blob: 5669ffd6695e72eff9e996cd7b8ad4f7e183cb1a (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
|
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include "bar.h"
extern void foo(char*);
void bar(char *ptr) {
if (((uintptr_t)ptr >> 56) != 0x2f) {
fprintf(stderr, "Top byte corrupted on Rust -> C FFI boundary!\n");
exit(1);
}
if (strcmp(ptr, "cd")) {
fprintf(stderr, "invalid data in memory; expected 'cd', got '%s'\n", ptr);
exit(1);
}
}
int main(void)
{
// Construct a pointer with an arbitrary tag in bits 56-59, simulating an MTE tag.
// It's only necessary that the tag is preserved across FFI bounds for this test.
char *ptr;
ptr = alloc_page();
if (ptr == MAP_FAILED)
{
perror("mmap() failed");
return EXIT_FAILURE;
}
// Store an arbitrary tag in bits 56-59 of the pointer (where an MTE tag may be),
// and a different value in the ignored top 4 bits.
ptr = (unsigned int *)((uintptr_t)ptr | 0x1fl << 56);
if (mte_enabled()) {
set_tag(ptr);
}
ptr[0] = 'a';
ptr[1] = 'b';
ptr[2] = '\0';
foo(ptr);
return 0;
}
|
