bpf_insn_array.c

  1// SPDX-License-Identifier: GPL-2.0
  2
  3#include <bpf/bpf.h>
  4#include <test_progs.h>
  5
  6#ifdef __x86_64__
  7static int map_create(__u32 map_type, __u32 max_entries)
  8{
  9	const char *map_name = "insn_array";
 10	__u32 key_size = 4;
 11	__u32 value_size = sizeof(struct bpf_insn_array_value);
 12
 13	return bpf_map_create(map_type, map_name, key_size, value_size, max_entries, NULL);
 14}
 15
 16static int prog_load(struct bpf_insn *insns, __u32 insn_cnt, int *fd_array, __u32 fd_array_cnt)
 17{
 18	LIBBPF_OPTS(bpf_prog_load_opts, opts);
 19
 20	opts.fd_array = fd_array;
 21	opts.fd_array_cnt = fd_array_cnt;
 22
 23	return bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "GPL", insns, insn_cnt, &opts);
 24}
 25
 26static void __check_success(struct bpf_insn *insns, __u32 insn_cnt, __u32 *map_in, __u32 *map_out)
 27{
 28	struct bpf_insn_array_value val = {};
 29	int prog_fd = -1, map_fd, i;
 30
 31	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, insn_cnt);
 32	if (!ASSERT_GE(map_fd, 0, "map_create"))
 33		return;
 34
 35	for (i = 0; i < insn_cnt; i++) {
 36		val.orig_off = map_in[i];
 37		if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem"))
 38			goto cleanup;
 39	}
 40
 41	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))
 42		goto cleanup;
 43
 44	prog_fd = prog_load(insns, insn_cnt, &map_fd, 1);
 45	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))
 46		goto cleanup;
 47
 48	for (i = 0; i < insn_cnt; i++) {
 49		char buf[64];
 50
 51		if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem"))
 52			goto cleanup;
 53
 54		snprintf(buf, sizeof(buf), "val.xlated_off should be equal map_out[%d]", i);
 55		ASSERT_EQ(val.xlated_off, map_out[i], buf);
 56	}
 57
 58cleanup:
 59	close(prog_fd);
 60	close(map_fd);
 61}
 62
 63/*
 64 * Load a program, which will not be anyhow mangled by the verifier.  Add an
 65 * insn_array map pointing to every instruction. Check that it hasn't changed
 66 * after the program load.
 67 */
 68static void check_one_to_one_mapping(void)
 69{
 70	struct bpf_insn insns[] = {
 71		BPF_MOV64_IMM(BPF_REG_0, 4),
 72		BPF_MOV64_IMM(BPF_REG_0, 3),
 73		BPF_MOV64_IMM(BPF_REG_0, 2),
 74		BPF_MOV64_IMM(BPF_REG_0, 1),
 75		BPF_MOV64_IMM(BPF_REG_0, 0),
 76		BPF_EXIT_INSN(),
 77	};
 78	__u32 map_in[] = {0, 1, 2, 3, 4, 5};
 79	__u32 map_out[] = {0, 1, 2, 3, 4, 5};
 80
 81	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);
 82}
 83
 84/*
 85 * Load a program with two patches (get jiffies, for simplicity). Add an
 86 * insn_array map pointing to every instruction. Check how it was changed
 87 * after the program load.
