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https://github.com/linuxboot/linuxboot
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initial script to extract firmware volumes and files from existing imgaes
This commit is contained in:
Trammell hudson
parent
cd93399c40
commit
d07129b7f7
242
bin/extract-firmware
Executable file
242
bin/extract-firmware
Executable file
@ -0,0 +1,242 @@
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#!/usr/bin/perl
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# Extract all of the files from a UEFI firmware image.
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#
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# This is a simple replacement for uefi-firmware-parser
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# with fewer features and more suited for reconstituting the
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# firmware later.
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#
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use warnings;
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use strict;
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use FindBin;
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use lib "$FindBin::Bin/../lib";
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use EFI;
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use Getopt::Long;
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use File::Basename;
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my $start_offset = 0; # 0x02c00000;
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local $/;
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while(<>)
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{
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process_region("rom", $_, $start_offset);
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}
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sub process_region
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{
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my $base = shift;
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my $data = shift;
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my $start_offset = shift || 0;
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my $length = length($data);
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warn sprintf "%s: length 0x%x bytes\n", $base, $length;
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my $start_unknown;
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# Search for the start of firmware volumes,
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# identified by their '_FVH' in the structure
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for(my $offset = $start_offset ; $offset < $length - 0x30 ; $offset += 16)
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{
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my $signature = substr($_, $offset + 0x28, 4);
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my $fv_length = EFI::read64($_, $offset + 0x20);
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if ($signature ne '_FVH' or $offset + $fv_length > $length)
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{
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# likely not a filesystem; report an unknown region
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# if we have started processing filesystems
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$start_unknown ||= $offset;
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next;
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}
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if (defined $start_unknown)
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{
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# We have a unknown region to write out
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my $len = $offset - $start_unknown;
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my $data = substr($_, $start_unknown, $len);
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warn sprintf "%s: 0x%08x unknown region 0x%x bytes\n",
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$base, $offset, $len;
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output(sprintf("%s/0x%08x.bin", $base, $start_unknown), $data);
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undef $start_unknown;
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}
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my $fv = substr($data, $offset, $fv_length);
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output(sprintf("%s/0x%08x.fv", $base, $offset), $fv);
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process_fv(sprintf("%s/0x%08x", $base, $offset), $fv);
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# skip to the end of the filesystem
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# should we care if this FV is not processed?
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$offset += $fv_length - 16;
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}
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}
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sub process_fv
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{
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my $base = shift;
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my $fv = shift;
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my $fv_length = length $fv;
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my $offset = EFI::read16($fv, 0x30);
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if ($offset >= $fv_length)
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{
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warn sprintf "%s: FV invalid data offset 0x%04x\n",
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$base, $offset;
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return 0;
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}
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my $guid = EFI::read_guid($fv, 16);
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warn sprintf "%s: FV length 0x%x %s\n",
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$base,
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$fv_length,
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$guid,
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;
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while($offset < $fv_length - 0x20)
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{
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my $len = EFI::read24($fv, $offset + 0x14);
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my $data_offset = 0x18;
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if ($len == 0xFFFFFF)
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{
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# Version 2 header with extended length
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$len = EFI::read64($fv, $offset + 0x18);
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# If we have an all-0xFF length, which indicates
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# the start of free space
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return 1 if ~$len == 0;
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# Looks good, adjust the starting offset
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$data_offset += 0x8;
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}
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if ($len == 0x0)
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{
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warn sprintf "%s: 0x%08x file has zero length?\n",
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$base,
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$offset;
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return 0;
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}
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if ($len + $offset > $fv_length)
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{
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warn sprintf "%s: 0x%08x file len 0x%x exceeds FV len\n",
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$base,
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$offset,
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$len;
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return 0;
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}
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my $data = substr($fv, $offset, $len);
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process_ffs($base, $data);
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$offset += $len;
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# align it
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$offset = ($offset + 7) & ~7;
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}
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return 1;
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}
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sub process_ffs
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{
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my $base = shift;
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my $ffs = shift;
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my $len = length($ffs);
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my $guid = EFI::read_guid($ffs, 0x00);
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if ($guid eq 'ffffffff-ffff-ffff-ffff-ffffffffffff')
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{
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# padding: do not output it
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# should check that everything is 0xFF first
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return;
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}
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warn sprintf "%s/%s: len %x\n",
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$base,
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$guid,
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$len,
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;
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output("$base/$guid.ffs", $ffs);
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# TODO: recursively expand embedded, compressed fv
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}
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sub output
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{
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my $name = shift,
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my $data = shift;
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my $dir = dirname($name);
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system(mkdir => -p => $dir)
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and die "$name: Unable to create directory\n";
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open FILE, '>', "$name"
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or die "$name: Unable to create output file: $!\n";
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print FILE $data;
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close FILE;
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}
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__END__
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sub read16
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{
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my $data = shift;
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my $offset = shift;
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return unpack("v", substr($data, $offset, 2));
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}
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sub read24
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{
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my $data = shift;
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my $offset = shift;
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return 0
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| ord(substr($data, $offset+2, 1)) << 16
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| ord(substr($data, $offset+1, 1)) << 8
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| ord(substr($data, $offset+0, 1)) << 0
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;
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}
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sub read32
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{
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my $data = shift;
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my $offset = shift;
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return unpack("V", substr($data, $offset, 4));
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}
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sub read64
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{
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my $data = shift;
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my $offset = shift;
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return read32($data, $offset+4) << 32 | read32($data, $offset+0);
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}
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sub read_guid
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{
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my $data = shift;
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my $offset = shift;
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my ($g1,$g2,$g3,$g4,@g5) = unpack("VvvnCCCCCC", substr($data, $offset, 16));
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return sprintf "%08x-%04x-%04x-%04x-%02x%02x%02x%02x%02x%02x",
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$g1,
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$g2,
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$g3,
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$g4,
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$g5[0],
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$g5[1],
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$g5[2],
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$g5[3],
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$g5[4],
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$g5[5],
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;
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}
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