1#!/usr/bin/env perl
  2# SPDX-License-Identifier: GPL-2.0
  3#
  4use warnings;
  5use strict;
  6use Math::BigInt;
  7use Fcntl "SEEK_SET";
  8
  9die "Format: $0 [-s <systemmap-file>] <vmlinux-file> <keyring-file>\n"
 10    if ($#ARGV != 1 && $#ARGV != 3 ||
 11	$#ARGV == 3 && $ARGV[0] ne "-s");
 12
 13my $sysmap = "";
 14if ($#ARGV == 3) {
 15    shift;
 16    $sysmap = $ARGV[0];
 17    shift;
 18}
 19
 20my $vmlinux = $ARGV[0];
 21my $keyring = $ARGV[1];
 22
 23#
 24# Parse the vmlinux section table
 25#
 26open FD, "objdump -h $vmlinux |" || die $vmlinux;
 27my @lines = <FD>;
 28close(FD) || die $vmlinux;
 29
 30my @sections = ();
 31
 32foreach my $line (@lines) {
 33    chomp($line);
 34    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]+)/
 35	) {
 36	my $seg  = $1;
 37	my $name = $2;
 38	my $len  = Math::BigInt->new("0x" . $3);
 39	my $vma  = Math::BigInt->new("0x" . $4);
 40	my $lma  = Math::BigInt->new("0x" . $5);
 41	my $foff = Math::BigInt->new("0x" . $6);
 42	my $align = 2 ** $7;
 43
 44	push @sections, { name => $name,
 45			  vma => $vma,
 46			  len => $len,
 47			  foff => $foff };
 48    }
 49}
 50
 51print "Have $#sections sections\n";
 52
 53#
 54# Try and parse the vmlinux symbol table.  If the vmlinux file has been created
 55# from a vmlinuz file with extract-vmlinux then the symbol table will be empty.
 56#
 57open FD, "nm $vmlinux 2>/dev/null |" || die $vmlinux;
 58@lines = <FD>;
 59close(FD) || die $vmlinux;
 60
 61my %symbols = ();
 62my $nr_symbols = 0;
 63
 64sub parse_symbols(@) {
 65    foreach my $line (@_) {
 66	chomp($line);
 67	if ($line =~ /([0-9a-f]+)\s([a-zA-Z])\s(\S+)/
 68	    ) {
 69	    my $addr = "0x" . $1;
 70	    my $type = $2;
 71	    my $name = $3;
 72
 73	    $symbols{$name} = $addr;
 74	    $nr_symbols++;
 75	}
 76    }
 77}
 78parse_symbols(@lines);
 79
 80if ($nr_symbols == 0 && $sysmap ne "") {
 81    print "No symbols in vmlinux, trying $sysmap\n";
 82
 83    open FD, "<$sysmap" || die $sysmap;
 84    @lines = <FD>;
 85    close(FD) || die $sysmap;
 86    parse_symbols(@lines);
 87}
 88
 89die "No symbols available\n"
 90    if ($nr_symbols == 0);
 91
 92print "Have $nr_symbols symbols\n";
 93
 94die "Can't find system certificate list"
 95    unless (exists($symbols{"__cert_list_start"}) &&
 96	    exists($symbols{"system_certificate_list_size"}));
 97
 98my $start = Math::BigInt->new($symbols{"__cert_list_start"});
 99my $end;
100my $size;
101my $size_sym = Math::BigInt->new($symbols{"system_certificate_list_size"});
102
103open FD, "<$vmlinux" || die $vmlinux;
104binmode(FD);
105
106my $s = undef;
107foreach my $sec (@sections) {
108    my $s_name = $sec->{name};
109    my $s_vma = $sec->{vma};
110    my $s_len = $sec->{len};
111    my $s_foff = $sec->{foff};
112    my $s_vend = $s_vma + $s_len;
113
114    next unless ($start >= $s_vma);
115    next if ($start >= $s_vend);
116
117    die "Certificate list size was not found on the same section\n"
118	if ($size_sym < $s_vma || $size_sym > $s_vend);
119
120    die "Cert object in multiple sections: ", $s_name, " and ", $s->{name}, "\n"
121	if ($s);
122
123    my $size_off = $size_sym -$s_vma + $s_foff;
124    my $packed;
125    die $vmlinux if (!defined(sysseek(FD, $size_off, SEEK_SET)));
126    sysread(FD, $packed, 8);
127    $size = unpack 'L!', $packed;
128    $end = $start + $size;
129
130    printf "Have %u bytes of certs at VMA 0x%x\n", $size, $start;
131
132    die "Cert object partially overflows section $s_name\n"
133	if ($end > $s_vend);
134
135    $s = $sec;
136}
137
138die "Cert object not inside a section\n"
139    unless ($s);
140
141print "Certificate list in section ", $s->{name}, "\n";
142
143my $foff = $start - $s->{vma} + $s->{foff};
144
145printf "Certificate list at file offset 0x%x\n", $foff;
146
147die $vmlinux if (!defined(sysseek(FD, $foff, SEEK_SET)));
148my $buf = "";
149my $len = sysread(FD, $buf, $size);
150die "$vmlinux" if (!defined($len));
151die "Short read on $vmlinux\n" if ($len != $size);
152close(FD) || die $vmlinux;
153
154open FD, ">$keyring" || die $keyring;
155binmode(FD);
156$len = syswrite(FD, $buf, $size);
157die "$keyring" if (!defined($len));
158die "Short write on $keyring\n" if ($len != $size);
159close(FD) || die $keyring;