[nrf noup] zephyr: Fix issues with ARM thumb decompression

fixup! [nrf noup] zephyr: Add support for ARM thumb filter

Fixes two issues with decompression, one with variables not being
declared at the correct level and the other with the test
decompression not checking the final decompressed image size

Signed-off-by: Jamie McCrae <[email protected]>
(cherry picked from commit 4fc8d2d)

Author: nordicjm

boot/zephyr/decompression.c

@@ -121,6 +121,7 @@ int bootutil_img_hash_decompress(struct enc_key_data *enc_state, int image_index
     uint32_t write_pos = 0;
     uint32_t protected_tlv_size = 0;
     uint32_t decompressed_image_size;
+    uint32_t output_size_total = 0;
     struct nrf_compress_implementation *compression_lzma = NULL;
     struct nrf_compress_implementation *compression_arm_thumb = NULL;
     TARGET_STATIC struct image_header modified_hdr;
@@ -300,7 +301,6 @@ int bootutil_img_hash_decompress(struct enc_key_data *enc_state, int image_index
                     uint8_t *output_arm_thumb = NULL;
                     uint32_t processed_size = 0;
                     uint32_t output_size_arm_thumb = 0;
-                    uint32_t output_size_arm_thumb_total = 0;
 
                     while (processed_size < output_size) {
                         uint32_t current_size = output_size - processed_size;
@@ -328,18 +328,12 @@ int bootutil_img_hash_decompress(struct enc_key_data *enc_state, int image_index
                         }
 
                         bootutil_sha_update(&sha_ctx, output_arm_thumb, output_size_arm_thumb);
-                        output_size_arm_thumb_total += output_size_arm_thumb;
+                        output_size_total += output_size_arm_thumb;
                         processed_size += current_size;
                     }
-
-                    if (output_size != output_size_arm_thumb_total) {
-                        BOOT_LOG_ERR("Decompression expected output_size mismatch: %d vs %d",
-                                     output_size, output_size_arm_thumb);
-                        rc = BOOT_EBADSTATUS;
-                        goto finish;
-                    }
                 } else {
                     bootutil_sha_update(&sha_ctx, output, output_size);
+                    output_size_total += output_size;
                 }
             }
 
@@ -349,6 +343,13 @@ int bootutil_img_hash_decompress(struct enc_key_data *enc_state, int image_index
         read_pos += copy_size;
     }
 
+    if (modified_hdr.ih_img_size != output_size_total) {
+        BOOT_LOG_ERR("Decompression expected output_size mismatch: %d vs %d",
+                     modified_hdr.ih_img_size, output_size_total);
+        rc = BOOT_EBADSTATUS;
+        goto finish;
+    }
+
     /* If there are any protected TLVs present, add them after the main decompressed image */
     if (modified_hdr.ih_protect_tlv_size > 0) {
         rc = boot_sha_protected_tlvs(hdr, fap, modified_hdr.ih_protect_tlv_size, tmp_buf,
@@ -869,6 +870,11 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
     TARGET_STATIC uint8_t decomp_buf[DECOMP_BUF_ALLOC_SIZE] __attribute__((aligned(4)));
     TARGET_STATIC struct image_header modified_hdr;
 
+#if defined(CONFIG_NRF_COMPRESS_ARM_THUMB)
+    uint8_t excess_data_buffer[DECOMP_BUF_EXTRA_SIZE];
+    bool excess_data_buffer_full = false;
+#endif
+
     hdr = boot_img_hdr(state, BOOT_SECONDARY_SLOT);
 
     /* Setup decompression system */
@@ -953,10 +959,6 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
     while (pos < hdr->ih_img_size) {
         uint32_t copy_size = hdr->ih_img_size - pos;
         uint32_t tmp_off = 0;
-#if defined(CONFIG_NRF_COMPRESS_ARM_THUMB)
-        uint8_t excess_data_buffer[DECOMP_BUF_EXTRA_SIZE];
-        bool excess_data_buffer_full = false;
-#endif
 
         if (copy_size > buf_size) {
             copy_size = buf_size;
@@ -1194,7 +1196,7 @@ int boot_copy_region_decompress(struct boot_loader_state *state, const struct fl
         uint32_t write_padding_size = write_alignment - (decomp_buf_size % write_alignment);
 
         /* Check if additional write padding should be applied to meet the minimum write size */
-        if (write_padding_size) {
+        if (write_alignment > 1 && write_padding_size) {
             uint8_t flash_erased_value;
 
             flash_erased_value = flash_area_erased_val(fap_dst);