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parse the Firmware Interface Table (FIT) on a ROM image

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This commit is contained in:
Trammell Hudson 2016-12-01 13:57:35 -05:00
parent 0b20cb297c
commit 3b0509758a
Failed to extract signature
1 changed files with 66 additions and 0 deletions
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fit-parse Executable file
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#!/usr/bin/perl
use warnings;
use strict;
undef $/;
my $rom = <>;
my $base = 0xFFFFFFFF - length($rom) + 1;
printf "ROM len: %08x\n", length($rom);
printf "ROM base: %08x\n", $base;
sub uint32
{
my $offset = shift;
return unpack("V", substr($rom, $offset - $base, 4));
}
sub uint64
{
my $offset = shift;
return unpack("Q", substr($rom, $offset - $base, 8));
}
# Assume the ROM is mapped to the top of 4GB
my $fit_ptr = uint32(0xFFFFFFC0);
my $fit_offset = $fit_ptr - $base;
printf "FIT pointer: %08x (offset %08x)\n", $fit_ptr, $fit_offset;
die "FIT pointer out of range?\n" if $fit_offset >= length($rom);
my $fit = substr($rom, $fit_ptr - $base, 8);
printf "Signature: '%s'\n", $fit;
die "Bad signature?\n" unless $fit eq '_FIT_ ';
my $entries = uint32($fit_ptr + 0x8);
my %entry_types = (
0x00 => "Header",
0x01 => "Microcode",
0x02 => "Startup ACM",
0x07 => "BIOS Startup Module",
0x08 => "TPM Policy",
0x09 => "BIOS Policy",
0x0A => "TXT Policy",
0x0B => "Key Manifest",
0x0C => "Boot Policy Manifest",
0x10 => "CSE Secure Boot",
0x2D => "TXTSX Policy",
0x2F => "JMP Debug Policy",
0x7F => "SKIP",
);
for my $i (1..$entries-1)
{
my ($address, $len, $ver, $type, $csum) = unpack(
"QVSCC", substr($rom, $fit_ptr - $base + $i*0x10, 0x10));
printf "%d: address %08x @ %08x: ver %04x type %s (0x%02x)\n",
$i,
$address,
$len,
$ver,
$entry_types{$type} || "Unknown",
$type,
;
}