From: Jan Kiszka <jan.kis...@siemens.com>
Depending on the type of the image (32-bit PE32 vs 64-bit PE32+), some
fields in the optional header have different offsets. Prepare for
parsing some of those by using an offset array of 2 elements, one for
each type. Existing constants were not affected by this so far, thus
those will gain identical values for both types.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
tools/bg_gen_unified_kernel | 38 ++++++++++++++++++++++++-------------
1 file changed, 25 insertions(+), 13 deletions(-)
diff --git a/tools/bg_gen_unified_kernel b/tools/bg_gen_unified_kernel
index 0c4dd9f..8fc9b05 100755
--- a/tools/bg_gen_unified_kernel
+++ b/tools/bg_gen_unified_kernel
@@ -48,13 +48,13 @@ class Section:
class PEHeaders:
- OPT_OFFS_SIZE_OF_INIT_DATA = 0x8
- OPT_OFFS_ADDRESS_OF_ENTRY_POINT = 0x10
- OPT_OFFS_BASE_OF_CODE = 0x14
- OPT_OFFS_SECTION_ALIGNMENT = 0x20
- OPT_OFFS_FILE_ALIGNMENT = 0x24
- OPT_OFFS_SIZE_OF_IMAGE = 0x38
- OPT_OFFS_SIZE_OF_HEADERS = 0x3C
+ OPT_OFFS_SIZE_OF_INIT_DATA = [0x8, 0x8]
+ OPT_OFFS_ADDRESS_OF_ENTRY_POINT = [0x10, 0x10]
+ OPT_OFFS_BASE_OF_CODE = [0x14, 0x14]
+ OPT_OFFS_SECTION_ALIGNMENT = [0x20, 0x20]
+ OPT_OFFS_FILE_ALIGNMENT = [0x24, 0x24]
+ OPT_OFFS_SIZE_OF_IMAGE = [0x38, 0x38]
+ OPT_OFFS_SIZE_OF_HEADERS = [0x3C, 0x3C]
def __init__(self, name, blob):
# Parse headers: DOS, COFF, optional header
@@ -93,6 +93,16 @@ class PEHeaders:
self.opt_header = blob[coff_offs:self.header_size]
+ magic = struct.unpack_from('<H', self.opt_header)[0]
+ if magic == 0x10b:
+ self.is_pe_plus = False
+ elif magic == 0x20b:
+ self.is_pe_plus = True
+ else:
+ print("Invalid %s, unknown optional header magic" % name,
+ file=sys.stderr)
+ exit(1)
+
section_offs = self.header_size
self.header_size += num_sections * 0x28
@@ -124,14 +134,16 @@ class PEHeaders:
section_offs += 0x28
- def get_opt_header_field(self, offset):
- format = '<%dxI' % offset
+ def get_opt_header_field(self, offsets):
+ offs = offsets[1 if self.is_pe_plus else 0]
+ format = '<%dxI' % offs
return struct.unpack_from(format, self.opt_header)[0]
- def set_opt_header_field(self, offset, val):
- format = '<%dsI%ds' % (offset, len(self.opt_header) - offset - 4)
- self.opt_header = struct.pack(format, self.opt_header[:offset], val,
- self.opt_header[offset+4:])
+ def set_opt_header_field(self, offsets, val):
+ offs = offsets[1 if self.is_pe_plus else 0]
+ format = '<%dsI%ds' % (offs, len(self.opt_header) - offs - 4)
+ self.opt_header = struct.pack(format, self.opt_header[:offs], val,
+ self.opt_header[offs+4:])
def get_size_of_init_data(self):
return self.get_opt_header_field(PEHeaders.OPT_OFFS_SIZE_OF_INIT_DATA)
--
2.43.0
--
You received this message because you are subscribed to the Google Groups "EFI
Boot Guard" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to efibootguard-dev+unsubscr...@googlegroups.com.
To view this discussion visit
https://groups.google.com/d/msgid/efibootguard-dev/7c3a45909aa8cc374e23b23331f07defdb08fc1d.1730627538.git.jan.kiszka%40siemens.com.
