Allow verification of some broken S-TRUST generated signatures.

NEWS

@@ -23,6 +23,9 @@ Noteworthy changes in version 2.0.8
 
  * Creating DSA2 keys is now possible.
 
+ * New option --extra-digest-algo for gpgsm to allow verification of
+   broken signatures.
+
 
 Noteworthy changes in version 2.0.7 (2007-09-10)
 ------------------------------------------------

common/ChangeLog

@@ -1,3 +1,9 @@
+2007-12-13  Werner Koch  <wk@g10code.com>
+
+	* sexputil.c (hash_algo_from_sigval): New.
+	* t-sexputil.c: New.
+	* Makefile.am (module_tests): Add it.
+
 2007-12-11  Werner Koch  <wk@g10code.com>
 
 	* asshelp.c (send_pinentry_environment): Allow using of old
@@ -1126,7 +1132,8 @@
 	(atoi_1,atoi_2,atoi_4,xtoi_1,xtoi_2): New.
 	
 	
- Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
+ Copyright 2001, 2002, 2003, 2004, 2005, 2006, 
+	   2007 Free Software Foundation, Inc.
 
  This file is free software; as a special exception the author gives
  unlimited permission to copy and/or distribute it, with or without

common/Makefile.am

@@ -107,7 +107,7 @@ status-codes.h: Makefile mkstrtable.awk exstatus.awk status.h
 #
 # Module tests
 #
-module_tests = t-convert t-gettime t-sysutils 
+module_tests = t-convert t-gettime t-sysutils t-sexputil
 module_maint_tests = t-helpfile
 
 t_common_ldadd = libcommon.a ../jnlib/libjnlib.a ../gl/libgnu.a \
@@ -117,5 +117,5 @@ t_convert_LDADD = $(t_common_ldadd)
 t_gettime_LDADD = $(t_common_ldadd)
 t_sysutils_LDADD = $(t_common_ldadd)
 t_helpfile_LDADD = $(t_common_ldadd)
-
+t_sexputil_LDADD = $(t_common_ldadd)
 

common/sexp-parse.h

@@ -44,7 +44,7 @@ snext (unsigned char const **buf)
    lists and may be passed as a positive number to skip over the
    remainder of an S-Expression if the current position is somewhere
    in an S-Expression.  The function may return an error code if it
-   encounters an impossible conditions */
+   encounters an impossible condition.  */
 static inline gpg_error_t
 sskip (unsigned char const **buf, int *depth)
 {

common/sexputil.c

@@ -1,5 +1,5 @@
 /* sexputil.c - Utility functions for S-expressions.
- * Copyright (C) 2005 Free Software Foundation, Inc.
+ * Copyright (C) 2005, 2007 Free Software Foundation, Inc.
  *
  * This file is part of GnuPG.
  *
@@ -40,8 +40,8 @@
    KEY is expected to be an canonical encoded S-expression with a
    public or private key. KEYLEN is the length of that buffer.
 
-   GRIP must be at least 20 bytes long On success 0 is return, on
+   GRIP must be at least 20 bytes long.  On success 0 is returned, on
-   error an aerror code. */
+   error an error code. */
 gpg_error_t
 keygrip_from_canon_sexp (const unsigned char *key, size_t keylen,
                          unsigned char *grip)
@@ -143,3 +143,49 @@ make_simple_sexp_from_hexstr (const char *line, size_t *nscanned)
 
   return buf;
 }
+
+
+/* Return the hash algorithm from a KSBA sig-val. SIGVAL is a
+   canonical encoded S-expression.  Return 0 if the hash algorithm is
+   not encoded in SIG-VAL or it is not supported by libgcrypt.  */
+int
+hash_algo_from_sigval (const unsigned char *sigval)
+{
+  const unsigned char *s = sigval;
+  size_t n;
+  int depth;
+  char buffer[50];
+
+  if (!s || *s != '(')
+    return 0; /* Invalid S-expression.  */
+  s++;
+  n = snext (&s);
+  if (!n)
+    return 0; /* Invalid S-expression.  */
+  if (!smatch (&s, n, "sig-val"))
+    return 0; /* Not a sig-val.  */
+  if (*s != '(')
+    return 0; /* Invalid S-expression.  */
+  s++;
+  /* Skip over the algo+parameter list.  */
+  depth = 1;
+  if (sskip (&s, &depth) || depth)
+    return 0; /* Invalid S-expression.  */
+  if (*s != '(')
+    return 0; /* No futher list.  */
+  /* Check whether this is (hash ALGO).  */
+  s++;
+  n = snext (&s);
+  if (!n)
+    return 0; /* Invalid S-expression.  */
+  if (!smatch (&s, n, "hash"))
+    return 0; /* Not a "hash" keyword.  */
+  n = snext (&s);
+  if (!n || n+1 >= sizeof (buffer))
+    return 0; /* Algorithm string is missing or too long.  */
+  memcpy (buffer, s, n);
+  buffer[n] = 0;
+  
+  return gcry_md_map_name (buffer);
+}
+

