1 /* Copyright (c) 2017 Yaakov Selkowitz <yselkowi@redhat.com> */
2 #include <sys/cdefs.h>
3 #include <sys/param.h>
4 #include <signal.h>
5 #include <stdlib.h>
6 #include <string.h>
7 #include <unistd.h>
8 #include <stdio.h>
9
10 #if defined(__AMDGCN__) || defined(__nvptx__)
11 /* Global constructors not supported on this target, yet. */
12 uintptr_t __stack_chk_guard = 0x00000aff; /* 0, 0, '\n', 255 */
13
14 #else
15 uintptr_t __stack_chk_guard = 0;
16
17 int getentropy (void *, size_t) _ATTRIBUTE((__weak__));
18
19 void
20 __attribute__((__constructor__))
__stack_chk_init(void)21 __stack_chk_init (void)
22 {
23 if (__stack_chk_guard != 0)
24 return;
25
26 if (getentropy) {
27 /* Use getentropy if available */
28 getentropy(&__stack_chk_guard, sizeof(__stack_chk_guard));
29 } else {
30 /* If getentropy is not available, use the "terminator canary". */
31 ((unsigned char *)&__stack_chk_guard)[0] = 0;
32 ((unsigned char *)&__stack_chk_guard)[1] = 0;
33 #if __SIZEOF_POINTER__ > 2
34 ((unsigned char *)&__stack_chk_guard)[2] = '\n';
35 ((unsigned char *)&__stack_chk_guard)[3] = 255;
36 #endif
37 }
38 }
39 #endif
40
41 void __stack_chk_fail (void) __attribute__((__noreturn__));
42
43 #define STACK_CHK_MSG "*** stack smashing detected ***: terminated"
44
45 void
46 __attribute__((__noreturn__))
__stack_chk_fail_weak(void)47 __stack_chk_fail_weak (void)
48 {
49 #ifdef TINY_STDIO
50 puts(STACK_CHK_MSG);
51 #else
52 static const char msg[] = STACK_CHK_MSG "\n";
53 write (2, msg, sizeof(msg)-1);
54 #endif
55 abort();
56 }
57 __weak_reference(__stack_chk_fail_weak, __stack_chk_fail);
58
59 #ifdef __ELF__
60 void
61 __attribute__((visibility ("hidden")))
__stack_chk_fail_local(void)62 __stack_chk_fail_local (void)
63 {
64 __stack_chk_fail();
65 }
66 #endif
67
