Updated p11kcv to support non-null input buffers to HMAC

CHANGELOG.md

@@ -5,6 +5,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 =======
+# [2.3.0]
+### Added
+- added the ability to specify a buffer length, when performing HMAC key check values (default is 0).
+
 # [2.2.0]
 ### Added
 - p11kcv will compute a Key Check Value on `CK_GENERIC_SECRET` keys as well. These are mapped to HMAC-SHA256.

configure.ac

@@ -14,7 +14,7 @@ dnl limitations under the License.
 
 
 AC_PREREQ([2.64])
-AC_INIT([pkcs11-tools], [2.2.0], [https://github.com/Mastercard/pkcs11-tools/issues], [pkcs11-tools], [https://github.com/Mastercard/pkcs11-tools])
+AC_INIT([pkcs11-tools], [2.3.0], [https://github.com/Mastercard/pkcs11-tools/issues], [pkcs11-tools], [https://github.com/Mastercard/pkcs11-tools])
 AC_CONFIG_MACRO_DIR([m4])
 
 dnl adding AM_MAINTAINER_MODE to address autotools issues with git

docs/MANUAL.md

@@ -518,7 +518,12 @@ For generating HMAC key on nCipher, you need to use one of the following key typ
 using `p11keygen`, it is possible to generate a session key and wrap it immediately under one or several wrapping keys. To achieve this, you simply need to add the `-W` optional parameter, followed by the wrapping parameters string, as explained in `p11wrap`. Note that by default, `p11keygen` will attempt to store a copy of the session key on the token. To prevent this (some PKCS\#11 library do not support this), add the `-r` optional parameter.
 
 ## p11kcv
-Computes the key check value of a symmetric key and prints it. This will work only on symmetric keys (`des` and `aes` keys).
+Computes the key check value of a symmetric key and prints it. This will work only on secret keys, i.e. DES, AES and HMAC keys.
+
+The key check value is computed as follows:
+- For DES keys, it performs a a signature (MACing) or an encryption on a block of 8 zeroized bytes, and outputting the 3 first ones.
+- For AES keys, it performs a a signature (MACing) or an encryption on a block of 16 zeroized bytes, and outputting the 3 first ones.
+- For HMAC keys, the key check value is computed by HMACing a null-length buffer. Alternatively, it is possible to specify a length, using the `-b` optional argument, in which case a zeroized buffer of the specified lenght is used as input to the HMAC.
 
 ## p11req
 Generate a PKCS\#10 CSR. Important options are:

include/pkcs11lib.h

@@ -684,7 +684,8 @@ func_rc pkcs11_info_ecsupport(pkcs11Context *p11Context);
 func_rc pkcs11_change_object_attributes(pkcs11Context *p11Context, char *label, CK_ATTRIBUTE *attr, size_t cnt, int interactive );
 
 /* kcv functions */
-void pkcs11_display_kcv( pkcs11Context *p11Context, char *label );
+#define MAX_KCV_CLEARTEXT_SIZE 256
+void pkcs11_display_kcv( pkcs11Context *p11Context, char *label, unsigned hmacdatasize );
 
 /* wrap/unwrap functions */
 func_rc pkcs11_prepare_wrappingctx(wrappedKeyCtx *wctx, char *wrappingjob);

lib/pkcs11_kcv.c

@@ -33,13 +33,17 @@
 
 /* target must point to a location with at least 3 bytes left */
 
-void pkcs11_display_kcv( pkcs11Context *p11Context, char *label )
+void pkcs11_display_kcv( pkcs11Context *p11Context, char *label, unsigned hmacdatasize )
 {
 
     pkcs11Search *search=NULL;
     pkcs11IdTemplate *idtmpl=NULL;
     CK_OBJECT_HANDLE *hndl_array=NULL;
 
+
+    if(hmacdatasize>MAX_KCV_CLEARTEXT_SIZE) {
+	fprintf(stderr, "Invalid HMAC block size specified (%d), must be between 0 and %d\n", hmacdatasize, MAX_KCV_CLEARTEXT_SIZE );
+    }
     /* trick: we treat "cert", "pubk", "prvk", "seck" and "data" in front of the templating system */
     /* so these specific labels can be used as shortcut for the corresponding object classes       */
 
@@ -91,9 +95,9 @@ void pkcs11_display_kcv( pkcs11Context *p11Context, char *label )
 		if( attrs!=NULL) {
 		    if (pkcs11_read_attr_from_handle (attrs, hndl_array[j]) == CK_TRUE) {
 			CK_RV rv;
-			CK_BYTE cleartext[16];
-			CK_BYTE encrypted[64];
-			CK_ULONG cleartext_len, encrypted_len;
+			CK_BYTE cleartext[MAX_KCV_CLEARTEXT_SIZE];
+			CK_BYTE processed[64];
+			CK_ULONG cleartext_len, processed_len;
 
 			CK_MECHANISM des_ecb = { CKM_DES_ECB, NULL_PTR, 0 };
 			CK_MECHANISM des3_ecb = { CKM_DES3_ECB, NULL_PTR, 0 };
@@ -130,64 +134,64 @@ void pkcs11_display_kcv( pkcs11Context *p11Context, char *label )
 			case CKK_DES:
 			    mechanism = &des_ecb;
 			    cleartext_len = 8L;
-			    encrypted_len = 8L;
+			    processed_len = 8L;
 			    keytypestr = "DES, single length";
 			    whattodo=encrypt;
 			    break;
 
 			case CKK_DES2:
 			    mechanism = &des3_ecb;
 			    cleartext_len = 8L;
-			    encrypted_len = 8L;
+			    processed_len = 8L;
 			    keytypestr = "3DES, double length";
 			    whattodo=encrypt;
 			    break;
 
