boot: bootutil: swap_scratch: Fix compressed image sector size check

Fixes an issue with compressed update support whereby it would wrong continue to check all sector sizes and error due to the sector sizes of the secondary slot being 0 until overflow Signed-off-by: Jamie McCrae <[email protected]>
rustammendel · Oct 14, 2024 · 08a71d1 · 08a71d1
1 parent d69933c
commit 08a71d1
Showing 1 changed file with 11 additions and 1 deletion.
diff --git a/boot/bootutil/src/swap_scratch.c b/boot/bootutil/src/swap_scratch.c
@@ -191,7 +191,17 @@ boot_slots_compatible(struct boot_loader_state *state)
             smaller = 1;
             i++;
         } else {
-            sz1 += boot_img_sector_size(state, BOOT_SECONDARY_SLOT, j);
+            size_t sector_size = boot_img_sector_size(state, BOOT_SECONDARY_SLOT, j);
+
+#ifdef MCUBOOT_DECOMPRESS_IMAGES
+            if (sector_size == 0) {
+                /* Since this supports decompressed images, we can safely exit if slot1 is
+                 * smaller than slot0.
+                 */
+                break;
+            }
+#endif
+            sz1 += sector_size;
             /* Guarantee that multiple sectors of the primary slot
              * fit into the secondary slot.
              */