Delta update fixes

- img_size: use 32-bit variable
- remove '+1' from pa_start calculation
- fix broken delta.c wb_diff check for distance between matching
  patterns (root cause for the delta+encrypt bug)

include/delta.h

@@ -67,7 +67,7 @@ int wb_diff_init(WB_DIFF_CTX *ctx, uint8_t *src_a, uint32_t len_a, uint8_t *src_
 int wb_diff(WB_DIFF_CTX *ctx, uint8_t *patch, uint32_t len);
 int wb_patch_init(WB_PATCH_CTX *bm, uint8_t *src, uint32_t ssz, uint8_t *patch, uint32_t psz);
 int wb_patch(WB_PATCH_CTX *ctx, uint8_t *dst, uint32_t len);
-int wolfBoot_get_delta_info(uint8_t part, int inverse, uint32_t **img_offset, uint16_t **img_size);
+int wolfBoot_get_delta_info(uint8_t part, int inverse, uint32_t **img_offset, uint32_t **img_size);
 
 #endif
 

src/delta.c

@@ -209,7 +209,7 @@ int wb_diff(WB_DIFF_CTX *ctx, uint8_t *patch, uint32_t len)
          * base for the sectors that have already been updated.
          */
 
-        pa_start = (WOLFBOOT_SECTOR_SIZE + 1) * page_start;
+        pa_start = WOLFBOOT_SECTOR_SIZE  * page_start;
         pa = ctx->src_a + pa_start;
         while (((uintptr_t)(pa - ctx->src_a) < (uintptr_t)ctx->size_a) && (p_off < len)) {
             if ((uintptr_t)(ctx->size_a - (pa - ctx->src_a)) < BLOCK_HDR_SIZE)
@@ -273,7 +273,8 @@ int wb_diff(WB_DIFF_CTX *ctx, uint8_t *patch, uint32_t len)
                 /* Don't try matching backwards if the distance between the two
                  * blocks is smaller than one sector.
                  */
-                if (WOLFBOOT_SECTOR_SIZE > (pb - ctx->src_b) - (page_start * WOLFBOOT_SECTOR_SIZE))
+                if (WOLFBOOT_SECTOR_SIZE > (page_start * WOLFBOOT_SECTOR_SIZE)
+                        - (pb - ctx->src_b))
                     break;
 
                 if ((memcmp(pb, (ctx->src_b + ctx->off_b), BLOCK_HDR_SIZE) == 0)) {

src/update_flash.c

@@ -212,7 +212,7 @@ static int wolfBoot_delta_update(struct wolfBoot_image *boot,
     uint32_t offset = 0;
     uint16_t ptr_len;
     uint32_t *img_offset;
-    uint16_t *img_size;
+    uint32_t *img_size;
     uint32_t total_size;
     WB_PATCH_CTX ctx;
 #ifdef EXT_ENCRYPTED