gpg,gpgsm: Add option --min-rsa-length.

* common/compliance.c (min_compliant_rsa_length): New.
(gnupg_pk_is_compliant): Take in account.
(gnupg_pk_is_allowed): Ditto.
(gnupg_set_compliance_extra_info): New.
* g10/gpg.c (oMinRSALength): New.
(opts): Add --min-rsa-length.
(main): Set value.
* g10/options.h (opt): Add field min_rsa_length.
* sm/gpgsm.c (oMinRSALength): New.
(opts): Add --min-rsa-length.
(main): Set value.
* sm/gpgsm.h (opt): Add field min_rsa_length.

8 files changed, 59 insertions, 9 deletions

diff --git a/common/compliance.c b/common/compliance.c
index 1cda1ec16..eaecee7b0 100644
--- a/common/compliance.c
+++ b/common/compliance.c
@@ -40,6 +40,10 @@
 static int initialized;
 static int module;
 
+/* This value is used by DSA and RSA checks in addition to the hard
+ * coded length checks.  It allows to increase the required key length
+ * using a confue file.  */
+static unsigned int min_compliant_rsa_length;
 
 /* Return the address of a compliance cache variable for COMPLIANCE.
  * If no such variable exists NULL is returned.  FOR_RNG returns the
@@ -178,9 +182,10 @@ gnupg_pk_is_compliant (enum gnupg_compliance_mode compliance, int algo,
           break;
 
         case is_rsa:
-          result = (keylength == 2048
-                    || keylength == 3072
-                    || keylength == 4096);
+          result = ((keylength == 2048
+                     || keylength == 3072
+                     || keylength == 4096)
+                    && keylength >= min_compliant_rsa_length);
           /* Although rsaPSS was not part of the original evaluation
            * we got word that we can claim compliance.  */
           (void)algo_flags;
@@ -192,7 +197,8 @@ gnupg_pk_is_compliant (enum gnupg_compliance_mode compliance, int algo,
 	      size_t P = gcry_mpi_get_nbits (key[0]);
 	      size_t Q = gcry_mpi_get_nbits (key[1]);
 	      result = (Q == 256
-			&& (P == 2048 || P == 3072));
+			&& (P == 2048 || P == 3072)
+                        && P >= min_compliant_rsa_length);
 	    }
 	  break;
 
@@ -258,9 +264,10 @@ gnupg_pk_is_allowed (enum gnupg_compliance_mode compliance,
               break;
 	    case PK_USE_ENCRYPTION:
 	    case PK_USE_SIGNING:
-	      result = (keylength == 2048
-                        || keylength == 3072
-                        || keylength == 4096);
+	      result = ((keylength == 2048
+                         || keylength == 3072
+                         || keylength == 4096)
+                        && keylength >= min_compliant_rsa_length);
               break;
 	    default:
 	      log_assert (!"reached");
@@ -275,7 +282,9 @@ gnupg_pk_is_allowed (enum gnupg_compliance_mode compliance,
 	    {
 	      size_t P = gcry_mpi_get_nbits (key[0]);
 	      size_t Q = gcry_mpi_get_nbits (key[1]);
-	      result = (Q == 256 && (P == 2048 || P == 3072));
+	      result = (Q == 256
+                        && (P == 2048 || P == 3072)
+                        && keylength >= min_compliant_rsa_length);
             }
           break;
 
@@ -683,3 +692,11 @@ gnupg_compliance_option_string (enum gnupg_compliance_mode compliance)
 
   log_assert (!"invalid compliance mode");
 }
+
+
+/* Set additional infos for example taken from config files at startup.  */
+void
+gnupg_set_compliance_extra_info (unsigned int min_rsa)
+{
+  min_compliant_rsa_length = min_rsa;
+}
diff --git a/common/compliance.h b/common/compliance.h
index 20b562eb8..e29ff4ee2 100644
--- a/common/compliance.h
+++ b/common/compliance.h
@@ -91,5 +91,7 @@ int gnupg_parse_compliance_option (const char *string,
 const char *gnupg_compliance_option_string (enum gnupg_compliance_mode
                                             compliance);
 
+void gnupg_set_compliance_extra_info (unsigned int min_rsa);
+
 
 #endif /*GNUPG_COMMON_COMPLIANCE_H*/
diff --git a/doc/gpg.texi b/doc/gpg.texi
index 3209a2d7a..eed213d78 100644
--- a/doc/gpg.texi
+++ b/doc/gpg.texi
@@ -2881,7 +2881,13 @@ SHA224, SHA384, and SHA512 digests.
 @opindex compliance
 This option can be used instead of one of the options above.  Valid
 values for @var{string} are the above option names (without the double
-dash) and possibly others as shown when using "help" for @var{value}.
+dash) and possibly others as shown when using "help" for @var{string}.
+
+@item --min-rsa-length @var{n}
+@opindex min-rsa-length
+This option adjusts the compliance mode "de-vs" for stricter key size
+requirements.  For example, a value of 3000 turns rsa2048 and dsa2048
+keys into non-VS-NfD compliant keys.
 
