linux/scripts/sign-file

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#!/usr/bin/perl -w
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
#
# Sign a module file using the given key.
#
my $USAGE =
"Usage: scripts/sign-file [-v] <hash algo> <key> <x509> <module> [<dest>]\n" .
" scripts/sign-file [-v] -s <raw sig> <hash algo> <x509> <module> [<dest>]\n";
use strict;
use FileHandle;
use IPC::Open2;
use Getopt::Std;
my %opts;
getopts('vs:', \%opts) or die $USAGE;
my $verbose = $opts{'v'};
my $signature_file = $opts{'s'};
die $USAGE if ($#ARGV > 4);
die $USAGE if (!$signature_file && $#ARGV < 3 || $signature_file && $#ARGV < 2);
my $dgst = shift @ARGV;
my $private_key;
if (!$signature_file) {
$private_key = shift @ARGV;
}
my $x509 = shift @ARGV;
my $module = shift @ARGV;
my ($dest, $keep_orig);
if (@ARGV) {
$dest = $ARGV[0];
$keep_orig = 1;
} else {
$dest = $module . "~";
}
die "Can't read private key\n" if (!$signature_file && !-r $private_key);
die "Can't read signature file\n" if ($signature_file && !-r $signature_file);
die "Can't read X.509 certificate\n" unless (-r $x509);
die "Can't read module\n" unless (-r $module);
#
# Function to read the contents of a file into a variable.
#
sub read_file($)
{
my ($file) = @_;
my $contents;
my $len;
open(FD, "<$file") || die $file;
binmode FD;
my @st = stat(FD);
die $file if (!@st);
$len = read(FD, $contents, $st[7]) || die $file;
close(FD) || die $file;
die "$file: Wanted length ", $st[7], ", got ", $len, "\n"
if ($len != $st[7]);
return $contents;
}
###############################################################################
#
# First of all, we have to parse the X.509 certificate to find certain details
# about it.
#
# We read the DER-encoded X509 certificate and parse it to extract the Subject
# name and Subject Key Identifier. Theis provides the data we need to build
# the certificate identifier.
#
# The signer's name part of the identifier is fabricated from the commonName,
# the organizationName or the emailAddress components of the X.509 subject
# name.
#
# The subject key ID is used to select which of that signer's certificates
# we're intending to use to sign the module.
#
###############################################################################
my $x509_certificate = read_file($x509);
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
my $UNIV = 0 << 6;
my $APPL = 1 << 6;
my $CONT = 2 << 6;
my $PRIV = 3 << 6;
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
my $CONS = 0x20;
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
my $BOOLEAN = 0x01;
my $INTEGER = 0x02;
my $BIT_STRING = 0x03;
my $OCTET_STRING = 0x04;
my $NULL = 0x05;
my $OBJ_ID = 0x06;
my $UTF8String = 0x0c;
my $SEQUENCE = 0x10;
my $SET = 0x11;
my $UTCTime = 0x17;
my $GeneralizedTime = 0x18;
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
my %OIDs = (
pack("CCC", 85, 4, 3) => "commonName",
pack("CCC", 85, 4, 6) => "countryName",
pack("CCC", 85, 4, 10) => "organizationName",
pack("CCC", 85, 4, 11) => "organizationUnitName",
pack("CCCCCCCCC", 42, 134, 72, 134, 247, 13, 1, 1, 1) => "rsaEncryption",
pack("CCCCCCCCC", 42, 134, 72, 134, 247, 13, 1, 1, 5) => "sha1WithRSAEncryption",
pack("CCCCCCCCC", 42, 134, 72, 134, 247, 13, 1, 9, 1) => "emailAddress",
pack("CCC", 85, 29, 35) => "authorityKeyIdentifier",
pack("CCC", 85, 29, 14) => "subjectKeyIdentifier",
pack("CCC", 85, 29, 19) => "basicConstraints"
);
