commit a310c5e42baf0ca4192228be1f04ca95491b57b4
author Daniel King <damaki.gh@gmail.com> Tue May 17 15:56:26 2016 -0300
committer Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com> Thu May 24 13:37:31 2018 +0200
tree a949e02622351d8f07a5564411e0a53c23132209
parent b8025c58265e3fe89d123900477818c57b94434c

Allow some parameters to be NULL if the length is 0.

This change permits users of the ChaCha20/Poly1305 algorithms
(and the AEAD construction thereof) to pass NULL pointers for
data that they do not need, and avoids the need to provide a valid
buffer for data that is not used.

library/poly1305.c

diff --git a/library/poly1305.c b/library/poly1305.c
index 9a61a85..f9bdf2c 100644
--- a/library/poly1305.c
+++ b/library/poly1305.c
@@ -293,12 +293,17 @@
     size_t queue_free_len;
     size_t nblocks;
 
-    if ( ( ctx == NULL ) || ( input == NULL ) )
+    if ( ctx == NULL )
     {
         return( MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA );
     }
+    else if ( ( ilen > 0U ) && ( input == NULL ) )
+    {
+        /* input pointer is allowed to be NULL only if ilen == 0 */
+        return( MBEDTLS_ERR_POLY1305_BAD_INPUT_DATA );
+    }
 
-    if ( ctx->queue_len > 0U )
+    if ( ( remaining > 0U ) && ( ctx->queue_len > 0U ) )
     {
         queue_free_len = ( POLY1305_BLOCK_SIZE_BYTES - ctx->queue_len );