Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0
2#include "bpf_misc.h"
3#include "bpf_experimental.h"
4
5struct {
6 __uint(type, BPF_MAP_TYPE_ARRAY);
7 __uint(max_entries, 8);
8 __type(key, __u32);
9 __type(value, __u64);
10} map SEC(".maps");
11
12struct {
13 __uint(type, BPF_MAP_TYPE_USER_RINGBUF);
14 __uint(max_entries, 8);
15} ringbuf SEC(".maps");
16
17struct vm_area_struct;
18struct bpf_map;
19
20struct buf_context {
21 char *buf;
22};
23
24struct num_context {
25 __u64 i;
26 __u64 j;
27};
28
29__u8 choice_arr[2] = { 0, 1 };
30
31static int unsafe_on_2nd_iter_cb(__u32 idx, struct buf_context *ctx)
32{
33 if (idx == 0) {
34 ctx->buf = (char *)(0xDEAD);
35 return 0;
36 }
37
38 if (bpf_probe_read_user(ctx->buf, 8, (void *)(0xBADC0FFEE)))
39 return 1;
40
41 return 0;
42}
43
44SEC("?raw_tp")
45__failure __msg("R1 type=scalar expected=fp")
46int unsafe_on_2nd_iter(void *unused)
47{
48 char buf[4];
49 struct buf_context loop_ctx = { .buf = buf };
50
51 bpf_loop(100, unsafe_on_2nd_iter_cb, &loop_ctx, 0);
52 return 0;
53}
54
55static int unsafe_on_zero_iter_cb(__u32 idx, struct num_context *ctx)
56{
57 ctx->i = 0;
58 return 0;
59}
60
61SEC("?raw_tp")
62__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
63int unsafe_on_zero_iter(void *unused)
64{
65 struct num_context loop_ctx = { .i = 32 };
66
67 bpf_loop(100, unsafe_on_zero_iter_cb, &loop_ctx, 0);
68 return choice_arr[loop_ctx.i];
69}
70
71static int widening_cb(__u32 idx, struct num_context *ctx)
72{
73 ++ctx->i;
74 return 0;
75}
76
77SEC("?raw_tp")
78__success
79int widening(void *unused)
80{
81 struct num_context loop_ctx = { .i = 0, .j = 1 };
82
83 bpf_loop(100, widening_cb, &loop_ctx, 0);
84 /* loop_ctx.j is not changed during callback iteration,
85 * verifier should not apply widening to it.
86 */
87 return choice_arr[loop_ctx.j];
88}
89
90static int loop_detection_cb(__u32 idx, struct num_context *ctx)
91{
92 for (;;) {}
93 return 0;
94}
95
96SEC("?raw_tp")
97__failure __msg("infinite loop detected")
98int loop_detection(void *unused)
99{
100 struct num_context loop_ctx = { .i = 0 };
101
102 bpf_loop(100, loop_detection_cb, &loop_ctx, 0);
103 return 0;
104}
105
106static __always_inline __u64 oob_state_machine(struct num_context *ctx)
107{
108 switch (ctx->i) {
109 case 0:
110 ctx->i = 1;
111 break;
112 case 1:
113 ctx->i = 32;
114 break;
115 }
116 return 0;
117}
118
119static __u64 for_each_map_elem_cb(struct bpf_map *map, __u32 *key, __u64 *val, void *data)
120{
121 return oob_state_machine(data);
122}
123
124SEC("?raw_tp")
125__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
126int unsafe_for_each_map_elem(void *unused)
127{
128 struct num_context loop_ctx = { .i = 0 };
129
130 bpf_for_each_map_elem(&map, for_each_map_elem_cb, &loop_ctx, 0);
131 return choice_arr[loop_ctx.i];
132}
133
134static __u64 ringbuf_drain_cb(struct bpf_dynptr *dynptr, void *data)
135{
136 return oob_state_machine(data);
137}
138
139SEC("?raw_tp")
140__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
