1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Linux Socket Filter - Kernel level socket filtering
4  *
5  * Based on the design of the Berkeley Packet Filter. The new
6  * internal format has been designed by PLUMgrid:
7  *
8  *	Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
9  *
10  * Authors:
11  *
12  *	Jay Schulist <jschlst@samba.org>
13  *	Alexei Starovoitov <ast@plumgrid.com>
14  *	Daniel Borkmann <dborkman@redhat.com>
15  *
16  * Andi Kleen - Fix a few bad bugs and races.
17  * Kris Katterjohn - Added many additional checks in bpf_check_classic()
18  */
19 
20 #include <uapi/linux/btf.h>
21 #include <linux/filter.h>
22 #include <linux/skbuff.h>
23 #include <linux/vmalloc.h>
24 #include <linux/random.h>
25 #include <linux/bpf.h>
26 #include <linux/btf.h>
27 #include <linux/objtool.h>
28 #include <linux/overflow.h>
29 #include <linux/rbtree_latch.h>
30 #include <linux/kallsyms.h>
31 #include <linux/rcupdate.h>
32 #include <linux/perf_event.h>
33 #include <linux/extable.h>
34 #include <linux/log2.h>
35 #include <linux/bpf_verifier.h>
36 #include <linux/nodemask.h>
37 #include <linux/nospec.h>
38 #include <linux/bpf_mem_alloc.h>
39 #include <linux/memcontrol.h>
40 #include <linux/execmem.h>
41 
42 #include <asm/barrier.h>
43 #include <linux/unaligned.h>
44 
45 /* Registers */
46 #define BPF_R0	regs[BPF_REG_0]
47 #define BPF_R1	regs[BPF_REG_1]
48 #define BPF_R2	regs[BPF_REG_2]
49 #define BPF_R3	regs[BPF_REG_3]
50 #define BPF_R4	regs[BPF_REG_4]
51 #define BPF_R5	regs[BPF_REG_5]
52 #define BPF_R6	regs[BPF_REG_6]
53 #define BPF_R7	regs[BPF_REG_7]
54 #define BPF_R8	regs[BPF_REG_8]
55 #define BPF_R9	regs[BPF_REG_9]
56 #define BPF_R10	regs[BPF_REG_10]
57 
58 /* Named registers */
59 #define DST	regs[insn->dst_reg]
60 #define SRC	regs[insn->src_reg]
61 #define FP	regs[BPF_REG_FP]
62 #define AX	regs[BPF_REG_AX]
63 #define ARG1	regs[BPF_REG_ARG1]
64 #define CTX	regs[BPF_REG_CTX]
65 #define OFF	insn->off
66 #define IMM	insn->imm
67 
68 struct bpf_mem_alloc bpf_global_ma;
69 bool bpf_global_ma_set;
70 
71 /* No hurry in this branch
72  *
73  * Exported for the bpf jit load helper.
74  */
bpf_internal_load_pointer_neg_helper(const struct sk_buff * skb,int k,unsigned int size)75 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
76 {
77 	u8 *ptr = NULL;
78 
79 	if (k >= SKF_NET_OFF) {
80 		ptr = skb_network_header(skb) + k - SKF_NET_OFF;
81 	} else if (k >= SKF_LL_OFF) {
82 		if (unlikely(!skb_mac_header_was_set(skb)))
83 			return NULL;
84 		ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
85 	}
86 	if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
87 		return ptr;
88 
89 	return NULL;
90 }
91 
92 /* tell bpf programs that include vmlinux.h kernel's PAGE_SIZE */
93 enum page_size_enum {
94 	__PAGE_SIZE = PAGE_SIZE
95 };
96 
bpf_prog_alloc_no_stats(unsigned int size,gfp_t gfp_extra_flags)97 struct bpf_prog *bpf_prog_alloc_no_stats(unsigned int size, gfp_t gfp_extra_flags)
98 {
99 	gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
100 	struct bpf_prog_aux *aux;
101 	struct bpf_prog *fp;
102 
103 	size = round_up(size, __PAGE_SIZE);
104 	fp = __vmalloc(size, gfp_flags);
105 	if (fp == NULL)
106 		return NULL;
107 
108 	aux = kzalloc(sizeof(*aux), bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags));
109 	if (aux == NULL) {
110 		vfree(fp);
111 		return NULL;
112 	}
113 	fp->active = alloc_percpu_gfp(int, bpf_memcg_flags(GFP_KERNEL | gfp_extra_flags));
114 	if (!fp->active) {
115 		vfree(fp);
116 		kfree(aux);
117 		return NULL;
118 	}
119 
120 	fp->pages = size / PAGE_SIZE;
121 	fp->aux = aux;
122 	fp->aux->prog = fp;
123 	fp->jit_requested = ebpf_jit_enabled();
124 	fp->blinding_requested = bpf_jit_blinding_enabled(fp);
125 #ifdef CONFIG_CGROUP_BPF
126 	aux->cgroup_atype = CGROUP_BPF_ATTACH_TYPE_INVALID;
127 #endif
128 
129 	INIT_LIST_HEAD_RCU(&fp->aux->ksym.lnode);
130 #ifdef CONFIG_FINEIBT
131 	INIT_LIST_HEAD_RCU(&fp->aux->ksym_prefix.lnode);
132 #endif
133 	mutex_init(&fp->aux->used_maps_mutex);
134 	mutex_init(&fp->aux->dst_mutex);
135 
136 	return fp;
137 }
138 
bpf_prog_alloc(unsigned int size,gfp_t gfp_extra_flags)139 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
140 {
141 	gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
142 	struct bpf_prog *prog;
143 	int cpu;
144 
145 	prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
146 	if (!prog)
147 		return NULL;
148 
149 	prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
150 	if (!prog->stats) {
151 		free_percpu(prog->active);
152 		kfree(prog->aux);
153 		vfree(prog);
154 		return NULL;
155 	}
156 
157 	for_each_possible_cpu(cpu) {
158 		struct bpf_prog_stats *pstats;
159 
160 		pstats = per_cpu_ptr(prog->stats, cpu);
161 		u64_stats_init(&pstats->syncp);
162 	}
163 	return prog;
164 }
165 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
166 
bpf_prog_alloc_jited_linfo(struct bpf_prog * prog)167 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
168 {
169 	if (!prog->aux->nr_linfo || !prog->jit_requested)
170 		return 0;
171 
172 	prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo,
173 					  sizeof(*prog->aux->jited_linfo),
174 					  bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN));
175 	if (!prog->aux->jited_linfo)
176 		return -ENOMEM;
177 
178 	return 0;
179 }
180 
bpf_prog_jit_attempt_done(struct bpf_prog * prog)181 void bpf_prog_jit_attempt_done(struct bpf_prog *prog)
182 {
183 	if (prog->aux->jited_linfo &&
184 	    (!prog->jited || !prog->aux->jited_linfo[0])) {
185 		kvfree(prog->aux->jited_linfo);
186 		prog->aux->jited_linfo = NULL;
187 	}
188 
189 	kfree(prog->aux->kfunc_tab);
190 	prog->aux->kfunc_tab = NULL;
191 }
192 
193 /* The jit engine is responsible to provide an array
194  * for insn_off to the jited_off mapping (insn_to_jit_off).
195  *
196  * The idx to this array is the insn_off.  Hence, the insn_off
197  * here is relative to the prog itself instead of the main prog.
198  * This array has one entry for each xlated bpf insn.
199  *
200  * jited_off is the byte off to the end of the jited insn.
201  *
202  * Hence, with
203  * insn_start:
204  *      The first bpf insn off of the prog.  The insn off
205  *      here is relative to the main prog.
206  *      e.g. if prog is a subprog, insn_start > 0
207  * linfo_idx:
208  *      The prog's idx to prog->aux->linfo and jited_linfo
209  *
210  * jited_linfo[linfo_idx] = prog->bpf_func
211  *
212  * For i > linfo_idx,
213  *
214  * jited_linfo[i] = prog->bpf_func +
215  *	insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
216  */
bpf_prog_fill_jited_linfo(struct bpf_prog * prog,const u32 * insn_to_jit_off)217 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
218 			       const u32 *insn_to_jit_off)
219 {
220 	u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
221 	const struct bpf_line_info *linfo;
222 	void **jited_linfo;
223 
224 	if (!prog->aux->jited_linfo || prog->aux->func_idx > prog->aux->func_cnt)
225 		/* Userspace did not provide linfo */
226 		return;
227 
228 	linfo_idx = prog->aux->linfo_idx;
229 	linfo = &prog->aux->linfo[linfo_idx];
230 	insn_start = linfo[0].insn_off;
231 	insn_end = insn_start + prog->len;
232 
233 	jited_linfo = &prog->aux->jited_linfo[linfo_idx];
234 	jited_linfo[0] = prog->bpf_func;
235 
236 	nr_linfo = prog->aux->nr_linfo - linfo_idx;
237 
238 	for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
239 		/* The verifier ensures that linfo[i].insn_off is
240 		 * strictly increasing
241 		 */
242 		jited_linfo[i] = prog->bpf_func +
243 			insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
244 }
245 
bpf_prog_realloc(struct bpf_prog * fp_old,unsigned int size,gfp_t gfp_extra_flags)246 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
247 				  gfp_t gfp_extra_flags)
248 {
249 	gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
250 	struct bpf_prog *fp;
251 	u32 pages;
252 
253 	size = round_up(size, PAGE_SIZE);
254 	pages = size / PAGE_SIZE;
255 	if (pages <= fp_old->pages)
256 		return fp_old;
257 
258 	fp = __vmalloc(size, gfp_flags);
259 	if (fp) {
260 		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
261 		fp->pages = pages;
262 		fp->aux->prog = fp;
263 
264 		/* We keep fp->aux from fp_old around in the new
265 		 * reallocated structure.
266 		 */
267 		fp_old->aux = NULL;
268 		fp_old->stats = NULL;
269 		fp_old->active = NULL;
270 		__bpf_prog_free(fp_old);
271 	}
272 
273 	return fp;
274 }
275 
__bpf_prog_free(struct bpf_prog * fp)276 void __bpf_prog_free(struct bpf_prog *fp)
277 {
278 	if (fp->aux) {
279 		mutex_destroy(&fp->aux->used_maps_mutex);
280 		mutex_destroy(&fp->aux->dst_mutex);
281 		kfree(fp->aux->poke_tab);
282 		kfree(fp->aux);
283 	}
284 	free_percpu(fp->stats);
285 	free_percpu(fp->active);
286 	vfree(fp);
287 }
288 
bpf_prog_calc_tag(struct bpf_prog * fp)289 int bpf_prog_calc_tag(struct bpf_prog *fp)
290 {
291 	const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
292 	u32 raw_size = bpf_prog_tag_scratch_size(fp);
293 	u32 digest[SHA1_DIGEST_WORDS];
294 	u32 ws[SHA1_WORKSPACE_WORDS];
295 	u32 i, bsize, psize, blocks;
296 	struct bpf_insn *dst;
297 	bool was_ld_map;
298 	u8 *raw, *todo;
299 	__be32 *result;
300 	__be64 *bits;
301 
302 	raw = vmalloc(raw_size);
303 	if (!raw)
304 		return -ENOMEM;
305 
306 	sha1_init(digest);
307 	memset(ws, 0, sizeof(ws));
308 
309 	/* We need to take out the map fd for the digest calculation
310 	 * since they are unstable from user space side.
