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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139#!/usr/bin/env perl# SPDX-License-Identifier: GPL-2.0## extract-mod-sig <part> <module-file>## Reads the module file and writes out some or all of the signature# section to stdout. Part is the bit to be written and is one of:## -0: The unsigned module, no signature data at all# -a: All of the signature data, including magic number# -d: Just the descriptor values as a sequence of numbers# -n: Just the signer's name# -k: Just the key ID# -s: Just the crypto signature or PKCS#7 message#use warnings;use strict;
die "Format: $0 -[0adnks] module-file >out\n" if ($#ARGV != 1);
my $part = $ARGV[0];my $modfile = $ARGV[1];
my $magic_number = "~Module signature appended~\n";
## Read the module contents#open FD, "<$modfile" || die $modfile;binmode(FD);my @st = stat(FD);die "$modfile" unless (@st);my $buf = "";my $len = sysread(FD, $buf, $st[7]);die "$modfile" unless (defined($len));die "Short read on $modfile\n" unless ($len == $st[7]);close(FD) || die $modfile;
print STDERR "Read ", $len, " bytes from module file\n";
die "The file is too short to have a sig magic number and descriptor\n" if ($len < 12 + length($magic_number));
## Check for the magic number and extract the information block#my $p = $len - length($magic_number);my $raw_magic = substr($buf, $p);
die "Magic number not found at $len\n" if ($raw_magic ne $magic_number);print STDERR "Found magic number at $len\n";
$p -= 12;my $raw_info = substr($buf, $p, 12);
my @info = unpack("CCCCCxxxN", $raw_info);my ($algo, $hash, $id_type, $name_len, $kid_len, $sig_len) = @info;
if ($id_type == 0) { print STDERR "Found PGP key identifier\n";} elsif ($id_type == 1) { print STDERR "Found X.509 cert identifier\n";} elsif ($id_type == 2) { print STDERR "Found PKCS#7/CMS encapsulation\n";} else { print STDERR "Found unsupported identifier type $id_type\n";}
## Extract the three pieces of info data#die "Insufficient name+kid+sig data in file\n" unless ($p >= $name_len + $kid_len + $sig_len);
$p -= $sig_len;my $raw_sig = substr($buf, $p, $sig_len);$p -= $kid_len;my $raw_kid = substr($buf, $p, $kid_len);$p -= $name_len;my $raw_name = substr($buf, $p, $name_len);
my $module_len = $p;
if ($sig_len > 0) { print STDERR "Found $sig_len bytes of signature ["; my $n = $sig_len > 16 ? 16 : $sig_len; foreach my $i (unpack("C" x $n, substr($raw_sig, 0, $n))) { printf STDERR "%02x", $i; } print STDERR "]\n";}
if ($kid_len > 0) { print STDERR "Found $kid_len bytes of key identifier ["; my $n = $kid_len > 16 ? 16 : $kid_len; foreach my $i (unpack("C" x $n, substr($raw_kid, 0, $n))) { printf STDERR "%02x", $i; } print STDERR "]\n";}
if ($name_len > 0) { print STDERR "Found $name_len bytes of signer's name [$raw_name]\n";}
## Produce the requested output#if ($part eq "-0") { # The unsigned module, no signature data at all binmode(STDOUT); print substr($buf, 0, $module_len);} elsif ($part eq "-a") { # All of the signature data, including magic number binmode(STDOUT); print substr($buf, $module_len);} elsif ($part eq "-d") { # Just the descriptor values as a sequence of numbers print join(" ", @info), "\n";} elsif ($part eq "-n") { # Just the signer's name print STDERR "No signer's name for PKCS#7 message type sig\n" if ($id_type == 2); binmode(STDOUT); print $raw_name;} elsif ($part eq "-k") { # Just the key identifier print STDERR "No key ID for PKCS#7 message type sig\n" if ($id_type == 2); binmode(STDOUT); print $raw_kid;} elsif ($part eq "-s") { # Just the crypto signature or PKCS#7 message binmode(STDOUT); print $raw_sig;}