1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Tests x86 Memory Protection Keys (see Documentation/x86/protection-keys.txt)
4  *
5  * There are examples in here of:
6  *  * how to set protection keys on memory
7  *  * how to set/clear bits in PKRU (the rights register)
8  *  * how to handle SEGV_PKRU signals and extract pkey-relevant
9  *    information from the siginfo
10  *
11  * Things to add:
12  *	make sure KSM and KSM COW breaking works
13  *	prefault pages in at malloc, or not
14  *	protect MPX bounds tables with protection keys?
15  *	make sure VMA splitting/merging is working correctly
16  *	OOMs can destroy mm->mmap (see exit_mmap()), so make sure it is immune to pkeys
17  *	look for pkey "leaks" where it is still set on a VMA but "freed" back to the kernel
18  *	do a plain mprotect() to a mprotect_pkey() area and make sure the pkey sticks
19  *
20  * Compile like this:
21  *	gcc      -o protection_keys    -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm
22  *	gcc -m32 -o protection_keys_32 -O2 -g -std=gnu99 -pthread -Wall protection_keys.c -lrt -ldl -lm
23  */
24 #define _GNU_SOURCE
25 #include <errno.h>
26 #include <linux/futex.h>
27 #include <sys/time.h>
28 #include <sys/syscall.h>
29 #include <string.h>
30 #include <stdio.h>
31 #include <stdint.h>
32 #include <stdbool.h>
33 #include <signal.h>
34 #include <assert.h>
35 #include <stdlib.h>
36 #include <ucontext.h>
37 #include <sys/mman.h>
38 #include <sys/types.h>
39 #include <sys/wait.h>
40 #include <sys/stat.h>
41 #include <fcntl.h>
42 #include <unistd.h>
43 #include <sys/ptrace.h>
44 #include <setjmp.h>
45 
46 #include "pkey-helpers.h"
47 
48 int iteration_nr = 1;
49 int test_nr;
50 
51 unsigned int shadow_pkru;
52 
53 #define HPAGE_SIZE	(1UL<<21)
54 #define ARRAY_SIZE(x) (sizeof(x) / sizeof(*(x)))
55 #define ALIGN_UP(x, align_to)	(((x) + ((align_to)-1)) & ~((align_to)-1))
56 #define ALIGN_DOWN(x, align_to) ((x) & ~((align_to)-1))
57 #define ALIGN_PTR_UP(p, ptr_align_to)	((typeof(p))ALIGN_UP((unsigned long)(p),	ptr_align_to))
58 #define ALIGN_PTR_DOWN(p, ptr_align_to)	((typeof(p))ALIGN_DOWN((unsigned long)(p),	ptr_align_to))
59 #define __stringify_1(x...)     #x
60 #define __stringify(x...)       __stringify_1(x)
61 
62 #define PTR_ERR_ENOTSUP ((void *)-ENOTSUP)
63 
64 int dprint_in_signal;
65 char dprint_in_signal_buffer[DPRINT_IN_SIGNAL_BUF_SIZE];
66 
67 extern void abort_hooks(void);
68 #define pkey_assert(condition) do {		\
69 	if (!(condition)) {			\
70 		dprintf0("assert() at %s::%d test_nr: %d iteration: %d\n", \
71 				__FILE__, __LINE__,	\
72 				test_nr, iteration_nr);	\
73 		dprintf0("errno at assert: %d", errno);	\
74 		abort_hooks();			\
75 		exit(__LINE__);			\
76 	}					\
77 } while (0)
78 
cat_into_file(char * str,char * file)79 void cat_into_file(char *str, char *file)
80 {
81 	int fd = open(file, O_RDWR);
82 	int ret;
83 
84 	dprintf2("%s(): writing '%s' to '%s'\n", __func__, str, file);
85 	/*
86 	 * these need to be raw because they are called under
87 	 * pkey_assert()
88 	 */
89 	if (fd < 0) {
90 		fprintf(stderr, "error opening '%s'\n", str);
91 		perror("error: ");
92 		exit(__LINE__);
93 	}
94 
95 	ret = write(fd, str, strlen(str));
96 	if (ret != strlen(str)) {
97 		perror("write to file failed");
98 		fprintf(stderr, "filename: '%s' str: '%s'\n", file, str);
99 		exit(__LINE__);
100 	}
101 	close(fd);
102 }
103 
104 #if CONTROL_TRACING > 0
105 static int warned_tracing;
tracing_root_ok(void)106 int tracing_root_ok(void)
107 {
108 	if (geteuid() != 0) {
109 		if (!warned_tracing)
110 			fprintf(stderr, "WARNING: not run as root, "
111 					"can not do tracing control\n");
112 		warned_tracing = 1;
113 		return 0;
114 	}
115 	return 1;
116 }
117 #endif
118 
tracing_on(void)119 void tracing_on(void)
120 {
121 #if CONTROL_TRACING > 0
122 #define TRACEDIR "/sys/kernel/debug/tracing"
123 	char pidstr[32];
124 
125 	if (!tracing_root_ok())
126 		return;
127 
128 	sprintf(pidstr, "%d", getpid());
129 	cat_into_file("0", TRACEDIR "/tracing_on");
130 	cat_into_file("\n", TRACEDIR "/trace");
131 	if (1) {
132 		cat_into_file("function_graph", TRACEDIR "/current_tracer");
133 		cat_into_file("1", TRACEDIR "/options/funcgraph-proc");
134 	} else {
135 		cat_into_file("nop", TRACEDIR "/current_tracer");
136 	}
137 	cat_into_file(pidstr, TRACEDIR "/set_ftrace_pid");
138 	cat_into_file("1", TRACEDIR "/tracing_on");
139 	dprintf1("enabled tracing\n");
140 #endif
141 }
142 
tracing_off(void)143 void tracing_off(void)
144 {
145 #if CONTROL_TRACING > 0
146 	if (!tracing_root_ok())
147 		return;
148 	cat_into_file("0", "/sys/kernel/debug/tracing/tracing_on");
149 #endif
150 }
151 
abort_hooks(void)152 void abort_hooks(void)
153 {
154 	fprintf(stderr, "running %s()...\n", __func__);
155 	tracing_off();
156 #ifdef SLEEP_ON_ABORT
157 	sleep(SLEEP_ON_ABORT);
158 #endif
159 }
160 
__page_o_noops(void)161 static inline void __page_o_noops(void)
162 {
163 	/* 8-bytes of instruction * 512 bytes = 1 page */
164 	asm(".rept 512 ; nopl 0x7eeeeeee(%eax) ; .endr");
165 }
166 
167 /*
168  * This attempts to have roughly a page of instructions followed by a few
169  * instructions that do a write, and another page of instructions.  That
170  * way, we are pretty sure that the write is in the second page of
171  * instructions and has at least a page of padding behind it.
172  *
173  * *That* lets us be sure to madvise() away the write instruction, which
174  * will then fault, which makes sure that the fault code handles
175  * execute-only memory properly.