311 	 */
312 	dst = (void *)raw;
313 	for (i = 0, was_ld_map = false; i < fp->len; i++) {
314 		dst[i] = fp->insnsi[i];
315 		if (!was_ld_map &&
316 		    dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
317 		    (dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
318 		     dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
319 			was_ld_map = true;
320 			dst[i].imm = 0;
321 		} else if (was_ld_map &&
322 			   dst[i].code == 0 &&
323 			   dst[i].dst_reg == 0 &&
324 			   dst[i].src_reg == 0 &&
325 			   dst[i].off == 0) {
326 			was_ld_map = false;
327 			dst[i].imm = 0;
328 		} else {
329 			was_ld_map = false;
330 		}
331 	}
332 
333 	psize = bpf_prog_insn_size(fp);
334 	memset(&raw[psize], 0, raw_size - psize);
335 	raw[psize++] = 0x80;
336 
337 	bsize  = round_up(psize, SHA1_BLOCK_SIZE);
338 	blocks = bsize / SHA1_BLOCK_SIZE;
339 	todo   = raw;
340 	if (bsize - psize >= sizeof(__be64)) {
341 		bits = (__be64 *)(todo + bsize - sizeof(__be64));
342 	} else {
343 		bits = (__be64 *)(todo + bsize + bits_offset);
344 		blocks++;
345 	}
346 	*bits = cpu_to_be64((psize - 1) << 3);
347 
348 	while (blocks--) {
349 		sha1_transform(digest, todo, ws);
350 		todo += SHA1_BLOCK_SIZE;
351 	}
352 
353 	result = (__force __be32 *)digest;
354 	for (i = 0; i < SHA1_DIGEST_WORDS; i++)
355 		result[i] = cpu_to_be32(digest[i]);
356 	memcpy(fp->tag, result, sizeof(fp->tag));
357 
358 	vfree(raw);
359 	return 0;
360 }
361 
bpf_adj_delta_to_imm(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)362 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
363 				s32 end_new, s32 curr, const bool probe_pass)
364 {
365 	const s64 imm_min = S32_MIN, imm_max = S32_MAX;
366 	s32 delta = end_new - end_old;
367 	s64 imm = insn->imm;
368 
369 	if (curr < pos && curr + imm + 1 >= end_old)
370 		imm += delta;
371 	else if (curr >= end_new && curr + imm + 1 < end_new)
372 		imm -= delta;
373 	if (imm < imm_min || imm > imm_max)
374 		return -ERANGE;
375 	if (!probe_pass)
376 		insn->imm = imm;
377 	return 0;
378 }
379 
bpf_adj_delta_to_off(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)380 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
381 				s32 end_new, s32 curr, const bool probe_pass)
382 {
383 	s64 off_min, off_max, off;
384 	s32 delta = end_new - end_old;
385 
386 	if (insn->code == (BPF_JMP32 | BPF_JA)) {
387 		off = insn->imm;
388 		off_min = S32_MIN;
389 		off_max = S32_MAX;
390 	} else {
391 		off = insn->off;
392 		off_min = S16_MIN;
393 		off_max = S16_MAX;
394 	}
395 
396 	if (curr < pos && curr + off + 1 >= end_old)
397 		off += delta;
398 	else if (curr >= end_new && curr + off + 1 < end_new)
399 		off -= delta;
400 	if (off < off_min || off > off_max)
401 		return -ERANGE;
402 	if (!probe_pass) {
403 		if (insn->code == (BPF_JMP32 | BPF_JA))
404 			insn->imm = off;
405 		else
406 			insn->off = off;
407 	}
408 	return 0;
409 }
410 
bpf_adj_branches(struct bpf_prog * prog,u32 pos,s32 end_old,s32 end_new,const bool probe_pass)411 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
412 			    s32 end_new, const bool probe_pass)
413 {
414 	u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
415 	struct bpf_insn *insn = prog->insnsi;
416 	int ret = 0;
417 
418 	for (i = 0; i < insn_cnt; i++, insn++) {
419 		u8 code;
420 
421 		/* In the probing pass we still operate on the original,
422 		 * unpatched image in order to check overflows before we
423 		 * do any other adjustments. Therefore skip the patchlet.
424 		 */
425 		if (probe_pass && i == pos) {
426 			i = end_new;
427 			insn = prog->insnsi + end_old;
428 		}
429 		if (bpf_pseudo_func(insn)) {
430 			ret = bpf_adj_delta_to_imm(insn, pos, end_old,
431 						   end_new, i, probe_pass);
432 			if (ret)
433 				return ret;
434 			continue;
435 		}
436 		code = insn->code;
437 		if ((BPF_CLASS(code) != BPF_JMP &&
438 		     BPF_CLASS(code) != BPF_JMP32) ||
439 		    BPF_OP(code) == BPF_EXIT)
440 			continue;
441 		/* Adjust offset of jmps if we cross patch boundaries. */
442 		if (BPF_OP(code) == BPF_CALL) {
443 			if (insn->src_reg != BPF_PSEUDO_CALL)
444 				continue;
445 			ret = bpf_adj_delta_to_imm(insn, pos, end_old,
446 						   end_new, i, probe_pass);
447 		} else {
448 			ret = bpf_adj_delta_to_off(insn, pos, end_old,
449 						   end_new, i, probe_pass);
450 		}
451 		if (ret)
452 			break;
453 	}
454 
455 	return ret;
456 }
457 
bpf_adj_linfo(struct bpf_prog * prog,u32 off,u32 delta)458 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
459 {
460 	struct bpf_line_info *linfo;
461 	u32 i, nr_linfo;
462 
463 	nr_linfo = prog->aux->nr_linfo;
464 	if (!nr_linfo || !delta)
465 		return;
466 
467 	linfo = prog->aux->linfo;
468 
469 	for (i = 0; i < nr_linfo; i++)
470 		if (off < linfo[i].insn_off)
471 			break;
472 
473 	/* Push all off < linfo[i].insn_off by delta */
474 	for (; i < nr_linfo; i++)
475 		linfo[i].insn_off += delta;
476 }
477 
bpf_patch_insn_single(struct bpf_prog * prog,u32 off,const struct bpf_insn * patch,u32 len)478 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
479 				       const struct bpf_insn *patch, u32 len)
480 {
481 	u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
482 	const u32 cnt_max = S16_MAX;
483 	struct bpf_prog *prog_adj;
484 	int err;
485 
486 	/* Since our patchlet doesn't expand the image, we're done. */
487 	if (insn_delta == 0) {
488 		memcpy(prog->insnsi + off, patch, sizeof(*patch));
489 		return prog;
490 	}
491 
492 	insn_adj_cnt = prog->len + insn_delta;
493 
494 	/* Reject anything that would potentially let the insn->off
495 	 * target overflow when we have excessive program expansions.
496 	 * We need to probe here before we do any reallocation where
497 	 * we afterwards may not fail anymore.
498 	 */
499 	if (insn_adj_cnt > cnt_max &&
500 	    (err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
501 		return ERR_PTR(err);
502 
503 	/* Several new instructions need to be inserted. Make room
504 	 * for them. Likely, there's no need for a new allocation as
505 	 * last page could have large enough tailroom.
506 	 */
507 	prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
508 				    GFP_USER);
509 	if (!prog_adj)
510 		return ERR_PTR(-ENOMEM);
511 
512 	prog_adj->len = insn_adj_cnt;
513 
514 	/* Patching happens in 3 steps:
515 	 *
516 	 * 1) Move over tail of insnsi from next instruction onwards,
517 	 *    so we can patch the single target insn with one or more
518 	 *    new ones (patching is always from 1 to n insns, n > 0).
519 	 * 2) Inject new instructions at the target location.
520 	 * 3) Adjust branch offsets if necessary.
521 	 */
522 	insn_rest = insn_adj_cnt - off - len;
523 
524 	memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
525 		sizeof(*patch) * insn_rest);
526 	memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
527 
528 	/* We are guaranteed to not fail at this point, otherwise
529 	 * the ship has sailed to reverse to the original state. An
530 	 * overflow cannot happen at this point.
531 	 */
532 	BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
533 
534 	bpf_adj_linfo(prog_adj, off, insn_delta);
535 
536 	return prog_adj;
537 }
538 
bpf_remove_insns(struct bpf_prog * prog,u32 off,u32 cnt)539 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
540 {
541 	/* Branch offsets can't overflow when program is shrinking, no need
542 	 * to call bpf_adj_branches(..., true) here
543 	 */
544 	memmove(prog->insnsi + off, prog->insnsi + off + cnt,
545 		sizeof(struct bpf_insn) * (prog->len - off - cnt));
546 	prog->len -= cnt;
547 
548 	return WARN_ON_ONCE(bpf_adj_branches(prog, off, off + cnt, off, false));
549 }
550 
bpf_prog_kallsyms_del_subprogs(struct bpf_prog * fp)551 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
552 {
553 	int i;
554 
555 	for (i = 0; i < fp->aux->real_func_cnt; i++)
556 		bpf_prog_kallsyms_del(fp->aux->func[i]);
557 }
558 
bpf_prog_kallsyms_del_all(struct bpf_prog * fp)559 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
560 {
561 	bpf_prog_kallsyms_del_subprogs(fp);
562 	bpf_prog_kallsyms_del(fp);
563 }
564 
565 #ifdef CONFIG_BPF_JIT
566 /* All BPF JIT sysctl knobs here. */
567 int bpf_jit_enable   __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
568 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
569 int bpf_jit_harden   __read_mostly;
570 long bpf_jit_limit   __read_mostly;
571 long bpf_jit_limit_max __read_mostly;
572 
573 static void
bpf_prog_ksym_set_addr(struct bpf_prog * prog)574 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
575 {
576 	WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
577 
578 	prog->aux->ksym.start = (unsigned long) prog->bpf_func;
579 	prog->aux->ksym.end   = prog->aux->ksym.start + prog->jited_len;
580 }
581 
582 static void
bpf_prog_ksym_set_name(struct bpf_prog * prog)583 bpf_prog_ksym_set_name(struct bpf_prog *prog)
584 {
585 	char *sym = prog->aux->ksym.name;
586 	const char *end = sym + KSYM_NAME_LEN;
587 	const struct btf_type *type;
588 	const char *func_name;
589 
590 	BUILD_BUG_ON(sizeof("bpf_prog_") +
591 		     sizeof(prog->tag) * 2 +
592 		     /* name has been null terminated.
