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![Mehmet Kayaalp](/assets/img/avatar_default.png)
When a certificate is inserted to the image using scripts/writekey, the value of __cert_list_end does not change. The updated size can be found out by reading the value pointed by the system_certificate_list_size symbol. Signed-off-by: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com> Signed-off-by: David Howells <dhowells@redhat.com>
157 lines
3.7 KiB
Perl
Executable file
157 lines
3.7 KiB
Perl
Executable file
#!/usr/bin/perl -w
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#
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use strict;
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use Math::BigInt;
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use Fcntl "SEEK_SET";
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die "Format: $0 [-s <systemmap-file>] <vmlinux-file> <keyring-file>\n"
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if ($#ARGV != 1 && $#ARGV != 3 ||
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$#ARGV == 3 && $ARGV[0] ne "-s");
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my $sysmap = "";
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if ($#ARGV == 3) {
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shift;
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$sysmap = $ARGV[0];
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shift;
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}
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my $vmlinux = $ARGV[0];
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my $keyring = $ARGV[1];
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#
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# Parse the vmlinux section table
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#
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open FD, "objdump -h $vmlinux |" || die $vmlinux;
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my @lines = <FD>;
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close(FD) || die $vmlinux;
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my @sections = ();
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foreach my $line (@lines) {
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chomp($line);
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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]+)/
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) {
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my $seg = $1;
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my $name = $2;
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my $len = Math::BigInt->new("0x" . $3);
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my $vma = Math::BigInt->new("0x" . $4);
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my $lma = Math::BigInt->new("0x" . $5);
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my $foff = Math::BigInt->new("0x" . $6);
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my $align = 2 ** $7;
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push @sections, { name => $name,
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vma => $vma,
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len => $len,
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foff => $foff };
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}
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}
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print "Have $#sections sections\n";
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#
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# Try and parse the vmlinux symbol table. If the vmlinux file has been created
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# from a vmlinuz file with extract-vmlinux then the symbol table will be empty.
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#
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open FD, "nm $vmlinux 2>/dev/null |" || die $vmlinux;
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@lines = <FD>;
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close(FD) || die $vmlinux;
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my %symbols = ();
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my $nr_symbols = 0;
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sub parse_symbols(@) {
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foreach my $line (@_) {
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chomp($line);
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if ($line =~ /([0-9a-f]+)\s([a-zA-Z])\s(\S+)/
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) {
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my $addr = "0x" . $1;
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my $type = $2;
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my $name = $3;
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$symbols{$name} = $addr;
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$nr_symbols++;
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}
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}
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}
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parse_symbols(@lines);
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if ($nr_symbols == 0 && $sysmap ne "") {
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print "No symbols in vmlinux, trying $sysmap\n";
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open FD, "<$sysmap" || die $sysmap;
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@lines = <FD>;
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close(FD) || die $sysmap;
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parse_symbols(@lines);
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}
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die "No symbols available\n"
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if ($nr_symbols == 0);
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print "Have $nr_symbols symbols\n";
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die "Can't find system certificate list"
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unless (exists($symbols{"__cert_list_start"}) &&
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exists($symbols{"system_certificate_list_size"}));
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my $start = Math::BigInt->new($symbols{"__cert_list_start"});
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my $end;
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my $size;
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my $size_sym = Math::BigInt->new($symbols{"system_certificate_list_size"});
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open FD, "<$vmlinux" || die $vmlinux;
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binmode(FD);
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my $s = undef;
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foreach my $sec (@sections) {
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my $s_name = $sec->{name};
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my $s_vma = $sec->{vma};
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my $s_len = $sec->{len};
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my $s_foff = $sec->{foff};
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my $s_vend = $s_vma + $s_len;
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next unless ($start >= $s_vma);
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next if ($start >= $s_vend);
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die "Certificate list size was not found on the same section\n"
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if ($size_sym < $s_vma || $size_sym > $s_vend);
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die "Cert object in multiple sections: ", $s_name, " and ", $s->{name}, "\n"
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if ($s);
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my $size_off = $size_sym -$s_vma + $s_foff;
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my $packed;
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die $vmlinux if (!defined(sysseek(FD, $size_off, SEEK_SET)));
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sysread(FD, $packed, 8);
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$size = unpack 'L!', $packed;
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$end = $start + $size;
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printf "Have %u bytes of certs at VMA 0x%x\n", $size, $start;
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die "Cert object partially overflows section $s_name\n"
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if ($end > $s_vend);
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$s = $sec;
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}
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die "Cert object not inside a section\n"
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unless ($s);
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print "Certificate list in section ", $s->{name}, "\n";
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my $foff = $start - $s->{vma} + $s->{foff};
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printf "Certificate list at file offset 0x%x\n", $foff;
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die $vmlinux if (!defined(sysseek(FD, $foff, SEEK_SET)));
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my $buf = "";
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my $len = sysread(FD, $buf, $size);
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die "$vmlinux" if (!defined($len));
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die "Short read on $vmlinux\n" if ($len != $size);
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close(FD) || die $vmlinux;
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open FD, ">$keyring" || die $keyring;
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binmode(FD);
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$len = syswrite(FD, $buf, $size);
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die "$keyring" if (!defined($len));
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die "Short write on $keyring\n" if ($len != $size);
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close(FD) || die $keyring;
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