176  */
177 __attribute__((__aligned__(PAGE_SIZE)))
lots_o_noops_around_write(int * write_to_me)178 void lots_o_noops_around_write(int *write_to_me)
179 {
180 	dprintf3("running %s()\n", __func__);
181 	__page_o_noops();
182 	/* Assume this happens in the second page of instructions: */
183 	*write_to_me = __LINE__;
184 	/* pad out by another page: */
185 	__page_o_noops();
186 	dprintf3("%s() done\n", __func__);
187 }
188 
189 /* Define some kernel-like types */
190 #define  u8 uint8_t
191 #define u16 uint16_t
192 #define u32 uint32_t
193 #define u64 uint64_t
194 
195 #ifdef __i386__
196 
197 #ifndef SYS_mprotect_key
198 # define SYS_mprotect_key	380
199 #endif
200 
201 #ifndef SYS_pkey_alloc
202 # define SYS_pkey_alloc		381
203 # define SYS_pkey_free		382
204 #endif
205 
206 #define REG_IP_IDX		REG_EIP
207 #define si_pkey_offset		0x14
208 
209 #else
210 
211 #ifndef SYS_mprotect_key
212 # define SYS_mprotect_key	329
213 #endif
214 
215 #ifndef SYS_pkey_alloc
216 # define SYS_pkey_alloc		330
217 # define SYS_pkey_free		331
218 #endif
219 
220 #define REG_IP_IDX		REG_RIP
221 #define si_pkey_offset		0x20
222 
223 #endif
224 
dump_mem(void * dumpme,int len_bytes)225 void dump_mem(void *dumpme, int len_bytes)
226 {
227 	char *c = (void *)dumpme;
228 	int i;
229 
230 	for (i = 0; i < len_bytes; i += sizeof(u64)) {
231 		u64 *ptr = (u64 *)(c + i);
232 		dprintf1("dump[%03d][@%p]: %016jx\n", i, ptr, *ptr);
233 	}
234 }
235 
236 /* Failed address bound checks: */
237 #ifndef SEGV_BNDERR
238 # define SEGV_BNDERR		3
239 #endif
240 
241 #ifndef SEGV_PKUERR
242 # define SEGV_PKUERR		4
243 #endif
244 
si_code_str(int si_code)245 static char *si_code_str(int si_code)
246 {
247 	if (si_code == SEGV_MAPERR)
248 		return "SEGV_MAPERR";
249 	if (si_code == SEGV_ACCERR)
250 		return "SEGV_ACCERR";
251 	if (si_code == SEGV_BNDERR)
252 		return "SEGV_BNDERR";
253 	if (si_code == SEGV_PKUERR)
254 		return "SEGV_PKUERR";
255 	return "UNKNOWN";
256 }
257 
258 int pkru_faults;
259 int last_si_pkey = -1;
signal_handler(int signum,siginfo_t * si,void * vucontext)260 void signal_handler(int signum, siginfo_t *si, void *vucontext)
261 {
262 	ucontext_t *uctxt = vucontext;
263 	int trapno;
264 	unsigned long ip;
265 	char *fpregs;
266 	u32 *pkru_ptr;
267 	u64 siginfo_pkey;
268 	u32 *si_pkey_ptr;
269 	int pkru_offset;
270 	fpregset_t fpregset;
271 
272 	dprint_in_signal = 1;
273 	dprintf1(">>>>===============SIGSEGV============================\n");
274 	dprintf1("%s()::%d, pkru: 0x%x shadow: %x\n", __func__, __LINE__,
275 			__rdpkru(), shadow_pkru);
276 
277 	trapno = uctxt->uc_mcontext.gregs[REG_TRAPNO];
278 	ip = uctxt->uc_mcontext.gregs[REG_IP_IDX];
279 	fpregset = uctxt->uc_mcontext.fpregs;
280 	fpregs = (void *)fpregset;
281 
282 	dprintf2("%s() trapno: %d ip: 0x%lx info->si_code: %s/%d\n", __func__,
283 			trapno, ip, si_code_str(si->si_code), si->si_code);
284 #ifdef __i386__
285 	/*
286 	 * 32-bit has some extra padding so that userspace can tell whether
287 	 * the XSTATE header is present in addition to the "legacy" FPU
288 	 * state.  We just assume that it is here.
289 	 */
290 	fpregs += 0x70;
291 #endif
292 	pkru_offset = pkru_xstate_offset();
293 	pkru_ptr = (void *)(&fpregs[pkru_offset]);
294 
295 	dprintf1("siginfo: %p\n", si);
296 	dprintf1(" fpregs: %p\n", fpregs);
297 	/*
298 	 * If we got a PKRU fault, we *HAVE* to have at least one bit set in
299 	 * here.
300 	 */
301 	dprintf1("pkru_xstate_offset: %d\n", pkru_xstate_offset());
302 	if (DEBUG_LEVEL > 4)
303 		dump_mem(pkru_ptr - 128, 256);
304 	pkey_assert(*pkru_ptr);
305 
306 	if ((si->si_code == SEGV_MAPERR) ||
307 	    (si->si_code == SEGV_ACCERR) ||
308 	    (si->si_code == SEGV_BNDERR)) {
309 		printf("non-PK si_code, exiting...\n");
310 		exit(4);
311 	}
312 
313 	si_pkey_ptr = (u32 *)(((u8 *)si) + si_pkey_offset);
314 	dprintf1("si_pkey_ptr: %p\n", si_pkey_ptr);
315 	dump_mem((u8 *)si_pkey_ptr - 8, 24);
316 	siginfo_pkey = *si_pkey_ptr;
317 	pkey_assert(siginfo_pkey < NR_PKEYS);
318 	last_si_pkey = siginfo_pkey;
319 
320 	dprintf1("signal pkru from xsave: %08x\n", *pkru_ptr);
321 	/* need __rdpkru() version so we do not do shadow_pkru checking */
322 	dprintf1("signal pkru from  pkru: %08x\n", __rdpkru());
323 	dprintf1("pkey from siginfo: %jx\n", siginfo_pkey);
324 	*(u64 *)pkru_ptr = 0x00000000;
325 	dprintf1("WARNING: set PRKU=0 to allow faulting instruction to continue\n");
326 	pkru_faults++;
327 	dprintf1("<<<<==================================================\n");
328 	dprint_in_signal = 0;
329 }
330 
wait_all_children(void)331 int wait_all_children(void)
332 {
333 	int status;
334 	return waitpid(-1, &status, 0);
335 }
336 
sig_chld(int x)337 void sig_chld(int x)
338 {
339 	dprint_in_signal = 1;
340 	dprintf2("[%d] SIGCHLD: %d\n", getpid(), x);
341 	dprint_in_signal = 0;
342 }
343 
setup_sigsegv_handler(void)344 void setup_sigsegv_handler(void)
345 {
346 	int r, rs;
347 	struct sigaction newact;
348 	struct sigaction oldact;
349 
350 	/* #PF is mapped to sigsegv */
351 	int signum  = SIGSEGV;
352 
353 	newact.sa_handler = 0;
354 	newact.sa_sigaction = signal_handler;
355 
356 	/*sigset_t - signals to block while in the handler */
357 	/* get the old signal mask. */
358 	rs = sigprocmask(SIG_SETMASK, 0, &newact.sa_mask);
359 	pkey_assert(rs == 0);
360 
361 	/* call sa_sigaction, not sa_handler*/
362 	newact.sa_flags = SA_SIGINFO;
363 
364 	newact.sa_restorer = 0;  /* void(*)(), obsolete */
365 	r = sigaction(signum, &newact, &oldact);
366 	r = sigaction(SIGALRM, &newact, &oldact);
367 	pkey_assert(r == 0);
368 }
369 
setup_handlers(void)370 void setup_handlers(void)
371 {
372 	signal(SIGCHLD, &sig_chld);
373 	setup_sigsegv_handler();
374 }
375 
fork_lazy_child(void)376 pid_t fork_lazy_child(void)
377 {
378 	pid_t forkret;
379 
380 	forkret = fork();
381 	pkey_assert(forkret >= 0);
382 	dprintf3("[%d] fork() ret: %d\n", getpid(), forkret);
383 
384 	if (!forkret) {
385 		/* in the child */
386 		while (1) {
387 			dprintf1("child sleeping...\n");
388 			sleep(30);
389 		}
390 	}
391 	return forkret;
392 }
393 
394 #ifndef PKEY_DISABLE_ACCESS
395 # define PKEY_DISABLE_ACCESS	0x1
396 #endif
397 
398 #ifndef PKEY_DISABLE_WRITE
399 # define PKEY_DISABLE_WRITE	0x2
400 #endif
401 
hw_pkey_get(int pkey,unsigned long flags)402 static u32 hw_pkey_get(int pkey, unsigned long flags)
403 {
404 	u32 mask = (PKEY_DISABLE_ACCESS|PKEY_DISABLE_WRITE);
405 	u32 pkru = __rdpkru();
406 	u32 shifted_pkru;
407 	u32 masked_pkru;
408 
409 	dprintf1("%s(pkey=%d, flags=%lx) = %x / %d\n",
410 			__func__, pkey, flags, 0, 0);
411 	dprintf2("%s() raw pkru: %x\n", __func__, pkru);
412 
413 	shifted_pkru = (pkru >> (pkey * PKRU_BITS_PER_PKEY));
414 	dprintf2("%s() shifted_pkru: %x\n", __func__, shifted_pkru);
415 	masked_pkru = shifted_pkru & mask;
416 	dprintf2("%s() masked  pkru: %x\n", __func__, masked_pkru);
417 	/*
418 	 * shift down the relevant bits to the lowest two, then
419 	 * mask off all the other high bits.
