aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/panic.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/panic.c')
-rw-r--r--kernel/panic.c47
1 files changed, 0 insertions, 47 deletions
diff --git a/kernel/panic.c b/kernel/panic.c
index 87445a894c3a..c35c9eca3eb2 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -329,62 +329,15 @@ EXPORT_SYMBOL(warn_on_slowpath);
329#warning You have selected the CONFIG_CC_STACKPROTECTOR option, but the gcc used does not support this. 329#warning You have selected the CONFIG_CC_STACKPROTECTOR option, but the gcc used does not support this.
330#endif 330#endif
331 331
332static unsigned long __stack_check_testing;
333
334/*
335 * Self test function for the stack-protector feature.
336 * This test requires that the local variable absolutely has
337 * a stack slot.
338 */
339static noinline void __stack_chk_test_func(void)
340{
341 unsigned long dummy_buffer[64]; /* force gcc to use the canary */
342
343 current->stack_canary = ~current->stack_canary;
344 refresh_stack_canary();
345 dummy_buffer[3] = 1; /* fool gcc into keeping the variable */
346}
347
348static int __stack_chk_test(void)
349{
350 printk(KERN_INFO "Testing -fstack-protector-all feature\n");
351 __stack_check_testing = (unsigned long)&__stack_chk_test_func;
352 __stack_chk_test_func();
353 if (__stack_check_testing) {
354 printk(KERN_ERR "-fstack-protector-all test failed\n");
355 WARN_ON(1);
356 };
357 current->stack_canary = ~current->stack_canary;
358 refresh_stack_canary();
359 return 0;
360}
361/* 332/*
362 * Called when gcc's -fstack-protector feature is used, and 333 * Called when gcc's -fstack-protector feature is used, and
363 * gcc detects corruption of the on-stack canary value 334 * gcc detects corruption of the on-stack canary value
364 */ 335 */
365void __stack_chk_fail(void) 336void __stack_chk_fail(void)
366{ 337{
367 if (__stack_check_testing == (unsigned long)&__stack_chk_test_func) {
368 long delta;
369
370 delta = (unsigned long)__builtin_return_address(0) -
371 __stack_check_testing;
372 /*
373 * The test needs to happen inside the test function, so
374 * check if the return address is close to that function.
375 * The function is only 2 dozen bytes long, but keep a wide
376 * safety margin to avoid panic()s for normal users regardless
377 * of the quality of the compiler.
378 */
379 if (delta >= 0 && delta <= 400) {
380 __stack_check_testing = 0;
381 return;
382 }
383 }
384 panic("stack-protector: Kernel stack is corrupted in: %p\n", 338 panic("stack-protector: Kernel stack is corrupted in: %p\n",
385 __builtin_return_address(0)); 339 __builtin_return_address(0));
386} 340}
387EXPORT_SYMBOL(__stack_chk_fail); 341EXPORT_SYMBOL(__stack_chk_fail);
388 342
389late_initcall(__stack_chk_test);
390#endif 343#endif