bootutil: Add compressed image flags and TLV, fix misc. bugs in bootutil

boot/bootutil/include/bootutil/image.h

@@ -71,6 +71,13 @@ struct flash_area;
  */
 #define IMAGE_F_ROM_FIXED 0x00000100
 
+/*
+ * Flags that indicate if the image data is compressed
+ */
+#define IMAGE_F_COMPRESSED_LZMA1 0x00000200
+#define IMAGE_F_COMPRESSED_LZMA2 0x00000400
+#define IMAGE_F_COMPRESSED_ARM_THUMB_FLT 0x00000800
+
 /*
  * ECSDA224 is with NIST P-224
  * ECSDA256 is with NIST P-256
@@ -101,6 +108,18 @@ struct flash_area;
 #define IMAGE_TLV_DEPENDENCY 0x40 /* Image depends on other image */
 #define IMAGE_TLV_SEC_CNT 0x50 /* security counter */
 #define IMAGE_TLV_BOOT_RECORD 0x60 /* measured boot record */
+/* The following flags relate to compressed images and are for the decompressed image data */
+#define IMAGE_TLV_DECOMP_SIZE 0x70 /* Decompressed image size excluding header/TLVs */
+#define IMAGE_TLV_DECOMP_SHA 0x71 /*
+ * Decompressed image shaX hash, this field must match
+ * the format and size of the raw slot (compressed)
+ * shaX hash
+ */
+#define IMAGE_TLV_DECOMP_SIGNATURE 0x72 /*
+ * Decompressed image signature, this field must match
+ * the format and size of the raw slot (compressed)
+ * signature
+ */
  /*
  * vendor reserved TLVs at xxA0-xxFF,
  * where xx denotes the upper byte
@@ -160,6 +179,12 @@ struct image_tlv {
 #define MUST_DECRYPT(fap, idx, hdr) \
  (flash_area_get_id(fap) == FLASH_AREA_IMAGE_SECONDARY(idx) && IS_ENCRYPTED(hdr))
 
+#define COMPRESSIONFLAGS (IMAGE_F_COMPRESSED_LZMA1 | IMAGE_F_COMPRESSED_LZMA2 \
+ | IMAGE_F_COMPRESSED_ARM_THUMB_FLT)
+#define IS_COMPRESSED(hdr) ((hdr)->ih_flags & COMPRESSIONFLAGS)
+#define MUST_DECOMPRESS(fap, idx, hdr) \
+ (flash_area_get_id(fap) == FLASH_AREA_IMAGE_SECONDARY(idx) && IS_COMPRESSED(hdr))
+
 _Static_assert(sizeof(struct image_header) == IMAGE_HEADER_SIZE,
  "struct image_header not required size");
 

boot/bootutil/src/loader.c

@@ -860,7 +860,9 @@ split_image_check(struct image_header *app_hdr,
  * Check that this is a valid header. Valid means that the magic is
  * correct, and that the sizes/offsets are "sane". Sane means that
  * there is no overflow on the arithmetic, and that the result fits
- * within the flash area we are in.
+ * within the flash area we are in. Also check the flags in the image
+ * and class the image as invalid if flags for encryption/compression
+ * are present but these features are not enabled.
  */
 static bool
 boot_is_header_valid(const struct image_header *hdr, const struct flash_area *fap)
@@ -875,10 +877,44 @@ boot_is_header_valid(const struct image_header *hdr, const struct flash_area *fa
  return false;
  }
 
+#ifdef MCUBOOT_DECOMPRESS_IMAGES
+ if (!MUST_DECOMPRESS(fap, BOOT_CURR_IMG(state), hdr)) {
+#else
+ if (1) {
+#endif
+ if (!boot_u32_safe_add(&size, size, hdr->ih_protect_tlv_size)) {
+ return false;
+ }
+ }
+
  if (size >= flash_area_get_size(fap)) {
  return false;
  }
 
+#if !defined(MCUBOOT_ENC_IMAGES)
+ if (IS_ENCRYPTED(hdr)) {
+ return false;
+ }
+#else
+ if ((hdr->ih_flags & IMAGE_F_ENCRYPTED_AES128) &&
+ (hdr->ih_flags & IMAGE_F_ENCRYPTED_AES256))
+ {
+ return false;
+ }
+#endif
+
+#if !defined(MCUBOOT_DECOMPRESS_IMAGES)
+ if (IS_COMPRESSED(hdr)) {
+ return false;
+ }
+#else
+ if ((hdr->ih_flags & IMAGE_F_COMPRESSED_LZMA1) &&
+ (hdr->ih_flags & IMAGE_F_COMPRESSED_LZMA2))
+ {
+ return false;
+ }
+#endif
+
  return true;
 }
 

boot/bootutil/src/swap_scratch.c

@@ -218,12 +218,14 @@ boot_slots_compatible(struct boot_loader_state *state)
 #endif
  }
 
+#ifndef MCUBOOT_DECOMPRESS_IMAGES
  if ((i != num_sectors_primary) ||
  (j != num_sectors_secondary) ||
  (primary_slot_sz != secondary_slot_sz)) {
  BOOT_LOG_WRN("Cannot upgrade: slots are not compatible");
  return 0;
  }
+#endif
 
  return 1;
 }

boot/zephyr/Kconfig

@@ -729,6 +729,33 @@ config MCUBOOT_BOOT_BANNER
 config BOOT_BANNER_STRING
  default "Using Zephyr OS build" if MCUBOOT_BOOT_BANNER
 
+config BOOT_DECOMPRESSION_SUPPORT
+ bool
+ help
+ Hidden symbol which should be selected if a system provided decompression support.
+
+if BOOT_DECOMPRESSION_SUPPORT
+
+menuconfig BOOT_DECOMPRESSION
+ bool "Decompression"
+ help
+ If enabled, will include support for compressed images being loaded to the secondary slot
+ which then get decompressed into the primary slot. This mode allows the secondary slot to
+ be smaller than primary slot which otherwise would not be allowed.
+
+if BOOT_DECOMPRESSION
+
+config BOOT_DECOMPRESSION_BUFFER_SIZE
+ int "Write buffer size"
+ range 16 16384
+ default 4096
+ help
+ The size of a secondary buffer used for writing decompressed data to the storage device.
+
+endif # BOOT_DECOMPRESSION
+
+endif # BOOT_DECOMPRESSION_SUPPORT
+
 endmenu
 
 config MCUBOOT_DEVICE_SETTINGS

boot/zephyr/include/mcuboot_config/mcuboot_config.h

@@ -127,6 +127,10 @@
 #define MCUBOOT_ENCRYPT_X25519
 #endif
 
+#ifdef CONFIG_BOOT_DECOMPRESSION
+#define MCUBOOT_DECOMPRESS_IMAGES
+#endif
+
 #ifdef CONFIG_BOOT_BOOTSTRAP
 #define MCUBOOT_BOOTSTRAP 1
 #endif

docs/release-notes.d/zephyr-compression.md

@@ -0,0 +1,7 @@
+- Added protected TLV size to image size check in bootutil
+- Added Kconfig for decompression support in Zephyr
+- Added compressed image flags and TLV to bootutil
+- Added support for removing images with conflicting flags in
+ bootutil
+- Added support for removing encrypted/compressed images when
+ MCUboot is compiled without support for them