420 	 */
421 	return masked_pkru;
422 }
423 
hw_pkey_set(int pkey,unsigned long rights,unsigned long flags)424 static int hw_pkey_set(int pkey, unsigned long rights, unsigned long flags)
425 {
426 	u32 mask = (PKEY_DISABLE_ACCESS|PKEY_DISABLE_WRITE);
427 	u32 old_pkru = __rdpkru();
428 	u32 new_pkru;
429 
430 	/* make sure that 'rights' only contains the bits we expect: */
431 	assert(!(rights & ~mask));
432 
433 	/* copy old pkru */
434 	new_pkru = old_pkru;
435 	/* mask out bits from pkey in old value: */
436 	new_pkru &= ~(mask << (pkey * PKRU_BITS_PER_PKEY));
437 	/* OR in new bits for pkey: */
438 	new_pkru |= (rights << (pkey * PKRU_BITS_PER_PKEY));
439 
440 	__wrpkru(new_pkru);
441 
442 	dprintf3("%s(pkey=%d, rights=%lx, flags=%lx) = %x pkru now: %x old_pkru: %x\n",
443 			__func__, pkey, rights, flags, 0, __rdpkru(), old_pkru);
444 	return 0;
445 }
446 
pkey_disable_set(int pkey,int flags)447 void pkey_disable_set(int pkey, int flags)
448 {
449 	unsigned long syscall_flags = 0;
450 	int ret;
451 	int pkey_rights;
452 	u32 orig_pkru = rdpkru();
453 
454 	dprintf1("START->%s(%d, 0x%x)\n", __func__,
455 		pkey, flags);
456 	pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
457 
458 	pkey_rights = hw_pkey_get(pkey, syscall_flags);
459 
460 	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
461 			pkey, pkey, pkey_rights);
462 	pkey_assert(pkey_rights >= 0);
463 
464 	pkey_rights |= flags;
465 
466 	ret = hw_pkey_set(pkey, pkey_rights, syscall_flags);
467 	assert(!ret);
468 	/*pkru and flags have the same format */
469 	shadow_pkru |= flags << (pkey * 2);
470 	dprintf1("%s(%d) shadow: 0x%x\n", __func__, pkey, shadow_pkru);
471 
472 	pkey_assert(ret >= 0);
473 
474 	pkey_rights = hw_pkey_get(pkey, syscall_flags);
475 	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
476 			pkey, pkey, pkey_rights);
477 
478 	dprintf1("%s(%d) pkru: 0x%x\n", __func__, pkey, rdpkru());
479 	if (flags)
480 		pkey_assert(rdpkru() > orig_pkru);
481 	dprintf1("END<---%s(%d, 0x%x)\n", __func__,
482 		pkey, flags);
483 }
484 
pkey_disable_clear(int pkey,int flags)485 void pkey_disable_clear(int pkey, int flags)
486 {
487 	unsigned long syscall_flags = 0;
488 	int ret;
489 	int pkey_rights = hw_pkey_get(pkey, syscall_flags);
490 	u32 orig_pkru = rdpkru();
491 
492 	pkey_assert(flags & (PKEY_DISABLE_ACCESS | PKEY_DISABLE_WRITE));
493 
494 	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
495 			pkey, pkey, pkey_rights);
496 	pkey_assert(pkey_rights >= 0);
497 
498 	pkey_rights |= flags;
499 
500 	ret = hw_pkey_set(pkey, pkey_rights, 0);
501 	/* pkru and flags have the same format */
502 	shadow_pkru &= ~(flags << (pkey * 2));
503 	pkey_assert(ret >= 0);
504 
505 	pkey_rights = hw_pkey_get(pkey, syscall_flags);
506 	dprintf1("%s(%d) hw_pkey_get(%d): %x\n", __func__,
507 			pkey, pkey, pkey_rights);
508 
509 	dprintf1("%s(%d) pkru: 0x%x\n", __func__, pkey, rdpkru());
510 	if (flags)
511 		assert(rdpkru() > orig_pkru);
512 }
513 
pkey_write_allow(int pkey)514 void pkey_write_allow(int pkey)
515 {
516 	pkey_disable_clear(pkey, PKEY_DISABLE_WRITE);
517 }
pkey_write_deny(int pkey)518 void pkey_write_deny(int pkey)
519 {
520 	pkey_disable_set(pkey, PKEY_DISABLE_WRITE);
521 }
pkey_access_allow(int pkey)522 void pkey_access_allow(int pkey)
523 {
524 	pkey_disable_clear(pkey, PKEY_DISABLE_ACCESS);
525 }
pkey_access_deny(int pkey)526 void pkey_access_deny(int pkey)
527 {
528 	pkey_disable_set(pkey, PKEY_DISABLE_ACCESS);
529 }
530 
sys_mprotect_pkey(void * ptr,size_t size,unsigned long orig_prot,unsigned long pkey)531 int sys_mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot,
532 		unsigned long pkey)
533 {
534 	int sret;
535 
536 	dprintf2("%s(0x%p, %zx, prot=%lx, pkey=%lx)\n", __func__,
537 			ptr, size, orig_prot, pkey);
538 
539 	errno = 0;
540 	sret = syscall(SYS_mprotect_key, ptr, size, orig_prot, pkey);
541 	if (errno) {
542 		dprintf2("SYS_mprotect_key sret: %d\n", sret);
543 		dprintf2("SYS_mprotect_key prot: 0x%lx\n", orig_prot);
544 		dprintf2("SYS_mprotect_key failed, errno: %d\n", errno);
545 		if (DEBUG_LEVEL >= 2)
546 			perror("SYS_mprotect_pkey");
547 	}
548 	return sret;
549 }
550 
sys_pkey_alloc(unsigned long flags,unsigned long init_val)551 int sys_pkey_alloc(unsigned long flags, unsigned long init_val)
552 {
553 	int ret = syscall(SYS_pkey_alloc, flags, init_val);
554 	dprintf1("%s(flags=%lx, init_val=%lx) syscall ret: %d errno: %d\n",
555 			__func__, flags, init_val, ret, errno);
556 	return ret;
557 }
558 
alloc_pkey(void)559 int alloc_pkey(void)
560 {
561 	int ret;
562 	unsigned long init_val = 0x0;
563 
564 	dprintf1("alloc_pkey()::%d, pkru: 0x%x shadow: %x\n",
565 			__LINE__, __rdpkru(), shadow_pkru);
566 	ret = sys_pkey_alloc(0, init_val);
567 	/*
568 	 * pkey_alloc() sets PKRU, so we need to reflect it in
569 	 * shadow_pkru:
570 	 */
571 	dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
572 			__LINE__, ret, __rdpkru(), shadow_pkru);
573 	if (ret) {
574 		/* clear both the bits: */
575 		shadow_pkru &= ~(0x3      << (ret * 2));
576 		dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
577 				__LINE__, ret, __rdpkru(), shadow_pkru);
578 		/*
579 		 * move the new state in from init_val
580 		 * (remember, we cheated and init_val == pkru format)
581 		 */
582 		shadow_pkru |=  (init_val << (ret * 2));
583 	}
584 	dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
585 			__LINE__, ret, __rdpkru(), shadow_pkru);
586 	dprintf1("alloc_pkey()::%d errno: %d\n", __LINE__, errno);
587 	/* for shadow checking: */
588 	rdpkru();
589 	dprintf4("alloc_pkey()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n",
590 			__LINE__, ret, __rdpkru(), shadow_pkru);
591 	return ret;
592 }
593 
sys_pkey_free(unsigned long pkey)594 int sys_pkey_free(unsigned long pkey)
595 {
596 	int ret = syscall(SYS_pkey_free, pkey);
597 	dprintf1("%s(pkey=%ld) syscall ret: %d\n", __func__, pkey, ret);
598 	return ret;
599 }
600 
601 /*
602  * I had a bug where pkey bits could be set by mprotect() but
603  * not cleared.  This ensures we get lots of random bit sets
604  * and clears on the vma and pte pkey bits.