common/t-sexputil.c

@@ -0,0 +1,82 @@
+/* t-sexputil.c - Module test for sexputil.c
+ *	Copyright (C) 2007 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "util.h"
+
+#define pass()  do { ; } while(0)
+#define fail(a)  do { fprintf (stderr, "%s:%d: test %d failed\n",\
+                               __FILE__,__LINE__, (a));          \
+                     exit (1);                                   \
+                   } while(0)
+
+
+static void
+test_hash_algo_from_sigval (void)
+{
+  int algo;
+  /* A real world example.  */
+  unsigned char example1_rsa_sha1[] = 
+    ("\x28\x37\x3A\x73\x69\x67\x2D\x76\x61\x6C\x28\x33\x3A\x72\x73\x61"
+     "\x28\x31\x3A\x73\x31\x32\x38\x3A\x17\xD2\xE9\x5F\xB4\x24\xD4\x1E"
+     "\x8C\xEE\x94\xDA\x41\x42\x1F\x26\x5E\xF4\x6D\xEC\x5B\xBD\x5B\x89"
+     "\x7A\x69\x11\x43\xE9\xD2\x23\x21\x25\x64\xA6\xB0\x56\xEF\xB4\xE9"
+     "\x06\xB2\x44\xF6\x80\x1E\xFF\x41\x23\xEB\xC9\xFA\xFD\x09\xBF\x9C"
+     "\x8E\xCF\x7F\xC3\x7F\x3A\x40\x48\x89\xDC\xBA\xB7\xDB\x9E\xF1\xBA"
+     "\x7C\x08\xEA\x74\x1D\x49\xE7\x65\xEF\x67\x79\xBC\x23\xD9\x49\xCD"
+     "\x05\x99\xD3\xD8\xB7\x7B\xC7\x0E\xF2\xB3\x01\x48\x0F\xC8\xEB\x05"
+     "\x7B\xFB\x61\xCC\x41\x04\x74\x6D\x33\x84\xB1\xE6\x6A\xD8\x0F\xBC"
+     "\x27\xAC\x43\x45\xFA\x04\xD1\x22\x29\x29\x28\x34\x3A\x68\x61\x73"
+     "\x68\x34\x3A\x73\x68\x61\x31\x29\x29");
+  /* The same but without the hash algo. */
+  unsigned char example1_rsa[] = 
+    ("\x28\x37\x3A\x73\x69\x67\x2D\x76\x61\x6C\x28\x33\x3A\x72\x73\x61"
+     "\x28\x31\x3A\x73\x31\x32\x38\x3A\x17\xD2\xE9\x5F\xB4\x24\xD4\x1E"
+     "\x8C\xEE\x94\xDA\x41\x42\x1F\x26\x5E\xF4\x6D\xEC\x5B\xBD\x5B\x89"
+     "\x7A\x69\x11\x43\xE9\xD2\x23\x21\x25\x64\xA6\xB0\x56\xEF\xB4\xE9"
+     "\x06\xB2\x44\xF6\x80\x1E\xFF\x41\x23\xEB\xC9\xFA\xFD\x09\xBF\x9C"
+     "\x8E\xCF\x7F\xC3\x7F\x3A\x40\x48\x89\xDC\xBA\xB7\xDB\x9E\xF1\xBA"
+     "\x7C\x08\xEA\x74\x1D\x49\xE7\x65\xEF\x67\x79\xBC\x23\xD9\x49\xCD"
+     "\x05\x99\xD3\xD8\xB7\x7B\xC7\x0E\xF2\xB3\x01\x48\x0F\xC8\xEB\x05"
+     "\x7B\xFB\x61\xCC\x41\x04\x74\x6D\x33\x84\xB1\xE6\x6A\xD8\x0F\xBC"
+     "\x27\xAC\x43\x45\xFA\x04\xD1\x22\x29\x29\x29");
+
+  algo = hash_algo_from_sigval (example1_rsa_sha1);
+  if (algo != GCRY_MD_SHA1)
+    fail (0);
+  algo = hash_algo_from_sigval (example1_rsa);
+  if (algo)
+    fail (0);
+}
+
+
+
+
+int
+main (int argc, char **argv)
+{
+  
+  test_hash_algo_from_sigval ();
+
+  return 0;
+}
+

