gpgsm: Allow parsing of PKCS#12 files with two private keys.

* sm/minip12.c (struct p12_parse_ctx_s): Add privatekey2.
(parse_shrouded_key_bag): Handle a second private key.
(p12_parse_free_kparms): New.

* sm/import.c (parse_p12): Factor some code out to ...
(p12_to_skey): this.
(parse_p12): Use p12_parse_free_kparms.
--

Take care: We allow parsing of a second private key but we are not yet
able to import the second private key.

The whole things is required to at least import the certificates of
current pkcs#12 files as created by the German Elster tax system.  No
test data, sorry.

sm/import.c

@@ -692,6 +692,85 @@ store_cert_cb (void *opaque,
 }
 
 
+/* Helper for parse_p12.  */
+static gpg_error_t
+p12_to_skey (gcry_mpi_t *kparms, const char *curve, gcry_sexp_t *r_skey)
+{
+  gpg_error_t err = 0;
+  struct rsa_secret_key_s sk;
+  gcry_ctx_t ecctx = NULL;
+
+  if (curve)
+    {
+      /* log_debug ("curve: %s\n", curve); */
+      /* gcry_log_debugmpi ("MPI[0]", kparms[0]); */
+
+      /* We need to get the public key.  */
+      err = gcry_mpi_ec_new (&ecctx, NULL, curve);
+      if (err)
+        {
+          log_error ("error creating context for curve '%s': %s\n",
+                     curve, gpg_strerror (err));
+          goto leave;
+        }
+      err = gcry_mpi_ec_set_mpi ("d", kparms[0], ecctx);
+      if (err)
+        {
+          log_error ("error setting 'd' into context of curve '%s': %s\n",
+                     curve, gpg_strerror (err));
+          goto leave;
+        }
+
+      kparms[1] = gcry_mpi_ec_get_mpi ("q", ecctx, 1);
+      if (!kparms[1])
+        {
+          log_error ("error computing 'q' from 'd' for curve '%s'\n", curve);
+          goto leave;
+        }
+
+      err = gcry_sexp_build (r_skey, NULL,
+                             "(private-key(ecc(curve %s)(q%m)(d%m)))",
+                             curve, kparms[1], kparms[0], NULL);
+    }
+  else /* RSA */
+    {
+      /*    print_mpi ("   n", kparms[0]); */
+      /*    print_mpi ("   e", kparms[1]); */
+      /*    print_mpi ("   d", kparms[2]); */
+      /*    print_mpi ("   p", kparms[3]); */
+      /*    print_mpi ("   q", kparms[4]); */
+      /*    print_mpi ("dmp1", kparms[5]); */
+      /*    print_mpi ("dmq1", kparms[6]); */
+      /*    print_mpi ("   u", kparms[7]); */
+
+      sk.n = kparms[0];
+      sk.e = kparms[1];
+      sk.d = kparms[2];
+      sk.q = kparms[3];
+      sk.p = kparms[4];
+      sk.u = kparms[7];
+      err = rsa_key_check (&sk);
+      if (err)
+        goto leave;
+      /*    print_mpi ("   n", sk.n); */
+      /*    print_mpi ("   e", sk.e); */
+      /*    print_mpi ("   d", sk.d); */
+      /*    print_mpi ("   p", sk.p); */
+      /*    print_mpi ("   q", sk.q); */
+      /*    print_mpi ("   u", sk.u); */
+
+      /* Create an S-expression from the parameters. */
+      err = gcry_sexp_build (r_skey, NULL,
+                             "(private-key(rsa(n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
+                             sk.n, sk.e, sk.d, sk.p, sk.q, sk.u, NULL);
+    }
+
+ leave:
+  gcry_ctx_release (ecctx);
+  return err;
+}
+
+
 /* Assume that the reader is at a pkcs#12 message and try to import
    certificates from that stupid format.  We will transfer secret
    keys to the agent.  */
@@ -706,7 +785,6 @@ parse_p12 (ctrl_t ctrl, ksba_reader_t reader, struct stats_s *stats)
   size_t p12buflen;
   size_t p12bufoff;
   gcry_mpi_t *kparms = NULL;
-  struct rsa_secret_key_s sk;
   char *passphrase = NULL;
   unsigned char *key = NULL;
   size_t keylen;
@@ -792,82 +870,9 @@ parse_p12 (ctrl_t ctrl, ksba_reader_t reader, struct stats_s *stats)
       goto leave;
     }
 
-  if (curve)
-    {
-      gcry_ctx_t ecctx = NULL;
 