 88 */
 89static void check_simple(void)
 90{
 91	struct bpf_insn insns[] = {
 92		BPF_MOV64_IMM(BPF_REG_0, 2),
 93		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),
 94		BPF_MOV64_IMM(BPF_REG_0, 1),
 95		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),
 96		BPF_MOV64_IMM(BPF_REG_0, 0),
 97		BPF_EXIT_INSN(),
 98	};
 99	__u32 map_in[] = {0, 1, 2, 3, 4, 5};
100	__u32 map_out[] = {0, 1, 4, 5, 8, 9};
101
102	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);
103}
104
105/*
106 * Verifier can delete code in two cases: nops & dead code. From insn
107 * array's point of view, the two cases are the same, so test using
108 * the simplest method: by loading some nops
109 */
110static void check_deletions(void)
111{
112	struct bpf_insn insns[] = {
113		BPF_MOV64_IMM(BPF_REG_0, 2),
114		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */
115		BPF_MOV64_IMM(BPF_REG_0, 1),
116		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */
117		BPF_MOV64_IMM(BPF_REG_0, 0),
118		BPF_EXIT_INSN(),
119	};
120	__u32 map_in[] = {0, 1, 2, 3, 4, 5};
121	__u32 map_out[] = {0, -1, 1, -1, 2, 3};
122
123	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);
124}
125
126/*
127 * Same test as check_deletions, but also add code which adds instructions
128 */
129static void check_deletions_with_functions(void)
130{
131	struct bpf_insn insns[] = {
132		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */
133		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),
134		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */
135		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
136		BPF_MOV64_IMM(BPF_REG_0, 1),
137		BPF_EXIT_INSN(),
138		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */
139		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_jiffies64),
140		BPF_JMP_IMM(BPF_JA, 0, 0, 0), /* nop */
141		BPF_MOV64_IMM(BPF_REG_0, 2),
142		BPF_EXIT_INSN(),
143	};
144	__u32 map_in[] =  { 0, 1,  2, 3, 4, 5, /* func */  6, 7,  8, 9, 10};
145	__u32 map_out[] = {-1, 0, -1, 3, 4, 5, /* func */ -1, 6, -1, 9, 10};
146
147	__check_success(insns, ARRAY_SIZE(insns), map_in, map_out);
148}
149
150/*
151 * Try to load a program with a map which points to outside of the program
152 */
153static void check_out_of_bounds_index(void)
154{
155	struct bpf_insn insns[] = {
156		BPF_MOV64_IMM(BPF_REG_0, 4),
157		BPF_MOV64_IMM(BPF_REG_0, 3),
158		BPF_MOV64_IMM(BPF_REG_0, 2),
159		BPF_MOV64_IMM(BPF_REG_0, 1),
160		BPF_MOV64_IMM(BPF_REG_0, 0),
161		BPF_EXIT_INSN(),
162	};
163	int prog_fd, map_fd;
164	struct bpf_insn_array_value val = {};
165	int key;
166
167	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1);
168	if (!ASSERT_GE(map_fd, 0, "map_create"))
169		return;
170
171	key = 0;
172	val.orig_off = ARRAY_SIZE(insns); /* too big */
173	if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &key, &val, 0), 0, "bpf_map_update_elem"))
174		goto cleanup;
175
176	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))
177		goto cleanup;
178
179	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);
180	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) {
181		close(prog_fd);
182		goto cleanup;
183	}
184
185cleanup:
186	close(map_fd);
187}
188
189/*
190 * Try to load a program with a map which points to the middle of 16-bit insn
191 */
192static void check_mid_insn_index(void)
193{
194	struct bpf_insn insns[] = {
195		BPF_LD_IMM64(BPF_REG_0, 0), /* 2 x 8 */
196		BPF_EXIT_INSN(),
197	};
198	int prog_fd, map_fd;
199	struct bpf_insn_array_value val = {};
200	int key;
201
202	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1);
203	if (!ASSERT_GE(map_fd, 0, "map_create"))
204		return;
205
206	key = 0;
207	val.orig_off = 1; /* middle of 16-byte instruction */
208	if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &key, &val, 0), 0, "bpf_map_update_elem"))
209		goto cleanup;
210
211	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))
212		goto cleanup;
213