###############################################################################
#
# Extract an ASN.1 element from a string and return information about it.
#
###############################################################################
sub asn1_extract($$@)
{
my ($cursor, $expected_tag, $optional) = @_;
return [ -1 ]
if ($cursor->[1] == 0 && $optional);
die $x509, ": ", $cursor->[0], ": ASN.1 data underrun (elem ", $cursor->[1], ")\n"
if ($cursor->[1] < 2);
my ($tag, $len) = unpack("CC", substr(${$cursor->[2]}, $cursor->[0], 2));
if ($expected_tag != -1 && $tag != $expected_tag) {
return [ -1 ]
if ($optional);
die $x509, ": ", $cursor->[0], ": ASN.1 unexpected tag (", $tag,
" not ", $expected_tag, ")\n";
}
$cursor->[0] += 2;
$cursor->[1] -= 2;
die $x509, ": ", $cursor->[0], ": ASN.1 long tag\n"
if (($tag & 0x1f) == 0x1f);
die $x509, ": ", $cursor->[0], ": ASN.1 indefinite length\n"
if ($len == 0x80);
if ($len > 0x80) {
my $l = $len - 0x80;
die $x509, ": ", $cursor->[0], ": ASN.1 data underrun (len len $l)\n"
if ($cursor->[1] < $l);
if ($l == 0x1) {
$len = unpack("C", substr(${$cursor->[2]}, $cursor->[0], 1));
} elsif ($l == 0x2) {
$len = unpack("n", substr(${$cursor->[2]}, $cursor->[0], 2));
} elsif ($l == 0x3) {
$len = unpack("C", substr(${$cursor->[2]}, $cursor->[0], 1)) << 16;
$len = unpack("n", substr(${$cursor->[2]}, $cursor->[0] + 1, 2));
} elsif ($l == 0x4) {
$len = unpack("N", substr(${$cursor->[2]}, $cursor->[0], 4));
} else {
die $x509, ": ", $cursor->[0], ": ASN.1 element too long (", $l, ")\n";
}
$cursor->[0] += $l;
$cursor->[1] -= $l;
}
die $x509, ": ", $cursor->[0], ": ASN.1 data underrun (", $len, ")\n"
if ($cursor->[1] < $len);
my $ret = [ $tag, [ $cursor->[0], $len, $cursor->[2] ] ];
$cursor->[0] += $len;
$cursor->[1] -= $len;
return $ret;
}
###############################################################################
#
# Retrieve the data referred to by a cursor
#
###############################################################################
sub asn1_retrieve($)
{
my ($cursor) = @_;
my ($offset, $len, $data) = @$cursor;
return substr($$data, $offset, $len);
}
###############################################################################
#
# Roughly parse the X.509 certificate
#
###############################################################################
my $cursor = [ 0, length($x509_certificate), \$x509_certificate ];
my $cert = asn1_extract($cursor, $UNIV | $CONS | $SEQUENCE);
my $tbs = asn1_extract($cert->[1], $UNIV | $CONS | $SEQUENCE);
my $version = asn1_extract($tbs->[1], $CONT | $CONS | 0, 1);
my $serial_number = asn1_extract($tbs->[1], $UNIV | $INTEGER);
my $sig_type = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE);
my $issuer = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE);
my $validity = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE);
my $subject = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE);
my $key = asn1_extract($tbs->[1], $UNIV | $CONS | $SEQUENCE);
my $issuer_uid = asn1_extract($tbs->[1], $CONT | $CONS | 1, 1);
my $subject_uid = asn1_extract($tbs->[1], $CONT | $CONS | 2, 1);
my $extension_list = asn1_extract($tbs->[1], $CONT | $CONS | 3, 1);
my $subject_key_id = ();
my $authority_key_id = ();
#
# Parse the extension list
#
if ($extension_list->[0] != -1) {
my $extensions = asn1_extract($extension_list->[1], $UNIV | $CONS | $SEQUENCE);
while ($extensions->[1]->[1] > 0) {
my $ext = asn1_extract($extensions->[1], $UNIV | $CONS | $SEQUENCE);
my $x_oid = asn1_extract($ext->[1], $UNIV | $OBJ_ID);
my $x_crit = asn1_extract($ext->[1], $UNIV | $BOOLEAN, 1);
my $x_val = asn1_extract($ext->[1], $UNIV | $OCTET_STRING);
my $raw_oid = asn1_retrieve($x_oid->[1]);
next if (!exists($OIDs{$raw_oid}));
my $x_type = $OIDs{$raw_oid};
my $raw_value = asn1_retrieve($x_val->[1]);
if ($x_type eq "subjectKeyIdentifier") {
my $vcursor = [ 0, length($raw_value), \$raw_value ];
$subject_key_id = asn1_extract($vcursor, $UNIV | $OCTET_STRING);
