Convert DER decoding functions to new DSA interface.

diff --git a/ChangeLog b/ChangeLog
index 09fdbb020509c22ee4bb7fd792664857136d3710..55577db283c96d31960e6cbfc6c6ddc4d9d485bc 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,19 @@
 2014-03-26  Niels Möller  <nisse@lysator.liu.se>
 
+       * der2dsa.c (dsa_params_from_der_iterator): Converted to new DSA
+       interface. Allow q_size == 0, meaning any q < p is allowed.
+       Additional validity checks.
+       (dsa_public_key_from_der_iterator): Converted to new DSA
+       interface. Also check that the public value is in the correct
+       range.
+       (dsa_openssl_private_key_from_der_iterator): Converted
+       to new DSA interface. Additional validity checks.
+       (dsa_openssl_private_key_from_der): Converted to new DSA
+       interface.
+       * tools/pkcs1-conv.c (convert_dsa_private_key): Update to use
+       struct dsa_params, and adapt to the der decoding changes.
+       (convert_public_key): Likewise.
+
        * examples/hogweed-benchmark.c: Update dsa benchmarking to use new
        DSA interface.
 

diff --git a/der2dsa.c b/der2dsa.c
index 9d439c3e8cff8966b4dca89138db7657374beb9e..ff6114e5428bcb00d65b27c71449b0bde9641b4d 100644 (file)
--- a/der2dsa.c
+++ b/der2dsa.c
@@ -6,6 +6,7 @@
 /* nettle, low-level cryptographics library
  *
  * Copyright (C) 2005, 2009 Niels Möller, Magnus Holmgren
+ * Copyright (C) 2014 Niels Möller
  *  
  * The nettle library is free software; you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as published by
@@ -38,9 +39,10 @@
  && asn1_der_get_bignum((i), (x), (l))                 \
  && mpz_sgn((x)) > 0)
 
+/* If q_bits > 0, q is required to be of exactly this size. */
 int
-dsa_params_from_der_iterator(struct dsa_public_key *pub,
-                            unsigned p_max_bits,
+dsa_params_from_der_iterator(struct dsa_params *params,
+                            unsigned max_bits, unsigned q_bits,
                             struct asn1_der_iterator *i)
 {
   /* Dss-Parms ::= SEQUENCE {
@@ -49,30 +51,41 @@ dsa_params_from_der_iterator(struct dsa_public_key *pub,
         g  INTEGER
      }
   */
-  return (i->type == ASN1_INTEGER
-         && asn1_der_get_bignum(i, pub->p, p_max_bits)
-         && mpz_sgn(pub->p) > 0
-         && GET(i, pub->q, DSA_SHA1_Q_BITS)
-         && GET(i, pub->g, p_max_bits)
-         && asn1_der_iterator_next(i) == ASN1_ITERATOR_END);
+  if (i->type == ASN1_INTEGER
+      && asn1_der_get_bignum(i, params->p, max_bits)
+      && mpz_sgn(params->p) > 0)
+    {
+      unsigned p_bits = mpz_sizeinbase (params->p, 2);
+      return (GET(i, params->q, q_bits ? q_bits : p_bits)
+             && (q_bits == 0 || mpz_sizeinbase(params->q, 2) == q_bits)
+             && mpz_cmp (params->q, params->p) < 0
+             && GET(i, params->g, p_bits)
+             && mpz_cmp (params->g, params->p) < 0
+             && asn1_der_iterator_next(i) == ASN1_ITERATOR_END);
+    }
+  else
+    return 0;
 }
 
 int
-dsa_public_key_from_der_iterator(struct dsa_public_key *pub,
-                                unsigned p_max_bits,
+dsa_public_key_from_der_iterator(const struct dsa_params *params,
+                                mpz_t pub,
                                 struct asn1_der_iterator *i)
 {
   /* DSAPublicKey ::= INTEGER
   */
 
   return (i->type == ASN1_INTEGER
-         && asn1_der_get_bignum(i, pub->y, p_max_bits)
-         && mpz_sgn(pub->y) > 0);
+         && asn1_der_get_bignum(i, pub,
+                                mpz_sizeinbase (params->p, 2))
+         && mpz_sgn(pub) > 0
+         && mpz_cmp(pub, params->p) < 0);
 }
 