 			case CKK_DES3:
 			    mechanism = &des3_ecb;
 			    cleartext_len = 8L;
-			    encrypted_len = 8L;
+			    processed_len = 8L;
 			    keytypestr = "3DES, triple length";
 			    whattodo=encrypt;
 			    break;
 
 			case CKK_AES:
 			    mechanism = &aes_ecb;
 			    cleartext_len = 16L;
-			    encrypted_len = 16L;
+			    processed_len = 16L;
 			    keytypestr = "AES";
 			    whattodo=encrypt;
 			    break;
 
 			case CKK_SHA_1_HMAC:
 			    mechanism = &sha1_hmac;
-			    cleartext_len = 0L;
-			    encrypted_len = 20L;
+			    cleartext_len = hmacdatasize;
+			    processed_len = 20L;
 			    keytypestr = "HMAC(SHA1)";
 			    whattodo=sign;
 			    break;
 
 			case CKK_SHA256_HMAC:
 			case CKK_GENERIC_SECRET:
 			    mechanism = &sha256_hmac;
-			    cleartext_len = 0L;
-			    encrypted_len = 32L;
+			    cleartext_len = hmacdatasize;
+			    processed_len = 32L;
 			    keytypestr = "HMAC(SHA256)";
 			    whattodo=sign;
 			    break;
 
 			case CKK_SHA384_HMAC:
 			    mechanism = &sha384_hmac;
-			    cleartext_len = 0L;
-			    encrypted_len = 48L;
+			    cleartext_len = hmacdatasize;
+			    processed_len = 48L;
 			    keytypestr = "HMAC(SHA384)";
 			    whattodo=sign;
 			    break;
 
 			case CKK_SHA512_HMAC:
 			    mechanism = &sha512_hmac;
-			    cleartext_len = 0L;
-			    encrypted_len = 64L;
+			    cleartext_len = hmacdatasize;
+			    processed_len = 64L;
 			    keytypestr = "HMAC(SHA384)";
 			    whattodo=sign;
 			    break;
@@ -220,13 +224,13 @@ void pkcs11_display_kcv( pkcs11Context *p11Context, char *label )
 			    p11Context->FunctionList.C_Encrypt ( p11Context->Session,
 								 cleartext,
 								 cleartext_len,
-								 encrypted,
-								 &encrypted_len	) :
+								 processed,
+								 &processed_len	) :
 			    p11Context->FunctionList.C_Sign ( p11Context->Session,
 							      cleartext,
 							      cleartext_len,
-							      encrypted,
-							      &encrypted_len );
+							      processed,
+							      &processed_len );
 			if(rv!=CKR_OK) {
 			    pkcs11_error(rv, whattodo == encrypt ? "C_Encrypt" : "C_Sign");
 			    pkcs11_delete_attrlist(attrs);
@@ -237,9 +241,9 @@ void pkcs11_display_kcv( pkcs11Context *p11Context, char *label )
 			printf("%-*s: KCV = %02.2x%02.2x%02.2x (%s)\n",
 			       LABEL_WIDTH,
 			       buffer,
-			       encrypted[0],
-			       encrypted[1],
-			       encrypted[2],
+			       processed[0],
+			       processed[1],
+			       processed[2],
 			       keytypestr);
 		    }
 		    pkcs11_delete_attrlist(attrs);

src/p11kcv.c

@@ -37,6 +37,8 @@ void print_usage(char *);
 int main( int argc, char **argv);
 
 
+
+
 void print_usage(char *progname)
 {
     fprintf( stderr, 
@@ -50,6 +52,7 @@ void print_usage(char *progname)
 	     "  -t <token label> : if present, -s option is ignored\n"
 	     "  -p <token PIN> | :::exec:<command> | :::nologin\n"
 	     "  -S : login with SO privilege\n"
+	     "  -b <len>: size of buffer to HMAC, for HMAC keys (max: %d, default: 0)\n"
 	     "  -h : print usage information\n"
 	     "  -V : print version information\n"
 	     "|\n"
@@ -86,7 +89,8 @@ void print_usage(char *progname)
 	     "    PKCS11PASSWORD    : password\n"
              "                        overriden by option -p\n"
 	     "\n"
-	     , pkcs11_ll_basename(progname) );
+	     , pkcs11_ll_basename(progname),
+	     MAX_KCV_CLEARTEXT_SIZE);
 
     exit( RC_ERROR_USAGE );
 }
@@ -105,6 +109,7 @@ int main( int argc, char ** argv )
     int interactive = 1;
     char * tokenlabel = NULL;
     int so=0;
+    unsigned hmacdatasize = 0;
 
     pkcs11Context * p11Context = NULL;
     func_rc retcode = rc_error_usage;
@@ -121,7 +126,7 @@ int main( int argc, char ** argv )
     password = getenv("PKCS11PASSWORD");
 
     /* get the command-line arguments */
-    while ( ( argnum = getopt( argc, argv, "l:m:p:s:t:ShV" ) ) != -1 )
+    while ( ( argnum = getopt( argc, argv, "l:m:p:s:t:Sb:hV" ) ) != -1 )
     {
 	switch ( argnum )
 	{
@@ -149,6 +154,10 @@ int main( int argc, char ** argv )
 	    slot = -1;
 	    break;
 
+	case 'b':
+	    hmacdatasize=strtoul(optarg, NULL, 10);
+	    break;
+
 	case 'S':
 	    so=1;
 	  break;
@@ -195,7 +204,7 @@ int main( int argc, char ** argv )
     {
 	char *label;
 	for(label=argv[optind];optind<argc; optind++) {
-	    pkcs11_display_kcv(p11Context, argv[optind]);
+	    pkcs11_display_kcv(p11Context, argv[optind], hmacdatasize);
 	}
 
 	pkcs11_close_session( p11Context );