boot: Change boot_enc_load to take slot number instead of image

In all cases where boot_enc_load is called it is known what slot
is addressed, so it is better to just pass the slot number
instead of making the boot_enc_load figure out slot number from
image index and provided flash area object.

Signed-off-by: Dominik Ermel <dominik.ermel@nordicsemi.no>

boot/boot_serial/src/boot_serial_encryption.c

@@ -36,7 +36,7 @@ boot_image_validate_encrypted(const struct flash_area *fa_p,
  memset(&boot_data, 0, sizeof(struct boot_loader_state));
  image_index = BOOT_CURR_IMG(state);
  if(IS_ENCRYPTED(hdr)) {
- rc = boot_enc_load(BOOT_CURR_ENC(state), image_index, hdr, fa_p, bs);
+ rc = boot_enc_load(BOOT_CURR_ENC(state), 1, hdr, fa_p, bs);
  if (rc < 0) {
  FIH_RET(fih_rc);
  }
@@ -218,7 +218,6 @@ decrypt_image_inplace(const struct flash_area *fa_p,
  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));
@@ -228,8 +227,6 @@ decrypt_image_inplace(const struct flash_area *fa_p,
  rc = flash_area_get_sector(fa_p, boot_status_off(fa_p), &sector);
 
 
- image_index = BOOT_CURR_IMG(state);
-
  if(IS_ENCRYPTED(hdr)) {
 #if 0 //Skip this step?, the image will just not boot if it's not decrypted properly
  static uint8_t tmpbuf[BOOT_TMPBUF_SZ];
@@ -241,7 +238,7 @@ decrypt_image_inplace(const struct flash_area *fa_p,
 #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);
+ rc = boot_enc_load(BOOT_CURR_ENC(state), 0, hdr, fa_p, bs);
  if (rc < 0) {
  FIH_RET(fih_rc);
  }

boot/bootutil/include/bootutil/enc_key.h

@@ -55,7 +55,7 @@ int boot_enc_init(struct enc_key_data *enc_state, uint8_t slot);
 int boot_enc_drop(struct enc_key_data *enc_state, uint8_t slot);
 int boot_enc_set_key(struct enc_key_data *enc_state, uint8_t slot,
  const struct boot_status *bs);
-int boot_enc_load(struct enc_key_data *enc_state, int image_index,
+int boot_enc_load(struct enc_key_data *enc_state, int slot,
  const struct image_header *hdr, const struct flash_area *fap,
  struct boot_status *bs);
 bool boot_enc_valid(struct enc_key_data *enc_state, int image_index,

boot/bootutil/src/encrypted.c

@@ -607,7 +607,7 @@ boot_decrypt_key(const uint8_t *buf, uint8_t *enckey)
  * Load encryption key.
  */
 int
-boot_enc_load(struct enc_key_data *enc_state, int image_index,
+boot_enc_load(struct enc_key_data *enc_state, int slot,
  const struct image_header *hdr, const struct flash_area *fap,
  struct boot_status *bs)
 {
@@ -619,15 +619,8 @@ boot_enc_load(struct enc_key_data *enc_state, int image_index,
 #else
  uint8_t buf[EXPECTED_ENC_LEN];
 #endif
- uint8_t slot;
  int rc;
 
- rc = flash_area_id_to_multi_image_slot(image_index, flash_area_get_id(fap));
- if (rc < 0) {
- return rc;
- }
- slot = rc;
-
  /* Already loaded... */
  if (enc_state[slot].valid) {
  return 1;

boot/bootutil/src/loader.c

@@ -781,7 +781,6 @@ boot_image_check(struct boot_loader_state *state, struct image_header *hdr,
  const struct flash_area *fap, struct boot_status *bs)
 {
  TARGET_STATIC uint8_t tmpbuf[BOOT_TMPBUF_SZ];
- uint8_t image_index;
  int rc;
  FIH_DECLARE(fih_rc, FIH_FAILURE);
 