}
}
}
###############################################################################
#
# Determine what we're going to use as the signer's name. In order of
# preference, take one of: commonName, organizationName or emailAddress.
#
###############################################################################
my $org = "";
my $cn = "";
my $email = "";
while ($subject->[1]->[1] > 0) {
my $rdn = asn1_extract($subject->[1], $UNIV | $CONS | $SET);
my $attr = asn1_extract($rdn->[1], $UNIV | $CONS | $SEQUENCE);
my $n_oid = asn1_extract($attr->[1], $UNIV | $OBJ_ID);
my $n_val = asn1_extract($attr->[1], -1);
my $raw_oid = asn1_retrieve($n_oid->[1]);
next if (!exists($OIDs{$raw_oid}));
my $n_type = $OIDs{$raw_oid};
my $raw_value = asn1_retrieve($n_val->[1]);
if ($n_type eq "organizationName") {
$org = $raw_value;
} elsif ($n_type eq "commonName") {
$cn = $raw_value;
} elsif ($n_type eq "emailAddress") {
$email = $raw_value;
}
}
my $signers_name = $email;
if ($org && $cn) {
# Don't use the organizationName if the commonName repeats it
if (length($org) <= length($cn) &&
substr($cn, 0, length($org)) eq $org) {
$signers_name = $cn;
goto got_id_name;
}
# Or a signifcant chunk of it
if (length($org) >= 7 &&
length($cn) >= 7 &&
substr($cn, 0, 7) eq substr($org, 0, 7)) {
$signers_name = $cn;
goto got_id_name;
}
$signers_name = $org . ": " . $cn;
} elsif ($org) {
$signers_name = $org;
} elsif ($cn) {
$signers_name = $cn;
}
got_id_name:
die $x509, ": ", "X.509: Couldn't find the Subject Key Identifier extension\n"
if (!$subject_key_id);
my $key_identifier = asn1_retrieve($subject_key_id->[1]);
###############################################################################
#
# Create and attach the module signature
#
###############################################################################
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
#
# Signature parameters
#
my $algo = 1; # Public-key crypto algorithm: RSA
my $hash = 0; # Digest algorithm
my $id_type = 1; # Identifier type: X.509
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
#
# Digest the data
#
my $prologue;
if ($dgst eq "sha1") {
$prologue = pack("C*",
0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
0x2B, 0x0E, 0x03, 0x02, 0x1A,
0x05, 0x00, 0x04, 0x14);
$hash = 2;
} elsif ($dgst eq "sha224") {
$prologue = pack("C*",
0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04,
0x05, 0x00, 0x04, 0x1C);
$hash = 7;
} elsif ($dgst eq "sha256") {
$prologue = pack("C*",
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01,
0x05, 0x00, 0x04, 0x20);
$hash = 4;
} elsif ($dgst eq "sha384") {
$prologue = pack("C*",
0x30, 0x41, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02,
0x05, 0x00, 0x04, 0x30);
$hash = 5;
} elsif ($dgst eq "sha512") {
$prologue = pack("C*",
0x30, 0x51, 0x30, 0x0d, 0x06, 0x09,
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03,
0x05, 0x00, 0x04, 0x40);
$hash = 6;
} else {
die "Unknown hash algorithm: $dgst\n";
}
my $signature;
if ($signature_file) {
$signature = read_file($signature_file);
} else {
#
# Generate the digest and read from openssl's stdout
#
my $digest;
$digest = readpipe("openssl dgst -$dgst -binary $module") || die "openssl dgst";
