Differential D19817 Diff 58992 src/secp256k1/examples/examples_util.h

Changeset View

Standalone View

src/secp256k1/examples/examples_util.h

This file was moved from src/secp256k1/examples/random.h.

	Show First 20 Lines • Show All 65 Lines • ▼ Show 20 Lines
	static void print_hex(unsigned char* data, size_t size) {			static void print_hex(unsigned char* data, size_t size) {
	size_t i;			size_t i;
	printf("0x");			printf("0x");
	for (i = 0; i < size; i++) {			for (i = 0; i < size; i++) {
	printf("%02x", data[i]);			printf("%02x", data[i]);
	}			}
	printf("\n");			printf("\n");
	}			}

				#if defined(_MSC_VER)
				// For SecureZeroMemory
				#include <Windows.h>
				#endif
				/* Cleanses memory to prevent leaking sensitive info. Won't be optimized out. */
				static SECP256K1_INLINE void secure_erase(void *ptr, size_t len) {
				#if defined(_MSC_VER)
				/* SecureZeroMemory is guaranteed not to be optimized out by MSVC. */
				SecureZeroMemory(ptr, len);
				#elif defined(__GNUC__)
				/* We use a memory barrier that scares the compiler away from optimizing out the memset.
				*
				* Quoting Adam Langley <agl@google.com> in commit ad1907fe73334d6c696c8539646c21b11178f20f
				* in BoringSSL (ISC License):
				* As best as we can tell, this is sufficient to break any optimisations that
				* might try to eliminate "superfluous" memsets.
				* This method used in memzero_explicit() the Linux kernel, too. Its advantage is that it is
				* pretty efficient, because the compiler can still implement the memset() efficently,
				* just not remove it entirely. See "Dead Store Elimination (Still) Considered Harmful" by
				* Yang et al. (USENIX Security 2017) for more background.
				*/
				memset(ptr, 0, len);
				__asm__ __volatile__("" : : "r"(ptr) : "memory");
				#else
				void (volatile const volatile_memset)(void *, int, size_t) = memset;
				volatile_memset(ptr, 0, len);
				#endif
				}