 int
-dsa_openssl_private_key_from_der_iterator(struct dsa_public_key *pub,
-                                         struct dsa_private_key *priv,
+dsa_openssl_private_key_from_der_iterator(struct dsa_params *params,
+                                         mpz_t pub,
+                                         mpz_t priv,
                                          unsigned p_max_bits,
                                          struct asn1_der_iterator *i)
 {
@@ -87,23 +100,31 @@ dsa_openssl_private_key_from_der_iterator(struct dsa_public_key *pub,
   */
 
   uint32_t version;
-  
-  return (i->type == ASN1_SEQUENCE
+
+  if (i->type == ASN1_SEQUENCE
          && asn1_der_decode_constructed_last(i) == ASN1_ITERATOR_PRIMITIVE
          && i->type == ASN1_INTEGER
          && asn1_der_get_uint32(i, &version)
          && version == 0
-         && GET(i, pub->p, p_max_bits)
-         && GET(i, pub->q, DSA_SHA1_Q_BITS)
-         && GET(i, pub->g, p_max_bits)
-         && GET(i, pub->y, p_max_bits)
-         && GET(i, priv->x, DSA_SHA1_Q_BITS)
-         && asn1_der_iterator_next(i) == ASN1_ITERATOR_END);
+      && GET(i, params->p, p_max_bits))
+    {
+      unsigned p_bits = mpz_sizeinbase (params->p, 2);
+      return (GET(i, params->q, DSA_SHA1_Q_BITS)
+             && GET(i, params->g, p_bits)
+             && mpz_cmp (params->g, params->p) < 0
+             && GET(i, pub, p_bits)
+             && mpz_cmp (pub, params->p) < 0
+             && GET(i, priv, DSA_SHA1_Q_BITS)
+             && asn1_der_iterator_next(i) == ASN1_ITERATOR_END);
+    }
+  else
+    return 0;
 }
 
 int
-dsa_openssl_private_key_from_der(struct dsa_public_key *pub,
-                                struct dsa_private_key *priv,
+dsa_openssl_private_key_from_der(struct dsa_params *params,
+                                mpz_t pub,
+                                mpz_t priv,
                                 unsigned p_max_bits,
                                 size_t length, const uint8_t *data)
 {
@@ -113,5 +134,6 @@ dsa_openssl_private_key_from_der(struct dsa_public_key *pub,
   res = asn1_der_iterator_first(&i, length, data);
 
   return (res == ASN1_ITERATOR_CONSTRUCTED
-         && dsa_openssl_private_key_from_der_iterator(pub, priv, p_max_bits, &i));
+         && dsa_openssl_private_key_from_der_iterator(params, pub, priv,
+                                                      p_max_bits, &i));
 }

diff --git a/dsa.h b/dsa.h
index e66918ed95aecb5bc980648310eacfebaa06e6e3..33bd00b2a7dd9f59ff03208b0823c064bc4cb7fc 100644 (file)
--- a/dsa.h
+++ b/dsa.h
@@ -293,23 +293,26 @@ dsa_sha256_keypair_from_sexp(struct dsa_params *params,
 struct asn1_der_iterator;
 
 int
-dsa_params_from_der_iterator(struct dsa_public_key *pub,
-                            unsigned p_max_bits,
-                            struct asn1_der_iterator *i);
+dsa_params_from_der_iterator(struct dsa_params *params,
+                            unsigned max_bits, unsigned q_bits,
+                            struct asn1_der_iterator *i);
+
 int
-dsa_public_key_from_der_iterator(struct dsa_public_key *pub,
-                                unsigned p_max_bits,
+dsa_public_key_from_der_iterator(const struct dsa_params *params,
+                                mpz_t pub,
                                 struct asn1_der_iterator *i);
 