605  */
alloc_random_pkey(void)606 int alloc_random_pkey(void)
607 {
608 	int max_nr_pkey_allocs;
609 	int ret;
610 	int i;
611 	int alloced_pkeys[NR_PKEYS];
612 	int nr_alloced = 0;
613 	int random_index;
614 	memset(alloced_pkeys, 0, sizeof(alloced_pkeys));
615 
616 	/* allocate every possible key and make a note of which ones we got */
617 	max_nr_pkey_allocs = NR_PKEYS;
618 	max_nr_pkey_allocs = 1;
619 	for (i = 0; i < max_nr_pkey_allocs; i++) {
620 		int new_pkey = alloc_pkey();
621 		if (new_pkey < 0)
622 			break;
623 		alloced_pkeys[nr_alloced++] = new_pkey;
624 	}
625 
626 	pkey_assert(nr_alloced > 0);
627 	/* select a random one out of the allocated ones */
628 	random_index = rand() % nr_alloced;
629 	ret = alloced_pkeys[random_index];
630 	/* now zero it out so we don't free it next */
631 	alloced_pkeys[random_index] = 0;
632 
633 	/* go through the allocated ones that we did not want and free them */
634 	for (i = 0; i < nr_alloced; i++) {
635 		int free_ret;
636 		if (!alloced_pkeys[i])
637 			continue;
638 		free_ret = sys_pkey_free(alloced_pkeys[i]);
639 		pkey_assert(!free_ret);
640 	}
641 	dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
642 			__LINE__, ret, __rdpkru(), shadow_pkru);
643 	return ret;
644 }
645 
mprotect_pkey(void * ptr,size_t size,unsigned long orig_prot,unsigned long pkey)646 int mprotect_pkey(void *ptr, size_t size, unsigned long orig_prot,
647 		unsigned long pkey)
648 {
649 	int nr_iterations = random() % 100;
650 	int ret;
651 
652 	while (0) {
653 		int rpkey = alloc_random_pkey();
654 		ret = sys_mprotect_pkey(ptr, size, orig_prot, pkey);
655 		dprintf1("sys_mprotect_pkey(%p, %zx, prot=0x%lx, pkey=%ld) ret: %d\n",
656 				ptr, size, orig_prot, pkey, ret);
657 		if (nr_iterations-- < 0)
658 			break;
659 
660 		dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
661 			__LINE__, ret, __rdpkru(), shadow_pkru);
662 		sys_pkey_free(rpkey);
663 		dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
664 			__LINE__, ret, __rdpkru(), shadow_pkru);
665 	}
666 	pkey_assert(pkey < NR_PKEYS);
667 
668 	ret = sys_mprotect_pkey(ptr, size, orig_prot, pkey);
669 	dprintf1("mprotect_pkey(%p, %zx, prot=0x%lx, pkey=%ld) ret: %d\n",
670 			ptr, size, orig_prot, pkey, ret);
671 	pkey_assert(!ret);
672 	dprintf1("%s()::%d, ret: %d pkru: 0x%x shadow: 0x%x\n", __func__,
673 			__LINE__, ret, __rdpkru(), shadow_pkru);
674 	return ret;
675 }
676 
677 struct pkey_malloc_record {
678 	void *ptr;
679 	long size;
680 	int prot;
681 };
682 struct pkey_malloc_record *pkey_malloc_records;
683 struct pkey_malloc_record *pkey_last_malloc_record;
684 long nr_pkey_malloc_records;
record_pkey_malloc(void * ptr,long size,int prot)685 void record_pkey_malloc(void *ptr, long size, int prot)
686 {
687 	long i;
688 	struct pkey_malloc_record *rec = NULL;
689 
690 	for (i = 0; i < nr_pkey_malloc_records; i++) {
691 		rec = &pkey_malloc_records[i];
692 		/* find a free record */
693 		if (rec)
694 			break;
695 	}
696 	if (!rec) {
697 		/* every record is full */
698 		size_t old_nr_records = nr_pkey_malloc_records;
699 		size_t new_nr_records = (nr_pkey_malloc_records * 2 + 1);
700 		size_t new_size = new_nr_records * sizeof(struct pkey_malloc_record);
701 		dprintf2("new_nr_records: %zd\n", new_nr_records);
702 		dprintf2("new_size: %zd\n", new_size);
703 		pkey_malloc_records = realloc(pkey_malloc_records, new_size);
704 		pkey_assert(pkey_malloc_records != NULL);
705 		rec = &pkey_malloc_records[nr_pkey_malloc_records];
706 		/*
707 		 * realloc() does not initialize memory, so zero it from
708 		 * the first new record all the way to the end.
