-add extra context argument for key deriviation, so that fs and gads do not collide

5 files changed, 28 insertions, 10 deletions

diff --git a/src/fs/fs_publish_ublock.c b/src/fs/fs_publish_ublock.c
index 71997fda0..75446e8a8 100644
--- a/src/fs/fs_publish_ublock.c
+++ b/src/fs/fs_publish_ublock.c
@@ -242,7 +242,7 @@ GNUNET_FS_publish_ublock_ (struct GNUNET_FS_Handle *h,
   ub_enc->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_FS_UBLOCK);
 
   /* derive signing-key from 'label' and public key of the namespace */
-  nsd = GNUNET_CRYPTO_ecc_key_derive (ns, label);
+  nsd = GNUNET_CRYPTO_ecc_key_derive (ns, label, "fs-ublock");
   GNUNET_CRYPTO_ecc_key_get_public (nsd,
                                     &ub_enc->verification_key);
   GNUNET_assert (GNUNET_OK ==
diff --git a/src/fs/fs_search.c b/src/fs/fs_search.c
index a0fec03a1..9bc254254 100644
--- a/src/fs/fs_search.c
+++ b/src/fs/fs_search.c
@@ -1104,6 +1104,7 @@ transmit_search_request (void *cls, size_t size, void *buf)
     memset (&sm->target, 0, sizeof (struct GNUNET_HashCode));
     GNUNET_CRYPTO_ecc_public_key_derive (&sc->uri->data.sks.ns,
                                          sc->uri->data.sks.identifier,
+                                         "fs-ublock",
                                          &dpub);
     GNUNET_CRYPTO_hash (&dpub,
                         sizeof (dpub),
@@ -1290,6 +1291,7 @@ GNUNET_FS_search_start_searching_ (struct GNUNET_FS_SearchContext *sc)
       sre->keyword = GNUNET_strdup (keyword);
       GNUNET_CRYPTO_ecc_public_key_derive (&anon_pub,
                                            keyword,
+                                           "fs-ublock",
                                            &sre->dpub);
       GNUNET_CRYPTO_hash (&sre->dpub, 
                           sizeof (struct GNUNET_CRYPTO_EccPublicKey), 
diff --git a/src/include/gnunet_crypto_lib.h b/src/include/gnunet_crypto_lib.h
index 1704fce07..96bbdc214 100644
--- a/src/include/gnunet_crypto_lib.h
+++ b/src/include/gnunet_crypto_lib.h
@@ -1,10 +1,10 @@
 /*
      This file is part of GNUnet.
-     (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2012 Christian Grothoff (and other contributing authors)
+     (C) 2001-2013 Christian Grothoff (and other contributing authors)
 
      GNUnet 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 2, or (at your
+     by the Free Software Foundation; either version 3, or (at your
      option) any later version.
 
      GNUnet is distributed in the hope that it will be useful, but
@@ -979,11 +979,14 @@ GNUNET_CRYPTO_ecc_verify (uint32_t purpose,
  *
  * @param priv original private key
  * @param label label to use for key deriviation
+ * @param context additional context to use for HKDF of 'h';
+ *        typically the name of the subsystem/application
  * @return derived private key
  */
 struct GNUNET_CRYPTO_EccPrivateKey *
 GNUNET_CRYPTO_ecc_key_derive (const struct GNUNET_CRYPTO_EccPrivateKey *priv,
-                              const char *label);
+                              const char *label,
+                              const char *context);
 
 
 /**
@@ -992,11 +995,14 @@ GNUNET_CRYPTO_ecc_key_derive (const struct GNUNET_CRYPTO_EccPrivateKey *priv,
  *
  * @param pub original public key
  * @param label label to use for key deriviation
+ * @param context additional context to use for HKDF of 'h'.
+ *        typically the name of the subsystem/application
  * @param result where to write the derived public key
  */
 void
 GNUNET_CRYPTO_ecc_public_key_derive (const struct GNUNET_CRYPTO_EccPublicKey *pub,
                                      const char *label,
+                                     const char *context,
                                      struct GNUNET_CRYPTO_EccPublicKey *result);
 