 int
-dsa_openssl_private_key_from_der_iterator(struct dsa_public_key *pub,
-                                         struct dsa_private_key *priv,
+dsa_openssl_private_key_from_der_iterator(struct dsa_params *params,
+                                         mpz_t pub,
+                                         mpz_t priv,
                                          unsigned p_max_bits,
                                          struct asn1_der_iterator *i);
 
 int
-dsa_openssl_private_key_from_der(struct dsa_public_key *pub,
-                                struct dsa_private_key *priv,
+dsa_openssl_private_key_from_der(struct dsa_params *params,
+                                mpz_t pub,
+                                mpz_t priv,
                                 unsigned p_max_bits, 
                                 size_t length, const uint8_t *data);
 

diff --git a/tools/pkcs1-conv.c b/tools/pkcs1-conv.c
index 1c73a97cefc62bd47a0b259e1481d564deb010ad..811ddc203c3fbeb2fd7ce3e527f4af2191b84062 100644 (file)
--- a/tools/pkcs1-conv.c
+++ b/tools/pkcs1-conv.c
@@ -5,6 +5,7 @@
 /* nettle, low-level cryptographics library
  *
  * Copyright (C) 2005, 2009 Niels Möller, Magnus Holmgren
+ * Copyright (C) 2014 Niels Möller
  *  
  * The nettle library is free software; you can redistribute it and/or modify
  * it under the terms of the GNU Lesser General Public License as published by
@@ -311,29 +312,30 @@ convert_rsa_private_key(struct nettle_buffer *buffer, size_t length, const uint8
 static int
 convert_dsa_private_key(struct nettle_buffer *buffer, size_t length, const uint8_t *data)
 {
-  struct dsa_public_key pub;
-  struct dsa_private_key priv;
+  struct dsa_params params;
+  mpz_t pub;
+  mpz_t priv;
   int res;
-  
-  dsa_public_key_init(&pub);
-  dsa_private_key_init(&priv);
 
-  if (dsa_openssl_private_key_from_der(&pub, &priv, 0,
+  dsa_params_init (&params);
+  mpz_init (pub);
+  mpz_init (priv);
+
+  if (dsa_openssl_private_key_from_der(&params, pub, priv, 0,
                                       length, data))
     {
       /* Reuses the buffer */
       nettle_buffer_reset(buffer);
-      res = dsa_keypair_to_sexp(buffer, NULL,
-                               (const struct dsa_params *) &pub,
-                               pub.y, priv.x);
+      res = dsa_keypair_to_sexp(buffer, NULL, &params, pub, priv);
     }
   else
     {
       werror("Invalid OpenSSL private key.\n");
       res = 0;
     }
-  dsa_public_key_clear(&pub);
-  dsa_private_key_clear(&priv);
+  dsa_params_clear (&params);
+  mpz_clear (pub);
+  mpz_clear (priv);
 
   return res;
 }
@@ -407,19 +409,21 @@ convert_public_key(struct nettle_buffer *buffer, size_t length, const uint8_t *d
              if (asn1_der_iterator_next(&j) == ASN1_ITERATOR_CONSTRUCTED
                  && asn1_der_decode_constructed_last(&j) == ASN1_ITERATOR_PRIMITIVE)
                {
-                 struct dsa_public_key pub;
+                 struct dsa_params params;
+                 mpz_t pub;
 
-                 dsa_public_key_init(&pub);
+                 dsa_params_init (&params);
+                 mpz_init (pub);
 
-                 if (dsa_params_from_der_iterator(&pub, 0, &i)
-                     && dsa_public_key_from_der_iterator(&pub, 0, &j))
+                 if (dsa_params_from_der_iterator(&params, 0, 0, &i)
+                     && dsa_public_key_from_der_iterator(&params, pub, &j))
                    {
                      nettle_buffer_reset(buffer);
                      res = dsa_keypair_to_sexp(buffer, NULL,
-                                               (const struct dsa_params *) &pub,
-                                               pub.y, NULL) > 0;
+                                               &params, pub, NULL) > 0;
                    }
-                 dsa_public_key_clear(&pub);
+                 dsa_params_clear(&params);
+                 mpz_clear(pub);
                }
              if (!res)
                werror("SubjectPublicKeyInfo: Invalid DSA key.\n");