141int unsafe_ringbuf_drain(void *unused)
142{
143 struct num_context loop_ctx = { .i = 0 };
144
145 bpf_user_ringbuf_drain(&ringbuf, ringbuf_drain_cb, &loop_ctx, 0);
146 return choice_arr[loop_ctx.i];
147}
148
149static __u64 find_vma_cb(struct task_struct *task, struct vm_area_struct *vma, void *data)
150{
151 return oob_state_machine(data);
152}
153
154SEC("?raw_tp")
155__failure __msg("invalid access to map value, value_size=2 off=32 size=1")
156int unsafe_find_vma(void *unused)
157{
158 struct task_struct *task = bpf_get_current_task_btf();
159 struct num_context loop_ctx = { .i = 0 };
160
161 bpf_find_vma(task, 0, find_vma_cb, &loop_ctx, 0);
162 return choice_arr[loop_ctx.i];
163}
164
165static int iter_limit_cb(__u32 idx, struct num_context *ctx)
166{
167 ctx->i++;
168 return 0;
169}
170
171SEC("?raw_tp")
172__success
173int bpf_loop_iter_limit_ok(void *unused)
174{
175 struct num_context ctx = { .i = 0 };
176
177 bpf_loop(1, iter_limit_cb, &ctx, 0);
178 return choice_arr[ctx.i];
179}
180
181SEC("?raw_tp")
182__failure __msg("invalid access to map value, value_size=2 off=2 size=1")
183int bpf_loop_iter_limit_overflow(void *unused)
184{
185 struct num_context ctx = { .i = 0 };
186
187 bpf_loop(2, iter_limit_cb, &ctx, 0);
188 return choice_arr[ctx.i];
189}
190
191static int iter_limit_level2a_cb(__u32 idx, struct num_context *ctx)
192{
193 ctx->i += 100;
194 return 0;
195}
196
197static int iter_limit_level2b_cb(__u32 idx, struct num_context *ctx)
198{
199 ctx->i += 10;
200 return 0;
201}
202
203static int iter_limit_level1_cb(__u32 idx, struct num_context *ctx)
204{
205 ctx->i += 1;
206 bpf_loop(1, iter_limit_level2a_cb, ctx, 0);
207 bpf_loop(1, iter_limit_level2b_cb, ctx, 0);
208 return 0;
209}
210
211/* Check that path visiting every callback function once had been
212 * reached by verifier. Variables 'ctx{1,2}i' below serve as flags,
213 * with each decimal digit corresponding to a callback visit marker.
214 */
215SEC("socket")
216__success __retval(111111)
217int bpf_loop_iter_limit_nested(void *unused)
218{
219 struct num_context ctx1 = { .i = 0 };
220 struct num_context ctx2 = { .i = 0 };
221 __u64 a, b, c;
222
223 bpf_loop(1, iter_limit_level1_cb, &ctx1, 0);
224 bpf_loop(1, iter_limit_level1_cb, &ctx2, 0);
225 a = ctx1.i;
226 b = ctx2.i;
227 /* Force 'ctx1.i' and 'ctx2.i' precise. */
228 c = choice_arr[(a + b) % 2];
229 /* This makes 'c' zero, but neither clang nor verifier know it. */
230 c /= 10;
231 /* Make sure that verifier does not visit 'impossible' states:
232 * enumerate all possible callback visit masks.
233 */
234 if (a != 0 && a != 1 && a != 11 && a != 101 && a != 111 &&
235 b != 0 && b != 1 && b != 11 && b != 101 && b != 111)
236 asm volatile ("r0 /= 0;" ::: "r0");
237 return 1000 * a + b + c;
238}
239
240struct iter_limit_bug_ctx {
241 __u64 a;
242 __u64 b;
243 __u64 c;
244};
245
246static __naked void iter_limit_bug_cb(void)
247{
248 /* This is the same as C code below, but written
249 * in assembly to control which branches are fall-through.
