GNUNET_CRYPTO_eddsa_key_from_file handles do_create correctly

The function GNUNET_CRYPTO_eddsa_key_from_file returns now
- GNUNET_OK on success,
- GNUNET_NO if do_create was set but we found an existing file,
- GNUNET_SYSERR on failure _or_ if the file didn't exist and
  do_create was not set

Fixes #7106

2 files changed, 17 insertions, 10 deletions

diff --git a/src/util/crypto_ecc_setup.c b/src/util/crypto_ecc_setup.c
index f7cd8c6d9..21ce48eef 100644
--- a/src/util/crypto_ecc_setup.c
+++ b/src/util/crypto_ecc_setup.c
@@ -134,8 +134,10 @@ read_from_file (const char *filename,
  * @param filename name of file to use to store the key
  * @param do_create should a file be created?
  * @param[out] pkey set to the private key from @a filename on success
- * @return #GNUNET_OK on success, #GNUNET_NO if @a do_create was set but
- *         we found an existing file, #GNUNET_SYSERR on failure
+ * @return - #GNUNET_OK on success,
+ *  - #GNUNET_NO if @a do_create was set but we found an existing file,
+ *  - #GNUNET_SYSERR on failure _or_ if the file didn't exist and @a
+ *    do_create was not set
  */
 enum GNUNET_GenericReturnValue
 GNUNET_CRYPTO_eddsa_key_from_file (const char *filename,
@@ -152,6 +154,11 @@ GNUNET_CRYPTO_eddsa_key_from_file (const char *filename,
     /* file existed, report that we didn't create it... */
     return (do_create) ? GNUNET_NO : GNUNET_OK;
   }
+  else if (! do_create)
+  {
+    return GNUNET_SYSERR;
+  }
+
   GNUNET_CRYPTO_eddsa_key_create (pkey);
   ret = GNUNET_DISK_fn_write (filename,
                               pkey,
diff --git a/src/util/test_crypto_eddsa.c b/src/util/test_crypto_eddsa.c
index 10d6a4e91..459619ff2 100644
--- a/src/util/test_crypto_eddsa.c
+++ b/src/util/test_crypto_eddsa.c
@@ -216,12 +216,16 @@ testCreateFromFile (void)
   struct GNUNET_CRYPTO_EddsaPublicKey p1;
   struct GNUNET_CRYPTO_EddsaPublicKey p2;
 
-  GNUNET_assert (0 <=
+  /* do_create == GNUNET_YES and non-existing file MUST return GNUNET_YES */
+  GNUNET_assert (0 == unlink (KEYFILE) || ENOENT == errno);
+  GNUNET_assert (GNUNET_YES ==
                  GNUNET_CRYPTO_eddsa_key_from_file (KEYFILE,
                                                     GNUNET_YES,
                                                     &key));
   GNUNET_CRYPTO_eddsa_key_get_public (&key,
                                       &p1);
+
+  /* do_create == GNUNET_YES and _existing_ file MUST return GNUNET_NO */
   GNUNET_assert (GNUNET_NO ==
                  GNUNET_CRYPTO_eddsa_key_from_file (KEYFILE,
                                                     GNUNET_YES,
@@ -231,16 +235,13 @@ testCreateFromFile (void)
   GNUNET_assert (0 ==
                  GNUNET_memcmp (&p1,
                                 &p2));
+
+  /* do_create == GNUNET_NO and non-existing file MUST return GNUNET_SYSERR */
   GNUNET_assert (0 == unlink (KEYFILE));
-  GNUNET_assert (GNUNET_OK ==
+  GNUNET_assert (GNUNET_SYSERR ==
                  GNUNET_CRYPTO_eddsa_key_from_file (KEYFILE,
                                                     GNUNET_NO,
                                                     &key));
-  GNUNET_CRYPTO_eddsa_key_get_public (&key,
-                                      &p2);
-  GNUNET_assert (0 !=
-                 GNUNET_memcmp (&p1,
-                                &p2));
   return GNUNET_OK;
 }
 
@@ -299,7 +300,6 @@ main (int argc, char *argv[])
     failure_count++;
   if (GNUNET_OK != testCreateFromFile ())
     failure_count++;
-  GNUNET_assert (0 == unlink (KEYFILE));
   perf_keygen ();
 
   if (0 != failure_count)