common/util.h

@@ -164,6 +164,7 @@ gpg_error_t keygrip_from_canon_sexp (const unsigned char *key, size_t keylen,
 int cmp_simple_canon_sexp (const unsigned char *a, const unsigned char *b);
 unsigned char *make_simple_sexp_from_hexstr (const char *line,
                                              size_t *nscanned);
+int hash_algo_from_sigval (const unsigned char *sigval);
 
 /*-- convert.c --*/
 int hex2bin (const char *string, void *buffer, size_t length);

doc/ChangeLog

@@ -1,3 +1,14 @@
+2007-12-13  Werner Koch  <wk@g10code.com>
+
+	* qualified.txt: Add 2 root certs from S-Trust for 2008-2012.
+	* examples/trustlist.txt: Ditto.
+
+	* gpgsm.texi (Esoteric Options): Document --extra-digest-algo.
+
+2007-12-12  Werner Koch  <wk@g10code.com>
+
+	* gpg.texi: Typo fixes.  From Christer Andersson.
+
 2007-12-04  Werner Koch  <wk@g10code.com>
 
 	* help.txt: New online help file.

doc/debugging.texi

@@ -182,7 +182,12 @@ such a certificate.  You may use the @code{relax} flag in
 fingerprint and this flag may only be added manually to
 @file{trustlist.txt}.
 
+@item Error message: ``digest algorithm N has not been enabled''
 
+The signature is broken.  You may try the option
+@option{--extra-digest-algo SHA256} to workaround the problem.  The
+number N is the internal algorighm indentifier; for example 8 refers to
+SHA-256.
 
 @end itemize
 

doc/examples/trustlist.txt

@@ -38,6 +38,17 @@ DB:45:3D:1B:B0:1A:F3:23:10:6B:DE:D0:09:61:57:AA:F4:25:E0:5B  S
 #       Issuer: /CN=11R-CA 1:PN/O=Bundesnetzagentur/C=DE
 A0:8B:DF:3B:AA:EE:3F:9D:64:6C:47:81:23:21:D4:A6:18:81:67:1D  S
 
+#          S/N: 00B3963E0E6C2D65125853E970665402E5
+#       Issuer: /CN=S-TRUST Qualified Root CA 2008-001:PN
+#               /O=Deutscher Sparkassen Verlag GmbH/L=Stuttgart/C=DE
+C9:2F:E6:50:DB:32:59:E0:CE:65:55:F3:8C:76:E0:B8:A8:FE:A3:CA  S
+
+#          S/N: 00C4216083F35C54F67B09A80C3C55FE7D
+#       Issuer: /CN=S-TRUST Qualified Root CA 2008-002:PN
+#               /O=Deutscher Sparkassen Verlag GmbH/L=Stuttgart/C=DE
+D5:C7:50:F2:FE:4E:EE:D7:C7:B1:E4:13:7B:FB:54:84:3A:7D:97:9B  S
+
+
 #Serial number: 00
 #       Issuer: /CN=CA Cert Signing Authority/OU=http:\x2f\x2fwww.
 #               cacert.org/O=Root CA/EMail=support@cacert.org

doc/gpg.texi

@@ -113,7 +113,7 @@ Developer information:
 @node GPG Commands
 @section Commands
 
-Commands are not distinguished from options execpt for the fact that
+Commands are not distinguished from options except for the fact that
 only one command is allowed.
 
 @command{@gpgname} may be run with no commands, in which case it will
@@ -876,7 +876,7 @@ encountered, you can explicitly stop parsing by using the special option
 @node GPG Configuration Options
 @subsection How to change the configuration
 
-These options are used to change the configuraton and are usually found
+These options are used to change the configuration and are usually found
 in the option file.
 
