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wolfBoot
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Fix fallback using encryption by storing the key after swaping 

partitions
pull/100/head
Daniele Lacamera 2021-01-11 13:07:07 +01:00
parent 23d013dc1d
commit 82da68028b
3 changed files with 29 additions and 2 deletions
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1
include/wolfboot/wolfboot.h
View File

@ -131,5 +131,6 @@ int wolfBoot_dualboot_candidate(void);
#define ENCRYPT_NONCE_SIZE 12 /* 96 bit*/
int wolfBoot_set_encrypt_key(const uint8_t *key, const uint8_t *nonce);
int wolfBoot_get_encrypt_key(uint8_t *key, uint8_t *nonce);
int wolfBoot_erase_encrypt_key(void);
#endif /* !WOLFBOOT_H */

16
src/libwolfboot.c
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@ -380,6 +380,9 @@ void RAMFUNCTION wolfBoot_success(void)
wolfBoot_set_partition_state(PART_BOOT, st);
hal_flash_lock();
}
#ifdef EXT_ENCRYPTED
wolfBoot_erase_encrypt_key();
#endif
}
uint16_t wolfBoot_find_header(uint8_t *haystack, uint16_t type, uint8_t **ptr)
@ -579,7 +582,6 @@ int wolfBoot_fallback_is_possible(void)
static uint8_t ENCRYPT_CACHE[NVM_CACHE_SIZE] __attribute__((aligned(32)));
#endif
static int RAMFUNCTION hal_set_key(const uint8_t *k, const uint8_t *nonce)
{
uint32_t addr = ENCRYPT_TMP_SECRET_OFFSET + WOLFBOOT_PARTITION_BOOT_ADDRESS;
@ -604,12 +606,22 @@ int RAMFUNCTION wolfBoot_set_encrypt_key(const uint8_t *key, const uint8_t *nonc
return 0;
}
int RAMFUNCTION wolfBoot_get_encrypt_key(uint8_t *k, uint8_t *nonce)
{
uint8_t *mem = (uint8_t *)(ENCRYPT_TMP_SECRET_OFFSET + WOLFBOOT_PARTITION_BOOT_ADDRESS);
XMEMCPY(k, mem, ENCRYPT_KEY_SIZE);
XMEMCPY(nonce, mem + ENCRYPT_KEY_SIZE, ENCRYPT_NONCE_SIZE);
return 0;
}
int RAMFUNCTION wolfBoot_erase_encrypt_key(void)
{
uint8_t ff[ENCRYPT_KEY_SIZE + ENCRYPT_NONCE_SIZE];
int i;
uint8_t *mem = (uint8_t *)ENCRYPT_TMP_SECRET_OFFSET + WOLFBOOT_PARTITION_BOOT_ADDRESS;
XMEMSET(ff, 0xFF, ENCRYPT_KEY_SIZE + ENCRYPT_NONCE_SIZE);
hal_set_key(ff, ff + ENCRYPT_KEY_SIZE);
if (XMEMCMP(mem, ff, ENCRYPT_KEY_SIZE + ENCRYPT_NONCE_SIZE) != 0)
hal_set_key(ff, ff + ENCRYPT_KEY_SIZE);
return 0;
}

14
src/update_flash.c
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@ -155,6 +155,10 @@ static int wolfBoot_update(int fallback_allowed)
uint32_t sector = 0;
uint8_t flag, st;
struct wolfBoot_image boot, update, swap;
#ifdef EXT_ENCRYPTED
uint8_t key[ENCRYPT_KEY_SIZE];
uint8_t nonce[ENCRYPT_NONCE_SIZE];
#endif
/* No Safety check on open: we might be in the middle of a broken update */
wolfBoot_open_image(&update, PART_UPDATE);
@ -197,6 +201,11 @@ static int wolfBoot_update(int fallback_allowed)
ext_flash_unlock();
#endif
/* Read encryption key/IV before starting the update */
#ifdef EXT_ENCRYPTED
wolfBoot_get_encrypt_key(key, nonce);
#endif
#ifndef DISABLE_BACKUP
/* Interruptible swap
* The status is saved in the sector flags of the update partition.
@ -264,6 +273,11 @@ static int wolfBoot_update(int fallback_allowed)
ext_flash_lock();
#endif
hal_flash_lock();
/* Save the encryption key after swapping */
#ifdef EXT_ENCRYPTED
wolfBoot_set_encrypt_key(key, nonce);
#endif
return 0;
}