250 *
251 * switch (bpf_get_prandom_u32()) {
252 * case 1: ctx->a = 42; break;
253 * case 2: ctx->b = 42; break;
254 * default: ctx->c = 42; break;
255 * }
256 */
257 asm volatile (
258 "r9 = r2;"
259 "call %[bpf_get_prandom_u32];"
260 "r1 = r0;"
261 "r2 = 42;"
262 "r0 = 0;"
263 "if r1 == 0x1 goto 1f;"
264 "if r1 == 0x2 goto 2f;"
265 "*(u64 *)(r9 + 16) = r2;"
266 "exit;"
267 "1: *(u64 *)(r9 + 0) = r2;"
268 "exit;"
269 "2: *(u64 *)(r9 + 8) = r2;"
270 "exit;"
271 :
272 : __imm(bpf_get_prandom_u32)
273 : __clobber_all
274 );
275}
276
277int tmp_var;
278SEC("socket")
279__failure __msg("infinite loop detected at insn 2")
280__naked void jgt_imm64_and_may_goto(void)
281{
282 asm volatile (" \
283 r0 = %[tmp_var] ll; \
284l0_%=: .byte 0xe5; /* may_goto */ \
285 .byte 0; /* regs */ \
286 .short -3; /* off -3 */ \
287 .long 0; /* imm */ \
288 if r0 > 10 goto l0_%=; \
289 r0 = 0; \
290 exit; \
291" :: __imm_addr(tmp_var)
292 : __clobber_all);
293}
294
295SEC("socket")
296__failure __msg("infinite loop detected at insn 1")
297__naked void may_goto_self(void)
298{
299 asm volatile (" \
300 r0 = *(u32 *)(r10 - 4); \
301l0_%=: .byte 0xe5; /* may_goto */ \
302 .byte 0; /* regs */ \
303 .short -1; /* off -1 */ \
304 .long 0; /* imm */ \
305 if r0 > 10 goto l0_%=; \
306 r0 = 0; \
307 exit; \
308" ::: __clobber_all);
309}
310
311SEC("socket")
312__success __retval(0)
313__naked void may_goto_neg_off(void)
314{
315 asm volatile (" \
316 r0 = *(u32 *)(r10 - 4); \
317 goto l0_%=; \
318 goto l1_%=; \
319l0_%=: .byte 0xe5; /* may_goto */ \
320 .byte 0; /* regs */ \
321 .short -2; /* off -2 */ \
322 .long 0; /* imm */ \
323 if r0 > 10 goto l0_%=; \
324l1_%=: r0 = 0; \
325 exit; \
326" ::: __clobber_all);
327}
328
329SEC("tc")
330__failure
331__flag(BPF_F_TEST_STATE_FREQ)
332int iter_limit_bug(struct __sk_buff *skb)
333{
334 struct iter_limit_bug_ctx ctx = { 7, 7, 7 };
335
336 bpf_loop(2, iter_limit_bug_cb, &ctx, 0);
337
338 /* This is the same as C code below,
339 * written in assembly to guarantee checks order.
340 *
341 * if (ctx.a == 42 && ctx.b == 42 && ctx.c == 7)
342 * asm volatile("r1 /= 0;":::"r1");
343 */
344 asm volatile (
345 "r1 = *(u64 *)%[ctx_a];"
346 "if r1 != 42 goto 1f;"
347 "r1 = *(u64 *)%[ctx_b];"
348 "if r1 != 42 goto 1f;"
349 "r1 = *(u64 *)%[ctx_c];"
350 "if r1 != 7 goto 1f;"
351 "r1 /= 0;"
352 "1:"
353 :
354 : [ctx_a]"m"(ctx.a),
355 [ctx_b]"m"(ctx.b),
356 [ctx_c]"m"(ctx.c)
357 : "r1"
358 );
359 return 0;
360}
361
362SEC("socket")
363__success __retval(0)
364__naked void ja_and_may_goto(void)
365{
366 asm volatile (" \
367l0_%=: .byte 0xe5; /* may_goto */ \
368 .byte 0; /* regs */ \
369 .short 1; /* off 1 */ \
370 .long 0; /* imm */ \
371 goto l0_%=; \
372 r0 = 0; \
373 exit; \
374" ::: __clobber_common);
375}
376
377SEC("socket")
378__success __retval(0)
379__naked void ja_and_may_goto2(void)
380{
381 asm volatile (" \
