glibc/sysdeps/i386/stackguard-macros.h

#include <stdint.h>

#define STACK_CHK_GUARD \
  ({ uintptr_t x; asm ("movl %%gs:0x14, %0" : "=r" (x)); x; })

#define POINTER_CHK_GUARD \
  ({							\
     uintptr_t x;					\
     asm ("movl %%gs:%c1, %0" : "=r" (x)		\
	  : "i" (offsetof (tcbhead_t, pointer_guard)));	\
     x;							\
   })
Split up stackguard-macros.h into sysdeps directories. 2012-05-16 01:34:30 +02:00			`#include <stdint.h>`

			`#define STACK_CHK_GUARD \`
			`({ uintptr_t x; asm ("movl %%gs:0x14, %0" : "=r" (x)); x; })`
BZ #15754: CVE-2013-4788 The pointer guard used for pointer mangling was not initialized for static applications resulting in the security feature being disabled. The pointer guard is now correctly initialized to a random value for static applications. Existing static applications need to be recompiled to take advantage of the fix. The test tst-ptrguard1-static and tst-ptrguard1 add regression coverage to ensure the pointer guards are sufficiently random and initialized to a default value. 2013-09-23 06:52:09 +02:00
			`#define POINTER_CHK_GUARD \`
			`({ \`
			`uintptr_t x; \`
			`asm ("movl %%gs:%c1, %0" : "=r" (x) \`
			`: "i" (offsetof (tcbhead_t, pointer_guard))); \`
			`x; \`
			`})`