 @end table
 
diff --git a/doc/gpgsm.texi b/doc/gpgsm.texi
index a3e1bc2e6..d3d83e4a5 100644
--- a/doc/gpgsm.texi
+++ b/doc/gpgsm.texi
@@ -667,6 +667,16 @@ 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 --compliance @var{string}
+@opindex compliance
+Set the compliance mode.  Valid values are shown when using "help" for
+@var{string}.
+
+@item --min-rsa-length @var{n}
+@opindex min-rsa-length
+This option adjusts the compliance mode "de-vs" for stricter key size
+requirements.  For example, a value of 3000 turns rsa2048 and dsa2048
+keys into non-VS-NfD compliant keys.
 
 @item --faked-system-time @var{epoch}
 @opindex faked-system-time
diff --git a/g10/gpg.c b/g10/gpg.c
index abab14426..81185523f 100644
--- a/g10/gpg.c
+++ b/g10/gpg.c
@@ -242,6 +242,7 @@ enum cmd_and_opt_values
     oPGP7,
     oPGP8,
     oDE_VS,
+    oMinRSALength,
     oRFC2440Text,
     oNoRFC2440Text,
     oCipherAlgo,
@@ -664,6 +665,7 @@ static ARGPARSE_OPTS opts[] = {
   ARGPARSE_s_n (oPGP6, "pgp6", "@"),
   ARGPARSE_s_n (oPGP7, "pgp7", "@"),
   ARGPARSE_s_n (oPGP8, "pgp8", "@"),
+  ARGPARSE_p_u (oMinRSALength, "min-rsa-length", "@"),
 
   ARGPARSE_s_n (oRFC2440Text,      "rfc2440-text", "@"),
   ARGPARSE_s_n (oNoRFC2440Text, "no-rfc2440-text", "@"),
@@ -2891,6 +2893,8 @@ main (int argc, char **argv)
             set_compliance_option (pargs.r_opt);
             break;
 
+	  case oMinRSALength: opt.min_rsa_length = pargs.r.ret_ulong; break;
+
           case oRFC2440Text: opt.rfc2440_text=1; break;
           case oNoRFC2440Text: opt.rfc2440_text=0; break;
 
@@ -3751,6 +3755,7 @@ main (int argc, char **argv)
       }
 
     set_debug (debug_level);
+    gnupg_set_compliance_extra_info (opt.min_rsa_length);
     if (DBG_CLOCK)
       log_clock ("start");
 
diff --git a/g10/options.h b/g10/options.h
index f91dbd5e7..03b46f8de 100644
--- a/g10/options.h
+++ b/g10/options.h
@@ -214,6 +214,7 @@ struct
   unsigned int screen_lines;
   byte *show_subpackets;
   int rfc2440_text;
+  unsigned int min_rsa_length;   /* Used for compliance checks.  */
 
   /* If true, let write failures on the status-fd exit the process. */
   int exit_on_status_write_error;
diff --git a/sm/gpgsm.c b/sm/gpgsm.c
index 5c1f0bb07..4af639faa 100644
--- a/sm/gpgsm.c
+++ b/sm/gpgsm.c
@@ -156,6 +156,7 @@ enum cmd_and_opt_values {
   oDisablePolicyChecks,
   oEnablePolicyChecks,
   oAutoIssuerKeyRetrieve,
+  oMinRSALength,
 
   oWithFingerprint,
   oWithMD5Fingerprint,
@@ -404,6 +405,9 @@ static ARGPARSE_OPTS opts[] = {
   ARGPARSE_s_s (oDisablePubkeyAlgo,  "disable-pubkey-algo", "@"),
   ARGPARSE_s_n (oIgnoreTimeConflict, "ignore-time-conflict", "@"),
   ARGPARSE_s_n (oNoRandomSeedFile,  "no-random-seed-file", "@"),
+
+  ARGPARSE_p_u (oMinRSALength, "min-rsa-length", "@"),
+
   ARGPARSE_s_n (oNoCommonCertsImport, "no-common-certs-import", "@"),
   ARGPARSE_s_s (oIgnoreCertExtension, "ignore-cert-extension", "@"),
   ARGPARSE_s_n (oNoAutostart, "no-autostart", "@"),
@@ -1381,6 +1385,8 @@ main ( int argc, char **argv)
           }
           break;
 
+        case oMinRSALength: opt.min_rsa_length = pargs.r.ret_ulong; break;
+
         default:
           if (configname)
             pargs.err = ARGPARSE_PRINT_WARNING;
@@ -1477,6 +1483,7 @@ main ( int argc, char **argv)
   gcry_control (GCRYCTL_RESUME_SECMEM_WARN);
 
   set_debug ();
+  gnupg_set_compliance_extra_info (opt.min_rsa_length);
 
   /* Although we always use gpgsm_exit, we better install a regualr
      exit handler so that at least the secure memory gets wiped
diff --git a/sm/gpgsm.h b/sm/gpgsm.h
index 9d9a303f8..21c677ebe 100644
--- a/sm/gpgsm.h
+++ b/sm/gpgsm.h
@@ -130,6 +130,8 @@ struct
                                the integrity of the software at
                                runtime. */
 
+  unsigned int min_rsa_length;   /* Used for compliance checks.  */
+
   strlist_t keyserver;
 
   /* A list of certificate extension OIDs which are ignored so that