593 		      * We should need +1 for the '_' preceding
594 		      * the name.  However, the null character
595 		      * is double counted between the name and the
596 		      * sizeof("bpf_prog_") above, so we omit
597 		      * the +1 here.
598 		      */
599 		     sizeof(prog->aux->name) > KSYM_NAME_LEN);
600 
601 	sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
602 	sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
603 
604 	/* prog->aux->name will be ignored if full btf name is available */
605 	if (prog->aux->func_info_cnt && prog->aux->func_idx < prog->aux->func_info_cnt) {
606 		type = btf_type_by_id(prog->aux->btf,
607 				      prog->aux->func_info[prog->aux->func_idx].type_id);
608 		func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
609 		snprintf(sym, (size_t)(end - sym), "_%s", func_name);
610 		return;
611 	}
612 
613 	if (prog->aux->name[0])
614 		snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
615 	else
616 		*sym = 0;
617 }
618 
bpf_get_ksym_start(struct latch_tree_node * n)619 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
620 {
621 	return container_of(n, struct bpf_ksym, tnode)->start;
622 }
623 
bpf_tree_less(struct latch_tree_node * a,struct latch_tree_node * b)624 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
625 					  struct latch_tree_node *b)
626 {
627 	return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
628 }
629 
bpf_tree_comp(void * key,struct latch_tree_node * n)630 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
631 {
632 	unsigned long val = (unsigned long)key;
633 	const struct bpf_ksym *ksym;
634 
635 	ksym = container_of(n, struct bpf_ksym, tnode);
636 
637 	if (val < ksym->start)
638 		return -1;
639 	/* Ensure that we detect return addresses as part of the program, when
640 	 * the final instruction is a call for a program part of the stack
641 	 * trace. Therefore, do val > ksym->end instead of val >= ksym->end.
642 	 */
643 	if (val > ksym->end)
644 		return  1;
645 
646 	return 0;
647 }
648 
649 static const struct latch_tree_ops bpf_tree_ops = {
650 	.less	= bpf_tree_less,
651 	.comp	= bpf_tree_comp,
652 };
653 
654 static DEFINE_SPINLOCK(bpf_lock);
655 static LIST_HEAD(bpf_kallsyms);
656 static struct latch_tree_root bpf_tree __cacheline_aligned;
657 
bpf_ksym_add(struct bpf_ksym * ksym)658 void bpf_ksym_add(struct bpf_ksym *ksym)
659 {
660 	spin_lock_bh(&bpf_lock);
661 	WARN_ON_ONCE(!list_empty(&ksym->lnode));
662 	list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
663 	latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
664 	spin_unlock_bh(&bpf_lock);
665 }
666 
__bpf_ksym_del(struct bpf_ksym * ksym)667 static void __bpf_ksym_del(struct bpf_ksym *ksym)
668 {
669 	if (list_empty(&ksym->lnode))
670 		return;
671 
672 	latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
673 	list_del_rcu(&ksym->lnode);
674 }
675 
bpf_ksym_del(struct bpf_ksym * ksym)676 void bpf_ksym_del(struct bpf_ksym *ksym)
677 {
678 	spin_lock_bh(&bpf_lock);
679 	__bpf_ksym_del(ksym);
680 	spin_unlock_bh(&bpf_lock);
681 }
682 
bpf_prog_kallsyms_candidate(const struct bpf_prog * fp)683 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
684 {
685 	return fp->jited && !bpf_prog_was_classic(fp);
686 }
687 
bpf_prog_kallsyms_add(struct bpf_prog * fp)688 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
689 {
690 	if (!bpf_prog_kallsyms_candidate(fp) ||
691 	    !bpf_token_capable(fp->aux->token, CAP_BPF))
692 		return;
693 
694 	bpf_prog_ksym_set_addr(fp);
695 	bpf_prog_ksym_set_name(fp);
696 	fp->aux->ksym.prog = true;
697 
698 	bpf_ksym_add(&fp->aux->ksym);
699 
700 #ifdef CONFIG_FINEIBT
701 	/*
702 	 * When FineIBT, code in the __cfi_foo() symbols can get executed
703 	 * and hence unwinder needs help.
704 	 */
705 	if (cfi_mode != CFI_FINEIBT)
706 		return;
707 
708 	snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN,
709 		 "__cfi_%s", fp->aux->ksym.name);
710 
711 	fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16;
712 	fp->aux->ksym_prefix.end   = (unsigned long) fp->bpf_func;
713 
714 	bpf_ksym_add(&fp->aux->ksym_prefix);
715 #endif
716 }
717 
bpf_prog_kallsyms_del(struct bpf_prog * fp)718 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
719 {
720 	if (!bpf_prog_kallsyms_candidate(fp))
721 		return;
722 
723 	bpf_ksym_del(&fp->aux->ksym);
724 #ifdef CONFIG_FINEIBT
725 	if (cfi_mode != CFI_FINEIBT)
726 		return;
727 	bpf_ksym_del(&fp->aux->ksym_prefix);
728 #endif
729 }
730 
bpf_ksym_find(unsigned long addr)731 static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
732 {
733 	struct latch_tree_node *n;
734 
735 	n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
736 	return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
737 }
738 
__bpf_address_lookup(unsigned long addr,unsigned long * size,unsigned long * off,char * sym)739 int __bpf_address_lookup(unsigned long addr, unsigned long *size,
740 				 unsigned long *off, char *sym)
741 {
742 	struct bpf_ksym *ksym;
743 	int ret = 0;
744 
745 	rcu_read_lock();
746 	ksym = bpf_ksym_find(addr);
747 	if (ksym) {
748 		unsigned long symbol_start = ksym->start;
749 		unsigned long symbol_end = ksym->end;
750 
751 		ret = strscpy(sym, ksym->name, KSYM_NAME_LEN);
752 
753 		if (size)
754 			*size = symbol_end - symbol_start;
755 		if (off)
756 			*off  = addr - symbol_start;
757 	}
758 	rcu_read_unlock();
759 
760 	return ret;
761 }
762 
is_bpf_text_address(unsigned long addr)763 bool is_bpf_text_address(unsigned long addr)
764 {
765 	bool ret;
766 
767 	rcu_read_lock();
768 	ret = bpf_ksym_find(addr) != NULL;
769 	rcu_read_unlock();
770 
771 	return ret;
772 }
773 
bpf_prog_ksym_find(unsigned long addr)774 struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
775 {
776 	struct bpf_ksym *ksym = bpf_ksym_find(addr);
777 
778 	return ksym && ksym->prog ?
779 	       container_of(ksym, struct bpf_prog_aux, ksym)->prog :
780 	       NULL;
781 }
782 
search_bpf_extables(unsigned long addr)783 const struct exception_table_entry *search_bpf_extables(unsigned long addr)
784 {
785 	const struct exception_table_entry *e = NULL;
786 	struct bpf_prog *prog;
787 
788 	rcu_read_lock();
789 	prog = bpf_prog_ksym_find(addr);
790 	if (!prog)
791 		goto out;
792 	if (!prog->aux->num_exentries)
793 		goto out;
794 
795 	e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
796 out:
797 	rcu_read_unlock();
798 	return e;
799 }
800 
bpf_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * sym)801 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
802 		    char *sym)
803 {
804 	struct bpf_ksym *ksym;
805 	unsigned int it = 0;
806 	int ret = -ERANGE;
807 
808 	if (!bpf_jit_kallsyms_enabled())
809 		return ret;
810 
811 	rcu_read_lock();
812 	list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
813 		if (it++ != symnum)
814 			continue;
815 
816 		strscpy(sym, ksym->name, KSYM_NAME_LEN);
817 
818 		*value = ksym->start;
819 		*type  = BPF_SYM_ELF_TYPE;
820 
821 		ret = 0;
822 		break;
823 	}
824 	rcu_read_unlock();
825 
826 	return ret;
827 }
828 
bpf_jit_add_poke_descriptor(struct bpf_prog * prog,struct bpf_jit_poke_descriptor * poke)829 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
830 				struct bpf_jit_poke_descriptor *poke)
831 {
832 	struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
833 	static const u32 poke_tab_max = 1024;
834 	u32 slot = prog->aux->size_poke_tab;
835 	u32 size = slot + 1;
836 
837 	if (size > poke_tab_max)
838 		return -ENOSPC;
839 	if (poke->tailcall_target || poke->tailcall_target_stable ||
840 	    poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
841 		return -EINVAL;
842 
843 	switch (poke->reason) {
844 	case BPF_POKE_REASON_TAIL_CALL:
845 		if (!poke->tail_call.map)
846 			return -EINVAL;
847 		break;
848 	default:
849 		return -EINVAL;
850 	}
851 
852 	tab = krealloc_array(tab, size, sizeof(*poke), GFP_KERNEL);
853 	if (!tab)
854 		return -ENOMEM;
855 
856 	memcpy(&tab[slot], poke, sizeof(*poke));
857 	prog->aux->size_poke_tab = size;
858 	prog->aux->poke_tab = tab;
859 
860 	return slot;
861 }
862 
863 /*
864  * BPF program pack allocator.
865  *
866  * Most BPF programs are pretty small. Allocating a hole page for each
867  * program is sometime a waste. Many small bpf program also adds pressure
868  * to instruction TLB. To solve this issue, we introduce a BPF program pack
869  * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
870  * to host BPF programs.
871  */
872 #define BPF_PROG_CHUNK_SHIFT	6
873 #define BPF_PROG_CHUNK_SIZE	(1 << BPF_PROG_CHUNK_SHIFT)
874 #define BPF_PROG_CHUNK_MASK	(~(BPF_PROG_CHUNK_SIZE - 1))
875 
876 struct bpf_prog_pack {
877 	struct list_head list;
878 	void *ptr;
879 	unsigned long bitmap[];
880 };
881 
bpf_jit_fill_hole_with_zero(void * area,unsigned int size)882 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size)
883 {
884 	memset(area, 0, size);
885 }
886 
887 #define BPF_PROG_SIZE_TO_NBITS(size)	(round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
888 
889 static DEFINE_MUTEX(pack_mutex);
890 static LIST_HEAD(pack_list);
891 
892 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with
893  * CONFIG_MMU=n. Use PAGE_SIZE in these cases.
