commit ebdc413f4465904c7de69a707dec09420640e0c9
author Manuel Pégourié-Gonnard <mpg@elzevir.fr> Fri Jul 26 16:50:44 2013 +0200
committer Paul Bakker <p.j.bakker@polarssl.org> Wed Aug 14 14:02:48 2013 +0200
tree 9f6316e66945ec679980bac0905291a203993f86
parent 0e7d2c0f9537d66007a1a914f4c7e5b064f4c6ac

Add 'no padding' mode

library/cipher.c

diff --git a/library/cipher.c b/library/cipher.c
index bbde944..70eef69 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -657,6 +657,23 @@
     return 0;
 }
 
+/*
+ * No padding: don't pad :)
+ *
+ * There is no add_padding function (check for NULL in cipher_finish)
+ * but a trivial get_padding function
+ */
+static int get_no_padding( unsigned char *input, size_t input_len,
+                              size_t *data_len )
+{
+    if( NULL == input || NULL == data_len )
+        return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
+
+    *data_len = input_len;
+
+    return 0;
+}
+
 int cipher_finish( cipher_context_t *ctx, unsigned char *output, size_t *olen)
 {
     int ret = 0;
@@ -677,12 +694,27 @@
     {
         if( POLARSSL_ENCRYPT == ctx->operation )
         {
+            /* check for 'no padding' mode */
+            if( NULL == ctx->add_padding )
+            {
+                if( 0 != ctx->unprocessed_len )
+                    return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
+
+                return 0;
+            }
+
             ctx->add_padding( ctx->unprocessed_data, cipher_get_iv_size( ctx ),
                     ctx->unprocessed_len );
         }
         else if ( cipher_get_block_size( ctx ) != ctx->unprocessed_len )
         {
-            /* For decrypt operations, expect a full block */
+            /*
+             * For decrypt operations, expect a full block,
+             * or an empty block if no padding
+             */
+            if( NULL == ctx->add_padding && 0 == ctx->unprocessed_len )
+                return 0;
+
             return POLARSSL_ERR_CIPHER_FULL_BLOCK_EXPECTED;
         }
 
@@ -743,6 +775,13 @@
         return 0;
     }
 
+    if( POLARSSL_PADDING_NONE == mode )
+    {
+        ctx->add_padding = NULL;
+        ctx->get_padding = get_no_padding;
+        return 0;
+    }
+
     return POLARSSL_ERR_CIPHER_BAD_INPUT_DATA;
 }