the-tree/scripts/extract-sys-certs.pl

0001 #!/usr/bin/env perl
0002 # SPDX-License-Identifier: GPL-2.0
0003 #
0004 use warnings;
0005 use strict;
0006 use Math::BigInt;
0007 use Fcntl "SEEK_SET";
0008
0009 die "Format: $0 [-s <systemmap-file>] <vmlinux-file> <keyring-file>\n"
0010     if ($#ARGV != 1 && $#ARGV != 3 ||
0011     $#ARGV == 3 && $ARGV[0] ne "-s");
0012
0013 my $sysmap = "";
0014 if ($#ARGV == 3) {
0015     shift;
0016     $sysmap = $ARGV[0];
0017     shift;
0018 }
0019
0020 my $vmlinux = $ARGV[0];
0021 my $keyring = $ARGV[1];
0022
0023 #
0024 # Parse the vmlinux section table
0025 #
0026 open FD, "objdump -h $vmlinux |" || die $vmlinux;
0027 my @lines = <FD>;
0028 close(FD) || die $vmlinux;
0029
0030 my @sections = ();
0031
0032 foreach my $line (@lines) {
0033     chomp($line);
0034     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]+)/
0035     ) {
0036     my $seg  = $1;
0037     my $name = $2;
0038     my $len  = Math::BigInt->new("0x" . $3);
0039     my $vma  = Math::BigInt->new("0x" . $4);
0040     my $lma  = Math::BigInt->new("0x" . $5);
0041     my $foff = Math::BigInt->new("0x" . $6);
0042     my $align = 2 ** $7;
0043
0044     push @sections, { name => $name,
0045               vma => $vma,
0046               len => $len,
0047               foff => $foff };
0048     }
0049 }
0050
0051 print "Have $#sections sections\n";
0052
0053 #
0054 # Try and parse the vmlinux symbol table.  If the vmlinux file has been created
0055 # from a vmlinuz file with extract-vmlinux then the symbol table will be empty.
0056 #
0057 open FD, "nm $vmlinux 2>/dev/null |" || die $vmlinux;
0058 @lines = <FD>;
0059 close(FD) || die $vmlinux;
0060
0061 my %symbols = ();
0062 my $nr_symbols = 0;
0063
0064 sub parse_symbols(@) {
0065     foreach my $line (@_) {
0066     chomp($line);
0067     if ($line =~ /([0-9a-f]+)\s([a-zA-Z])\s(\S+)/
0068         ) {
0069         my $addr = "0x" . $1;
0070         my $type = $2;
0071         my $name = $3;
0072
0073         $symbols{$name} = $addr;
0074         $nr_symbols++;
0075     }
0076     }
0077 }
0078 parse_symbols(@lines);
0079
0080 if ($nr_symbols == 0 && $sysmap ne "") {
0081     print "No symbols in vmlinux, trying $sysmap\n";
0082
0083     open FD, "<$sysmap" || die $sysmap;
0084     @lines = <FD>;
0085     close(FD) || die $sysmap;
0086     parse_symbols(@lines);
0087 }
0088
0089 die "No symbols available\n"
0090     if ($nr_symbols == 0);
0091
0092 print "Have $nr_symbols symbols\n";
0093
0094 die "Can't find system certificate list"
0095     unless (exists($symbols{"__cert_list_start"}) &&
0096         exists($symbols{"system_certificate_list_size"}));
0097
0098 my $start = Math::BigInt->new($symbols{"__cert_list_start"});
0099 my $end;
0100 my $size;
0101 my $size_sym = Math::BigInt->new($symbols{"system_certificate_list_size"});
0102
0103 open FD, "<$vmlinux" || die $vmlinux;
0104 binmode(FD);
0105
0106 my $s = undef;
0107 foreach my $sec (@sections) {
0108     my $s_name = $sec->{name};
0109     my $s_vma = $sec->{vma};
0110     my $s_len = $sec->{len};
0111     my $s_foff = $sec->{foff};
0112     my $s_vend = $s_vma + $s_len;
0113
0114     next unless ($start >= $s_vma);
0115     next if ($start >= $s_vend);
0116
0117     die "Certificate list size was not found on the same section\n"
0118     if ($size_sym < $s_vma || $size_sym > $s_vend);
0119
0120     die "Cert object in multiple sections: ", $s_name, " and ", $s->{name}, "\n"
0121     if ($s);
0122
0123     my $size_off = $size_sym -$s_vma + $s_foff;
0124     my $packed;
0125     die $vmlinux if (!defined(sysseek(FD, $size_off, SEEK_SET)));
0126     sysread(FD, $packed, 8);
0127     $size = unpack 'L!', $packed;
0128     $end = $start + $size;
0129
0130     printf "Have %u bytes of certs at VMA 0x%x\n", $size, $start;
0131
0132     die "Cert object partially overflows section $s_name\n"
0133     if ($end > $s_vend);
0134
0135     $s = $sec;
0136 }
0137
0138 die "Cert object not inside a section\n"
0139     unless ($s);
0140
0141 print "Certificate list in section ", $s->{name}, "\n";
0142
0143 my $foff = $start - $s->{vma} + $s->{foff};
0144
0145 printf "Certificate list at file offset 0x%x\n", $foff;
0146
0147 die $vmlinux if (!defined(sysseek(FD, $foff, SEEK_SET)));
0148 my $buf = "";
0149 my $len = sysread(FD, $buf, $size);
0150 die "$vmlinux" if (!defined($len));
0151 die "Short read on $vmlinux\n" if ($len != $size);
0152 close(FD) || die $vmlinux;
0153
0154 open FD, ">$keyring" || die $keyring;
0155 binmode(FD);
0156 $len = syswrite(FD, $buf, $size);
0157 die "$keyring" if (!defined($len));
0158 die "Short write on $keyring\n" if ($len != $size);
0159 close(FD) || die $keyring;