894  */
895 #ifdef PMD_SIZE
896 /* PMD_SIZE is really big for some archs. It doesn't make sense to
897  * reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to
898  * 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be
899  * greater than or equal to 2MB.
900  */
901 #define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes())
902 #else
903 #define BPF_PROG_PACK_SIZE PAGE_SIZE
904 #endif
905 
906 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)
907 
alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)908 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)
909 {
910 	struct bpf_prog_pack *pack;
911 	int err;
912 
913 	pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)),
914 		       GFP_KERNEL);
915 	if (!pack)
916 		return NULL;
917 	pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE);
918 	if (!pack->ptr)
919 		goto out;
920 	bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE);
921 	bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);
922 
923 	set_vm_flush_reset_perms(pack->ptr);
924 	err = set_memory_rox((unsigned long)pack->ptr,
925 			     BPF_PROG_PACK_SIZE / PAGE_SIZE);
926 	if (err)
927 		goto out;
928 	list_add_tail(&pack->list, &pack_list);
929 	return pack;
930 
931 out:
932 	bpf_jit_free_exec(pack->ptr);
933 	kfree(pack);
934 	return NULL;
935 }
936 
bpf_prog_pack_alloc(u32 size,bpf_jit_fill_hole_t bpf_fill_ill_insns)937 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns)
938 {
939 	unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size);
940 	struct bpf_prog_pack *pack;
941 	unsigned long pos;
942 	void *ptr = NULL;
943 
944 	mutex_lock(&pack_mutex);
945 	if (size > BPF_PROG_PACK_SIZE) {
946 		size = round_up(size, PAGE_SIZE);
947 		ptr = bpf_jit_alloc_exec(size);
948 		if (ptr) {
949 			int err;
950 
951 			bpf_fill_ill_insns(ptr, size);
952 			set_vm_flush_reset_perms(ptr);
953 			err = set_memory_rox((unsigned long)ptr,
954 					     size / PAGE_SIZE);
955 			if (err) {
956 				bpf_jit_free_exec(ptr);
957 				ptr = NULL;
958 			}
959 		}
960 		goto out;
961 	}
962 	list_for_each_entry(pack, &pack_list, list) {
963 		pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
964 						 nbits, 0);
965 		if (pos < BPF_PROG_CHUNK_COUNT)
966 			goto found_free_area;
967 	}
968 
969 	pack = alloc_new_pack(bpf_fill_ill_insns);
970 	if (!pack)
971 		goto out;
972 
973 	pos = 0;
974 
975 found_free_area:
976 	bitmap_set(pack->bitmap, pos, nbits);
977 	ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT);
978 
979 out:
980 	mutex_unlock(&pack_mutex);
981 	return ptr;
982 }
983 
bpf_prog_pack_free(void * ptr,u32 size)984 void bpf_prog_pack_free(void *ptr, u32 size)
985 {
986 	struct bpf_prog_pack *pack = NULL, *tmp;
987 	unsigned int nbits;
988 	unsigned long pos;
989 
990 	mutex_lock(&pack_mutex);
991 	if (size > BPF_PROG_PACK_SIZE) {
992 		bpf_jit_free_exec(ptr);
993 		goto out;
994 	}
995 
996 	list_for_each_entry(tmp, &pack_list, list) {
997 		if (ptr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > ptr) {
998 			pack = tmp;
999 			break;
1000 		}
1001 	}
1002 
1003 	if (WARN_ONCE(!pack, "bpf_prog_pack bug\n"))
1004 		goto out;
1005 
1006 	nbits = BPF_PROG_SIZE_TO_NBITS(size);
1007 	pos = ((unsigned long)ptr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT;
1008 
1009 	WARN_ONCE(bpf_arch_text_invalidate(ptr, size),
1010 		  "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n");
1011 
1012 	bitmap_clear(pack->bitmap, pos, nbits);
1013 	if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
1014 				       BPF_PROG_CHUNK_COUNT, 0) == 0) {
1015 		list_del(&pack->list);
1016 		bpf_jit_free_exec(pack->ptr);
1017 		kfree(pack);
1018 	}
1019 out:
1020 	mutex_unlock(&pack_mutex);
1021 }
1022 
1023 static atomic_long_t bpf_jit_current;
1024 
1025 /* Can be overridden by an arch's JIT compiler if it has a custom,
1026  * dedicated BPF backend memory area, or if neither of the two
1027  * below apply.
1028  */
bpf_jit_alloc_exec_limit(void)1029 u64 __weak bpf_jit_alloc_exec_limit(void)
1030 {
1031 #if defined(MODULES_VADDR)
1032 	return MODULES_END - MODULES_VADDR;
1033 #else
1034 	return VMALLOC_END - VMALLOC_START;
1035 #endif
1036 }
1037 
bpf_jit_charge_init(void)1038 static int __init bpf_jit_charge_init(void)
1039 {
1040 	/* Only used as heuristic here to derive limit. */
1041 	bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
1042 	bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1,
1043 					    PAGE_SIZE), LONG_MAX);
1044 	return 0;
1045 }
1046 pure_initcall(bpf_jit_charge_init);
1047 
bpf_jit_charge_modmem(u32 size)1048 int bpf_jit_charge_modmem(u32 size)
1049 {
1050 	if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) {
1051 		if (!bpf_capable()) {
1052 			atomic_long_sub(size, &bpf_jit_current);
1053 			return -EPERM;
1054 		}
1055 	}
1056 
1057 	return 0;
1058 }
1059 
bpf_jit_uncharge_modmem(u32 size)1060 void bpf_jit_uncharge_modmem(u32 size)
1061 {
1062 	atomic_long_sub(size, &bpf_jit_current);
1063 }
1064 
bpf_jit_alloc_exec(unsigned long size)1065 void *__weak bpf_jit_alloc_exec(unsigned long size)
1066 {
1067 	return execmem_alloc(EXECMEM_BPF, size);
1068 }
1069 
bpf_jit_free_exec(void * addr)1070 void __weak bpf_jit_free_exec(void *addr)
1071 {
1072 	execmem_free(addr);
1073 }
1074 
1075 struct bpf_binary_header *
bpf_jit_binary_alloc(unsigned int proglen,u8 ** image_ptr,unsigned int alignment,bpf_jit_fill_hole_t bpf_fill_ill_insns)1076 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
1077 		     unsigned int alignment,
1078 		     bpf_jit_fill_hole_t bpf_fill_ill_insns)
1079 {
1080 	struct bpf_binary_header *hdr;
1081 	u32 size, hole, start;
1082 
1083 	WARN_ON_ONCE(!is_power_of_2(alignment) ||
1084 		     alignment > BPF_IMAGE_ALIGNMENT);
1085 
1086 	/* Most of BPF filters are really small, but if some of them
1087 	 * fill a page, allow at least 128 extra bytes to insert a
1088 	 * random section of illegal instructions.
1089 	 */
1090 	size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
1091 
1092 	if (bpf_jit_charge_modmem(size))
1093 		return NULL;
1094 	hdr = bpf_jit_alloc_exec(size);
1095 	if (!hdr) {
1096 		bpf_jit_uncharge_modmem(size);
1097 		return NULL;
1098 	}
1099 
1100 	/* Fill space with illegal/arch-dep instructions. */
1101 	bpf_fill_ill_insns(hdr, size);
1102 
1103 	hdr->size = size;
1104 	hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
1105 		     PAGE_SIZE - sizeof(*hdr));
1106 	start = get_random_u32_below(hole) & ~(alignment - 1);
1107 
1108 	/* Leave a random number of instructions before BPF code. */
1109 	*image_ptr = &hdr->image[start];
1110 
1111 	return hdr;
1112 }
1113 
bpf_jit_binary_free(struct bpf_binary_header * hdr)1114 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
1115 {
1116 	u32 size = hdr->size;
1117 
1118 	bpf_jit_free_exec(hdr);
1119 	bpf_jit_uncharge_modmem(size);
1120 }
1121 
1122 /* Allocate jit binary from bpf_prog_pack allocator.
1123  * Since the allocated memory is RO+X, the JIT engine cannot write directly
1124  * to the memory. To solve this problem, a RW buffer is also allocated at
1125  * as the same time. The JIT engine should calculate offsets based on the
1126  * RO memory address, but write JITed program to the RW buffer. Once the
1127  * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies
1128  * the JITed program to the RO memory.
1129  */
1130 struct bpf_binary_header *
bpf_jit_binary_pack_alloc(unsigned int proglen,u8 ** image_ptr,unsigned int alignment,struct bpf_binary_header ** rw_header,u8 ** rw_image,bpf_jit_fill_hole_t bpf_fill_ill_insns)1131 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
1132 			  unsigned int alignment,
1133 			  struct bpf_binary_header **rw_header,
1134 			  u8 **rw_image,
1135 			  bpf_jit_fill_hole_t bpf_fill_ill_insns)
1136 {
1137 	struct bpf_binary_header *ro_header;
1138 	u32 size, hole, start;
1139 
1140 	WARN_ON_ONCE(!is_power_of_2(alignment) ||
1141 		     alignment > BPF_IMAGE_ALIGNMENT);
1142 
1143 	/* add 16 bytes for a random section of illegal instructions */
1144 	size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE);
1145 
1146 	if (bpf_jit_charge_modmem(size))
1147 		return NULL;
1148 	ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns);
1149 	if (!ro_header) {
1150 		bpf_jit_uncharge_modmem(size);
1151 		return NULL;
1152 	}
1153 
1154 	*rw_header = kvmalloc(size, GFP_KERNEL);
1155 	if (!*rw_header) {
1156 		bpf_prog_pack_free(ro_header, size);
1157 		bpf_jit_uncharge_modmem(size);
1158 		return NULL;
1159 	}
1160 
1161 	/* Fill space with illegal/arch-dep instructions. */
1162 	bpf_fill_ill_insns(*rw_header, size);
1163 	(*rw_header)->size = size;
1164 
1165 	hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)),
1166 		     BPF_PROG_CHUNK_SIZE - sizeof(*ro_header));
1167 	start = get_random_u32_below(hole) & ~(alignment - 1);
1168 
1169 	*image_ptr = &ro_header->image[start];
1170 	*rw_image = &(*rw_header)->image[start];
1171 
1172 	return ro_header;
1173 }
1174 
1175 /* Copy JITed text from rw_header to its final location, the ro_header. */
bpf_jit_binary_pack_finalize(struct bpf_binary_header * ro_header,struct bpf_binary_header * rw_header)1176 int bpf_jit_binary_pack_finalize(struct bpf_binary_header *ro_header,
1177 				 struct bpf_binary_header *rw_header)
1178 {
1179 	void *ptr;
1180 
1181 	ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size);
1182 
1183 	kvfree(rw_header);
1184 
1185 	if (IS_ERR(ptr)) {
1186 		bpf_prog_pack_free(ro_header, ro_header->size);
1187 		return PTR_ERR(ptr);
1188 	}
1189 	return 0;
1190 }
1191 
1192 /* bpf_jit_binary_pack_free is called in two different scenarios:
1193  *   1) when the program is freed after;
1194  *   2) when the JIT engine fails (before bpf_jit_binary_pack_finalize).
