| 1 | /* |
| 2 | * Memory tagging, write-only tag checking |
| 3 | * |
| 4 | * SPDX-License-Identifier: GPL-2.0-or-later |
| 5 | */ |
| 6 | |
| 7 | #include "mte.h" |
| 8 | |
| 9 | void pass(int sig, siginfo_t *info, void *uc) |
| 10 | { |
| 11 | exit(0); |
| 12 | } |
| 13 | |
| 14 | int main(int ac, char **av) |
| 15 | { |
| 16 | struct sigaction sa; |
| 17 | int *p0, *p1, *p2; |
| 18 | long excl = 1; |
| 19 | |
| 20 | enable_mte(PR_MTE_TCF_SYNC | PR_MTE_STORE_ONLY); |
| 21 | p0 = alloc_mte_mem(sizeof(*p0)); |
| 22 | |
| 23 | /* Create two differently tagged pointers. */ |
| 24 | asm("irg %0,%1,%2" : "=r"(p1) : "r"(p0), "r"(excl)); |
| 25 | asm("gmi %0,%1,%0" : "+r"(excl) : "r" (p1)); |
| 26 | assert(excl != 1); |
| 27 | asm("irg %0,%1,%2" : "=r"(p2) : "r"(p0), "r"(excl)); |
| 28 | assert(p1 != p2); |
| 29 | |
| 30 | /* Store the tag from the first pointer. */ |
| 31 | asm("stg %0, [%0]" : : "r"(p1)); |
| 32 | |
| 33 | /* |
| 34 | * We write to p1 (stg above makes this check pass) and read from |
| 35 | * p2 (improperly tagged, but since it's a read, we don't care). |
| 36 | */ |
| 37 | *p1 = *p2; |
| 38 | |
| 39 | /* enable handler */ |
| 40 | memset(&sa, 0, sizeof(sa)); |
| 41 | sa.sa_sigaction = pass; |
| 42 | sa.sa_flags = SA_SIGINFO; |
| 43 | sigaction(SIGSEGV, &sa, NULL); |
| 44 | |
| 45 | /* now we write to badly tagged p2, should fault. */ |
| 46 | *p2 = 0; |
| 47 | |
| 48 | abort(); |
| 49 | } |