X-Git-Url: https://git.distorted.org.uk/~mdw/catacomb/blobdiff_plain/c4377d0e42d4d0e3e9781f9d9a8c1a499222aafe..HEAD:/base/ct.h

diff --git a/base/ct.h b/base/ct.h
index 3066e4f2..445d889d 100644
--- a/base/ct.h
+++ b/base/ct.h
@@ -36,7 +36,7 @@
 
 #include <mLib/bits.h>
 
-/*----- Functions provided ------------------------------------------------*/
+/*----- Miscellaneous constant-time utilities -----------------------------*/
 
 /* --- @ct_inteq@ --- *
  *
@@ -103,6 +103,44 @@ extern void ct_condcopy(uint32 /*a*/,
 
 extern int ct_memeq(const void */*p*/, const void */*q*/, size_t /*n*/);
 
+/*----- Utilities for testing ---------------------------------------------*/
+
+/* --- @ct_poison@ --- *
+ *
+ * Arguments:	@const void *p@ = pointer to a secret
+ *		@size_t sz@ = size of the secret
+ *
+ * Returns:	---
+ *
+ * Use:		Ordinarily, does nothing.  If the process is running under
+ *		the control of Valgrind's `memcheck' utility, then mark the
+ *		secret as `uninitialized', so that Valgrind warns about
+ *		conditional execution or memory addressing based on the value
+ *		of the secret.
+ *
+ *		Credit for this idea goes to Adam Langley, who described it
+ *		in https://www.imperialviolet.org/2010/04/01/ctgrind.html,
+ *		though this implementation doesn't require patching Valgrind.
+ */
+
+extern void ct_poison(const void */*p*/, size_t /*sz*/);
+
+/* --- @ct_remedy@ --- *
+ *
+ * Arguments:	@const void *p@ = pointer to a secret
+ *		@size_t sz@ = size of the secret
+ *
+ * Returns:	---
+ *
+ * Use:		Ordinarily, does nothing.  If the process is running under
+ *		the control of Valgrind's `memcheck' utility, then mark the
+ *		secret as `initialized'.  This is intended to reverse the
+ *		effect of @ct_poison@ so that a test program can verify
+ *		function outputs wihtout Valgrind warning.
+ */
+
+extern void ct_remedy(const void */*p*/, size_t /*sz*/);
+
 /*----- That's all, folks -------------------------------------------------*/
 
 #ifdef __cplusplus