@@ -792,13 +791,11 @@ boot_image_check(struct boot_loader_state *state, struct image_header *hdr,
  (void)bs;
  (void)rc;
 
- image_index = BOOT_CURR_IMG(state);
-
 /* In the case of ram loading the image has already been decrypted as it is
  * decrypted when copied in ram */
 #if defined(MCUBOOT_ENC_IMAGES) && !defined(MCUBOOT_RAM_LOAD)
- if (MUST_DECRYPT(fap, image_index, hdr)) {
- rc = boot_enc_load(BOOT_CURR_ENC(state), image_index, hdr, fap, bs);
+ if (MUST_DECRYPT(fap, BOOT_CURR_IMG(state), hdr)) {
+ rc = boot_enc_load(BOOT_CURR_ENC(state), 1, hdr, fap, bs);
  if (rc < 0) {
  FIH_RET(fih_rc);
  }
@@ -808,8 +805,9 @@ boot_image_check(struct boot_loader_state *state, struct image_header *hdr,
  }
 #endif
 
- FIH_CALL(bootutil_img_validate, fih_rc, BOOT_CURR_ENC(state), image_index,
- hdr, fap, tmpbuf, BOOT_TMPBUF_SZ, NULL, 0, NULL);
+ FIH_CALL(bootutil_img_validate, fih_rc, BOOT_CURR_ENC(state),
+ BOOT_CURR_IMG(state), hdr, fap, tmpbuf, BOOT_TMPBUF_SZ,
+ NULL, 0, NULL);
 
  FIH_RET(fih_rc);
 }
@@ -1403,7 +1401,7 @@ boot_copy_image(struct boot_loader_state *state, struct boot_status *bs)
 
 #ifdef MCUBOOT_ENC_IMAGES
  if (IS_ENCRYPTED(boot_img_hdr(state, BOOT_SECONDARY_SLOT))) {
- rc = boot_enc_load(BOOT_CURR_ENC(state), image_index,
+ rc = boot_enc_load(BOOT_CURR_ENC(state), BOOT_SECONDARY_SLOT,
  boot_img_hdr(state, BOOT_SECONDARY_SLOT),
  fap_secondary_slot, bs);
 
@@ -1527,7 +1525,7 @@ boot_swap_image(struct boot_loader_state *state, struct boot_status *bs)
 #ifdef MCUBOOT_ENC_IMAGES
  if (IS_ENCRYPTED(hdr)) {
  fap = BOOT_IMG_AREA(state, BOOT_PRIMARY_SLOT);
- rc = boot_enc_load(BOOT_CURR_ENC(state), image_index, hdr, fap, bs);
+ rc = boot_enc_load(BOOT_CURR_ENC(state), 0, hdr, fap, bs);
  assert(rc >= 0);
 
  if (rc == 0) {
@@ -1551,7 +1549,7 @@ boot_swap_image(struct boot_loader_state *state, struct boot_status *bs)
  hdr = boot_img_hdr(state, BOOT_SECONDARY_SLOT);
  if (IS_ENCRYPTED(hdr)) {
  fap = BOOT_IMG_AREA(state, BOOT_SECONDARY_SLOT);
- rc = boot_enc_load(BOOT_CURR_ENC(state), image_index, hdr, fap, bs);
+ rc = boot_enc_load(BOOT_CURR_ENC(state), 1, hdr, fap, bs);
  assert(rc >= 0);
 
  if (rc == 0) {
@@ -2750,7 +2748,7 @@ boot_decrypt_and_copy_image_to_sram(struct boot_loader_state *state,
  goto done;
  }
 
- rc = boot_enc_load(BOOT_CURR_ENC(state), image_index, hdr, fap_src, &bs);
+ rc = boot_enc_load(BOOT_CURR_ENC(state), slot, hdr, fap_src, &bs);
  if (rc < 0) {
  goto done;
  }