commit a2bdcb9e3ae86ce01f6e33067a1f5d16860f0008
author Gilles Peskine <Gilles.Peskine@arm.com> Tue Jan 21 15:02:14 2020 +0100
committer Gilles Peskine <Gilles.Peskine@arm.com> Tue Jan 21 15:02:14 2020 +0100
tree 8f63770e18cf692b35339d01aee2257bcfbc917c
parent d27a88438fe785f0906c01e3216044d1c98be875

Remove redundant block_size validity check

Check the value only once, as soon as we've obtained it.

library/cipher.c

diff --git a/library/cipher.c b/library/cipher.c
index b62f1d5..409c3fe 100644
--- a/library/cipher.c
+++ b/library/cipher.c
@@ -527,6 +527,10 @@
 
     *olen = 0;
     block_size = mbedtls_cipher_get_block_size( ctx );
+    if ( 0 == block_size )
+    {
+        return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT );
+    }
 
     if( ctx->cipher_info->mode == MBEDTLS_MODE_ECB )
     {
@@ -562,11 +566,6 @@
     }
 #endif
 
-    if ( 0 == block_size )
-    {
-        return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT );
-    }
-
     if( input == output &&
        ( ctx->unprocessed_len != 0 || ilen % block_size ) )
     {
@@ -625,11 +624,6 @@
          */
         if( 0 != ilen )
         {
-            if( 0 == block_size )
-            {
-                return( MBEDTLS_ERR_CIPHER_INVALID_CONTEXT );
-            }
-
             /* Encryption: only cache partial blocks
              * Decryption w/ padding: always keep at least one whole block
              * Decryption w/o padding: only cache partial blocks