382l0_%=: r0 = 0; \
383 .byte 0xe5; /* may_goto */ \
384 .byte 0; /* regs */ \
385 .short 1; /* off 1 */ \
386 .long 0; /* imm */ \
387 goto l0_%=; \
388 r0 = 0; \
389 exit; \
390" ::: __clobber_common);
391}
392
393SEC("socket")
394__success __retval(0)
395__naked void jlt_and_may_goto(void)
396{
397 asm volatile (" \
398l0_%=: call %[bpf_jiffies64]; \
399 .byte 0xe5; /* may_goto */ \
400 .byte 0; /* regs */ \
401 .short 1; /* off 1 */ \
402 .long 0; /* imm */ \
403 if r0 < 10 goto l0_%=; \
404 r0 = 0; \
405 exit; \
406" :: __imm(bpf_jiffies64)
407 : __clobber_all);
408}
409
410#ifdef CAN_USE_GOTOL
411SEC("socket")
412__success __retval(0)
413__naked void gotol_and_may_goto(void)
414{
415 asm volatile (" \
416l0_%=: r0 = 0; \
417 .byte 0xe5; /* may_goto */ \
418 .byte 0; /* regs */ \
419 .short 1; /* off 1 */ \
420 .long 0; /* imm */ \
421 gotol l0_%=; \
422 r0 = 0; \
423 exit; \
424" ::: __clobber_common);
425}
426#endif
427
428SEC("socket")
429__success __retval(0)
430__naked void ja_and_may_goto_subprog(void)
431{
432 asm volatile (" \
433 call subprog_with_may_goto; \
434 exit; \
435" ::: __clobber_all);
436}
437
438static __naked __noinline __used
439void subprog_with_may_goto(void)
440{
441 asm volatile (" \
442l0_%=: .byte 0xe5; /* may_goto */ \
443 .byte 0; /* regs */ \
444 .short 1; /* off 1 */ \
445 .long 0; /* imm */ \
446 goto l0_%=; \
447 r0 = 0; \
448 exit; \
449" ::: __clobber_all);
450}
451
452#define ARR_SZ 1000000
453int zero;
454char arr[ARR_SZ];
455
456SEC("socket")
457__success __retval(0xd495cdc0)
458int cond_break1(const void *ctx)
459{
460 unsigned long i;
461 unsigned int sum = 0;
462
463 for (i = zero; i < ARR_SZ && can_loop; i++)
464 sum += i;
465 for (i = zero; i < ARR_SZ; i++) {
466 barrier_var(i);
467 sum += i + arr[i];
468 cond_break;
469 }
470
471 return sum;
472}
473
474SEC("socket")
475__success __retval(999000000)
476int cond_break2(const void *ctx)
477{
478 int i, j;
479 int sum = 0;
480
481 for (i = zero; i < 1000 && can_loop; i++)
482 for (j = zero; j < 1000; j++) {
483 sum += i + j;
484 cond_break;
485 }
486 return sum;
487}
488
489static __noinline int loop(void)
490{
491 int i, sum = 0;
492
493 for (i = zero; i <= 1000000 && can_loop; i++)
494 sum += i;
495
496 return sum;
497}
498
499SEC("socket")
500__success __retval(0x6a5a2920)
501int cond_break3(const void *ctx)
502{
503 return loop();
504}
505
506SEC("socket")
507__success __retval(1)
508int cond_break4(const void *ctx)
509{
510 int cnt = zero;
511
512 for (;;) {
513 /* should eventually break out of the loop */
514 cond_break;
515 cnt++;
516 }
517 /* if we looped a bit, it's a success */
518 return cnt > 1 ? 1 : 0;
519}
520
521static __noinline int static_subprog(void)
522{
523 int cnt = zero;
524
525 for (;;) {
526 cond_break;
527 cnt++;
528 }
529
530 return cnt;
531}
532
533SEC("socket")
534__success __retval(1)
535int cond_break5(const void *ctx)