-      /* log_debug ("curve: %s\n", curve); */
+  err = p12_to_skey (kparms, curve, &s_key);
-      /* gcry_log_debugmpi ("MPI[0]", kparms[0]); */
+  p12_parse_free_kparms (kparms);
-
-      /* We need to get the public key.  */
-      err = gcry_mpi_ec_new (&ecctx, NULL, curve);
-      if (err)
-        {
-          log_error ("error creating context for curve '%s': %s\n",
-                     curve, gpg_strerror (err));
-          goto leave;
-        }
-      err = gcry_mpi_ec_set_mpi ("d", kparms[0], ecctx);
-      if (err)
-        {
-          log_error ("error setting 'd' into context of curve '%s': %s\n",
-                     curve, gpg_strerror (err));
-          gcry_ctx_release (ecctx);
-          goto leave;
-        }
-
-      kparms[1] = gcry_mpi_ec_get_mpi ("q", ecctx, 1);
-      if (!kparms[1])
-        {
-          log_error ("error computing 'q' from 'd' for curve '%s'\n", curve);
-          gcry_ctx_release (ecctx);
-          goto leave;
-        }
-
-      gcry_ctx_release (ecctx);
-
-      err = gcry_sexp_build (&s_key, NULL,
-                             "(private-key(ecc(curve %s)(q%m)(d%m)))",
-                             curve, kparms[1], kparms[0], NULL);
-    }
-  else /* RSA */
-    {
-      /*    print_mpi ("   n", kparms[0]); */
-      /*    print_mpi ("   e", kparms[1]); */
-      /*    print_mpi ("   d", kparms[2]); */
-      /*    print_mpi ("   p", kparms[3]); */
-      /*    print_mpi ("   q", kparms[4]); */
-      /*    print_mpi ("dmp1", kparms[5]); */
-      /*    print_mpi ("dmq1", kparms[6]); */
-      /*    print_mpi ("   u", kparms[7]); */
-
-      sk.n = kparms[0];
-      sk.e = kparms[1];
-      sk.d = kparms[2];
-      sk.q = kparms[3];
-      sk.p = kparms[4];
-      sk.u = kparms[7];
-      err = rsa_key_check (&sk);
-      if (err)
-        goto leave;
-      /*    print_mpi ("   n", sk.n); */
-      /*    print_mpi ("   e", sk.e); */
-      /*    print_mpi ("   d", sk.d); */
-      /*    print_mpi ("   p", sk.p); */
-      /*    print_mpi ("   q", sk.q); */
-      /*    print_mpi ("   u", sk.u); */
-
-      /* Create an S-expression from the parameters. */
-      err = gcry_sexp_build (&s_key, NULL,
-                             "(private-key(rsa(n%m)(e%m)(d%m)(p%m)(q%m)(u%m)))",
-                             sk.n, sk.e, sk.d, sk.p, sk.q, sk.u, NULL);
-    }
-
-  /* The next is very ugly - we really should not rely on our
-   * knowledge of p12_parse internals.  */
-  for (i=0; i < 8; i++)
-    gcry_mpi_release (kparms[i]);
-  gcry_free (kparms);
   kparms = NULL;
   if (err)
     {

sm/minip12.c

@@ -168,6 +168,9 @@ struct p12_parse_ctx_s
 
   /* The private key as an MPI array.   */
   gcry_mpi_t *privatekey;
+
+  /* A second private key as an MPI array.   */
+  gcry_mpi_t *privatekey2;
 };
 
 
@@ -1248,6 +1251,7 @@ parse_shrouded_key_bag (struct p12_parse_ctx_s *ctx, tlv_parser_t tlv)
   int is_pbes2 = 0;
   int is_aes256 = 0;
   int digest_algo = GCRY_MD_SHA1;
+  gcry_mpi_t *privatekey;
 
   where = "shrouded_key_bag";
   if (opt_verbose)
@@ -1565,19 +1569,26 @@ parse_shrouded_key_bag (struct p12_parse_ctx_s *ctx, tlv_parser_t tlv)
   if (tlv_expect_sequence (tlv))
     goto bailout;
 
