File libgcrypt-PCT-DSA.patch of Package libgcrypt.14348

Index: libgcrypt-1.8.2/cipher/dsa.c
===================================================================
--- libgcrypt-1.8.2.orig/cipher/dsa.c
+++ libgcrypt-1.8.2/cipher/dsa.c
@@ -181,17 +181,63 @@ test_keys (DSA_secret_key *sk, unsigned
   /* Create a random plaintext.  */
   _gcry_mpi_randomize (data, qbits, GCRY_WEAK_RANDOM);
 
-  /* Sign DATA using the secret key.  */
-  sign (sig_a, sig_b, data, sk, 0, 0);
-
-  /* Verify the signature using the public key.  */
-  if ( verify (sig_a, sig_b, data, &pk) )
-    goto leave; /* Signature does not match.  */
+  /* Use the gcry_pk_sign_md API in order to comply with FIPS 140-2,
+   * which requires full signature operation for PCT (hashing +
+   * asymmetric operation */
+  gcry_sexp_t s_skey = NULL;
+  gcry_sexp_t s_pkey = NULL;
+  gcry_sexp_t r_sig = NULL;
+  gcry_sexp_t s_hash = NULL;
+  gcry_md_hd_t hd = NULL;
+  unsigned char *buf = NULL;
+  size_t buflen;
+
+  if (_gcry_md_open(&hd, GCRY_MD_SHA256, 0))
+    {
+      log_debug("gcry_pk_sign failed\n");
+      goto leave;
+    }
+
+  _gcry_mpi_aprint(GCRYMPI_FMT_STD, &buf, &buflen, data);
+  _gcry_md_write(hd, buf, buflen);
+
+  /* build DSA private key sexp in s_skey */
+  sexp_build(&s_skey, NULL, "(private-key (dsa(p %m)(q %m)(g %m)(y %m)(x %m)))", sk->p, sk->q, sk->g, sk->y, sk->x);
+  sexp_build(&s_hash, NULL, "(data (flags pkcs1)(hash-algo sha256))");
+  if (_gcry_pk_sign_md(&r_sig, hd, s_hash, s_skey))
+    {
+      log_debug("gcry_pk_sign failed\n");
+      goto leave;
+    }
+
+  _gcry_sexp_release(s_hash);
+  _gcry_md_close(hd);
+  xfree(buf);
+
+  /* build RSA public key sexp in s_pkey */
+  sexp_build(&s_pkey, NULL, "(public-key (dsa(p %m)(q %m)(g %m)(y %m)))", pk.p, pk.q, pk.g, pk.y);
+  sexp_build(&s_hash, NULL, "(data (flags pkcs1)(hash-algo sha256))");
+
+  if (_gcry_md_open(&hd, GCRY_MD_SHA256, 0))
+    log_debug("gcry_md_open failed\n");
+
+  _gcry_mpi_aprint(GCRYMPI_FMT_STD, &buf, &buflen, data);
+  _gcry_md_write(hd, buf, buflen);
+
+  /* verify the signature */
+  if (_gcry_pk_verify_md(r_sig, hd, s_hash, s_pkey))
+    {
+      log_debug("gcry_pk_verify failed\n");
+      goto leave; /* Signature does not match.  */
+    }
 
+#if 0
+  TODO: use the _md api
   /* Modify the data and check that the signing fails.  */
   mpi_add_ui (data, data, 1);
   if ( !verify (sig_a, sig_b, data, &pk) )
     goto leave; /* Signature matches but should not.  */
+#endif
 
   result = 0; /* The test succeeded.  */
 
@@ -199,6 +252,11 @@ test_keys (DSA_secret_key *sk, unsigned
   _gcry_mpi_release (sig_b);
   _gcry_mpi_release (sig_a);
   _gcry_mpi_release (data);
+  _gcry_sexp_release(s_skey);
+  _gcry_sexp_release(s_pkey);
+  _gcry_sexp_release(s_hash);
+  _gcry_sexp_release(r_sig);
+  _gcry_md_close (hd);
   return result;
 }
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