536{
537 int cnt1 = zero, cnt2;
538
539 for (;;) {
540 cond_break;
541 cnt1++;
542 }
543
544 cnt2 = static_subprog();
545
546 /* main and subprog have to loop a bit */
547 return cnt1 > 1 && cnt2 > 1 ? 1 : 0;
548}
549
550#define ARR2_SZ 1000
551SEC(".data.arr2")
552char arr2[ARR2_SZ];
553
554SEC("socket")
555__success __flag(BPF_F_TEST_STATE_FREQ)
556int loop_inside_iter(const void *ctx)
557{
558 struct bpf_iter_num it;
559 int *v, sum = 0;
560 __u64 i = 0;
561
562 bpf_iter_num_new(&it, 0, ARR2_SZ);
563 while ((v = bpf_iter_num_next(&it))) {
564 if (i < ARR2_SZ)
565 sum += arr2[i++];
566 }
567 bpf_iter_num_destroy(&it);
568 return sum;
569}
570
571SEC("socket")
572__success __flag(BPF_F_TEST_STATE_FREQ)
573int loop_inside_iter_signed(const void *ctx)
574{
575 struct bpf_iter_num it;
576 int *v, sum = 0;
577 long i = 0;
578
579 bpf_iter_num_new(&it, 0, ARR2_SZ);
580 while ((v = bpf_iter_num_next(&it))) {
581 if (i < ARR2_SZ && i >= 0)
582 sum += arr2[i++];
583 }
584 bpf_iter_num_destroy(&it);
585 return sum;
586}
587
588volatile const int limit = ARR2_SZ;
589
590SEC("socket")
591__success __flag(BPF_F_TEST_STATE_FREQ)
592int loop_inside_iter_volatile_limit(const void *ctx)
593{
594 struct bpf_iter_num it;
595 int *v, sum = 0;
596 __u64 i = 0;
597
598 bpf_iter_num_new(&it, 0, ARR2_SZ);
599 while ((v = bpf_iter_num_next(&it))) {
600 if (i < limit)
601 sum += arr2[i++];
602 }
603 bpf_iter_num_destroy(&it);
604 return sum;
605}
606
607#define ARR_LONG_SZ 1000
608
609SEC(".data.arr_long")
610long arr_long[ARR_LONG_SZ];
611
612SEC("socket")
613__success
614int test1(const void *ctx)
615{
616 long i;
617
618 for (i = 0; i < ARR_LONG_SZ && can_loop; i++)
619 arr_long[i] = i;
620 return 0;
621}
622
623SEC("socket")
624__success
625int test2(const void *ctx)
626{
627 __u64 i;
628
629 for (i = zero; i < ARR_LONG_SZ && can_loop; i++) {
630 barrier_var(i);
631 arr_long[i] = i;
632 }
633 return 0;
634}
635
636SEC(".data.arr_foo")
637struct {
638 int a;
639 int b;
640} arr_foo[ARR_LONG_SZ];
641
642SEC("socket")
643__success
644int test3(const void *ctx)
645{
646 __u64 i;
647
648 for (i = zero; i < ARR_LONG_SZ && can_loop; i++) {
649 barrier_var(i);
650 arr_foo[i].a = i;
651 arr_foo[i].b = i;
652 }
653 return 0;
654}
655
656SEC("socket")
657__success
658int test4(const void *ctx)
659{
660 long i;
661
662 for (i = zero + ARR_LONG_SZ - 1; i < ARR_LONG_SZ && i >= 0 && can_loop; i--) {
663 barrier_var(i);
664 arr_foo[i].a = i;
665 arr_foo[i].b = i;
666 }
667 return 0;
668}
669
670char buf[10] SEC(".data.buf");
671
672SEC("socket")
673__description("check add const")
674__success
675__naked void check_add_const(void)
676{
677 /* typical LLVM generated loop with may_goto */
678 asm volatile (" \
679 call %[bpf_ktime_get_ns]; \
680 if r0 > 9 goto l1_%=; \
681l0_%=: r1 = %[buf]; \
682 r2 = r0; \
683 r1 += r2; \
684 r3 = *(u8 *)(r1 +0); \
