projects/linux·blob master · refs

159 lines · 3.7 KiB

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;