drbd-svn can't handle modular hmac, and crashes if hash can't be found

Hi,

A few minor issues.

1. CONFIG_CRYPTO_HMAC can be defined as a module; the drbd code currently requires it to be built into the kernel, apparently for no good reason.

2. If the hash algorithm itself isn't available (like sha1.ko wasn't loaded yet), crypto_alloc_hash() returns -ENOENT. It does not return NULL, which is what the drbd code currently checks for. This leads to crashes later.

3. Once #2 is fixed, the user tools try to report the error, and the error message contains a typo, an extra ")". "Failure: (120) The 'cram-hmac-alg' you specified is not known in )the kernel." It also doesn't tell the user what to do to fix it.

The attached patch fixes the above issues, and applies cleanly to your current svn. Please review and apply.

Mark

P.S. Since drbd no longer requires any exported symbols from the hmac/hash module, is there any reason to check CONFIG_CRYPTO_HMAC at all? A simpler check on CONFIG_CRYPTO to make sure the basic API exists should be all you need...

Index: drbd/drbd_receiver.c
===================================================================
@@ -2894,7 +2894,7 @@
 	return 0;
 }
 
-#ifndef CONFIG_CRYPTO_HMAC
+#if !defined(CONFIG_CRYPTO_HMAC) && !defined(CONFIG_CRYPTO_HMAC_MODULE)
 STATIC int drbd_do_auth(drbd_dev *mdev)
 {
 	ERR( "This kernel was build without CONFIG_CRYPTO_HMAC.\n");

Index: drbd/drbd_nl.c
===================================================================
@@ -1052,7 +1052,8 @@
 	if( new_conf->cram_hmac_alg[0] != 0) {
 		snprintf(hmac_name,HMAC_NAME_L,"hmac(%s)",new_conf->cram_hmac_alg);
 		tfm = crypto_alloc_hash(hmac_name, 0, CRYPTO_ALG_ASYNC);
-		if (tfm == NULL) {
+		if (IS_ERR(tfm)) {
+			tfm = NULL;
 			retcode=CRAMAlgNotAvail;
 			goto fail;
 		}

Index: user/drbdsetup.c
===================================================================
@@ -359,8 +359,8 @@
 	EM(MDIOError) = "IO error(s) orruced during initial access to meta-data.\n",
 	EM(MDInvalid) = "No valid meta-data signature found.\n)"
 	"Use 'drbdadm create-md res' to initialize meta-data area.\n",
-	EM(CRAMAlgNotAvail) = "The 'cram-hmac-alg' you specified is not known in )"
-	"the kernel.\n",
+	EM(CRAMAlgNotAvail) = "The 'cram-hmac-alg' you specified is not known in "
+	"the kernel. (maybe you need to modprobe it, or modprobe hmac?)\n",
 	EM(CRAMAlgNotDigest) = "The 'cram-hmac-alg' you specified is not a digest.",
 	EM(KMallocFailed) = "kmalloc() failed. Out of memory?",
 	EM(DiscardNotAllowed) = "--discard-my-data not allowed when primary.",

/ 2007-01-14 09:18:44 -0800
\ Mark Glines:

right... we know 't was unfinished code,
but checked in anyways, to get it going.

thanks, will do.

we build against older kernels as well,
and as long as debian, suse, redhat & co have their
vendor kernels the way they are, this probably needs to stay this way. we should be able to relax it for builds against newer kernels, though.

: Lars Ellenberg                            Tel +43-1-8178292-55 :
: LINBIT Information Technologies GmbH      Fax +43-1-8178292-82 :
: Vivenotgasse 48, A-1120 Vienna/Europe    http://www.linbit.com :

FYI, it's working here on 2.6.20-rc4 (PPC) with CONFIG_CRYPTO_HMAC and CONFIG_CRYPTO_SHA1 both configured as modules. So now I'm watching my new cluster sync up for the first time:

drbd0: Writing meta data super block now.
drbd0: conn( WFConnection -> WFReportParams )
drbd0: Handshake successful: DRBD Network Protocol version 85
drbd0: Peer authenticated usind 20 bytes of 'sha1' HMAC
drbd0: peer( Unknown -> Secondary ) conn( WFReportParams -> WFBitMapS ) pdsk( DUnknown -> Inconsistent )
drbd0: Writing meta data super block now.
drbd0: conn( WFBitMapS -> SyncSource )
drbd0: Began resync as SyncSource (will sync 9775216 KB [2443804 bits set]).

Makes sense. Thanks again!

Mark