 @table @gnupgtabopt
@@ -2456,13 +2456,13 @@ listed. @option{--list-config} is only usable with
 
 @item --gpgconf-list
 @opindex gpgconf-list
-This command is simliar to @option{--list-config} but in general only
+This command is similar to @option{--list-config} but in general only
 internally used by the @command{gpgconf} tool.
 
 @item --gpgconf-test
 @opindex gpgconf-test
 This is more or less dummy action.  However it parses the configuration
-file and returns with failure if the configuraion file would prevent
+file and returns with failure if the configuration file would prevent
 @command{gpg} from startup.  Thus it may be used to run a syntax check
 on the configuration file.
 
@@ -2560,7 +2560,7 @@ For existing users the a small
 helper script is provided to create these files (@pxref{addgnupghome}).
 @end ifclear
 
-For internal purposes @command{@gpgname} creates and maintaines a few other
+For internal purposes @command{@gpgname} creates and maintains a few other
 files; They all live in in the current home directory (@pxref{option
 --homedir}).  Only the @command{@gpgname} may modify these files.
 
@@ -2686,7 +2686,7 @@ user for the filename.
 @include specify-user-id.texi
 @end ifset
 
-@mansect return vaue
+@mansect return value
 @chapheading RETURN VALUE
 
 The program returns 0 if everything was fine, 1 if at least

doc/gpgsm.texi

@@ -569,6 +569,19 @@ encryption.  For convenience the strings @code{3DES}, @code{AES} and
 
 @table @gnupgtabopt
 
+@item --extra-digest-algo @var{name}
+@opindex extra-digest-algo
+Sometimes signatures are broken in that they announce a different digest
+algorithm than actually used.  @command{gpgsm} uses a one-pass data
+processing model and thus needs to rely on the announcde digest
+algorithms to properly hash the data.  As a workaround this option may
+be used to tell gpg to also hash the data using the algorithm
+@var{name}; this slows processing down a little bit but allows to verify
+such broken signatures.  If @command{gpgsm} prints an error like
+``digest algo 8 has not been enabled'' you may want to try this option,
+with @samp{SHA256} for @var{name}.
+
+
 @item --faked-system-time @var{epoch}
 @opindex faked-system-time
 This option is only useful for testing; it sets the system time back or

doc/qualified.txt

@@ -180,6 +180,35 @@ E0:BF:1B:91:91:6B:88:E4:F1:15:92:22:CE:37:23:96:B1:4A:2E:5C  de
 7A:3C:1B:60:2E:BD:A4:A1:E0:EB:AD:7A:BA:4F:D1:43:69:A9:39:FC  de
 
 
+#           ID: 0xA8FEA3CA
+#          S/N: 00B3963E0E6C2D65125853E970665402E5
+#       Issuer: /CN=S-TRUST Qualified Root CA 2008-001:PN
+#               /O=Deutscher Sparkassen Verlag GmbH/L=Stuttgart/C=DE
+#      Subject: /CN=S-TRUST Qualified Root CA 2008-001:PN
+#               /O=Deutscher Sparkassen Verlag GmbH/L=Stuttgart/C=DE
+#     validity: 2008-01-01 00:00:00 through 2012-12-30 23:59:59
+#     key type: 2048 bit RSA
+#    key usage: certSign crlSign
+# chain length: 1
+#[checked: 2007-12-13 via received ZIP file with qualified signature from 
+#         /CN=Dr. Matthias Stehle/O=Deutscher Sparkassenverlag
+#         /C=DE/SerialNumber=DSV0000000008/SN=Stehle/GN=Matthias Georg]
+C9:2F:E6:50:DB:32:59:E0:CE:65:55:F3:8C:76:E0:B8:A8:FE:A3:CA
+
+#           ID: 0x3A7D979B
+#          S/N: 00C4216083F35C54F67B09A80C3C55FE7D
+#       Issuer: /CN=S-TRUST Qualified Root CA 2008-002:PN
+#               /O=Deutscher Sparkassen Verlag GmbH/L=Stuttgart/C=DE
+#      Subject: /CN=S-TRUST Qualified Root CA 2008-002:PN
+#               /O=Deutscher Sparkassen Verlag GmbH/L=Stuttgart/C=DE
+#     validity: 2008-01-01 00:00:00 through 2012-12-30 23:59:59
+#     key type: 2048 bit RSA
+#    key usage: certSign crlSign
+# chain length: 1
+#[checked: 2007-12-13 via received ZIP file with qualified signature from 
+#         /CN=Dr. Matthias Stehle/O=Deutscher Sparkassenverlag
+#         /C=DE/SerialNumber=DSV0000000008/SN=Stehle/GN=Matthias Georg"]
+D5:C7:50:F2:FE:4E:EE:D7:C7:B1:E4:13:7B:FB:54:84:3A:7D:97:9B
 
 
 #*******************************************

doc/specify-user-id.texi

@@ -121,7 +121,7 @@ This should return the Root cert of the issuer.  See note above.
 
