[nrf noup] boot/bootutil/loader: image discovery by ih_load_address

Align all image's matching exercises to MCUBOOT_CHECK_HEADER_LOAD_ADDRES.
This method uses ih_load_address field of the image header instead
of reset vector address. This allows to match
incoming image to the partition even when it is for instance encrypted,
as the image header is always plain-text.

Firmware need to be signed with
imgtool.py sign --rom-fixed <partition_address> parameter in order to
involve this feature.

ref.: NCSIDB-1173

Signed-off-by: Andrzej Puzdrowski <andrzej.puzdrowski@nordicsemi.no>

Author: nvlsianpu

boot/bootutil/src/loader.c

@@ -1043,30 +1043,38 @@ boot_validated_swap_type(struct boot_loader_state *state,
 #if defined(MCUBOOT_IS_SECOND_STAGE) || CONFIG_MCUBOOT_NETWORK_CORE_IMAGE_NUMBER != -1
     const struct flash_area *secondary_fa = BOOT_IMG_AREA(state, BOOT_SLOT_SECONDARY);
     struct image_header *hdr = boot_img_hdr(state, BOOT_SLOT_SECONDARY);
-    uint32_t reset_addr = 0;
+    uint32_t internal_img_addr = 0;
     int rc = 0;
     /* Patch needed for NCS. Since image 0 (the app) and image 1 (the other
      * B1 slot S0 or S1) share the same secondary slot, we need to check
      * whether the update candidate in the secondary slot is intended for
-     * image 0 or image 1 primary by looking at the address of the reset
-     * vector. Note that there are good reasons for not using img_num from
-     * the swap info.
+     * image 0 or image 1 primary. With MCUBOOT_CHECK_HEADER_LOAD_ADDRESS the
+     * image header load address is used; otherwise the reset vector is read
+     * from the image. Note that there are good reasons for not using img_num
+     * from the swap info.
      */
     NSIB_OWNED_UNSET(BOOT_CURR_IMG(state));
 
     if (hdr->ih_magic == IMAGE_MAGIC) {
-        rc = flash_area_read(secondary_fa, hdr->ih_hdr_size +
-                             sizeof(uint32_t), &reset_addr,
-                             sizeof(reset_addr));
+#ifdef MCUBOOT_CHECK_HEADER_LOAD_ADDRESS
+        internal_img_addr = hdr->ih_load_addr;
+#else
+        rc = flash_area_read(secondary_fa, hdr->ih_hdr_size + RESET_OFFSET,
+                             &internal_img_addr, sizeof(internal_img_addr));
         if (rc != 0) {
             return BOOT_SWAP_TYPE_FAIL;
         }
+#endif
+
+        BOOT_LOG_DBG("boot_validated_swap_type: image %d addr 0x%x",
+                     BOOT_CURR_IMG(state), internal_img_addr);
 
         sec_slot_touch(state);
 
 #ifdef  MCUBOOT_IS_SECOND_STAGE
 #if CONFIG_MCUBOOT_NETWORK_CORE_IMAGE_NUMBER != -1
-        if(!(reset_addr >= NETCPU_APP_SLOT_OFFSET && reset_addr < NETCPU_APP_SLOT_END))
+        if (!(internal_img_addr >= NETCPU_APP_SLOT_OFFSET &&
+              internal_img_addr < NETCPU_APP_SLOT_END))
 #endif
         {
             const struct flash_area *primary_fa;
@@ -1077,9 +1085,14 @@ boot_validated_swap_type(struct boot_loader_state *state,
             if (rc != 0) {
                 return BOOT_SWAP_TYPE_FAIL;
             }
+
+            const uint32_t pri_off = flash_area_get_off(primary_fa);
+            const uint32_t pri_end = pri_off + flash_area_get_size(primary_fa);
+
             /* Check start and end of primary slot for current image */
-            if (reset_addr >= SECOND_STAGE_INACTIVE_MCUBOOT_OFFSET &&
-                reset_addr <= (SECOND_STAGE_INACTIVE_MCUBOOT_OFFSET + SECOND_STAGE_INACTIVE_MCUBOOT_SIZE)) {
+            if (internal_img_addr >= SECOND_STAGE_INACTIVE_MCUBOOT_OFFSET &&
+                internal_img_addr < (SECOND_STAGE_INACTIVE_MCUBOOT_OFFSET +
+                                     SECOND_STAGE_INACTIVE_MCUBOOT_SIZE)) {
                 if (BOOT_CURR_IMG(state) == CONFIG_MCUBOOT_APPLICATION_IMAGE_NUMBER) {
                     /* This is not the s0/s1 upgrade image but the application image, pretend
                      * there is no image so the NSIB update can be loaded
@@ -1088,21 +1101,22 @@ boot_validated_swap_type(struct boot_loader_state *state,
                 }
 
                 NSIB_OWNED_SET(BOOT_CURR_IMG(state));
-            } else if (reset_addr >= SECOND_STAGE_ACTIVE_MCUBOOT_OFFSET &&
-                       reset_addr <= (SECOND_STAGE_ACTIVE_MCUBOOT_OFFSET + SECOND_STAGE_ACTIVE_MCUBOOT_SIZE)) {
+            } else if (internal_img_addr >= SECOND_STAGE_ACTIVE_MCUBOOT_OFFSET &&
+                       internal_img_addr < (SECOND_STAGE_ACTIVE_MCUBOOT_OFFSET +
+                                            SECOND_STAGE_ACTIVE_MCUBOOT_SIZE)) {
                 /* NSIB upgrade but for the wrong slot, must be erased */
                 BOOT_LOG_ERR("Image in slot is for wrong s0/s1 image");
                 flash_area_erase(secondary_fa, 0, secondary_fa->fa_size);
                 sec_slot_untouch(state);
                 BOOT_LOG_ERR("Cleaned-up secondary slot of image %d", BOOT_CURR_IMG(state));
                 return BOOT_SWAP_TYPE_FAIL;
-            } else if (reset_addr < primary_fa->fa_off || reset_addr > (primary_fa->fa_off + primary_fa->fa_size)) {
+            } else if (internal_img_addr < pri_off || internal_img_addr >= pri_end) {
                 /* The image in the secondary slot is not intended for any */
                 return BOOT_SWAP_TYPE_NONE;
             }
 
-            if ((primary_fa->fa_off == SECOND_STAGE_ACTIVE_MCUBOOT_OFFSET) ||
-                (primary_fa->fa_off == SECOND_STAGE_INACTIVE_MCUBOOT_OFFSET)) {
+            if ((pri_off == SECOND_STAGE_ACTIVE_MCUBOOT_OFFSET) ||
+                (pri_off == SECOND_STAGE_INACTIVE_MCUBOOT_OFFSET)) {
                 NSIB_OWNED_SET(BOOT_CURR_IMG(state));
             }
         }
@@ -1134,8 +1148,8 @@ boot_validated_swap_type(struct boot_loader_state *state,
          * update and indicate to the caller of this function that no update is
          * available
          */
-        if (upgrade_valid && reset_addr >= NETCPU_APP_SLOT_OFFSET &&
-            reset_addr < NETCPU_APP_SLOT_END) {
+        if (upgrade_valid && internal_img_addr >= NETCPU_APP_SLOT_OFFSET &&
+            internal_img_addr < NETCPU_APP_SLOT_END) {
             struct image_header *hdr = (struct image_header *)secondary_fa->fa_off;
             uint32_t vtable_addr = (uint32_t)hdr + hdr->ih_hdr_size;
             uint32_t *net_core_fw_addr = (uint32_t *)(vtable_addr);