 
diff --git a/src/util/crypto_ecc.c b/src/util/crypto_ecc.c
index 191892bce..4d949eaf8 100644
--- a/src/util/crypto_ecc.c
+++ b/src/util/crypto_ecc.c
@@ -926,11 +926,14 @@ GNUNET_CRYPTO_ecc_ecdh (const struct GNUNET_CRYPTO_EccPrivateKey *priv,
  *
  * @param pub public key for deriviation
  * @param label label for deriviation
+ * @param context additional context to use for HKDF of 'h';
+ *        typically the name of the subsystem/application
  * @return h value
  */ 
 static gcry_mpi_t 
 derive_h (const struct GNUNET_CRYPTO_EccPublicKey *pub,
-          const char *label)
+          const char *label,
+          const char *context)
 {
   gcry_mpi_t h;
   struct GNUNET_HashCode hc;
@@ -939,6 +942,7 @@ derive_h (const struct GNUNET_CRYPTO_EccPublicKey *pub,
                      "key-derivation", strlen ("key-derivation"),
                      pub, sizeof (*pub),
                      label, strlen (label),
+                     context, strlen (context),
                      NULL, 0);
   mpi_scan (&h, (unsigned char *) &hc, sizeof (hc));
   return h;
@@ -953,11 +957,14 @@ derive_h (const struct GNUNET_CRYPTO_EccPublicKey *pub,
  *
  * @param priv original private key
  * @param label label to use for key deriviation
+ * @param context additional context to use for HKDF of 'h';
+ *        typically the name of the subsystem/application
  * @return derived private key
  */
 struct GNUNET_CRYPTO_EccPrivateKey *
 GNUNET_CRYPTO_ecc_key_derive (const struct GNUNET_CRYPTO_EccPrivateKey *priv,
-                              const char *label)
+                              const char *label,
+                              const char *context)
 {
   struct GNUNET_CRYPTO_EccPublicKey pub;
   struct GNUNET_CRYPTO_EccPrivateKey *ret;
@@ -970,7 +977,7 @@ GNUNET_CRYPTO_ecc_key_derive (const struct GNUNET_CRYPTO_EccPrivateKey *priv,
   GNUNET_assert (0 == gcry_mpi_ec_new (&ctx, NULL, CURVE));
   n = gcry_mpi_ec_get_mpi ("n", ctx, 0 /* no copy */);
   GNUNET_CRYPTO_ecc_key_get_public (priv, &pub);
-  h = derive_h (&pub, label);
+  h = derive_h (&pub, label, context);
   mpi_scan (&x, priv->d, sizeof (priv->d));
   d = gcry_mpi_new (256);
   gcry_mpi_mulm (d, h, x, n);
@@ -989,11 +996,14 @@ GNUNET_CRYPTO_ecc_key_derive (const struct GNUNET_CRYPTO_EccPrivateKey *priv,
  *
  * @param pub original public key
  * @param label label to use for key deriviation
+ * @param context additional context to use for HKDF of 'h';
+ *        typically the name of the subsystem/application
  * @param result where to write the derived public key
  */
 void
 GNUNET_CRYPTO_ecc_public_key_derive (const struct GNUNET_CRYPTO_EccPublicKey *pub,
                                      const char *label,
+                                     const char *context,
                                      struct GNUNET_CRYPTO_EccPublicKey *result)
 {
   gcry_ctx_t ctx;
@@ -1017,7 +1027,7 @@ GNUNET_CRYPTO_ecc_public_key_derive (const struct GNUNET_CRYPTO_EccPublicKey *pu
   gcry_mpi_release (q_y);
 
   /* calulcate h_mod_n = h % n */
-  h = derive_h (pub, label);
+  h = derive_h (pub, label, context);
   n = gcry_mpi_ec_get_mpi ("n", ctx, 0 /* no copy */);
   h_mod_n = gcry_mpi_new (256);
   gcry_mpi_mod (h_mod_n, h, n);
diff --git a/src/util/test_crypto_ecc.c b/src/util/test_crypto_ecc.c
index 891256b11..00d264e0f 100644
--- a/src/util/test_crypto_ecc.c
+++ b/src/util/test_crypto_ecc.c
@@ -95,9 +95,9 @@ testDeriveSignVerify ()
   struct GNUNET_CRYPTO_EccPublicKey pkey;
   struct GNUNET_CRYPTO_EccPublicKey dpub;
 
-  dpriv = GNUNET_CRYPTO_ecc_key_derive (key, "test-derive");
+  dpriv = GNUNET_CRYPTO_ecc_key_derive (key, "test-derive", "test-CTX");
   GNUNET_CRYPTO_ecc_key_get_public (key, &pkey);
-  GNUNET_CRYPTO_ecc_public_key_derive (&pkey, "test-derive", &dpub);
+  GNUNET_CRYPTO_ecc_public_key_derive (&pkey, "test-derive", "test-CTX", &dpub);
   purp.size = htonl (sizeof (struct GNUNET_CRYPTO_EccSignaturePurpose));
   purp.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_TEST);