 
 @item By exact match on serial number and issuer's DN.
-This is indicated by a hash mark, followed by the hexadecmal
+This is indicated by a hash mark, followed by the hexadecimal
 representation of the serial number, then followed by a slash and the
 RFC-2253 encoded DN of the issuer. See note above.
 

sm/ChangeLog

@@ -1,3 +1,10 @@
+2007-12-13  Werner Koch  <wk@g10code.com>
+
+	* gpgsm.c (main): Add option --extra-digest-algo.
+	* gpgsm.h (struct): Add EXTRA_DIGEST_ALGO.
+	* verify.c (gpgsm_verify): Use it.  Use the hash algorithm from
+	the signature value.
+
 2007-12-11  Werner Koch  <wk@g10code.com>
 
 	* certchain.c (do_validate_chain): Log AUDIT_ROOT_TRUSTED.

sm/gpgsm.c

@@ -174,6 +174,7 @@ enum cmd_and_opt_values {
   oOpenPGP,
   oCipherAlgo,
   oDigestAlgo,
+  oExtraDigestAlgo,
   oCompressAlgo,
   oCommandFD,
   oNoVerbose,
@@ -388,6 +389,7 @@ static ARGPARSE_OPTS opts[] = {
     { oCipherAlgo, "cipher-algo", 2 , N_("|NAME|use cipher algorithm NAME")},
     { oDigestAlgo, "digest-algo", 2 ,
       N_("|NAME|use message digest algorithm NAME")},
+    { oExtraDigestAlgo, "extra-digest-algo", 2 , "@" },
 #if 0
     { oCompressAlgo, "compress-algo", 1 , N_("|N|use compress algorithm N")},
 #endif
@@ -842,6 +844,7 @@ main ( int argc, char **argv)
   int use_random_seed = 1;
   int with_fpr = 0;
   char *def_digest_string = NULL;
+  char *extra_digest_algo = NULL;
   enum cmd_and_opt_values cmd = 0;
   struct server_control_s ctrl;
   certlist_t recplist = NULL;
@@ -1298,6 +1301,10 @@ main ( int argc, char **argv)
           }
           break;
 
+        case oExtraDigestAlgo: 
+          extra_digest_algo = pargs.r.ret_str;
+          break;
+
         case oIgnoreTimeConflict: opt.ignore_time_conflict = 1; break;
         case oNoRandomSeedFile: use_random_seed = 0; break;
 
@@ -1441,6 +1448,12 @@ main ( int argc, char **argv)
           if (our_md_test_algo(opt.def_digest_algo) )
             log_error (_("selected digest algorithm is invalid\n"));
         }
+      if (extra_digest_algo)
+        {
+          opt.extra_digest_algo = gcry_md_map_name (extra_digest_algo);
+          if (our_md_test_algo (opt.extra_digest_algo) )
+            log_error (_("selected digest algorithm is invalid\n"));
+        }
     }
 
   if (log_get_errorcount(0))

sm/gpgsm.h

@@ -92,6 +92,9 @@ struct
 
   char *local_user;       /* NULL or argument to -u */
 
+  int extra_digest_algo;  /* A digest algorithm also used for
+                             verification of signatures.  */
+
   int always_trust;       /* Trust the given keys even if there is no
                              valid certification chain */
   int skip_verify;        /* do not check signatures on data */

sm/sign.c

@@ -491,7 +491,7 @@ gpgsm_sign (ctrl_t ctrl, certlist_t signerlist,
       unsigned char *digest;
       size_t digest_len;
       /* Fixme do this for all signers and get the algo to use from
-         the signer's certificate - does not make mich sense, but we
+         the signer's certificate - does not make much sense, but we
          should do this consistent as we have already done it above. */
       algo = GCRY_MD_SHA1; 
       hash_data (data_fd, data_md);
@@ -530,7 +530,7 @@ gpgsm_sign (ctrl_t ctrl, certlist_t signerlist,
     }
 
