bootutil: Define new magic for the updated image trailer layout
The magic value applies to images built with maximum write alignment
values other than 8 bytes, whose trailer region is generated in a
different layout.
Signed-off-by: Gustavo Henrique Nihei <gustavo.nihei@espressif.com>
diff --git a/scripts/imgtool/image.py b/scripts/imgtool/image.py
index 66cee43..2f0a1fa 100644
--- a/scripts/imgtool/image.py
+++ b/scripts/imgtool/image.py
@@ -81,12 +81,6 @@
TLV_INFO_MAGIC = 0x6907
TLV_PROT_INFO_MAGIC = 0x6908
-boot_magic = bytes([
- 0x77, 0xc2, 0x95, 0xf3,
- 0x60, 0xd2, 0xef, 0x7f,
- 0x35, 0x52, 0x50, 0x0f,
- 0x2c, 0xb6, 0x79, 0x80, ])
-
STRUCT_ENDIAN_DICT = {
'little': '<',
'big': '>'
@@ -98,6 +92,9 @@
INVALID_SIGNATURE
""")
+def align_up(num, align):
+ assert (align & (align - 1) == 0) and align != 0
+ return (num + (align - 1)) & ~(align - 1)
class TLV():
def __init__(self, endian, magic=TLV_INFO_MAGIC):
@@ -160,6 +157,21 @@
self.enctlv_len = 0
self.max_align = DEFAULT_MAX_ALIGN if max_align is None else int(max_align)
+ if self.max_align == DEFAULT_MAX_ALIGN:
+ self.boot_magic = bytes([
+ 0x77, 0xc2, 0x95, 0xf3,
+ 0x60, 0xd2, 0xef, 0x7f,
+ 0x35, 0x52, 0x50, 0x0f,
+ 0x2c, 0xb6, 0x79, 0x80, ])
+ else:
+ align_lsb = self.max_align & 0x00ff
+ align_msb = (self.max_align & 0xff00) >> 8
+ self.boot_magic = bytes([
+ align_lsb, align_msb, 0x2d, 0xe1,
+ 0x5d, 0x29, 0x41, 0x0b,
+ 0x8d, 0x77, 0x67, 0x9c,
+ 0x11, 0x0f, 0x1f, 0x8a, ])
+
if security_counter == 'auto':
# Security counter has not been explicitly provided,
# generate it from the version number
@@ -231,11 +243,11 @@
self.enctlv_len)
trailer_addr = (self.base_addr + self.slot_size) - trailer_size
padding = bytearray([self.erased_val] *
- (trailer_size - len(boot_magic)))
- padding += boot_magic
+ (trailer_size - len(self.boot_magic)))
+ padding += self.boot_magic
if self.confirm and not self.overwrite_only:
magic_size = 16
- magic_align_size = (int((magic_size - 1) / self.max_align) + 1) * self.max_align
+ magic_align_size = align_up(magic_size, self.max_align)
image_ok_idx = -(magic_align_size + self.max_align)
padding[image_ok_idx] = 0x01 # image_ok = 0x01
h.puts(trailer_addr, bytes(padding))
@@ -521,7 +533,7 @@
save_enctlv, enctlv_len):
# NOTE: should already be checked by the argument parser
magic_size = 16
- magic_align_size = (int((magic_size - 1) / self.max_align) + 1) * self.max_align
+ magic_align_size = align_up(magic_size, self.max_align)
if overwrite_only:
return self.max_align * 2 + magic_align_size
else:
@@ -533,9 +545,9 @@
if enckey is not None:
if save_enctlv:
# TLV saved by the bootloader is aligned
- keylen = (int((enctlv_len - 1) / self.max_align) + 1) * self.max_align
+ keylen = align_up(enctlv_len, self.max_align)
else:
- keylen = (int((16 - 1) / self.max_align) + 1) * self.max_align
+ keylen = align_up(16, self.max_align)
trailer += keylen * 2 # encryption keys
trailer += self.max_align * 4 # image_ok/copy_done/swap_info/swap_size
trailer += magic_align_size
@@ -548,11 +560,11 @@
self.save_enctlv, self.enctlv_len)
padding = size - (len(self.payload) + tsize)
pbytes = bytearray([self.erased_val] * padding)
- pbytes += bytearray([self.erased_val] * (tsize - len(boot_magic)))
- pbytes += boot_magic
+ pbytes += bytearray([self.erased_val] * (tsize - len(self.boot_magic)))
+ pbytes += self.boot_magic
if self.confirm and not self.overwrite_only:
magic_size = 16
- magic_align_size = (int((magic_size - 1) / self.max_align) + 1) * self.max_align
+ magic_align_size = align_up(magic_size, self.max_align)
image_ok_idx = -(magic_align_size + self.max_align)
pbytes[image_ok_idx] = 0x01 # image_ok = 0x01
self.payload += pbytes