MODSIGN: Specify the hash algorithm on sign-file command line

Make the script usable without a .config file.

Signed-off-by: Michal Marek <mmarek@suse.cz>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

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

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;
@@ -17,35 +17,19 @@ 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.
 #
@@ -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