- Allocate buffer large enough to contain UNIX_PATH_MAX size pathnames in case of...

[oweals/gnunet.git] / src / util / crypto_symmetric.c

diff --git a/src/util/crypto_symmetric.c b/src/util/crypto_symmetric.c
index 97e2a4cfbc6ab9a70363a4cbc3558b5efde9f30a..a7c6336564f4d1e63265c2c2470a58a51dcce0a2 100644 (file)
--- a/src/util/crypto_symmetric.c
+++ b/src/util/crypto_symmetric.c
@@ -39,10 +39,10 @@
 void
 GNUNET_CRYPTO_symmetric_create_session_key (struct GNUNET_CRYPTO_SymmetricSessionKey *key)
 {
-  gcry_randomize (key->aes_key, 
+  gcry_randomize (key->aes_key,
                   GNUNET_CRYPTO_AES_KEY_LENGTH,
                   GCRY_STRONG_RANDOM);
-  gcry_randomize (key->twofish_key, 
+  gcry_randomize (key->twofish_key,
                   GNUNET_CRYPTO_AES_KEY_LENGTH,
                   GCRY_STRONG_RANDOM);
 }
@@ -66,12 +66,12 @@ setup_cipher_aes (gcry_cipher_hd_t *handle,
   GNUNET_assert (0 ==
                  gcry_cipher_open (handle, GCRY_CIPHER_AES256,
                                    GCRY_CIPHER_MODE_CFB, 0));
-  rc = gcry_cipher_setkey (*handle, 
-                           sessionkey->aes_key, 
+  rc = gcry_cipher_setkey (*handle,
+                           sessionkey->aes_key,
                            sizeof (sessionkey->aes_key));
   GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
-  rc = gcry_cipher_setiv (*handle, 
-                          iv->aes_iv, 
+  rc = gcry_cipher_setiv (*handle,
+                          iv->aes_iv,
                           sizeof (iv->aes_iv));
   GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
   return GNUNET_OK;
@@ -94,13 +94,13 @@ setup_cipher_twofish (gcry_cipher_hd_t *handle,
   int rc;
 
   GNUNET_assert (0 ==
-                 gcry_cipher_open (handle, GCRY_CIPHER_TWOFISH, 
+                 gcry_cipher_open (handle, GCRY_CIPHER_TWOFISH,
                                    GCRY_CIPHER_MODE_CFB, 0));
-  rc = gcry_cipher_setkey (*handle, 
-                           sessionkey->twofish_key, 
+  rc = gcry_cipher_setkey (*handle,
+                           sessionkey->twofish_key,
                            sizeof (sessionkey->twofish_key));
   GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
-  rc = gcry_cipher_setiv (*handle, 
+  rc = gcry_cipher_setiv (*handle,
                           iv->twofish_iv,
                           sizeof (iv->twofish_iv));
   GNUNET_assert ((0 == rc) || ((char) rc == GPG_ERR_WEAK_KEY));
@@ -109,55 +109,58 @@ setup_cipher_twofish (gcry_cipher_hd_t *handle,
 
 
 /**
- * Encrypt a block with the public key of another
- * host that uses the same cyper.
+ * Encrypt a block with a symmetric session key.
  *
  * @param block the block to encrypt
- * @param len the size of the @a block
+ * @param size the size of the @a block
  * @param sessionkey the key used to encrypt
- * @param iv the initialization vector to use, use INITVALUE
- *        for streams.
+ * @param iv the initialization vector to use, use INITVALUE for streams
  * @param result the output parameter in which to store the encrypted result
- * @returns the size of the encrypted block, -1 for errors
+ *               can be the same or overlap with @c block
+ * @returns the size of the encrypted block, -1 for errors.
+ *          Due to the use of CFB and therefore an effective stream cipher,
+ *          this size should be the same as @c len.
  */
 ssize_t
-GNUNET_CRYPTO_symmetric_encrypt (const void *block, 
-                                 size_t len,
+GNUNET_CRYPTO_symmetric_encrypt (const void *block,
+                                 size_t size,
                                  const struct GNUNET_CRYPTO_SymmetricSessionKey *sessionkey,
                                  const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
                                  void *result)
 {
   gcry_cipher_hd_t handle;
-  char tmp[len];
+  char tmp[size];
 
   if (GNUNET_OK != setup_cipher_aes (&handle, sessionkey, iv))
     return -1;
-  GNUNET_assert (0 == gcry_cipher_encrypt (handle, tmp, len, block, len));
+  GNUNET_assert (0 == gcry_cipher_encrypt (handle, tmp, size, block, size));
   gcry_cipher_close (handle);
   if (GNUNET_OK != setup_cipher_twofish (&handle, sessionkey, iv))
     return -1;
-  GNUNET_assert (0 == gcry_cipher_encrypt (handle, result, len, tmp, len));
+  GNUNET_assert (0 == gcry_cipher_encrypt (handle, result, size, tmp, size));
   gcry_cipher_close (handle);
   memset (tmp, 0, sizeof (tmp));
-  return len;
+  return size;
 }
 
 
 /**
- * Decrypt a given block with the sessionkey.
+ * Decrypt a given block with the session key.
  *
  * @param block the data to decrypt, encoded as returned by encrypt
  * @param size the size of the @a block to decrypt
  * @param sessionkey the key used to decrypt
- * @param iv the initialization vector to use, use INITVALUE
- *        for streams.
+ * @param iv the initialization vector to use, use INITVALUE for streams
  * @param result address to store the result at
- * @return -1 on failure, size of decrypted block on success
+ *               can be the same or overlap with @c block
+ * @return -1 on failure, size of decrypted block on success.
+ *         Due to the use of CFB and therefore an effective stream cipher,
+ *         this size should be the same as @c size.
  */
 ssize_t
 GNUNET_CRYPTO_symmetric_decrypt (const void *block, size_t size,
                                  const struct GNUNET_CRYPTO_SymmetricSessionKey *sessionkey,
-                                 const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv, 
+                                 const struct GNUNET_CRYPTO_SymmetricInitializationVector *iv,
                                  void *result)
 {
   gcry_cipher_hd_t handle;
@@ -219,13 +222,13 @@ GNUNET_CRYPTO_symmetric_derive_iv_v (struct GNUNET_CRYPTO_SymmetricInitializatio
   memcpy (&aes_salt[salt_len], "AES!", 4);
   memcpy (twofish_salt, salt, salt_len);
   memcpy (&twofish_salt[salt_len], "FISH", 4);
-  GNUNET_CRYPTO_kdf_v (iv->aes_iv, sizeof (iv->aes_iv), 
-                       aes_salt, salt_len + 4, 
-                       skey->aes_key, sizeof (skey->aes_key), 
+  GNUNET_CRYPTO_kdf_v (iv->aes_iv, sizeof (iv->aes_iv),
+                       aes_salt, salt_len + 4,
+                       skey->aes_key, sizeof (skey->aes_key),
                        argp);
   GNUNET_CRYPTO_kdf_v (iv->twofish_iv, sizeof (iv->twofish_iv),
-                       twofish_salt, salt_len + 4, 
-                       skey->twofish_key, sizeof (skey->twofish_key), 
+                       twofish_salt, salt_len + 4,
+                       skey->twofish_key, sizeof (skey->twofish_key),
                        argp);
 }