commit 8c0fd1e881cf052c7a0f59c1bc167b97391034b4
author Simon Butcher <simonb@redtangent.net> Sun Apr 22 22:58:07 2018 +0100
committer Simon Butcher <simonb@redtangent.net> Mon Jun 11 14:03:22 2018 +0100
tree 6029ca286ee89af90b715c4c6f0386986ebfd150
parent 0301884f007b4025f4a743e450cdd10a99f03053

Add cipher abstraction and test cases for OFB block mode

Adds OFB as additional block mode in the cipher abstraction, and additional
test cases for that block mode.

library/cipher.c

diff --git a/library/cipher.c b/library/cipher.c
index a5cd61c..2c599e5 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -191,10 +191,11 @@
     ctx->operation = operation;
 
     /*
-     * For CFB and CTR mode always use the encryption key schedule
+     * For OFB, CFB and CTR mode always use the encryption key schedule
      */
     if( MBEDTLS_ENCRYPT == operation ||
         MBEDTLS_MODE_CFB == ctx->cipher_info->mode ||
+        MBEDTLS_MODE_OFB == ctx->cipher_info->mode ||
         MBEDTLS_MODE_CTR == ctx->cipher_info->mode )
     {
         return ctx->cipher_info->base->setkey_enc_func( ctx->cipher_ctx, key,
@@ -424,6 +425,21 @@
     }
 #endif /* MBEDTLS_CIPHER_MODE_CFB */
 
+#if defined(MBEDTLS_CIPHER_MODE_OFB)
+    if( ctx->cipher_info->mode == MBEDTLS_MODE_OFB )
+    {
+        if( 0 != ( ret = ctx->cipher_info->base->ofb_func( ctx->cipher_ctx,
+                ilen, &ctx->unprocessed_len, ctx->iv, input, output ) ) )
+        {
+            return( ret );
+        }
+
+        *olen = ilen;
+
+        return( 0 );
+    }
+#endif /* MBEDTLS_CIPHER_MODE_OFB */
+
 #if defined(MBEDTLS_CIPHER_MODE_CTR)
     if( ctx->cipher_info->mode == MBEDTLS_MODE_CTR )
     {
@@ -639,6 +655,7 @@
     *olen = 0;
 
     if( MBEDTLS_MODE_CFB == ctx->cipher_info->mode ||
+        MBEDTLS_MODE_OFB == ctx->cipher_info->mode ||
         MBEDTLS_MODE_CTR == ctx->cipher_info->mode ||
         MBEDTLS_MODE_GCM == ctx->cipher_info->mode ||
         MBEDTLS_MODE_STREAM == ctx->cipher_info->mode )