709 		 */
710 		for (i = 0; i < new_nr_records - old_nr_records; i++)
711 			memset(rec + i, 0, sizeof(*rec));
712 	}
713 	dprintf3("filling malloc record[%d/%p]: {%p, %ld}\n",
714 		(int)(rec - pkey_malloc_records), rec, ptr, size);
715 	rec->ptr = ptr;
716 	rec->size = size;
717 	rec->prot = prot;
718 	pkey_last_malloc_record = rec;
719 	nr_pkey_malloc_records++;
720 }
721 
free_pkey_malloc(void * ptr)722 void free_pkey_malloc(void *ptr)
723 {
724 	long i;
725 	int ret;
726 	dprintf3("%s(%p)\n", __func__, ptr);
727 	for (i = 0; i < nr_pkey_malloc_records; i++) {
728 		struct pkey_malloc_record *rec = &pkey_malloc_records[i];
729 		dprintf4("looking for ptr %p at record[%ld/%p]: {%p, %ld}\n",
730 				ptr, i, rec, rec->ptr, rec->size);
731 		if ((ptr <  rec->ptr) ||
732 		    (ptr >= rec->ptr + rec->size))
733 			continue;
734 
735 		dprintf3("found ptr %p at record[%ld/%p]: {%p, %ld}\n",
736 				ptr, i, rec, rec->ptr, rec->size);
737 		nr_pkey_malloc_records--;
738 		ret = munmap(rec->ptr, rec->size);
739 		dprintf3("munmap ret: %d\n", ret);
740 		pkey_assert(!ret);
741 		dprintf3("clearing rec->ptr, rec: %p\n", rec);
742 		rec->ptr = NULL;
743 		dprintf3("done clearing rec->ptr, rec: %p\n", rec);
744 		return;
745 	}
746 	pkey_assert(false);
747 }
748 
749 
malloc_pkey_with_mprotect(long size,int prot,u16 pkey)750 void *malloc_pkey_with_mprotect(long size, int prot, u16 pkey)
751 {
752 	void *ptr;
753 	int ret;
754 
755 	rdpkru();
756 	dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
757 			size, prot, pkey);
758 	pkey_assert(pkey < NR_PKEYS);
759 	ptr = mmap(NULL, size, prot, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
760 	pkey_assert(ptr != (void *)-1);
761 	ret = mprotect_pkey((void *)ptr, PAGE_SIZE, prot, pkey);
762 	pkey_assert(!ret);
763 	record_pkey_malloc(ptr, size, prot);
764 	rdpkru();
765 
766 	dprintf1("%s() for pkey %d @ %p\n", __func__, pkey, ptr);
767 	return ptr;
768 }
769 
malloc_pkey_anon_huge(long size,int prot,u16 pkey)770 void *malloc_pkey_anon_huge(long size, int prot, u16 pkey)
771 {
772 	int ret;
773 	void *ptr;
774 
775 	dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
776 			size, prot, pkey);
777 	/*
778 	 * Guarantee we can fit at least one huge page in the resulting
779 	 * allocation by allocating space for 2:
780 	 */
781 	size = ALIGN_UP(size, HPAGE_SIZE * 2);
782 	ptr = mmap(NULL, size, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
783 	pkey_assert(ptr != (void *)-1);
784 	record_pkey_malloc(ptr, size, prot);
785 	mprotect_pkey(ptr, size, prot, pkey);
786 
787 	dprintf1("unaligned ptr: %p\n", ptr);
788 	ptr = ALIGN_PTR_UP(ptr, HPAGE_SIZE);
789 	dprintf1("  aligned ptr: %p\n", ptr);
790 	ret = madvise(ptr, HPAGE_SIZE, MADV_HUGEPAGE);
791 	dprintf1("MADV_HUGEPAGE ret: %d\n", ret);
792 	ret = madvise(ptr, HPAGE_SIZE, MADV_WILLNEED);
793 	dprintf1("MADV_WILLNEED ret: %d\n", ret);
794 	memset(ptr, 0, HPAGE_SIZE);
795 
796 	dprintf1("mmap()'d thp for pkey %d @ %p\n", pkey, ptr);
797 	return ptr;
798 }
799 
800 int hugetlb_setup_ok;
801 #define GET_NR_HUGE_PAGES 10
setup_hugetlbfs(void)802 void setup_hugetlbfs(void)
803 {
804 	int err;
805 	int fd;
806 	char buf[] = "123";
807 
808 	if (geteuid() != 0) {
809 		fprintf(stderr, "WARNING: not run as root, can not do hugetlb test\n");
810 		return;
811 	}
812 
813 	cat_into_file(__stringify(GET_NR_HUGE_PAGES), "/proc/sys/vm/nr_hugepages");
814 
815 	/*
816 	 * Now go make sure that we got the pages and that they
817 	 * are 2M pages.  Someone might have made 1G the default.
818 	 */
819 	fd = open("/sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages", O_RDONLY);
820 	if (fd < 0) {
821 		perror("opening sysfs 2M hugetlb config");
822 		return;
823 	}
824 
825 	/* -1 to guarantee leaving the trailing \0 */
826 	err = read(fd, buf, sizeof(buf)-1);
827 	close(fd);
828 	if (err <= 0) {
829 		perror("reading sysfs 2M hugetlb config");
830 		return;
831 	}
832 
833 	if (atoi(buf) != GET_NR_HUGE_PAGES) {
834 		fprintf(stderr, "could not confirm 2M pages, got: '%s' expected %d\n",
835 			buf, GET_NR_HUGE_PAGES);
836 		return;
837 	}
838 
839 	hugetlb_setup_ok = 1;
840 }
841 
malloc_pkey_hugetlb(long size,int prot,u16 pkey)842 void *malloc_pkey_hugetlb(long size, int prot, u16 pkey)
843 {
844 	void *ptr;
845 	int flags = MAP_ANONYMOUS|MAP_PRIVATE|MAP_HUGETLB;
846 
847 	if (!hugetlb_setup_ok)
848 		return PTR_ERR_ENOTSUP;
849 
850 	dprintf1("doing %s(%ld, %x, %x)\n", __func__, size, prot, pkey);
851 	size = ALIGN_UP(size, HPAGE_SIZE * 2);
852 	pkey_assert(pkey < NR_PKEYS);
853 	ptr = mmap(NULL, size, PROT_NONE, flags, -1, 0);
854 	pkey_assert(ptr != (void *)-1);
855 	mprotect_pkey(ptr, size, prot, pkey);
856 
857 	record_pkey_malloc(ptr, size, prot);
858 
859 	dprintf1("mmap()'d hugetlbfs for pkey %d @ %p\n", pkey, ptr);
860 	return ptr;
861 }
862 
malloc_pkey_mmap_dax(long size,int prot,u16 pkey)863 void *malloc_pkey_mmap_dax(long size, int prot, u16 pkey)
864 {
865 	void *ptr;
866 	int fd;
867 
868 	dprintf1("doing %s(size=%ld, prot=0x%x, pkey=%d)\n", __func__,
869 			size, prot, pkey);
870 	pkey_assert(pkey < NR_PKEYS);
871 	fd = open("/dax/foo", O_RDWR);
872 	pkey_assert(fd >= 0);
873 
874 	ptr = mmap(0, size, prot, MAP_SHARED, fd, 0);
875 	pkey_assert(ptr != (void *)-1);
876 
877 	mprotect_pkey(ptr, size, prot, pkey);
878 
879 	record_pkey_malloc(ptr, size, prot);
880 
881 	dprintf1("mmap()'d for pkey %d @ %p\n", pkey, ptr);
882 	close(fd);
883 	return ptr;
884 }
885 
886 void *(*pkey_malloc[])(long size, int prot, u16 pkey) = {
887 
888 	malloc_pkey_with_mprotect,
889 	malloc_pkey_anon_huge,
890 	malloc_pkey_hugetlb
891 /* can not do direct with the pkey_mprotect() API:
892 	malloc_pkey_mmap_direct,
893 	malloc_pkey_mmap_dax,
894 */
895 };
896 
malloc_pkey(long size,int prot,u16 pkey)897 void *malloc_pkey(long size, int prot, u16 pkey)
898 {
899 	void *ret;
900 	static int malloc_type;
901 	int nr_malloc_types = ARRAY_SIZE(pkey_malloc);
902 
903 	pkey_assert(pkey < NR_PKEYS);
904 
905 	while (1) {
906 		pkey_assert(malloc_type < nr_malloc_types);
907 
908 		ret = pkey_malloc[malloc_type](size, prot, pkey);
909 		pkey_assert(ret != (void *)-1);
910 
911 		malloc_type++;
912 		if (malloc_type >= nr_malloc_types)
913 			malloc_type = (random()%nr_malloc_types);
914 
915 		/* try again if the malloc_type we tried is unsupported */
916 		if (ret == PTR_ERR_ENOTSUP)
917 			continue;
918 
919 		break;
920 	}
921 
922 	dprintf3("%s(%ld, prot=%x, pkey=%x) returning: %p\n", __func__,
923 			size, prot, pkey, ret);
924 	return ret;
925 }
926 
927 int last_pkru_faults;
928 #define UNKNOWN_PKEY -2
expected_pk_fault(int pkey)929 void expected_pk_fault(int pkey)
930 {
931 	dprintf2("%s(): last_pkru_faults: %d pkru_faults: %d\n",
932 			__func__, last_pkru_faults, pkru_faults);
933 	dprintf2("%s(%d): last_si_pkey: %d\n", __func__, pkey, last_si_pkey);
934 	pkey_assert(last_pkru_faults + 1 == pkru_faults);
935 
936        /*
937 	* For exec-only memory, we do not know the pkey in
938 	* advance, so skip this check.
939 	*/
940 	if (pkey != UNKNOWN_PKEY)
941 		pkey_assert(last_si_pkey == pkey);
942 
943 	/*
944 	 * The signal handler shold have cleared out PKRU to let the
945 	 * test program continue.  We now have to restore it.
