Check if a image was encrypted into the first slot, and decrypt it
+ * in place. this operation is not power failsafe.
+ *
+ * The operation is done by checking the last flash sector, and using it as a
+ * temporarely scratch partition. The
+ *
+ * @param[in] fa_p flash area pointer
+ * @param[in] hdr boot image header pointer
+ *
+ * @return FIH_SUCCESS on success, error code otherwise
+ */
+inline static fih_int
+decrypt_image_inplace(const struct flash_area *fa_p,
+ struct image_header *hdr)
+{
+ fih_int fih_rc = FIH_FAILURE;
+ int rc;
+ struct boot_loader_state boot_data;
+ struct boot_loader_state *state = &boot_data;
+ struct boot_status _bs;
+ struct boot_status *bs = &_bs;
+ size_t size;
+ size_t sect_size;
+ size_t sect_count;
+ size_t sect;
+ uint8_t image_index;
+ struct flash_sector sector;
+
+ memset(&boot_data, 0, sizeof(struct boot_loader_state));
+ memset(&_bs, 0, sizeof(struct boot_status));
+
+ /* Get size from last sector to know page/sector erase size */
+ rc = flash_area_sector_from_off(boot_status_off(fa_p), §or);
+
+
+ image_index = BOOT_CURR_IMG(state);
+
+ if (MUST_DECRYPT(fa_p, image_index, hdr)) {
+#if 0 //Skip this step?, the image will just not boot if it's not decrypted properly
+ /* First check if the encrypted image is a good image before decrypting */
+ FIH_CALL(boot_image_validate_encrypted,fih_rc,_fa_p,&_hdr);
+ if (fih_not_eq(fih_rc, FIH_SUCCESS)) {
+ FIH_RET(fih_rc);
+ }
+#endif
+ memset(&boot_data, 0, sizeof(struct boot_loader_state));
+ /* Load the encryption keys into cache */
+ rc = boot_enc_load(BOOT_CURR_ENC(state), image_index, hdr, fa_p, bs);
+ if (rc < 0) {
+ FIH_RET(fih_rc);
+ }
+ if (rc == 0 && boot_enc_set_key(BOOT_CURR_ENC(state), 0, bs)) {
+ FIH_RET(fih_rc);
+ }
+ }
+ else
+ {
+ /* Expected encrypted image! */
+ FIH_RET(fih_rc);
+ }
+
+ uint32_t src_size = 0;
+ rc = read_image_size(fa_p,hdr, &src_size);
+ if (rc != 0) {
+ FIH_RET(fih_rc);
+ }
+
+ sect_size = sector.fs_size;
+ sect_count = fa_p->fa_size / sect_size;
+ for (sect = 0, size = 0; size < src_size && sect < sect_count; sect++) {
+ rc = decrypt_region_inplace(state, fa_p,hdr, size, sect_size);
+ if (rc != 0) {
+ FIH_RET(fih_rc);
+ }
+ size += sect_size;
+ }
+
+ fih_rc = FIH_SUCCESS;
+ FIH_RET(fih_rc);
+}
+
+int
+boot_handle_enc_fw()
+{
+ int rc = -1;
+ fih_int fih_rc = FIH_FAILURE;
+
+ rc = flash_area_open(FLASH_AREA_IMAGE_PRIMARY(0), &_fa_p);
+ assert(rc == 0);
+
+ rc = boot_image_load_header(_fa_p, &_hdr);
+ if (rc != 0) {
+ goto out;
+ }
+
+ if (IS_ENCRYPTED(&_hdr)) {
+ //encrypted, we need to decrypt in place
+ FIH_CALL(decrypt_image_inplace,fih_rc,_fa_p,&_hdr);
+ if (fih_not_eq(fih_rc, FIH_SUCCESS)) {
+ rc = -1;
+ goto out;
+ }
+ }
+ else
+ {
+ rc = 0;
+ }
+
+out:
+ flash_area_close(_fa_p);
+ return rc;
+}
+#endif
/**
* Gather information on image and prepare for booting.