diff options
Diffstat (limited to 'scripts/extract-sys-certs.pl')
| -rwxr-xr-x | scripts/extract-sys-certs.pl | 159 |
1 files changed, 159 insertions, 0 deletions
diff --git a/scripts/extract-sys-certs.pl b/scripts/extract-sys-certs.pl new file mode 100755 index 000000000..fa8ab1511 --- /dev/null +++ b/scripts/extract-sys-certs.pl @@ -0,0 +1,159 @@ +#!/usr/bin/env perl +# SPDX-License-Identifier: GPL-2.0 +# +use warnings; +use strict; +use Math::BigInt; +use Fcntl "SEEK_SET"; + +die "Format: $0 [-s <systemmap-file>] <vmlinux-file> <keyring-file>\n" + if ($#ARGV != 1 && $#ARGV != 3 || + $#ARGV == 3 && $ARGV[0] ne "-s"); + +my $sysmap = ""; +if ($#ARGV == 3) { + shift; + $sysmap = $ARGV[0]; + shift; +} + +my $vmlinux = $ARGV[0]; +my $keyring = $ARGV[1]; + +# +# Parse the vmlinux section table +# +open FD, "objdump -h $vmlinux |" || die $vmlinux; +my @lines = <FD>; +close(FD) || die $vmlinux; + +my @sections = (); + +foreach my $line (@lines) { + chomp($line); + if ($line =~ /\s*([0-9]+)\s+(\S+)\s+([0-9a-f]+)\s+([0-9a-f]+)\s+([0-9a-f]+)\s+([0-9a-f]+)\s+2[*][*]([0-9]+)/ + ) { + my $seg = $1; + my $name = $2; + my $len = Math::BigInt->new("0x" . $3); + my $vma = Math::BigInt->new("0x" . $4); + my $lma = Math::BigInt->new("0x" . $5); + my $foff = Math::BigInt->new("0x" . $6); + my $align = 2 ** $7; + + push @sections, { name => $name, + vma => $vma, + len => $len, + foff => $foff }; + } +} + +print "Have $#sections sections\n"; + +# +# Try and parse the vmlinux symbol table. If the vmlinux file has been created +# from a vmlinuz file with extract-vmlinux then the symbol table will be empty. +# +open FD, "nm $vmlinux 2>/dev/null |" || die $vmlinux; +@lines = <FD>; +close(FD) || die $vmlinux; + +my %symbols = (); +my $nr_symbols = 0; + +sub parse_symbols(@) { + foreach my $line (@_) { + chomp($line); + if ($line =~ /([0-9a-f]+)\s([a-zA-Z])\s(\S+)/ + ) { + my $addr = "0x" . $1; + my $type = $2; + my $name = $3; + + $symbols{$name} = $addr; + $nr_symbols++; + } + } +} +parse_symbols(@lines); + +if ($nr_symbols == 0 && $sysmap ne "") { + print "No symbols in vmlinux, trying $sysmap\n"; + + open FD, "<$sysmap" || die $sysmap; + @lines = <FD>; + close(FD) || die $sysmap; + parse_symbols(@lines); +} + +die "No symbols available\n" + if ($nr_symbols == 0); + +print "Have $nr_symbols symbols\n"; + +die "Can't find system certificate list" + unless (exists($symbols{"__cert_list_start"}) && + exists($symbols{"system_certificate_list_size"})); + +my $start = Math::BigInt->new($symbols{"__cert_list_start"}); +my $end; +my $size; +my $size_sym = Math::BigInt->new($symbols{"system_certificate_list_size"}); + +open FD, "<$vmlinux" || die $vmlinux; +binmode(FD); + +my $s = undef; +foreach my $sec (@sections) { + my $s_name = $sec->{name}; + my $s_vma = $sec->{vma}; + my $s_len = $sec->{len}; + my $s_foff = $sec->{foff}; + my $s_vend = $s_vma + $s_len; + + next unless ($start >= $s_vma); + next if ($start >= $s_vend); + + die "Certificate list size was not found on the same section\n" + if ($size_sym < $s_vma || $size_sym > $s_vend); + + die "Cert object in multiple sections: ", $s_name, " and ", $s->{name}, "\n" + if ($s); + + my $size_off = $size_sym -$s_vma + $s_foff; + my $packed; + die $vmlinux if (!defined(sysseek(FD, $size_off, SEEK_SET))); + sysread(FD, $packed, 8); + $size = unpack 'L!', $packed; + $end = $start + $size; + + printf "Have %u bytes of certs at VMA 0x%x\n", $size, $start; + + die "Cert object partially overflows section $s_name\n" + if ($end > $s_vend); + + $s = $sec; +} + +die "Cert object not inside a section\n" + unless ($s); + +print "Certificate list in section ", $s->{name}, "\n"; + +my $foff = $start - $s->{vma} + $s->{foff}; + +printf "Certificate list at file offset 0x%x\n", $foff; + +die $vmlinux if (!defined(sysseek(FD, $foff, SEEK_SET))); +my $buf = ""; +my $len = sysread(FD, $buf, $size); +die "$vmlinux" if (!defined($len)); +die "Short read on $vmlinux\n" if ($len != $size); +close(FD) || die $vmlinux; + +open FD, ">$keyring" || die $keyring; +binmode(FD); +$len = syswrite(FD, $buf, $size); +die "$keyring" if (!defined($len)); +die "Short write on $keyring\n" if ($len != $size); +close(FD) || die $keyring; |