685 .byte 0xe5; /* may_goto */ \
686 .byte 0; /* regs */ \
687 .short 4; /* off of l1_%=: */ \
688 .long 0; /* imm */ \
689 r0 = r2; \
690 r0 += 1; \
691 if r2 < 9 goto l0_%=; \
692 exit; \
693l1_%=: r0 = 0; \
694 exit; \
695" :
696 : __imm(bpf_ktime_get_ns),
697 __imm_ptr(buf)
698 : __clobber_common);
699}
700
701SEC("socket")
702__failure
703__msg("*(u8 *)(r7 +0) = r0")
704__msg("invalid access to map value, value_size=10 off=10 size=1")
705__naked void check_add_const_3regs(void)
706{
707 asm volatile (
708 "r6 = %[buf];"
709 "r7 = %[buf];"
710 "call %[bpf_ktime_get_ns];"
711 "r1 = r0;" /* link r0.id == r1.id == r2.id */
712 "r2 = r0;"
713 "r1 += 1;" /* r1 == r0+1 */
714 "r2 += 2;" /* r2 == r0+2 */
715 "if r0 > 8 goto 1f;" /* r0 range [0, 8] */
716 "r6 += r1;" /* r1 range [1, 9] */
717 "r7 += r2;" /* r2 range [2, 10] */
718 "*(u8 *)(r6 +0) = r0;" /* safe, within bounds */
719 "*(u8 *)(r7 +0) = r0;" /* unsafe, out of bounds */
720 "1: exit;"
721 :
722 : __imm(bpf_ktime_get_ns),
723 __imm_ptr(buf)
724 : __clobber_common);
725}
726
727SEC("socket")
728__failure
729__msg("*(u8 *)(r8 -1) = r0")
730__msg("invalid access to map value, value_size=10 off=10 size=1")
731__naked void check_add_const_3regs_2if(void)
732{
733 asm volatile (
734 "r6 = %[buf];"
735 "r7 = %[buf];"
736 "r8 = %[buf];"
737 "call %[bpf_ktime_get_ns];"
738 "if r0 < 2 goto 1f;"
739 "r1 = r0;" /* link r0.id == r1.id == r2.id */
740 "r2 = r0;"
741 "r1 += 1;" /* r1 == r0+1 */
742 "r2 += 2;" /* r2 == r0+2 */
743 "if r2 > 11 goto 1f;" /* r2 range [0, 11] -> r0 range [-2, 9]; r1 range [-1, 10] */
744 "if r0 s< 0 goto 1f;" /* r0 range [0, 9] -> r1 range [1, 10]; r2 range [2, 11]; */
745 "r6 += r0;" /* r0 range [0, 9] */
746 "r7 += r1;" /* r1 range [1, 10] */
747 "r8 += r2;" /* r2 range [2, 11] */
748 "*(u8 *)(r6 +0) = r0;" /* safe, within bounds */
749 "*(u8 *)(r7 -1) = r0;" /* safe */
750 "*(u8 *)(r8 -1) = r0;" /* unsafe */
751 "1: exit;"
752 :
753 : __imm(bpf_ktime_get_ns),
754 __imm_ptr(buf)
755 : __clobber_common);
756}
757
758SEC("socket")
759__failure
760__flag(BPF_F_TEST_STATE_FREQ)
761__naked void check_add_const_regsafe_off(void)
762{
763 asm volatile (
764 "r8 = %[buf];"
765 "call %[bpf_ktime_get_ns];"
766 "r6 = r0;"
767 "call %[bpf_ktime_get_ns];"
768 "r7 = r0;"
769 "call %[bpf_ktime_get_ns];"
770 "r1 = r0;" /* same ids for r1 and r0 */
771 "if r6 > r7 goto 1f;" /* this jump can't be predicted */
772 "r1 += 1;" /* r1.off == +1 */
773 "goto 2f;"
774 "1: r1 += 100;" /* r1.off == +100 */
775 "goto +0;" /* verify r1.off in regsafe() after this insn */
776 "2: if r0 > 8 goto 3f;" /* r0 range [0,8], r1 range either [1,9] or [100,108]*/
777 "r8 += r1;"
778 "*(u8 *)(r8 +0) = r0;" /* potentially unsafe, buf size is 10 */
779 "3: exit;"
780 :
781 : __imm(bpf_ktime_get_ns),
782 __imm_ptr(buf)
783 : __clobber_common);
784}
785
786char _license[] SEC("license") = "GPL";