1195  * For case 2), we need to free both the RO memory and the RW buffer.
1196  *
1197  * bpf_jit_binary_pack_free requires proper ro_header->size. However,
1198  * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size
1199  * must be set with either bpf_jit_binary_pack_finalize (normal path) or
1200  * bpf_arch_text_copy (when jit fails).
1201  */
bpf_jit_binary_pack_free(struct bpf_binary_header * ro_header,struct bpf_binary_header * rw_header)1202 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header,
1203 			      struct bpf_binary_header *rw_header)
1204 {
1205 	u32 size = ro_header->size;
1206 
1207 	bpf_prog_pack_free(ro_header, size);
1208 	kvfree(rw_header);
1209 	bpf_jit_uncharge_modmem(size);
1210 }
1211 
1212 struct bpf_binary_header *
bpf_jit_binary_pack_hdr(const struct bpf_prog * fp)1213 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp)
1214 {
1215 	unsigned long real_start = (unsigned long)fp->bpf_func;
1216 	unsigned long addr;
1217 
1218 	addr = real_start & BPF_PROG_CHUNK_MASK;
1219 	return (void *)addr;
1220 }
1221 
1222 static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog * fp)1223 bpf_jit_binary_hdr(const struct bpf_prog *fp)
1224 {
1225 	unsigned long real_start = (unsigned long)fp->bpf_func;
1226 	unsigned long addr;
1227 
1228 	addr = real_start & PAGE_MASK;
1229 	return (void *)addr;
1230 }
1231 
1232 /* This symbol is only overridden by archs that have different
1233  * requirements than the usual eBPF JITs, f.e. when they only
1234  * implement cBPF JIT, do not set images read-only, etc.
1235  */
bpf_jit_free(struct bpf_prog * fp)1236 void __weak bpf_jit_free(struct bpf_prog *fp)
1237 {
1238 	if (fp->jited) {
1239 		struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
1240 
1241 		bpf_jit_binary_free(hdr);
1242 		WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
1243 	}
1244 
1245 	bpf_prog_unlock_free(fp);
1246 }
1247 
bpf_jit_get_func_addr(const struct bpf_prog * prog,const struct bpf_insn * insn,bool extra_pass,u64 * func_addr,bool * func_addr_fixed)1248 int bpf_jit_get_func_addr(const struct bpf_prog *prog,
1249 			  const struct bpf_insn *insn, bool extra_pass,
1250 			  u64 *func_addr, bool *func_addr_fixed)
1251 {
1252 	s16 off = insn->off;
1253 	s32 imm = insn->imm;
1254 	u8 *addr;
1255 	int err;
1256 
1257 	*func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
1258 	if (!*func_addr_fixed) {
1259 		/* Place-holder address till the last pass has collected
1260 		 * all addresses for JITed subprograms in which case we
1261 		 * can pick them up from prog->aux.
1262 		 */
1263 		if (!extra_pass)
1264 			addr = NULL;
1265 		else if (prog->aux->func &&
1266 			 off >= 0 && off < prog->aux->real_func_cnt)
1267 			addr = (u8 *)prog->aux->func[off]->bpf_func;
1268 		else
1269 			return -EINVAL;
1270 	} else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
1271 		   bpf_jit_supports_far_kfunc_call()) {
1272 		err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr);
1273 		if (err)
1274 			return err;
1275 	} else {
1276 		/* Address of a BPF helper call. Since part of the core
1277 		 * kernel, it's always at a fixed location. __bpf_call_base
1278 		 * and the helper with imm relative to it are both in core
1279 		 * kernel.
1280 		 */
1281 		addr = (u8 *)__bpf_call_base + imm;
1282 	}
1283 
1284 	*func_addr = (unsigned long)addr;
1285 	return 0;
1286 }
1287 
bpf_jit_blind_insn(const struct bpf_insn * from,const struct bpf_insn * aux,struct bpf_insn * to_buff,bool emit_zext)1288 static int bpf_jit_blind_insn(const struct bpf_insn *from,
1289 			      const struct bpf_insn *aux,
1290 			      struct bpf_insn *to_buff,
1291 			      bool emit_zext)
1292 {
1293 	struct bpf_insn *to = to_buff;
1294 	u32 imm_rnd = get_random_u32();
1295 	s16 off;
1296 
1297 	BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
1298 	BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
1299 
1300 	/* Constraints on AX register:
1301 	 *
1302 	 * AX register is inaccessible from user space. It is mapped in
1303 	 * all JITs, and used here for constant blinding rewrites. It is
1304 	 * typically "stateless" meaning its contents are only valid within
1305 	 * the executed instruction, but not across several instructions.
1306 	 * There are a few exceptions however which are further detailed
1307 	 * below.
1308 	 *
1309 	 * Constant blinding is only used by JITs, not in the interpreter.
1310 	 * The interpreter uses AX in some occasions as a local temporary
1311 	 * register e.g. in DIV or MOD instructions.
1312 	 *
1313 	 * In restricted circumstances, the verifier can also use the AX
1314 	 * register for rewrites as long as they do not interfere with
1315 	 * the above cases!
1316 	 */
1317 	if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
1318 		goto out;
1319 
1320 	if (from->imm == 0 &&
1321 	    (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
1322 	     from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
1323 		*to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
1324 		goto out;
1325 	}
1326 
1327 	switch (from->code) {
1328 	case BPF_ALU | BPF_ADD | BPF_K:
1329 	case BPF_ALU | BPF_SUB | BPF_K:
1330 	case BPF_ALU | BPF_AND | BPF_K:
1331 	case BPF_ALU | BPF_OR  | BPF_K:
1332 	case BPF_ALU | BPF_XOR | BPF_K:
1333 	case BPF_ALU | BPF_MUL | BPF_K:
1334 	case BPF_ALU | BPF_MOV | BPF_K:
1335 	case BPF_ALU | BPF_DIV | BPF_K:
1336 	case BPF_ALU | BPF_MOD | BPF_K:
1337 		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1338 		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1339 		*to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1340 		break;
1341 
1342 	case BPF_ALU64 | BPF_ADD | BPF_K:
1343 	case BPF_ALU64 | BPF_SUB | BPF_K:
1344 	case BPF_ALU64 | BPF_AND | BPF_K:
1345 	case BPF_ALU64 | BPF_OR  | BPF_K:
1346 	case BPF_ALU64 | BPF_XOR | BPF_K:
1347 	case BPF_ALU64 | BPF_MUL | BPF_K:
1348 	case BPF_ALU64 | BPF_MOV | BPF_K:
1349 	case BPF_ALU64 | BPF_DIV | BPF_K:
1350 	case BPF_ALU64 | BPF_MOD | BPF_K:
1351 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1352 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1353 		*to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1354 		break;
1355 
1356 	case BPF_JMP | BPF_JEQ  | BPF_K:
1357 	case BPF_JMP | BPF_JNE  | BPF_K:
1358 	case BPF_JMP | BPF_JGT  | BPF_K:
1359 	case BPF_JMP | BPF_JLT  | BPF_K:
1360 	case BPF_JMP | BPF_JGE  | BPF_K:
1361 	case BPF_JMP | BPF_JLE  | BPF_K:
1362 	case BPF_JMP | BPF_JSGT | BPF_K:
1363 	case BPF_JMP | BPF_JSLT | BPF_K:
1364 	case BPF_JMP | BPF_JSGE | BPF_K:
1365 	case BPF_JMP | BPF_JSLE | BPF_K:
1366 	case BPF_JMP | BPF_JSET | BPF_K:
1367 		/* Accommodate for extra offset in case of a backjump. */
1368 		off = from->off;
1369 		if (off < 0)
1370 			off -= 2;
1371 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1372 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1373 		*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
1374 		break;
1375 
1376 	case BPF_JMP32 | BPF_JEQ  | BPF_K:
1377 	case BPF_JMP32 | BPF_JNE  | BPF_K:
1378 	case BPF_JMP32 | BPF_JGT  | BPF_K:
1379 	case BPF_JMP32 | BPF_JLT  | BPF_K:
1380 	case BPF_JMP32 | BPF_JGE  | BPF_K:
1381 	case BPF_JMP32 | BPF_JLE  | BPF_K:
1382 	case BPF_JMP32 | BPF_JSGT | BPF_K:
1383 	case BPF_JMP32 | BPF_JSLT | BPF_K:
1384 	case BPF_JMP32 | BPF_JSGE | BPF_K:
1385 	case BPF_JMP32 | BPF_JSLE | BPF_K:
1386 	case BPF_JMP32 | BPF_JSET | BPF_K:
1387 		/* Accommodate for extra offset in case of a backjump. */
1388 		off = from->off;
1389 		if (off < 0)
1390 			off -= 2;
1391 		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1392 		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1393 		*to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
1394 				      off);
1395 		break;
1396 
1397 	case BPF_LD | BPF_IMM | BPF_DW:
1398 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
1399 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1400 		*to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
1401 		*to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
1402 		break;
1403 	case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
1404 		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
1405 		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1406 		if (emit_zext)
1407 			*to++ = BPF_ZEXT_REG(BPF_REG_AX);
1408 		*to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
1409 		break;
1410 
1411 	case BPF_ST | BPF_MEM | BPF_DW:
1412 	case BPF_ST | BPF_MEM | BPF_W:
1413 	case BPF_ST | BPF_MEM | BPF_H:
1414 	case BPF_ST | BPF_MEM | BPF_B:
1415 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1416 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1417 		*to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
1418 		break;
1419 	}
1420 out:
1421 	return to - to_buff;
1422 }
1423 
bpf_prog_clone_create(struct bpf_prog * fp_other,gfp_t gfp_extra_flags)1424 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
1425 					      gfp_t gfp_extra_flags)
1426 {
1427 	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
1428 	struct bpf_prog *fp;
1429 
1430 	fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
1431 	if (fp != NULL) {
1432 		/* aux->prog still points to the fp_other one, so
1433 		 * when promoting the clone to the real program,
1434 		 * this still needs to be adapted.