#
# Generate the binary signature, which will be just the integer that
# comprises the signature with no metadata attached.
#
my $pid;
$pid = open2(*read_from, *write_to,
"openssl rsautl -sign -inkey $private_key -keyform PEM") ||
die "openssl rsautl";
binmode write_to;
print write_to $prologue . $digest || die "pipe to openssl rsautl";
close(write_to) || die "pipe to openssl rsautl";
binmode read_from;
read(read_from, $signature, 4096) || die "pipe from openssl rsautl";
close(read_from) || die "pipe from openssl rsautl";
waitpid($pid, 0) || die;
die "openssl rsautl died: $?" if ($? >> 8);
}
$signature = pack("n", length($signature)) . $signature,
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
#
# Build the signed binary
#
my $unsigned_module = read_file($module);
my $magic_number = "~Module signature appended~\n";
my $info = pack("CCCCCxxxN",
$algo, $hash, $id_type,
length($signers_name),
length($key_identifier),
length($signature));
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
if ($verbose) {
print "Size of unsigned module: ", length($unsigned_module), "\n";
print "Size of signer's name : ", length($signers_name), "\n";
print "Size of key identifier : ", length($key_identifier), "\n";
print "Size of signature : ", length($signature), "\n";
print "Size of information : ", length($info), "\n";
print "Size of magic number : ", length($magic_number), "\n";
print "Signer's name : '", $signers_name, "'\n";
print "Digest : $dgst\n";
}
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
open(FD, ">$dest") || die $dest;
binmode FD;
print FD
$unsigned_module,
$signers_name,
$key_identifier,
$signature,
$info,
$magic_number
;
close FD || die $dest;
MODSIGN: Sign modules during the build process If CONFIG_MODULE_SIG is set, then this patch will cause all modules files to to have signatures added. The following steps will occur: (1) The module will be linked to foo.ko.unsigned instead of foo.ko (2) The module will be stripped using both "strip -x -g" and "eu-strip" to ensure minimal size for inclusion in an initramfs. (3) The signature will be generated on the stripped module. (4) The signature will be appended to the module, along with some information about the signature and a magic string that indicates the presence of the signature. Step (3) requires private and public keys to be available. By default these are expected to be found in files: signing_key.priv signing_key.x509 in the base directory of the build. The first is the private key in PEM form and the second is the X.509 certificate in DER form as can be generated from openssl: openssl req \ -new -x509 -outform PEM -out signing_key.x509 \ -keyout signing_key.priv -nodes \ -subj "/CN=H2G2/O=Magrathea/CN=Slartibartfast" If the secret key is not found then signing will be skipped and the unsigned module from (1) will just be copied to foo.ko. If signing occurs, lines like the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped SIGN [M] fs/foo/foo.ko will appear in the build log. If the signature step will be skipped and the following will be seen: LD [M] fs/foo/foo.ko.unsigned STRIP [M] fs/foo/foo.ko.stripped NO SIGN [M] fs/foo/foo.ko NOTE! After the signature step, the signed module _must_not_ be passed through strip. The unstripped, unsigned module is still available at the name on the LD [M] line. This restriction may affect packaging tools (such as rpmbuild) and initramfs composition tools. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2012-09-26 11:11:06 +02:00
if (!$keep_orig) {
rename($dest, $module) || die $module;
}