D15173.id.diff
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	Index: head/lib/libc/secure/stack_protector.c
	===================================================================
	--- head/lib/libc/secure/stack_protector.c
	+++ head/lib/libc/secure/stack_protector.c
	@@ -54,15 +54,27 @@
	__guard_setup(void)
	{
	static const int mib[2] = { CTL_KERN, KERN_ARND };
	+ volatile long tmp_stack_chk_guard[nitems(__stack_chk_guard)];
	size_t len;
	- int error;
	+ int error, idx;

	if (__stack_chk_guard[0] != 0)
	return;
	- error = _elf_aux_info(AT_CANARY, __stack_chk_guard,
	- sizeof(__stack_chk_guard));
	- if (error == 0 && __stack_chk_guard[0] != 0)
	+ /*
	+ * Avoid using functions which might have stack protection
	+ * enabled, to update the __stack_chk_guard. First fetch the
	+ * data into a temporal array, then do manual volatile copy to
	+ * not allow optimizer to call memcpy() behind us.
	+ */
	+ error = _elf_aux_info(AT_CANARY, (void *)tmp_stack_chk_guard,
	+ sizeof(tmp_stack_chk_guard));
	+ if (error == 0 && tmp_stack_chk_guard[0] != 0) {
	+ for (idx = 0; idx < nitems(__stack_chk_guard); idx++) {
	+ __stack_chk_guard[idx] = tmp_stack_chk_guard[idx];
	+ tmp_stack_chk_guard[idx] = 0;
	+ }
	return;
	+ }

	len = sizeof(__stack_chk_guard);
	if (__sysctl(mib, nitems(mib), __stack_chk_guard, &len, NULL, 0) ==