xref: /aosp_15_r20/external/musl/src/env/__stack_chk_fail.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1 #include <string.h>
2 #include <stdint.h>
3 #include "pthread_impl.h"
4 
5 uintptr_t __stack_chk_guard;
6 
__init_ssp(void * entropy)7 void __init_ssp(void *entropy)
8 {
9 	if (entropy) memcpy(&__stack_chk_guard, entropy, sizeof(uintptr_t));
10 	else __stack_chk_guard = (uintptr_t)&__stack_chk_guard * 1103515245;
11 
12 #if UINTPTR_MAX >= 0xffffffffffffffff
13 	/* Sacrifice 8 bits of entropy on 64bit to prevent leaking/
14 	 * overwriting the canary via string-manipulation functions.
15 	 * The NULL byte is on the second byte so that off-by-ones can
16 	 * still be detected. Endianness is taken care of
17 	 * automatically. */
18 	((char *)&__stack_chk_guard)[1] = 0;
19 #endif
20 
21 	__pthread_self()->canary = __stack_chk_guard;
22 }
23 
__stack_chk_fail(void)24 void __stack_chk_fail(void)
25 {
26 	a_crash();
27 }
28 
29 hidden void __stack_chk_fail_local(void);
30 
31 weak_alias(__stack_chk_fail, __stack_chk_fail_local);
32