1435 		 */
1436 		memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
1437 	}
1438 
1439 	return fp;
1440 }
1441 
bpf_prog_clone_free(struct bpf_prog * fp)1442 static void bpf_prog_clone_free(struct bpf_prog *fp)
1443 {
1444 	/* aux was stolen by the other clone, so we cannot free
1445 	 * it from this path! It will be freed eventually by the
1446 	 * other program on release.
1447 	 *
1448 	 * At this point, we don't need a deferred release since
1449 	 * clone is guaranteed to not be locked.
1450 	 */
1451 	fp->aux = NULL;
1452 	fp->stats = NULL;
1453 	fp->active = NULL;
1454 	__bpf_prog_free(fp);
1455 }
1456 
bpf_jit_prog_release_other(struct bpf_prog * fp,struct bpf_prog * fp_other)1457 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
1458 {
1459 	/* We have to repoint aux->prog to self, as we don't
1460 	 * know whether fp here is the clone or the original.
1461 	 */
1462 	fp->aux->prog = fp;
1463 	bpf_prog_clone_free(fp_other);
1464 }
1465 
bpf_jit_blind_constants(struct bpf_prog * prog)1466 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
1467 {
1468 	struct bpf_insn insn_buff[16], aux[2];
1469 	struct bpf_prog *clone, *tmp;
1470 	int insn_delta, insn_cnt;
1471 	struct bpf_insn *insn;
1472 	int i, rewritten;
1473 
1474 	if (!prog->blinding_requested || prog->blinded)
1475 		return prog;
1476 
1477 	clone = bpf_prog_clone_create(prog, GFP_USER);
1478 	if (!clone)
1479 		return ERR_PTR(-ENOMEM);
1480 
1481 	insn_cnt = clone->len;
1482 	insn = clone->insnsi;
1483 
1484 	for (i = 0; i < insn_cnt; i++, insn++) {
1485 		if (bpf_pseudo_func(insn)) {
1486 			/* ld_imm64 with an address of bpf subprog is not
1487 			 * a user controlled constant. Don't randomize it,
1488 			 * since it will conflict with jit_subprogs() logic.
1489 			 */
1490 			insn++;
1491 			i++;
1492 			continue;
1493 		}
1494 
1495 		/* We temporarily need to hold the original ld64 insn
1496 		 * so that we can still access the first part in the
1497 		 * second blinding run.
1498 		 */
1499 		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
1500 		    insn[1].code == 0)
1501 			memcpy(aux, insn, sizeof(aux));
1502 
1503 		rewritten = bpf_jit_blind_insn(insn, aux, insn_buff,
1504 						clone->aux->verifier_zext);
1505 		if (!rewritten)
1506 			continue;
1507 
1508 		tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
1509 		if (IS_ERR(tmp)) {
1510 			/* Patching may have repointed aux->prog during
1511 			 * realloc from the original one, so we need to
1512 			 * fix it up here on error.
1513 			 */
1514 			bpf_jit_prog_release_other(prog, clone);
1515 			return tmp;
1516 		}
1517 
1518 		clone = tmp;
1519 		insn_delta = rewritten - 1;
1520 
1521 		/* Walk new program and skip insns we just inserted. */
1522 		insn = clone->insnsi + i + insn_delta;
1523 		insn_cnt += insn_delta;
1524 		i        += insn_delta;
1525 	}
1526 
1527 	clone->blinded = 1;
1528 	return clone;
1529 }
1530 #endif /* CONFIG_BPF_JIT */
1531 
1532 /* Base function for offset calculation. Needs to go into .text section,
1533  * therefore keeping it non-static as well; will also be used by JITs
1534  * anyway later on, so do not let the compiler omit it. This also needs
1535  * to go into kallsyms for correlation from e.g. bpftool, so naming
1536  * must not change.
1537  */
__bpf_call_base(u64 r1,u64 r2,u64 r3,u64 r4,u64 r5)1538 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1539 {
1540 	return 0;
1541 }
1542 EXPORT_SYMBOL_GPL(__bpf_call_base);
1543 
1544 /* All UAPI available opcodes. */
1545 #define BPF_INSN_MAP(INSN_2, INSN_3)		\
1546 	/* 32 bit ALU operations. */		\
1547 	/*   Register based. */			\
1548 	INSN_3(ALU, ADD,  X),			\
1549 	INSN_3(ALU, SUB,  X),			\
1550 	INSN_3(ALU, AND,  X),			\
1551 	INSN_3(ALU, OR,   X),			\
1552 	INSN_3(ALU, LSH,  X),			\
1553 	INSN_3(ALU, RSH,  X),			\
1554 	INSN_3(ALU, XOR,  X),			\
1555 	INSN_3(ALU, MUL,  X),			\
1556 	INSN_3(ALU, MOV,  X),			\
1557 	INSN_3(ALU, ARSH, X),			\
1558 	INSN_3(ALU, DIV,  X),			\
1559 	INSN_3(ALU, MOD,  X),			\
1560 	INSN_2(ALU, NEG),			\
1561 	INSN_3(ALU, END, TO_BE),		\
1562 	INSN_3(ALU, END, TO_LE),		\
1563 	/*   Immediate based. */		\
1564 	INSN_3(ALU, ADD,  K),			\
1565 	INSN_3(ALU, SUB,  K),			\
1566 	INSN_3(ALU, AND,  K),			\
1567 	INSN_3(ALU, OR,   K),			\
1568 	INSN_3(ALU, LSH,  K),			\
1569 	INSN_3(ALU, RSH,  K),			\
1570 	INSN_3(ALU, XOR,  K),			\
1571 	INSN_3(ALU, MUL,  K),			\
1572 	INSN_3(ALU, MOV,  K),			\
1573 	INSN_3(ALU, ARSH, K),			\
1574 	INSN_3(ALU, DIV,  K),			\
1575 	INSN_3(ALU, MOD,  K),			\
1576 	/* 64 bit ALU operations. */		\
1577 	/*   Register based. */			\
1578 	INSN_3(ALU64, ADD,  X),			\
1579 	INSN_3(ALU64, SUB,  X),			\
1580 	INSN_3(ALU64, AND,  X),			\
1581 	INSN_3(ALU64, OR,   X),			\
1582 	INSN_3(ALU64, LSH,  X),			\
1583 	INSN_3(ALU64, RSH,  X),			\
1584 	INSN_3(ALU64, XOR,  X),			\
1585 	INSN_3(ALU64, MUL,  X),			\
1586 	INSN_3(ALU64, MOV,  X),			\
1587 	INSN_3(ALU64, ARSH, X),			\
1588 	INSN_3(ALU64, DIV,  X),			\
1589 	INSN_3(ALU64, MOD,  X),			\
1590 	INSN_2(ALU64, NEG),			\
1591 	INSN_3(ALU64, END, TO_LE),		\
1592 	/*   Immediate based. */		\
1593 	INSN_3(ALU64, ADD,  K),			\
1594 	INSN_3(ALU64, SUB,  K),			\
1595 	INSN_3(ALU64, AND,  K),			\
1596 	INSN_3(ALU64, OR,   K),			\
1597 	INSN_3(ALU64, LSH,  K),			\
1598 	INSN_3(ALU64, RSH,  K),			\
1599 	INSN_3(ALU64, XOR,  K),			\
1600 	INSN_3(ALU64, MUL,  K),			\
1601 	INSN_3(ALU64, MOV,  K),			\
1602 	INSN_3(ALU64, ARSH, K),			\
1603 	INSN_3(ALU64, DIV,  K),			\
1604 	INSN_3(ALU64, MOD,  K),			\
1605 	/* Call instruction. */			\
1606 	INSN_2(JMP, CALL),			\
1607 	/* Exit instruction. */			\
1608 	INSN_2(JMP, EXIT),			\
1609 	/* 32-bit Jump instructions. */		\
1610 	/*   Register based. */			\
1611 	INSN_3(JMP32, JEQ,  X),			\
1612 	INSN_3(JMP32, JNE,  X),			\
1613 	INSN_3(JMP32, JGT,  X),			\
1614 	INSN_3(JMP32, JLT,  X),			\
1615 	INSN_3(JMP32, JGE,  X),			\
1616 	INSN_3(JMP32, JLE,  X),			\
1617 	INSN_3(JMP32, JSGT, X),			\
1618 	INSN_3(JMP32, JSLT, X),			\
1619 	INSN_3(JMP32, JSGE, X),			\
1620 	INSN_3(JMP32, JSLE, X),			\
1621 	INSN_3(JMP32, JSET, X),			\
1622 	/*   Immediate based. */		\
1623 	INSN_3(JMP32, JEQ,  K),			\
1624 	INSN_3(JMP32, JNE,  K),			\
1625 	INSN_3(JMP32, JGT,  K),			\
1626 	INSN_3(JMP32, JLT,  K),			\
1627 	INSN_3(JMP32, JGE,  K),			\
1628 	INSN_3(JMP32, JLE,  K),			\
1629 	INSN_3(JMP32, JSGT, K),			\
1630 	INSN_3(JMP32, JSLT, K),			\
1631 	INSN_3(JMP32, JSGE, K),			\
1632 	INSN_3(JMP32, JSLE, K),			\
1633 	INSN_3(JMP32, JSET, K),			\
1634 	/* Jump instructions. */		\
1635 	/*   Register based. */			\
1636 	INSN_3(JMP, JEQ,  X),			\
1637 	INSN_3(JMP, JNE,  X),			\
1638 	INSN_3(JMP, JGT,  X),			\
1639 	INSN_3(JMP, JLT,  X),			\
1640 	INSN_3(JMP, JGE,  X),			\
1641 	INSN_3(JMP, JLE,  X),			\
1642 	INSN_3(JMP, JSGT, X),			\
1643 	INSN_3(JMP, JSLT, X),			\
1644 	INSN_3(JMP, JSGE, X),			\
1645 	INSN_3(JMP, JSLE, X),			\
1646 	INSN_3(JMP, JSET, X),			\
1647 	/*   Immediate based. */		\
1648 	INSN_3(JMP, JEQ,  K),			\
1649 	INSN_3(JMP, JNE,  K),			\
1650 	INSN_3(JMP, JGT,  K),			\
1651 	INSN_3(JMP, JLT,  K),			\
1652 	INSN_3(JMP, JGE,  K),			\
1653 	INSN_3(JMP, JLE,  K),			\
1654 	INSN_3(JMP, JSGT, K),			\
1655 	INSN_3(JMP, JSLT, K),			\
1656 	INSN_3(JMP, JSGE, K),			\
1657 	INSN_3(JMP, JSLE, K),			\
1658 	INSN_3(JMP, JSET, K),			\
1659 	INSN_2(JMP, JA),			\
1660 	INSN_2(JMP32, JA),			\
1661 	/* Store instructions. */		\
1662 	/*   Register based. */			\
1663 	INSN_3(STX, MEM,  B),			\
1664 	INSN_3(STX, MEM,  H),			\
1665 	INSN_3(STX, MEM,  W),			\
1666 	INSN_3(STX, MEM,  DW),			\
1667 	INSN_3(STX, ATOMIC, W),			\
1668 	INSN_3(STX, ATOMIC, DW),		\
1669 	/*   Immediate based. */		\
1670 	INSN_3(ST, MEM, B),			\
1671 	INSN_3(ST, MEM, H),			\
1672 	INSN_3(ST, MEM, W),			\
1673 	INSN_3(ST, MEM, DW),			\
1674 	/* Load instructions. */		\
1675 	/*   Register based. */			\
1676 	INSN_3(LDX, MEM, B),			\
1677 	INSN_3(LDX, MEM, H),			\
1678 	INSN_3(LDX, MEM, W),			\
1679 	INSN_3(LDX, MEM, DW),			\
1680 	INSN_3(LDX, MEMSX, B),			\
1681 	INSN_3(LDX, MEMSX, H),			\
1682 	INSN_3(LDX, MEMSX, W),			\
1683 	/*   Immediate based. */		\
1684 	INSN_3(LD, IMM, DW)
1685 
bpf_opcode_in_insntable(u8 code)1686 bool bpf_opcode_in_insntable(u8 code)
1687 {
1688 #define BPF_INSN_2_TBL(x, y)    [BPF_##x | BPF_##y] = true
1689 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
1690 	static const bool public_insntable[256] = {
1691 		[0 ... 255] = false,
1692 		/* Now overwrite non-defaults ... */
1693 		BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
1694 		/* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
1695 		[BPF_LD | BPF_ABS | BPF_B] = true,
1696 		[BPF_LD | BPF_ABS | BPF_H] = true,
1697 		[BPF_LD | BPF_ABS | BPF_W] = true,
1698 		[BPF_LD | BPF_IND | BPF_B] = true,
1699 		[BPF_LD | BPF_IND | BPF_H] = true,
1700 		[BPF_LD | BPF_IND | BPF_W] = true,
1701 		[BPF_JMP | BPF_JCOND] = true,
1702 	};
1703 #undef BPF_INSN_3_TBL
1704 #undef BPF_INSN_2_TBL
1705 	return public_insntable[code];
1706 }
1707 
1708 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1709 /**
1710  *	___bpf_prog_run - run eBPF program on a given context
1711  *	@regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
1712  *	@insn: is the array of eBPF instructions
1713  *
1714  * Decode and execute eBPF instructions.
