Merge commit '8b9bcec' into dtls

* commit '8b9bcec':
  Stop assuming chars are signed
  Fix len miscalculation in buffer-based allocator
  Fix NULL dereference in buffer-based allocator
  Add test_suite_memory_buffer_alloc
  Add memory_buffer_alloc_self_test()
  Fix missing bound check
  Add test for ctr_drbg_update() input sanitizing
  Refactor for clearer correctness/security
  Stop assuming chars are signed

Conflicts:
	library/ssl_tls.c

include/polarssl/ctr_drbg.h

@@ -188,6 +188,10 @@ int ctr_drbg_reseed( ctr_drbg_context *ctx,
  * \param ctx           CTR_DRBG context
  * \param additional    Additional data to update state with
  * \param add_len       Length of additional data
+ *
+ * \note                If add_len is greater than CTR_DRBG_MAX_SEED_INPUT,
+ *                      only the first CTR_DRBG_MAX_SEED_INPUT bytes are used,
+ *                      the remaining ones are silently discarded.
  */
 void ctr_drbg_update( ctr_drbg_context *ctx,
                       const unsigned char *additional, size_t add_len );

include/polarssl/memory_buffer_alloc.h

@@ -115,6 +115,15 @@ void memory_buffer_alloc_status( void );
  */
 int memory_buffer_alloc_verify( void );
 
+#if defined(POLARSSL_SELF_TEST)
+/**
+ * \brief          Checkup routine
+ *
+ * \return         0 if successful, or 1 if a test failed
+ */
+int memory_buffer_alloc_self_test( int verbose );
+#endif
+
 #ifdef __cplusplus
 }
 #endif