946 	 */
947 	if (__rdpkru() != 0)
948 		pkey_assert(0);
949 
950 	__wrpkru(shadow_pkru);
951 	dprintf1("%s() set PKRU=%x to restore state after signal nuked it\n",
952 			__func__, shadow_pkru);
953 	last_pkru_faults = pkru_faults;
954 	last_si_pkey = -1;
955 }
956 
957 #define do_not_expect_pk_fault(msg)	do {			\
958 	if (last_pkru_faults != pkru_faults)			\
959 		dprintf0("unexpected PK fault: %s\n", msg);	\
960 	pkey_assert(last_pkru_faults == pkru_faults);		\
961 } while (0)
962 
963 int test_fds[10] = { -1 };
964 int nr_test_fds;
__save_test_fd(int fd)965 void __save_test_fd(int fd)
966 {
967 	pkey_assert(fd >= 0);
968 	pkey_assert(nr_test_fds < ARRAY_SIZE(test_fds));
969 	test_fds[nr_test_fds] = fd;
970 	nr_test_fds++;
971 }
972 
get_test_read_fd(void)973 int get_test_read_fd(void)
974 {
975 	int test_fd = open("/etc/passwd", O_RDONLY);
976 	__save_test_fd(test_fd);
977 	return test_fd;
978 }
979 
close_test_fds(void)980 void close_test_fds(void)
981 {
982 	int i;
983 
984 	for (i = 0; i < nr_test_fds; i++) {
985 		if (test_fds[i] < 0)
986 			continue;
987 		close(test_fds[i]);
988 		test_fds[i] = -1;
989 	}
990 	nr_test_fds = 0;
991 }
992 
993 #define barrier() __asm__ __volatile__("": : :"memory")
read_ptr(int * ptr)994 __attribute__((noinline)) int read_ptr(int *ptr)
995 {
996 	/*
997 	 * Keep GCC from optimizing this away somehow
998 	 */
999 	barrier();
1000 	return *ptr;
1001 }
1002 
test_read_of_write_disabled_region(int * ptr,u16 pkey)1003 void test_read_of_write_disabled_region(int *ptr, u16 pkey)
1004 {
1005 	int ptr_contents;
1006 
1007 	dprintf1("disabling write access to PKEY[1], doing read\n");
1008 	pkey_write_deny(pkey);
1009 	ptr_contents = read_ptr(ptr);
1010 	dprintf1("*ptr: %d\n", ptr_contents);
1011 	dprintf1("\n");
1012 }
test_read_of_access_disabled_region(int * ptr,u16 pkey)1013 void test_read_of_access_disabled_region(int *ptr, u16 pkey)
1014 {
1015 	int ptr_contents;
1016 
1017 	dprintf1("disabling access to PKEY[%02d], doing read @ %p\n", pkey, ptr);
1018 	rdpkru();
1019 	pkey_access_deny(pkey);
1020 	ptr_contents = read_ptr(ptr);
1021 	dprintf1("*ptr: %d\n", ptr_contents);
1022 	expected_pk_fault(pkey);
1023 }
test_write_of_write_disabled_region(int * ptr,u16 pkey)1024 void test_write_of_write_disabled_region(int *ptr, u16 pkey)
1025 {
1026 	dprintf1("disabling write access to PKEY[%02d], doing write\n", pkey);
1027 	pkey_write_deny(pkey);
1028 	*ptr = __LINE__;
1029 	expected_pk_fault(pkey);
1030 }
test_write_of_access_disabled_region(int * ptr,u16 pkey)1031 void test_write_of_access_disabled_region(int *ptr, u16 pkey)
1032 {
1033 	dprintf1("disabling access to PKEY[%02d], doing write\n", pkey);
1034 	pkey_access_deny(pkey);
1035 	*ptr = __LINE__;
1036 	expected_pk_fault(pkey);
1037 }
test_kernel_write_of_access_disabled_region(int * ptr,u16 pkey)1038 void test_kernel_write_of_access_disabled_region(int *ptr, u16 pkey)
1039 {
1040 	int ret;
1041 	int test_fd = get_test_read_fd();
1042 
1043 	dprintf1("disabling access to PKEY[%02d], "
1044 		 "having kernel read() to buffer\n", pkey);
1045 	pkey_access_deny(pkey);
1046 	ret = read(test_fd, ptr, 1);
1047 	dprintf1("read ret: %d\n", ret);
1048 	pkey_assert(ret);
1049 }
test_kernel_write_of_write_disabled_region(int * ptr,u16 pkey)1050 void test_kernel_write_of_write_disabled_region(int *ptr, u16 pkey)
1051 {
1052 	int ret;
1053 	int test_fd = get_test_read_fd();
1054 
1055 	pkey_write_deny(pkey);
1056 	ret = read(test_fd, ptr, 100);
1057 	dprintf1("read ret: %d\n", ret);
1058 	if (ret < 0 && (DEBUG_LEVEL > 0))
1059 		perror("verbose read result (OK for this to be bad)");
1060 	pkey_assert(ret);
1061 }
1062 
test_kernel_gup_of_access_disabled_region(int * ptr,u16 pkey)1063 void test_kernel_gup_of_access_disabled_region(int *ptr, u16 pkey)
1064 {
1065 	int pipe_ret, vmsplice_ret;
1066 	struct iovec iov;
1067 	int pipe_fds[2];
1068 
1069 	pipe_ret = pipe(pipe_fds);
1070 
1071 	pkey_assert(pipe_ret == 0);
1072 	dprintf1("disabling access to PKEY[%02d], "
1073 		 "having kernel vmsplice from buffer\n", pkey);
1074 	pkey_access_deny(pkey);
1075 	iov.iov_base = ptr;
1076 	iov.iov_len = PAGE_SIZE;
1077 	vmsplice_ret = vmsplice(pipe_fds[1], &iov, 1, SPLICE_F_GIFT);
1078 	dprintf1("vmsplice() ret: %d\n", vmsplice_ret);
1079 	pkey_assert(vmsplice_ret == -1);
1080 
1081 	close(pipe_fds[0]);
1082 	close(pipe_fds[1]);
1083 }
1084 
test_kernel_gup_write_to_write_disabled_region(int * ptr,u16 pkey)1085 void test_kernel_gup_write_to_write_disabled_region(int *ptr, u16 pkey)
1086 {
1087 	int ignored = 0xdada;
1088 	int futex_ret;
1089 	int some_int = __LINE__;
1090 
1091 	dprintf1("disabling write to PKEY[%02d], "
1092 		 "doing futex gunk in buffer\n", pkey);
1093 	*ptr = some_int;
1094 	pkey_write_deny(pkey);
1095 	futex_ret = syscall(SYS_futex, ptr, FUTEX_WAIT, some_int-1, NULL,
1096 			&ignored, ignored);
1097 	if (DEBUG_LEVEL > 0)
1098 		perror("futex");
1099 	dprintf1("futex() ret: %d\n", futex_ret);
1100 }
1101 
1102 /* Assumes that all pkeys other than 'pkey' are unallocated */
test_pkey_syscalls_on_non_allocated_pkey(int * ptr,u16 pkey)1103 void test_pkey_syscalls_on_non_allocated_pkey(int *ptr, u16 pkey)
1104 {
1105 	int err;
1106 	int i;
1107 
1108 	/* Note: 0 is the default pkey, so don't mess with it */
1109 	for (i = 1; i < NR_PKEYS; i++) {
1110 		if (pkey == i)
1111 			continue;
1112 
1113 		dprintf1("trying get/set/free to non-allocated pkey: %2d\n", i);
1114 		err = sys_pkey_free(i);
1115 		pkey_assert(err);
1116 
1117 		err = sys_pkey_free(i);
1118 		pkey_assert(err);
1119 
1120 		err = sys_mprotect_pkey(ptr, PAGE_SIZE, PROT_READ, i);
1121 		pkey_assert(err);
1122 	}
1123 }
1124 
1125 /* Assumes that all pkeys other than 'pkey' are unallocated */
test_pkey_syscalls_bad_args(int * ptr,u16 pkey)1126 void test_pkey_syscalls_bad_args(int *ptr, u16 pkey)
1127 {
1128 	int err;
1129 	int bad_pkey = NR_PKEYS+99;
1130 
1131 	/* pass a known-invalid pkey in: */
1132 	err = sys_mprotect_pkey(ptr, PAGE_SIZE, PROT_READ, bad_pkey);
1133 	pkey_assert(err);
1134 }
1135 
1136 /* Assumes that all pkeys other than 'pkey' are unallocated */
test_pkey_alloc_exhaust(int * ptr,u16 pkey)1137 void test_pkey_alloc_exhaust(int *ptr, u16 pkey)
1138 {
1139 	int err;
1140 	int allocated_pkeys[NR_PKEYS] = {0};
1141 	int nr_allocated_pkeys = 0;
1142 	int i;
1143 
1144 	for (i = 0; i < NR_PKEYS*2; i++) {
1145 		int new_pkey;
1146 		dprintf1("%s() alloc loop: %d\n", __func__, i);
1147 		new_pkey = alloc_pkey();
1148 		dprintf4("%s()::%d, err: %d pkru: 0x%x shadow: 0x%x\n", __func__,
1149 				__LINE__, err, __rdpkru(), shadow_pkru);
1150 		rdpkru(); /* for shadow checking */
1151 		dprintf2("%s() errno: %d ENOSPC: %d\n", __func__, errno, ENOSPC);
1152 		if ((new_pkey == -1) && (errno == ENOSPC)) {
1153 			dprintf2("%s() failed to allocate pkey after %d tries\n",
1154 				__func__, nr_allocated_pkeys);
1155 			break;
1156 		}
1157 		pkey_assert(nr_allocated_pkeys < NR_PKEYS);
1158 		allocated_pkeys[nr_allocated_pkeys++] = new_pkey;
1159 	}
1160 
1161 	dprintf3("%s()::%d\n", __func__, __LINE__);
1162 
1163 	/*
1164 	 * ensure it did not reach the end of the loop without
1165 	 * failure:
1166 	 */
1167 	pkey_assert(i < NR_PKEYS*2);
1168 
1169 	/*
1170 	 * There are 16 pkeys supported in hardware.  Three are
1171 	 * allocated by the time we get here:
1172 	 *   1. The default key (0)
1173 	 *   2. One possibly consumed by an execute-only mapping.