214	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);
215	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)")) {
216		close(prog_fd);
217		goto cleanup;
218	}
219
220cleanup:
221	close(map_fd);
222}
223
224static void check_incorrect_index(void)
225{
226	check_out_of_bounds_index();
227	check_mid_insn_index();
228}
229
230static int set_bpf_jit_harden(char *level)
231{
232	char old_level;
233	int err = -1;
234	int fd = -1;
235
236	fd = open("/proc/sys/net/core/bpf_jit_harden", O_RDWR | O_NONBLOCK);
237	if (fd < 0) {
238		ASSERT_FAIL("open .../bpf_jit_harden returned %d (errno=%d)", fd, errno);
239		return -1;
240	}
241
242	err = read(fd, &old_level, 1);
243	if (err != 1) {
244		ASSERT_FAIL("read from .../bpf_jit_harden returned %d (errno=%d)", err, errno);
245		err = -1;
246		goto end;
247	}
248
249	lseek(fd, 0, SEEK_SET);
250
251	err = write(fd, level, 1);
252	if (err != 1) {
253		ASSERT_FAIL("write to .../bpf_jit_harden returned %d (errno=%d)", err, errno);
254		err = -1;
255		goto end;
256	}
257
258	err = 0;
259	*level = old_level;
260end:
261	if (fd >= 0)
262		close(fd);
263	return err;
264}
265
266static void check_blindness(void)
267{
268	struct bpf_insn insns[] = {
269		BPF_MOV64_IMM(BPF_REG_0, 4),
270		BPF_MOV64_IMM(BPF_REG_0, 3),
271		BPF_MOV64_IMM(BPF_REG_0, 2),
272		BPF_MOV64_IMM(BPF_REG_0, 1),
273		BPF_EXIT_INSN(),
274	};
275	int prog_fd = -1, map_fd;
276	struct bpf_insn_array_value val = {};
277	char bpf_jit_harden = '@'; /* non-exizsting value */
278	int i;
279
280	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns));
281	if (!ASSERT_GE(map_fd, 0, "map_create"))
282		return;
283
284	for (i = 0; i < ARRAY_SIZE(insns); i++) {
285		val.orig_off = i;
286		if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem"))
287			goto cleanup;
288	}
289
290	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))
291		goto cleanup;
292
293	bpf_jit_harden = '2';
294	if (set_bpf_jit_harden(&bpf_jit_harden)) {
295		bpf_jit_harden = '@'; /* open, read or write failed => no write was done */
296		goto cleanup;
297	}
298
299	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);
300	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))
301		goto cleanup;
302
303	for (i = 0; i < ARRAY_SIZE(insns); i++) {
304		char fmt[32];
305
306		if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem"))
307			goto cleanup;
308
309		snprintf(fmt, sizeof(fmt), "val should be equal 3*%d", i);
310		ASSERT_EQ(val.xlated_off, i * 3, fmt);
311	}
312
313cleanup:
314	/* restore the old one */
315	if (bpf_jit_harden != '@')
316		set_bpf_jit_harden(&bpf_jit_harden);
317
318	close(prog_fd);
319	close(map_fd);
320}
321
322/* Once map was initialized, it should be frozen */
323static void check_load_unfrozen_map(void)
324{
325	struct bpf_insn insns[] = {
326		BPF_MOV64_IMM(BPF_REG_0, 0),
327		BPF_EXIT_INSN(),
328	};
329	int prog_fd = -1, map_fd;
330	struct bpf_insn_array_value val = {};
331	int i;
332
333	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns));
334	if (!ASSERT_GE(map_fd, 0, "map_create"))
335		return;
336
337	for (i = 0; i < ARRAY_SIZE(insns); i++) {
338		val.orig_off = i;
339		if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem"))
340			goto cleanup;
341	}
342
343	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);
344	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)"))
345		goto cleanup;
346
347	/* correctness: now freeze the map, the program should load fine */
348
349	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))
350		goto cleanup;
351
352	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);
353	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))
354		goto cleanup;
355
356	for (i = 0; i < ARRAY_SIZE(insns); i++) {
357		if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem"))
358			goto cleanup;
359
360		ASSERT_EQ(val.xlated_off, i, "val should be equal i");
361	}
362
363cleanup:
364	close(prog_fd);