   /* We need to write at least a minimal list of our capabilities to
-     try to convince some MUAs to use 3DEs and not the crippled
+     try to convince some MUAs to use 3DES and not the crippled
      RC2. Our list is:
 
         aes128-CBC

sm/verify.c

@@ -203,10 +203,20 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, FILE *out_fp)
                 }
               else
                 {
+                  if (DBG_X509)
+                    log_debug ("enabling hash algorithm %d (%s)\n",
+                               algo, algoid? algoid:"");
                   gcry_md_enable (data_md, algo);
                   audit_log_i (ctrl->audit, AUDIT_DATA_HASH_ALGO, algo);
                 }
             }
+          if (opt.extra_digest_algo)
+            {
+              if (DBG_X509)
+                log_debug ("enabling extra hash algorithm %d\n", 
+                           opt.extra_digest_algo);
+              gcry_md_enable (data_md, opt.extra_digest_algo);
+            }
           if (is_detached)
             {
               if (data_fd == -1)
@@ -271,6 +281,7 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, FILE *out_fp)
       char *msgdigest = NULL;
       size_t msgdigestlen;
       char *ctattr;
+      int sigval_hash_algo;
       int info_pkalgo;
       unsigned int verifyflags;
 
@@ -331,7 +342,8 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, FILE *out_fp)
                              &algo, &is_enabled)
                || !is_enabled)
             {
-              log_error ("digest algo %d has not been enabled\n", algo);
+              log_error ("digest algo %d (%s) has not been enabled\n", 
+                         algo, algoid?algoid:"");
               audit_log_s (ctrl->audit, AUDIT_SIG_STATUS, "unsupported");
               goto next_signer;
             }
@@ -389,8 +401,16 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, FILE *out_fp)
           audit_log_s (ctrl->audit, AUDIT_SIG_STATUS, "bad");
           goto next_signer;
         }
+      sigval_hash_algo = hash_algo_from_sigval (sigval);
       if (DBG_X509)
-        log_debug ("signer %d - signature available", signer);
+        {
+          log_debug ("signer %d - signature available (sigval hash=%d)",
+                     signer, sigval_hash_algo);
+/*           log_printhex ("sigval    ", sigval, */
+/*                         gcry_sexp_canon_len (sigval, 0, NULL, NULL)); */
+        }
+      if (!sigval_hash_algo)
+        sigval_hash_algo = algo; /* Fallback used e.g. with old libksba. */
 
       /* Find the certificate of the signer */
       keydb_search_reset (kh);
@@ -438,8 +458,8 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, FILE *out_fp)
           gcry_md_hd_t md;
           unsigned char *s;
 
-          /* check that the message digest in the signed attributes
+          /* Check that the message digest in the signed attributes
-             matches the one we calculated on the data */
+             matches the one we calculated on the data.  */
           s = gcry_md_read (data_md, algo);
           if ( !s || !msgdigestlen
                || gcry_md_get_algo_dlen (algo) != msgdigestlen
@@ -456,7 +476,7 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, FILE *out_fp)
               goto next_signer; 
             }
             
-          rc = gcry_md_open (&md, algo, 0);
+          rc = gcry_md_open (&md, sigval_hash_algo, 0);
           if (rc)
             {
               log_error ("md_open failed: %s\n", gpg_strerror (rc));
@@ -476,14 +496,14 @@ gpgsm_verify (ctrl_t ctrl, int in_fd, int data_fd, FILE *out_fp)
               audit_log_s (ctrl->audit, AUDIT_SIG_STATUS, "error");
               goto next_signer;
             }
-          rc = gpgsm_check_cms_signature (cert, sigval, md, algo, 
+          rc = gpgsm_check_cms_signature (cert, sigval, md, 
-                                          &info_pkalgo);
+                                          sigval_hash_algo, &info_pkalgo);
           gcry_md_close (md);
         }
       else
         {
-          rc = gpgsm_check_cms_signature (cert, sigval, data_md, algo, 
+          rc = gpgsm_check_cms_signature (cert, sigval, data_md, 
-                                          &info_pkalgo);
+                                          algo, &info_pkalgo);
         }
 
       if (rc)