1715  *
1716  * Return: whatever value is in %BPF_R0 at program exit
1717  */
___bpf_prog_run(u64 * regs,const struct bpf_insn * insn)1718 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
1719 {
1720 #define BPF_INSN_2_LBL(x, y)    [BPF_##x | BPF_##y] = &&x##_##y
1721 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
1722 	static const void * const jumptable[256] __annotate_jump_table = {
1723 		[0 ... 255] = &&default_label,
1724 		/* Now overwrite non-defaults ... */
1725 		BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
1726 		/* Non-UAPI available opcodes. */
1727 		[BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
1728 		[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
1729 		[BPF_ST  | BPF_NOSPEC] = &&ST_NOSPEC,
1730 		[BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
1731 		[BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
1732 		[BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
1733 		[BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
1734 		[BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B,
1735 		[BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H,
1736 		[BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W,
1737 	};
1738 #undef BPF_INSN_3_LBL
1739 #undef BPF_INSN_2_LBL
1740 	u32 tail_call_cnt = 0;
1741 
1742 #define CONT	 ({ insn++; goto select_insn; })
1743 #define CONT_JMP ({ insn++; goto select_insn; })
1744 
1745 select_insn:
1746 	goto *jumptable[insn->code];
1747 
1748 	/* Explicitly mask the register-based shift amounts with 63 or 31
1749 	 * to avoid undefined behavior. Normally this won't affect the
1750 	 * generated code, for example, in case of native 64 bit archs such
1751 	 * as x86-64 or arm64, the compiler is optimizing the AND away for
1752 	 * the interpreter. In case of JITs, each of the JIT backends compiles
1753 	 * the BPF shift operations to machine instructions which produce
1754 	 * implementation-defined results in such a case; the resulting
1755 	 * contents of the register may be arbitrary, but program behaviour
1756 	 * as a whole remains defined. In other words, in case of JIT backends,
1757 	 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation.
1758 	 */
1759 	/* ALU (shifts) */
1760 #define SHT(OPCODE, OP)					\
1761 	ALU64_##OPCODE##_X:				\
1762 		DST = DST OP (SRC & 63);		\
1763 		CONT;					\
1764 	ALU_##OPCODE##_X:				\
1765 		DST = (u32) DST OP ((u32) SRC & 31);	\
1766 		CONT;					\
1767 	ALU64_##OPCODE##_K:				\
1768 		DST = DST OP IMM;			\
1769 		CONT;					\
1770 	ALU_##OPCODE##_K:				\
1771 		DST = (u32) DST OP (u32) IMM;		\
1772 		CONT;
1773 	/* ALU (rest) */
1774 #define ALU(OPCODE, OP)					\
1775 	ALU64_##OPCODE##_X:				\
1776 		DST = DST OP SRC;			\
1777 		CONT;					\
1778 	ALU_##OPCODE##_X:				\
1779 		DST = (u32) DST OP (u32) SRC;		\
1780 		CONT;					\
1781 	ALU64_##OPCODE##_K:				\
1782 		DST = DST OP IMM;			\
1783 		CONT;					\
1784 	ALU_##OPCODE##_K:				\
1785 		DST = (u32) DST OP (u32) IMM;		\
1786 		CONT;
1787 	ALU(ADD,  +)
1788 	ALU(SUB,  -)
1789 	ALU(AND,  &)
1790 	ALU(OR,   |)
1791 	ALU(XOR,  ^)
1792 	ALU(MUL,  *)
1793 	SHT(LSH, <<)
1794 	SHT(RSH, >>)
1795 #undef SHT
1796 #undef ALU
1797 	ALU_NEG:
1798 		DST = (u32) -DST;
1799 		CONT;
1800 	ALU64_NEG:
1801 		DST = -DST;
1802 		CONT;
1803 	ALU_MOV_X:
1804 		switch (OFF) {
1805 		case 0:
1806 			DST = (u32) SRC;
1807 			break;
1808 		case 8:
1809 			DST = (u32)(s8) SRC;
1810 			break;
1811 		case 16:
1812 			DST = (u32)(s16) SRC;
1813 			break;
1814 		}
1815 		CONT;
1816 	ALU_MOV_K:
1817 		DST = (u32) IMM;
1818 		CONT;
1819 	ALU64_MOV_X:
1820 		switch (OFF) {
1821 		case 0:
1822 			DST = SRC;
1823 			break;
1824 		case 8:
1825 			DST = (s8) SRC;
1826 			break;
1827 		case 16:
1828 			DST = (s16) SRC;
1829 			break;
1830 		case 32:
1831 			DST = (s32) SRC;
1832 			break;
1833 		}
1834 		CONT;
1835 	ALU64_MOV_K:
1836 		DST = IMM;
1837 		CONT;
1838 	LD_IMM_DW:
1839 		DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
1840 		insn++;
1841 		CONT;
1842 	ALU_ARSH_X:
1843 		DST = (u64) (u32) (((s32) DST) >> (SRC & 31));
1844 		CONT;
1845 	ALU_ARSH_K:
1846 		DST = (u64) (u32) (((s32) DST) >> IMM);
1847 		CONT;
1848 	ALU64_ARSH_X:
1849 		(*(s64 *) &DST) >>= (SRC & 63);
1850 		CONT;
1851 	ALU64_ARSH_K:
1852 		(*(s64 *) &DST) >>= IMM;
1853 		CONT;
1854 	ALU64_MOD_X:
1855 		switch (OFF) {
1856 		case 0:
1857 			div64_u64_rem(DST, SRC, &AX);
1858 			DST = AX;
1859 			break;
1860 		case 1:
1861 			AX = div64_s64(DST, SRC);
1862 			DST = DST - AX * SRC;
1863 			break;
1864 		}
1865 		CONT;
1866 	ALU_MOD_X:
1867 		switch (OFF) {
1868 		case 0:
1869 			AX = (u32) DST;
1870 			DST = do_div(AX, (u32) SRC);
1871 			break;
1872 		case 1:
1873 			AX = abs((s32)DST);
1874 			AX = do_div(AX, abs((s32)SRC));
1875 			if ((s32)DST < 0)
1876 				DST = (u32)-AX;
1877 			else
1878 				DST = (u32)AX;
1879 			break;
1880 		}
1881 		CONT;
1882 	ALU64_MOD_K:
1883 		switch (OFF) {
1884 		case 0:
1885 			div64_u64_rem(DST, IMM, &AX);
1886 			DST = AX;
1887 			break;
1888 		case 1:
1889 			AX = div64_s64(DST, IMM);
1890 			DST = DST - AX * IMM;
1891 			break;
1892 		}
1893 		CONT;
1894 	ALU_MOD_K:
1895 		switch (OFF) {
1896 		case 0:
1897 			AX = (u32) DST;
1898 			DST = do_div(AX, (u32) IMM);
1899 			break;
1900 		case 1:
1901 			AX = abs((s32)DST);
1902 			AX = do_div(AX, abs((s32)IMM));
1903 			if ((s32)DST < 0)
1904 				DST = (u32)-AX;
1905 			else
1906 				DST = (u32)AX;
1907 			break;
1908 		}
1909 		CONT;
1910 	ALU64_DIV_X:
1911 		switch (OFF) {
1912 		case 0:
1913 			DST = div64_u64(DST, SRC);
1914 			break;
1915 		case 1:
1916 			DST = div64_s64(DST, SRC);
1917 			break;
1918 		}
1919 		CONT;
1920 	ALU_DIV_X:
1921 		switch (OFF) {
1922 		case 0:
1923 			AX = (u32) DST;
1924 			do_div(AX, (u32) SRC);
1925 			DST = (u32) AX;
1926 			break;
1927 		case 1:
1928 			AX = abs((s32)DST);
1929 			do_div(AX, abs((s32)SRC));
1930 			if (((s32)DST < 0) == ((s32)SRC < 0))
1931 				DST = (u32)AX;
1932 			else
1933 				DST = (u32)-AX;
1934 			break;
1935 		}
1936 		CONT;
1937 	ALU64_DIV_K:
1938 		switch (OFF) {
1939 		case 0:
1940 			DST = div64_u64(DST, IMM);
1941 			break;
1942 		case 1:
1943 			DST = div64_s64(DST, IMM);
1944 			break;
1945 		}
1946 		CONT;
1947 	ALU_DIV_K:
1948 		switch (OFF) {
1949 		case 0:
1950 			AX = (u32) DST;
1951 			do_div(AX, (u32) IMM);
1952 			DST = (u32) AX;
1953 			break;
1954 		case 1:
1955 			AX = abs((s32)DST);
1956 			do_div(AX, abs((s32)IMM));
1957 			if (((s32)DST < 0) == ((s32)IMM < 0))
1958 				DST = (u32)AX;
1959 			else
1960 				DST = (u32)-AX;
1961 			break;
1962 		}
1963 		CONT;
1964 	ALU_END_TO_BE:
1965 		switch (IMM) {
1966 		case 16:
1967 			DST = (__force u16) cpu_to_be16(DST);
1968 			break;
1969 		case 32:
1970 			DST = (__force u32) cpu_to_be32(DST);
1971 			break;
1972 		case 64:
1973 			DST = (__force u64) cpu_to_be64(DST);
1974 			break;
1975 		}
1976 		CONT;
1977 	ALU_END_TO_LE:
1978 		switch (IMM) {
1979 		case 16:
1980 			DST = (__force u16) cpu_to_le16(DST);
1981 			break;
1982 		case 32:
1983 			DST = (__force u32) cpu_to_le32(DST);
1984 			break;
1985 		case 64:
1986 			DST = (__force u64) cpu_to_le64(DST);
1987 			break;
1988 		}
1989 		CONT;
1990 	ALU64_END_TO_LE:
1991 		switch (IMM) {
1992 		case 16:
1993 			DST = (__force u16) __swab16(DST);
1994 			break;
1995 		case 32:
1996 			DST = (__force u32) __swab32(DST);
1997 			break;
1998 		case 64:
1999 			DST = (__force u64) __swab64(DST);
2000 			break;
2001 		}
2002 		CONT;
2003 
2004 	/* CALL */
2005 	JMP_CALL:
2006 		/* Function call scratches BPF_R1-BPF_R5 registers,
2007 		 * preserves BPF_R6-BPF_R9, and stores return value
2008 		 * into BPF_R0.