1174 	 *   3. One allocated by the test code and passed in via
1175 	 *      'pkey' to this function.
1176 	 * Ensure that we can allocate at least another 13 (16-3).
1177 	 */
1178 	pkey_assert(i >= NR_PKEYS-3);
1179 
1180 	for (i = 0; i < nr_allocated_pkeys; i++) {
1181 		err = sys_pkey_free(allocated_pkeys[i]);
1182 		pkey_assert(!err);
1183 		rdpkru(); /* for shadow checking */
1184 	}
1185 }
1186 
1187 /*
1188  * pkey 0 is special.  It is allocated by default, so you do not
1189  * have to call pkey_alloc() to use it first.  Make sure that it
1190  * is usable.
1191  */
test_mprotect_with_pkey_0(int * ptr,u16 pkey)1192 void test_mprotect_with_pkey_0(int *ptr, u16 pkey)
1193 {
1194 	long size;
1195 	int prot;
1196 
1197 	assert(pkey_last_malloc_record);
1198 	size = pkey_last_malloc_record->size;
1199 	/*
1200 	 * This is a bit of a hack.  But mprotect() requires
1201 	 * huge-page-aligned sizes when operating on hugetlbfs.
1202 	 * So, make sure that we use something that's a multiple
1203 	 * of a huge page when we can.
1204 	 */
1205 	if (size >= HPAGE_SIZE)
1206 		size = HPAGE_SIZE;
1207 	prot = pkey_last_malloc_record->prot;
1208 
1209 	/* Use pkey 0 */
1210 	mprotect_pkey(ptr, size, prot, 0);
1211 
1212 	/* Make sure that we can set it back to the original pkey. */
1213 	mprotect_pkey(ptr, size, prot, pkey);
1214 }
1215 
test_ptrace_of_child(int * ptr,u16 pkey)1216 void test_ptrace_of_child(int *ptr, u16 pkey)
1217 {
1218 	__attribute__((__unused__)) int peek_result;
1219 	pid_t child_pid;
1220 	void *ignored = 0;
1221 	long ret;
1222 	int status;
1223 	/*
1224 	 * This is the "control" for our little expermient.  Make sure
1225 	 * we can always access it when ptracing.
1226 	 */
1227 	int *plain_ptr_unaligned = malloc(HPAGE_SIZE);
1228 	int *plain_ptr = ALIGN_PTR_UP(plain_ptr_unaligned, PAGE_SIZE);
1229 
1230 	/*
1231 	 * Fork a child which is an exact copy of this process, of course.
1232 	 * That means we can do all of our tests via ptrace() and then plain
1233 	 * memory access and ensure they work differently.
1234 	 */
1235 	child_pid = fork_lazy_child();
1236 	dprintf1("[%d] child pid: %d\n", getpid(), child_pid);
1237 
1238 	ret = ptrace(PTRACE_ATTACH, child_pid, ignored, ignored);
1239 	if (ret)
1240 		perror("attach");
1241 	dprintf1("[%d] attach ret: %ld %d\n", getpid(), ret, __LINE__);
1242 	pkey_assert(ret != -1);
1243 	ret = waitpid(child_pid, &status, WUNTRACED);
1244 	if ((ret != child_pid) || !(WIFSTOPPED(status))) {
1245 		fprintf(stderr, "weird waitpid result %ld stat %x\n",
1246 				ret, status);
1247 		pkey_assert(0);
1248 	}
1249 	dprintf2("waitpid ret: %ld\n", ret);
1250 	dprintf2("waitpid status: %d\n", status);
1251 
1252 	pkey_access_deny(pkey);
1253 	pkey_write_deny(pkey);
1254 
1255 	/* Write access, untested for now:
1256 	ret = ptrace(PTRACE_POKEDATA, child_pid, peek_at, data);
1257 	pkey_assert(ret != -1);
1258 	dprintf1("poke at %p: %ld\n", peek_at, ret);
1259 	*/
1260 
1261 	/*
1262 	 * Try to access the pkey-protected "ptr" via ptrace:
1263 	 */
1264 	ret = ptrace(PTRACE_PEEKDATA, child_pid, ptr, ignored);
1265 	/* expect it to work, without an error: */
1266 	pkey_assert(ret != -1);
1267 	/* Now access from the current task, and expect an exception: */
1268 	peek_result = read_ptr(ptr);
1269 	expected_pk_fault(pkey);
1270 
1271 	/*
1272 	 * Try to access the NON-pkey-protected "plain_ptr" via ptrace:
1273 	 */
1274 	ret = ptrace(PTRACE_PEEKDATA, child_pid, plain_ptr, ignored);
1275 	/* expect it to work, without an error: */
1276 	pkey_assert(ret != -1);
1277 	/* Now access from the current task, and expect NO exception: */
1278 	peek_result = read_ptr(plain_ptr);
1279 	do_not_expect_pk_fault("read plain pointer after ptrace");
1280 
1281 	ret = ptrace(PTRACE_DETACH, child_pid, ignored, 0);
1282 	pkey_assert(ret != -1);
1283 
1284 	ret = kill(child_pid, SIGKILL);
1285 	pkey_assert(ret != -1);
1286 
1287 	wait(&status);
1288 
1289 	free(plain_ptr_unaligned);
1290 }
1291 
get_pointer_to_instructions(void)1292 void *get_pointer_to_instructions(void)
1293 {
1294 	void *p1;
1295 
1296 	p1 = ALIGN_PTR_UP(&lots_o_noops_around_write, PAGE_SIZE);
1297 	dprintf3("&lots_o_noops: %p\n", &lots_o_noops_around_write);
1298 	/* lots_o_noops_around_write should be page-aligned already */
1299 	assert(p1 == &lots_o_noops_around_write);
1300 
1301 	/* Point 'p1' at the *second* page of the function: */
1302 	p1 += PAGE_SIZE;
1303 
1304 	/*
1305 	 * Try to ensure we fault this in on next touch to ensure
1306 	 * we get an instruction fault as opposed to a data one
1307 	 */
1308 	madvise(p1, PAGE_SIZE, MADV_DONTNEED);
1309 
1310 	return p1;
1311 }
1312 
test_executing_on_unreadable_memory(int * ptr,u16 pkey)1313 void test_executing_on_unreadable_memory(int *ptr, u16 pkey)
1314 {
1315 	void *p1;
1316 	int scratch;
1317 	int ptr_contents;
1318 	int ret;
1319 
1320 	p1 = get_pointer_to_instructions();
1321 	lots_o_noops_around_write(&scratch);
1322 	ptr_contents = read_ptr(p1);
1323 	dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
1324 
