042df2e2da
- It is opt-out for now so as to give it maximum testing, but it may be turned opt-in for stable branches depending on the consensus. You can turn it off with WITHOUT_SSP. - WITHOUT_SSP was previously used to disable the build of GNU libssp. It is harmless to steal the knob as SSP symbols have been provided by libc for a long time, GNU libssp should not have been much used. - SSP is disabled in a few corners such as system bootstrap programs (sys/boot), process bootstrap code (rtld, csu) and SSP symbols themselves. - It should be safe to use -fstack-protector-all to build world, however libc will be automatically downgraded to -fstack-protector because it breaks rtld otherwise. - This option is unavailable on ia64. Enable GCC stack protection (aka Propolice) for kernel: - It is opt-out for now so as to give it maximum testing. - Do not compile your kernel with -fstack-protector-all, it won't work. Submitted by: Jeremie Le Hen <jeremie@le-hen.org>
36 lines
819 B
C
36 lines
819 B
C
#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/types.h>
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/libkern.h>
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#if defined(__SSP__) || defined(__SSP_ALL__)
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long __stack_chk_guard[8] = {};
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void __stack_chk_fail(void);
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void
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__stack_chk_fail(void)
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{
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panic("stack overflow detected; backtrace may be corrupted");
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}
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#define __arraycount(__x) (sizeof(__x) / sizeof(__x[0]))
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static void
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__stack_chk_init(void *dummy __unused)
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{
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size_t i;
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long guard[__arraycount(__stack_chk_guard)];
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arc4rand(guard, sizeof(guard), 0);
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for (i = 0; i < __arraycount(guard); i++)
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__stack_chk_guard[i] = guard[i];
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}
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/* SI_SUB_EVENTHANDLER is right after SI_SUB_LOCK used by arc4rand() init. */
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SYSINIT(stack_chk, SI_SUB_EVENTHANDLER, SI_ORDER_ANY, __stack_chk_init, NULL);
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#endif
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