From 2a650772b4e1c78a4fd20bc88433930e5551fe9c Mon Sep 17 00:00:00 2001 From: Jussi Kivilinna Date: Sat, 1 Dec 2018 13:43:09 +0200 Subject: common/mischelp: use platform memory zeroing function for wipememory * common/mischelp.h (wipememory): Replace macro with function prototype. (wipememory2): Remove. * common/mischelp.c (wipememory): New. * configure.ac (AC_CHECK_FUNCS): Check for 'explicit_bzero'. -- In new wipememory function, memory is cleared through platform provided secure memory zeroing function, SecureZeroMemory or explicit_bzero. If none of these is available, memset is called through volatile function pointer to so that compiler won't optimize away the call. Signed-off-by: Jussi Kivilinna --- common/mischelp.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'common/mischelp.c') diff --git a/common/mischelp.c b/common/mischelp.c index 75ba60714..81dd501f8 100644 --- a/common/mischelp.c +++ b/common/mischelp.c @@ -49,6 +49,22 @@ #include "mischelp.h" +void +wipememory (void *ptr, size_t len) +{ +#if defined(HAVE_W32_SYSTEM) && defined(SecureZeroMemory) + SecureZeroMemory (ptr, len); +#elif defined(HAVE_EXPLICIT_BZERO) + explicit_bzero (ptr, len); +#else + /* Prevent compiler from optimizing away the call to memset by accessing + memset through volatile pointer. */ + static void *(*volatile memset_ptr)(void *, int, size_t) = (void *)memset; + memset_ptr (ptr, 0, len); +#endif +} + + /* Check whether the files NAME1 and NAME2 are identical. This is for example achieved by comparing the inode numbers of the files. */ int -- cgit v1.2.3