-  if (ctx->privatekey)
+  if (ctx->privatekey2)
     {
       err = gpg_error (GPG_ERR_DUP_VALUE);
-      log_error ("a private key has already been received\n");
+      log_error ("two private kesy have already been received\n");
       goto bailout;
     }
-  ctx->privatekey = gcry_calloc (10, sizeof *ctx->privatekey);
+  privatekey = gcry_calloc (10, sizeof *privatekey);
-  if (!ctx->privatekey)
+  if (!privatekey)
     {
       err = gpg_error_from_syserror ();
       log_error ("error allocating privatekey element array\n");
       goto bailout;
     }
+  if (ctx->privatekey)
+    {
+      log_info ("a private key has already been received - reading second\n");
+      ctx->privatekey2 = privatekey;
+    }
+  else
+    ctx->privatekey = privatekey;
 
   where = "shrouded_key_bag.reading.key-parameters";
   if (ctx->curve)  /* ECC case.  */
@@ -1600,7 +1611,7 @@ parse_shrouded_key_bag (struct p12_parse_ctx_s *ctx, tlv_parser_t tlv)
         goto bailout;
       if (opt_verbose > 1)
         log_printhex (data, datalen, "ecc q=");
-      err = gcry_mpi_scan (ctx->privatekey, GCRYMPI_FMT_USG,
+      err = gcry_mpi_scan (privatekey, GCRYMPI_FMT_USG,
                            data, datalen, NULL);
       if (err)
         {
@@ -1623,7 +1634,7 @@ parse_shrouded_key_bag (struct p12_parse_ctx_s *ctx, tlv_parser_t tlv)
             }
 
           err = tlv_expect_mpinteger (tlv, firstparam,
-                                      ctx->privatekey+keyelem_count);
+                                      privatekey+keyelem_count);
           if (firstparam && gpg_err_code (err) == GPG_ERR_FALSE)
             ; /* Ignore the first value iff it is zero. */
           else if (err)
@@ -1918,6 +1929,7 @@ p12_parse (const unsigned char *buffer, size_t length, const char *pw,
   size_t oidlen;
   int intval;
   unsigned int startlevel;
+  int i;
 
   *r_badpass = 0;
 
@@ -2037,6 +2049,15 @@ p12_parse (const unsigned char *buffer, size_t length, const char *pw,
   else
     gcry_free (ctx.curve);
 
+  /* We have no way yet to return the second private key.  */
+  if (ctx.privatekey2)
+    {
+      for (i=0; ctx.privatekey2[i]; i++)
+        gcry_mpi_release (ctx.privatekey2[i]);
+      gcry_free (ctx.privatekey2);
+      ctx.privatekey2 = NULL;
+    }
+
   return ctx.privatekey;
 
  bailout:
@@ -2050,13 +2071,18 @@ p12_parse (const unsigned char *buffer, size_t length, const char *pw,
              gpg_strerror (err));
   if (ctx.privatekey)
     {
-      int i;
-
       for (i=0; ctx.privatekey[i]; i++)
         gcry_mpi_release (ctx.privatekey[i]);
       gcry_free (ctx.privatekey);
       ctx.privatekey = NULL;
     }
+  if (ctx.privatekey2)
+    {
+      for (i=0; ctx.privatekey2[i]; i++)
+        gcry_mpi_release (ctx.privatekey2[i]);
+      gcry_free (ctx.privatekey2);
+      ctx.privatekey2 = NULL;
+    }
   tlv_parser_release (tlv);
   gcry_free (ctx.curve);
   if (r_curve)
@@ -2065,6 +2091,22 @@ p12_parse (const unsigned char *buffer, size_t length, const char *pw,
 }
 
 
+/* Free the parameters as returned by p12_parse.  */
+void
+p12_parse_free_kparms (gcry_mpi_t *kparms)
+{
+  int i;
+
+  if (kparms)
+    {
+      for (i=0; i < 8; i++)
+        gcry_mpi_release (kparms[i]);
+      gcry_free (kparms);
+    }
+}
+
+
+
 
 static size_t
 compute_tag_length (size_t n)

sm/minip12.h

@@ -29,6 +29,7 @@ gcry_mpi_t *p12_parse (const unsigned char *buffer, size_t length,
                        const char *pw,
                        void (*certcb)(void*, const unsigned char*, size_t),
                        void *certcbarg, int *r_badpass, char **r_curve);
+void p12_parse_free_kparms (gcry_mpi_t *kparms);
 
 unsigned char *p12_build (gcry_mpi_t *kparms,
                           const void *cert, size_t certlen,

sm/t-minip12.c

@@ -580,13 +580,7 @@ run_one_test (const char *name, const char *desc, const char *pass,
       ret = 0;
     }
 
-  if (result)
+  p12_parse_free_kparms (result);
-    {
-      int i;
-      for (i=0; result[i]; i++)
-        gcry_mpi_release (result[i]);
-      gcry_free (result);
-    }
   xfree (certstr);
   xfree (resulthash);
   xfree (curve);