[PATCH v2 2/4] MODSIGN: Specify the hash algorithm on sign-file command line

From: Michal Marek
Date: Thu Jan 24 2013 - 16:20:56 EST


Make the script usable without a .config file.

Signed-off-by: Michal Marek <mmarek@xxxxxxx>
---
v2: Add the hash algorithm as the first positional argument

---
Makefile | 2 +-
scripts/sign-file | 53 ++++++++++++++++-------------------------------------
2 files changed, 17 insertions(+), 38 deletions(-)

diff --git a/Makefile b/Makefile
index 51a9bda..0e7e736 100644
--- a/Makefile
+++ b/Makefile
@@ -723,7 +723,7 @@ ifeq ($(CONFIG_MODULE_SIG),y)
MODSECKEY = ./signing_key.priv
MODPUBKEY = ./signing_key.x509
export MODPUBKEY
-mod_sign_cmd = perl $(srctree)/scripts/sign-file $(MODSECKEY) $(MODPUBKEY)
+mod_sign_cmd = perl $(srctree)/scripts/sign-file $(CONFIG_MODULE_SIG_HASH) $(MODSECKEY) $(MODPUBKEY)
else
mod_sign_cmd = true
endif
diff --git a/scripts/sign-file b/scripts/sign-file
index 974a20b..2c2bbd1 100755
--- a/scripts/sign-file
+++ b/scripts/sign-file
@@ -4,7 +4,7 @@
#
# Format:
#
-# ./scripts/sign-file [-v] <key> <x509> <module> [<dest>]
+# ./scripts/sign-file [-v] <hash algo> <key> <x509> <module> [<dest>]
#
#
use strict;
@@ -17,36 +17,20 @@ if ($#ARGV >= 0 && $ARGV[0] eq "-v") {
shift;
}

-die "Format: ./scripts/sign-file [-v] <key> <x509> <module> [<dest>]\n"
- if ($#ARGV != 2 && $#ARGV != 3);
+die "Format: ./scripts/sign-file [-v] <hash algo> <key> <x509> <module> [<dest>]\n"
+ if ($#ARGV != 3 && $#ARGV != 4);

-my $private_key = $ARGV[0];
-my $x509 = $ARGV[1];
-my $module = $ARGV[2];
-my $dest = ($#ARGV == 3) ? $ARGV[3] : $ARGV[2] . "~";
+my $dgst = $ARGV[0];
+my $private_key = $ARGV[1];
+my $x509 = $ARGV[2];
+my $module = $ARGV[3];
+my $dest = ($#ARGV == 4) ? $ARGV[4] : $ARGV[3] . "~";

die "Can't read private key\n" unless (-r $private_key);
die "Can't read X.509 certificate\n" unless (-r $x509);
die "Can't read module\n" unless (-r $module);

#
-# Read the kernel configuration
-#
-my %config = (
- CONFIG_MODULE_SIG_SHA512 => 1
- );
-
-if (-r ".config") {
- open(FD, "<.config") || die ".config";
- while (<FD>) {
- if ($_ =~ /^(CONFIG_.*)=[ym]/) {
- $config{$1} = 1;
- }
- }
- close(FD);
-}
-
-#
# Function to read the contents of a file into a variable.
#
sub read_file($)
@@ -321,51 +305,46 @@ my $id_type = 1; # Identifier type: X.509
#
# Digest the data
#
-my ($dgst, $prologue) = ();
-if (exists $config{"CONFIG_MODULE_SIG_SHA1"}) {
+my $prologue;
+if ($dgst eq "sha1") {
$prologue = pack("C*",
0x30, 0x21, 0x30, 0x09, 0x06, 0x05,
0x2B, 0x0E, 0x03, 0x02, 0x1A,
0x05, 0x00, 0x04, 0x14);
- $dgst = "-sha1";
$hash = 2;
-} elsif (exists $config{"CONFIG_MODULE_SIG_SHA224"}) {
+} elsif ($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);
- $dgst = "-sha224";
$hash = 7;
-} elsif (exists $config{"CONFIG_MODULE_SIG_SHA256"}) {
+} elsif ($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);
- $dgst = "-sha256";
$hash = 4;
-} elsif (exists $config{"CONFIG_MODULE_SIG_SHA384"}) {
+} elsif ($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);
- $dgst = "-sha384";
$hash = 5;
-} elsif (exists $config{"CONFIG_MODULE_SIG_SHA512"}) {
+} elsif ($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);
- $dgst = "-sha512";
$hash = 6;
} else {
- die "Can't determine hash algorithm";
+ die "Unknown hash algorithm: $dgst\n";
}

#
# Generate the digest and read from openssl's stdout
#
my $digest;
-$digest = readpipe("openssl dgst $dgst -binary $module") || die "openssl dgst";
+$digest = readpipe("openssl dgst -$dgst -binary $module") || die "openssl dgst";

#
# Generate the binary signature, which will be just the integer that comprises
--
1.7.8.3

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