66 lines
1.5 KiB
C
66 lines
1.5 KiB
C
#include "first.h"
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#include "safe_memclear.h"
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#include <string.h>
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#if defined(_WIN32) && !defined(__CYGWIN__)
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#include <WinBase.h>
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/*(Windows XP and later provide SecureZeroMemory())*/
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#define HAVE_SECUREZEROMEMORY
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#endif
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#if !defined(HAVE_MEMSET_S) \
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&& !defined(HAVE_EXPLICIT_BZERO) \
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&& !defined(HAVE_EXPLICIT_MEMSET) \
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&& !defined(HAVE_SECUREZEROMEMORY)
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typedef void *(*safe_memclear_func_t)(void *, int, size_t);
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extern volatile safe_memclear_func_t safe_memclear_func;
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volatile safe_memclear_func_t safe_memclear_func = memset;
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# if defined(HAVE_WEAK_SYMBOLS)
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/* it seems weak functions are never inlined, even for static builds */
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__attribute__((weak)) void __li_safe_memset_hook(void *buf, size_t len);
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void __li_safe_memset_hook(void *buf, size_t len)
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{
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UNUSED(buf);
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UNUSED(len);
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}
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# endif /* HAVE_WEAK_SYMBOLS */
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static void* safe_memset(void *s, int c, size_t n)
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{
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if (n > 0) {
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volatile unsigned volatile_zero = 0;
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volatile unsigned char *vs = (volatile unsigned char*)s;
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do {
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safe_memclear_func(s, c, n);
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} while (vs[volatile_zero] != (unsigned char)c);
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# if defined(HAVE_WEAK_SYMBOLS)
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__li_safe_memset_hook(s, n);
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# endif /* HAVE_WEAK_SYMBOLS */
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}
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return s;
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}
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#endif
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void safe_memclear(void *s, size_t n) {
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#if defined(HAVE_MEMSET_S)
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memset_s(s, n, 0, n);
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#elif defined(HAVE_EXPLICIT_BZERO)
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explicit_bzero(s, n);
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#elif defined(HAVE_EXPLICIT_MEMSET)
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explicit_memset(s, 0, n);
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#elif defined(HAVE_SECUREZEROMEMORY)
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SecureZeroMemory(s, n);
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#else
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safe_memset(s, 0, n);
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#endif
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}
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