Goal is that multiple faults would be required to bypass a boot-time signature check. - Also strengthens some address range checks for safe app memory addresses - Change pre-enable logic to also check the bootloader signature before enabling SBV2 on ESP32 Add some additional checks for invalid sections: - Sections only partially in DRAM or IRAM are invalid - If a section is in D/IRAM, allow the possibility only some is in D/IRAM - Only pass sections that are entirely in the same type of RTC memory region
138 lines
4.6 KiB
C
138 lines
4.6 KiB
C
// Copyright 2020 Espressif Systems (Shanghai) PTE LTD
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
#ifndef _ROM_SECURE_BOOT_H_
|
|
#define _ROM_SECURE_BOOT_H_
|
|
|
|
#include <stdint.h>
|
|
#include "rsa_pss.h"
|
|
|
|
#ifdef __cplusplus
|
|
extern "C" {
|
|
#endif
|
|
|
|
struct ets_secure_boot_sig_block;
|
|
struct ets_secure_boot_signature_t;
|
|
|
|
typedef struct ets_secure_boot_sig_block ets_secure_boot_sig_block_t;
|
|
typedef struct ets_secure_boot_signature ets_secure_boot_signature_t;
|
|
typedef struct ets_secure_boot_key_digests ets_secure_boot_key_digests_t;
|
|
|
|
/* 64KB 'staging buffer' for loading the verified bootloader
|
|
|
|
Comes from the "shared buffers" region (see shared_buffers.h)
|
|
|
|
The bootloader can't be safely linked into this address range
|
|
(may be possible with some cleverness.)
|
|
*/
|
|
#define SECURE_BOOT_STAGING_BUFFER_START ((uint32_t)(g_shared_buffers.secure_boot_staging_buf))
|
|
#define SECURE_BOOT_STAGING_BUFFER_SZ sizeof(g_shared_buffers.secure_boot_staging_buf)
|
|
#define SECURE_BOOT_STAGING_BUFFER_END (SECURE_BOOT_STAGING_BUFFER_START + SECURE_BOOT_STAGING_BUFFER_SZ)
|
|
|
|
/* Anti-FI measure: use full words for success/fail, instead of
|
|
0/non-zero
|
|
*/
|
|
typedef enum {
|
|
SB_SUCCESS = 0x3A5A5AA5,
|
|
SB_FAILED = 0x7533885E,
|
|
} ets_secure_boot_status_t;
|
|
|
|
|
|
/* Verify and stage-load the bootloader image
|
|
(reconfigures cache to map, loads trusted key digests from efuse,
|
|
copies the bootloader into the staging buffer.)
|
|
|
|
If allow_key_revoke is true and aggressive revoke efuse is set,
|
|
any failed signature has its associated key revoked in efuse.
|
|
|
|
If result is SB_SUCCESS, the "simple hash" of the bootloader
|
|
is copied into verified_hash.
|
|
*/
|
|
ets_secure_boot_status_t ets_secure_boot_verify_stage_bootloader(uint8_t *verified_hash, bool allow_key_revoke);
|
|
|
|
/* Verify bootloader image (reconfigures cache to map),
|
|
with key digests provided as parameters.)
|
|
|
|
Can be used to verify secure boot status before enabling
|
|
secure boot permanently.
|
|
|
|
If stage_load parameter is true, bootloader is copied into staging
|
|
buffer in RAM at the same time.
|
|
|
|
If result is SB_SUCCESS, the "simple hash" of the bootloader is
|
|
copied into verified_hash.
|
|
*/
|
|
ets_secure_boot_status_t ets_secure_boot_verify_bootloader_with_keys(uint8_t *verified_hash, const ets_secure_boot_key_digests_t *trusted_keys, bool stage_load);
|
|
|
|
/* Read key digests from efuse. Any revoked/missing digests will be
|
|
marked as NULL
|
|
*/
|
|
ETS_STATUS ets_secure_boot_read_key_digests(ets_secure_boot_key_digests_t *trusted_keys);
|
|
|
|
/* Verify supplied signature against supplied digest, using
|
|
supplied trusted key digests.
|
|
|
|
Doesn't reconfigure cache or any other hardware access except for RSA peripheral.
|
|
|
|
If result is SB_SUCCESS, the image_digest value is copied into verified_digest.
|
|
*/
|
|
ets_secure_boot_status_t ets_secure_boot_verify_signature(const ets_secure_boot_signature_t *sig, const uint8_t *image_digest, const ets_secure_boot_key_digests_t *trusted_keys, uint8_t *verified_digest);
|
|
|
|
/* Revoke a public key digest in efuse.
|
|
@param index Digest to revoke. Must be 0, 1 or 2.
|
|
*/
|
|
void ets_secure_boot_revoke_public_key_digest(int index);
|
|
|
|
#define ETS_SECURE_BOOT_V2_SIGNATURE_MAGIC 0xE7
|
|
|
|
/* Secure Boot V2 signature block
|
|
|
|
(Up to 3 in a signature sector are appended to the image)
|
|
*/
|
|
struct ets_secure_boot_sig_block {
|
|
uint8_t magic_byte;
|
|
uint8_t version;
|
|
uint8_t _reserved1;
|
|
uint8_t _reserved2;
|
|
uint8_t image_digest[32];
|
|
ets_rsa_pubkey_t key;
|
|
uint8_t signature[384];
|
|
uint32_t block_crc;
|
|
uint8_t _padding[16];
|
|
};
|
|
|
|
_Static_assert(sizeof(ets_secure_boot_sig_block_t) == 1216, "invalid sig block size");
|
|
|
|
#define SECURE_BOOT_NUM_BLOCKS 3
|
|
|
|
/* V2 Secure boot signature sector (up to 3 blocks) */
|
|
struct ets_secure_boot_signature {
|
|
ets_secure_boot_sig_block_t block[SECURE_BOOT_NUM_BLOCKS];
|
|
uint8_t _padding[4096 - (sizeof(ets_secure_boot_sig_block_t) * SECURE_BOOT_NUM_BLOCKS)];
|
|
};
|
|
|
|
_Static_assert(sizeof(ets_secure_boot_signature_t) == 4096, "invalid sig sector size");
|
|
|
|
#define MAX_KEY_DIGESTS 3
|
|
|
|
struct ets_secure_boot_key_digests {
|
|
const void *key_digests[MAX_KEY_DIGESTS];
|
|
bool allow_key_revoke;
|
|
};
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* _ROM_SECURE_BOOT_H_ */
|