365	close(map_fd);
366}
367
368/* Map can be used only by one BPF program */
369static void check_no_map_reuse(void)
370{
371	struct bpf_insn insns[] = {
372		BPF_MOV64_IMM(BPF_REG_0, 0),
373		BPF_EXIT_INSN(),
374	};
375	int prog_fd = -1, map_fd, extra_fd = -1;
376	struct bpf_insn_array_value val = {};
377	int i;
378
379	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, ARRAY_SIZE(insns));
380	if (!ASSERT_GE(map_fd, 0, "map_create"))
381		return;
382
383	for (i = 0; i < ARRAY_SIZE(insns); i++) {
384		val.orig_off = i;
385		if (!ASSERT_EQ(bpf_map_update_elem(map_fd, &i, &val, 0), 0, "bpf_map_update_elem"))
386			goto cleanup;
387	}
388
389	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))
390		goto cleanup;
391
392	prog_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);
393	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))
394		goto cleanup;
395
396	for (i = 0; i < ARRAY_SIZE(insns); i++) {
397		if (!ASSERT_EQ(bpf_map_lookup_elem(map_fd, &i, &val), 0, "bpf_map_lookup_elem"))
398			goto cleanup;
399
400		ASSERT_EQ(val.xlated_off, i, "val should be equal i");
401	}
402
403	extra_fd = prog_load(insns, ARRAY_SIZE(insns), &map_fd, 1);
404	if (!ASSERT_EQ(extra_fd, -EBUSY, "program should have been rejected (extra_fd != -EBUSY)"))
405		goto cleanup;
406
407	/* correctness: check that prog is still loadable without fd_array */
408	extra_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0);
409	if (!ASSERT_GE(extra_fd, 0, "bpf(BPF_PROG_LOAD): expected no error"))
410		goto cleanup;
411
412cleanup:
413	close(extra_fd);
414	close(prog_fd);
415	close(map_fd);
416}
417
418static void check_bpf_no_lookup(void)
419{
420	struct bpf_insn insns[] = {
421		BPF_LD_MAP_FD(BPF_REG_1, 0),
422		BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
423		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
424		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
425		BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
426		BPF_EXIT_INSN(),
427	};
428	int prog_fd = -1, map_fd;
429
430	map_fd = map_create(BPF_MAP_TYPE_INSN_ARRAY, 1);
431	if (!ASSERT_GE(map_fd, 0, "map_create"))
432		return;
433
434	insns[0].imm = map_fd;
435
436	if (!ASSERT_EQ(bpf_map_freeze(map_fd), 0, "bpf_map_freeze"))
437		goto cleanup;
438
439	prog_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0);
440	if (!ASSERT_EQ(prog_fd, -EINVAL, "program should have been rejected (prog_fd != -EINVAL)"))
441		goto cleanup;
442
443	/* correctness: check that prog is still loadable with normal map */
444	close(map_fd);
445	map_fd = map_create(BPF_MAP_TYPE_ARRAY, 1);
446	insns[0].imm = map_fd;
447	prog_fd = prog_load(insns, ARRAY_SIZE(insns), NULL, 0);
448	if (!ASSERT_GE(prog_fd, 0, "bpf(BPF_PROG_LOAD)"))
449		goto cleanup;
450
451cleanup:
452	close(prog_fd);
453	close(map_fd);
454}
455
456static void check_bpf_side(void)
457{
458	check_bpf_no_lookup();
459}
460
461static void __test_bpf_insn_array(void)
462{
463	/* Test if offsets are adjusted properly */
464
465	if (test__start_subtest("one2one"))
466		check_one_to_one_mapping();
467
468	if (test__start_subtest("simple"))
469		check_simple();
470
471	if (test__start_subtest("deletions"))
472		check_deletions();
473
474	if (test__start_subtest("deletions-with-functions"))
475		check_deletions_with_functions();
476
477	if (test__start_subtest("blindness"))
478		check_blindness();
479
480	/* Check all kinds of operations and related restrictions */
481
482	if (test__start_subtest("incorrect-index"))
483		check_incorrect_index();
484
485	if (test__start_subtest("load-unfrozen-map"))
486		check_load_unfrozen_map();
487
488	if (test__start_subtest("no-map-reuse"))
489		check_no_map_reuse();
490
491	if (test__start_subtest("bpf-side-ops"))
492		check_bpf_side();
493}
494#else
495static void __test_bpf_insn_array(void)
496{
497	test__skip();
498}
499#endif
500
501void test_bpf_insn_array(void)
502{
503	__test_bpf_insn_array();
504}