1325 	ret = mprotect_pkey(p1, PAGE_SIZE, PROT_EXEC, (u64)pkey);
1326 	pkey_assert(!ret);
1327 	pkey_access_deny(pkey);
1328 
1329 	dprintf2("pkru: %x\n", rdpkru());
1330 
1331 	/*
1332 	 * Make sure this is an *instruction* fault
1333 	 */
1334 	madvise(p1, PAGE_SIZE, MADV_DONTNEED);
1335 	lots_o_noops_around_write(&scratch);
1336 	do_not_expect_pk_fault("executing on PROT_EXEC memory");
1337 	ptr_contents = read_ptr(p1);
1338 	dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
1339 	expected_pk_fault(pkey);
1340 }
1341 
test_implicit_mprotect_exec_only_memory(int * ptr,u16 pkey)1342 void test_implicit_mprotect_exec_only_memory(int *ptr, u16 pkey)
1343 {
1344 	void *p1;
1345 	int scratch;
1346 	int ptr_contents;
1347 	int ret;
1348 
1349 	dprintf1("%s() start\n", __func__);
1350 
1351 	p1 = get_pointer_to_instructions();
1352 	lots_o_noops_around_write(&scratch);
1353 	ptr_contents = read_ptr(p1);
1354 	dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
1355 
1356 	/* Use a *normal* mprotect(), not mprotect_pkey(): */
1357 	ret = mprotect(p1, PAGE_SIZE, PROT_EXEC);
1358 	pkey_assert(!ret);
1359 
1360 	dprintf2("pkru: %x\n", rdpkru());
1361 
1362 	/* Make sure this is an *instruction* fault */
1363 	madvise(p1, PAGE_SIZE, MADV_DONTNEED);
1364 	lots_o_noops_around_write(&scratch);
1365 	do_not_expect_pk_fault("executing on PROT_EXEC memory");
1366 	ptr_contents = read_ptr(p1);
1367 	dprintf2("ptr (%p) contents@%d: %x\n", p1, __LINE__, ptr_contents);
1368 	expected_pk_fault(UNKNOWN_PKEY);
1369 
1370 	/*
1371 	 * Put the memory back to non-PROT_EXEC.  Should clear the
1372 	 * exec-only pkey off the VMA and allow it to be readable
1373 	 * again.  Go to PROT_NONE first to check for a kernel bug
1374 	 * that did not clear the pkey when doing PROT_NONE.
1375 	 */
1376 	ret = mprotect(p1, PAGE_SIZE, PROT_NONE);
1377 	pkey_assert(!ret);
1378 
1379 	ret = mprotect(p1, PAGE_SIZE, PROT_READ|PROT_EXEC);
1380 	pkey_assert(!ret);
1381 	ptr_contents = read_ptr(p1);
1382 	do_not_expect_pk_fault("plain read on recently PROT_EXEC area");
1383 }
1384 
test_mprotect_pkey_on_unsupported_cpu(int * ptr,u16 pkey)1385 void test_mprotect_pkey_on_unsupported_cpu(int *ptr, u16 pkey)
1386 {
1387 	int size = PAGE_SIZE;
1388 	int sret;
1389 
1390 	if (cpu_has_pku()) {
1391 		dprintf1("SKIP: %s: no CPU support\n", __func__);
1392 		return;
1393 	}
1394 
1395 	sret = syscall(SYS_mprotect_key, ptr, size, PROT_READ, pkey);
1396 	pkey_assert(sret < 0);
1397 }
1398 
1399 void (*pkey_tests[])(int *ptr, u16 pkey) = {
1400 	test_read_of_write_disabled_region,
1401 	test_read_of_access_disabled_region,
1402 	test_write_of_write_disabled_region,
1403 	test_write_of_access_disabled_region,
1404 	test_kernel_write_of_access_disabled_region,
1405 	test_kernel_write_of_write_disabled_region,
1406 	test_kernel_gup_of_access_disabled_region,
1407 	test_kernel_gup_write_to_write_disabled_region,
1408 	test_executing_on_unreadable_memory,
1409 	test_implicit_mprotect_exec_only_memory,
1410 	test_mprotect_with_pkey_0,
1411 	test_ptrace_of_child,
1412 	test_pkey_syscalls_on_non_allocated_pkey,
1413 	test_pkey_syscalls_bad_args,
1414 	test_pkey_alloc_exhaust,
1415 };
1416 
run_tests_once(void)1417 void run_tests_once(void)
1418 {
1419 	int *ptr;
1420 	int prot = PROT_READ|PROT_WRITE;
1421 
1422 	for (test_nr = 0; test_nr < ARRAY_SIZE(pkey_tests); test_nr++) {
1423 		int pkey;
1424 		int orig_pkru_faults = pkru_faults;
1425 
1426 		dprintf1("======================\n");
1427 		dprintf1("test %d preparing...\n", test_nr);
1428 
1429 		tracing_on();
1430 		pkey = alloc_random_pkey();
1431 		dprintf1("test %d starting with pkey: %d\n", test_nr, pkey);
1432 		ptr = malloc_pkey(PAGE_SIZE, prot, pkey);
1433 		dprintf1("test %d starting...\n", test_nr);
1434 		pkey_tests[test_nr](ptr, pkey);
1435 		dprintf1("freeing test memory: %p\n", ptr);
1436 		free_pkey_malloc(ptr);
1437 		sys_pkey_free(pkey);
1438 
1439 		dprintf1("pkru_faults: %d\n", pkru_faults);
1440 		dprintf1("orig_pkru_faults: %d\n", orig_pkru_faults);
1441 
1442 		tracing_off();
1443 		close_test_fds();
1444 
1445 		printf("test %2d PASSED (iteration %d)\n", test_nr, iteration_nr);
1446 		dprintf1("======================\n\n");
1447 	}
1448 	iteration_nr++;
1449 }
1450 
pkey_setup_shadow(void)1451 void pkey_setup_shadow(void)
1452 {
1453 	shadow_pkru = __rdpkru();
1454 }
1455 
main(void)1456 int main(void)
1457 {
1458 	int nr_iterations = 22;
1459 
1460 	setup_handlers();
1461 
1462 	printf("has pku: %d\n", cpu_has_pku());
1463 
1464 	if (!cpu_has_pku()) {
1465 		int size = PAGE_SIZE;
1466 		int *ptr;
1467 
1468 		printf("running PKEY tests for unsupported CPU/OS\n");
1469 
1470 		ptr  = mmap(NULL, size, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
1471 		assert(ptr != (void *)-1);
1472 		test_mprotect_pkey_on_unsupported_cpu(ptr, 1);
1473 		exit(0);
1474 	}
1475 
1476 	pkey_setup_shadow();
1477 	printf("startup pkru: %x\n", rdpkru());
1478 	setup_hugetlbfs();
1479 
1480 	while (nr_iterations-- > 0)
1481 		run_tests_once();
1482 
1483 	printf("done (all tests OK)\n");
1484 	return 0;
1485 }
1486