From 74433a19bb6f4cef607680fa4d1d7d81ca3826aa Mon Sep 17 00:00:00 2001 From: Damien Miller Date: Tue, 16 Aug 2016 13:28:23 +1000 Subject: [PATCH] fix false positives when compiled with msan Our explicit_bzero successfully confused clang -fsanitize-memory in to thinking that memset is never called to initialise memory. Ensure that it is called in a way that the compiler recognises. --- openbsd-compat/explicit_bzero.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/openbsd-compat/explicit_bzero.c b/openbsd-compat/explicit_bzero.c index 3c85a4843..5078134d1 100644 --- a/openbsd-compat/explicit_bzero.c +++ b/openbsd-compat/explicit_bzero.c @@ -7,6 +7,8 @@ #include "includes.h" +#include + /* * explicit_bzero - don't let the compiler optimize away bzero */ @@ -32,6 +34,17 @@ static void (* volatile ssh_bzero)(void *, size_t) = bzero; void explicit_bzero(void *p, size_t n) { + /* + * clang -fsanitize=memory needs to intercept memset-like functions + * to correctly detect memory initialisation. Make sure one is called + * directly since our indirection trick above sucessfully confuses it. + */ +#if defined(__has_feature) +# if __has_feature(memory_sanitizer) + memset(p, 0, n); +# endif +#endif + ssh_bzero(p, n); }