2009 		 */
2010 		BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
2011 						       BPF_R4, BPF_R5);
2012 		CONT;
2013 
2014 	JMP_CALL_ARGS:
2015 		BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
2016 							    BPF_R3, BPF_R4,
2017 							    BPF_R5,
2018 							    insn + insn->off + 1);
2019 		CONT;
2020 
2021 	JMP_TAIL_CALL: {
2022 		struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
2023 		struct bpf_array *array = container_of(map, struct bpf_array, map);
2024 		struct bpf_prog *prog;
2025 		u32 index = BPF_R3;
2026 
2027 		if (unlikely(index >= array->map.max_entries))
2028 			goto out;
2029 
2030 		if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT))
2031 			goto out;
2032 
2033 		tail_call_cnt++;
2034 
2035 		prog = READ_ONCE(array->ptrs[index]);
2036 		if (!prog)
2037 			goto out;
2038 
2039 		/* ARG1 at this point is guaranteed to point to CTX from
2040 		 * the verifier side due to the fact that the tail call is
2041 		 * handled like a helper, that is, bpf_tail_call_proto,
2042 		 * where arg1_type is ARG_PTR_TO_CTX.
2043 		 */
2044 		insn = prog->insnsi;
2045 		goto select_insn;
2046 out:
2047 		CONT;
2048 	}
2049 	JMP_JA:
2050 		insn += insn->off;
2051 		CONT;
2052 	JMP32_JA:
2053 		insn += insn->imm;
2054 		CONT;
2055 	JMP_EXIT:
2056 		return BPF_R0;
2057 	/* JMP */
2058 #define COND_JMP(SIGN, OPCODE, CMP_OP)				\
2059 	JMP_##OPCODE##_X:					\
2060 		if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) {	\
2061 			insn += insn->off;			\
2062 			CONT_JMP;				\
2063 		}						\
2064 		CONT;						\
2065 	JMP32_##OPCODE##_X:					\
2066 		if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) {	\
2067 			insn += insn->off;			\
2068 			CONT_JMP;				\
2069 		}						\
2070 		CONT;						\
2071 	JMP_##OPCODE##_K:					\
2072 		if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) {	\
2073 			insn += insn->off;			\
2074 			CONT_JMP;				\
2075 		}						\
2076 		CONT;						\
2077 	JMP32_##OPCODE##_K:					\
2078 		if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) {	\
2079 			insn += insn->off;			\
2080 			CONT_JMP;				\
2081 		}						\
2082 		CONT;
2083 	COND_JMP(u, JEQ, ==)
2084 	COND_JMP(u, JNE, !=)
2085 	COND_JMP(u, JGT, >)
2086 	COND_JMP(u, JLT, <)
2087 	COND_JMP(u, JGE, >=)
2088 	COND_JMP(u, JLE, <=)
2089 	COND_JMP(u, JSET, &)
2090 	COND_JMP(s, JSGT, >)
2091 	COND_JMP(s, JSLT, <)
2092 	COND_JMP(s, JSGE, >=)
2093 	COND_JMP(s, JSLE, <=)
2094 #undef COND_JMP
2095 	/* ST, STX and LDX*/
2096 	ST_NOSPEC:
2097 		/* Speculation barrier for mitigating Speculative Store Bypass.
2098 		 * In case of arm64, we rely on the firmware mitigation as
2099 		 * controlled via the ssbd kernel parameter. Whenever the
2100 		 * mitigation is enabled, it works for all of the kernel code
2101 		 * with no need to provide any additional instructions here.
2102 		 * In case of x86, we use 'lfence' insn for mitigation. We
2103 		 * reuse preexisting logic from Spectre v1 mitigation that
2104 		 * happens to produce the required code on x86 for v4 as well.
2105 		 */
2106 		barrier_nospec();
2107 		CONT;
2108 #define LDST(SIZEOP, SIZE)						\
2109 	STX_MEM_##SIZEOP:						\
2110 		*(SIZE *)(unsigned long) (DST + insn->off) = SRC;	\
2111 		CONT;							\
2112 	ST_MEM_##SIZEOP:						\
2113 		*(SIZE *)(unsigned long) (DST + insn->off) = IMM;	\
2114 		CONT;							\
2115 	LDX_MEM_##SIZEOP:						\
2116 		DST = *(SIZE *)(unsigned long) (SRC + insn->off);	\
2117 		CONT;							\
2118 	LDX_PROBE_MEM_##SIZEOP:						\
2119 		bpf_probe_read_kernel_common(&DST, sizeof(SIZE),	\
2120 			      (const void *)(long) (SRC + insn->off));	\
2121 		DST = *((SIZE *)&DST);					\
2122 		CONT;
2123 
2124 	LDST(B,   u8)
2125 	LDST(H,  u16)
2126 	LDST(W,  u32)
2127 	LDST(DW, u64)
2128 #undef LDST
2129 
2130 #define LDSX(SIZEOP, SIZE)						\
2131 	LDX_MEMSX_##SIZEOP:						\
2132 		DST = *(SIZE *)(unsigned long) (SRC + insn->off);	\
2133 		CONT;							\
2134 	LDX_PROBE_MEMSX_##SIZEOP:					\
2135 		bpf_probe_read_kernel_common(&DST, sizeof(SIZE),		\
2136 				      (const void *)(long) (SRC + insn->off));	\
2137 		DST = *((SIZE *)&DST);					\
2138 		CONT;
2139 
2140 	LDSX(B,   s8)
2141 	LDSX(H,  s16)
2142 	LDSX(W,  s32)
2143 #undef LDSX
2144 
2145 #define ATOMIC_ALU_OP(BOP, KOP)						\
2146 		case BOP:						\
2147 			if (BPF_SIZE(insn->code) == BPF_W)		\
2148 				atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
2149 					     (DST + insn->off));	\
2150 			else						\
2151 				atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
2152 					       (DST + insn->off));	\
2153 			break;						\
2154 		case BOP | BPF_FETCH:					\
2155 			if (BPF_SIZE(insn->code) == BPF_W)		\
2156 				SRC = (u32) atomic_fetch_##KOP(		\
2157 					(u32) SRC,			\
2158 					(atomic_t *)(unsigned long) (DST + insn->off)); \
2159 			else						\
2160 				SRC = (u64) atomic64_fetch_##KOP(	\
2161 					(u64) SRC,			\
2162 					(atomic64_t *)(unsigned long) (DST + insn->off)); \
2163 			break;
2164 
2165 	STX_ATOMIC_DW:
2166 	STX_ATOMIC_W:
2167 		switch (IMM) {
2168 		ATOMIC_ALU_OP(BPF_ADD, add)
2169 		ATOMIC_ALU_OP(BPF_AND, and)
2170 		ATOMIC_ALU_OP(BPF_OR, or)
2171 		ATOMIC_ALU_OP(BPF_XOR, xor)
2172 #undef ATOMIC_ALU_OP
2173 
2174 		case BPF_XCHG:
2175 			if (BPF_SIZE(insn->code) == BPF_W)
2176 				SRC = (u32) atomic_xchg(
2177 					(atomic_t *)(unsigned long) (DST + insn->off),
2178 					(u32) SRC);
2179 			else
2180 				SRC = (u64) atomic64_xchg(
2181 					(atomic64_t *)(unsigned long) (DST + insn->off),
2182 					(u64) SRC);
2183 			break;
2184 		case BPF_CMPXCHG:
2185 			if (BPF_SIZE(insn->code) == BPF_W)
2186 				BPF_R0 = (u32) atomic_cmpxchg(
2187 					(atomic_t *)(unsigned long) (DST + insn->off),
2188 					(u32) BPF_R0, (u32) SRC);
2189 			else
2190 				BPF_R0 = (u64) atomic64_cmpxchg(
2191 					(atomic64_t *)(unsigned long) (DST + insn->off),
2192 					(u64) BPF_R0, (u64) SRC);
2193 			break;
2194 
2195 		default:
2196 			goto default_label;
2197 		}
2198 		CONT;
2199 
2200 	default_label:
2201 		/* If we ever reach this, we have a bug somewhere. Die hard here
2202 		 * instead of just returning 0; we could be somewhere in a subprog,
2203 		 * so execution could continue otherwise which we do /not/ want.
2204 		 *
2205 		 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
2206 		 */
2207 		pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n",
2208 			insn->code, insn->imm);
2209 		BUG_ON(1);
2210 		return 0;
2211 }
2212 
2213 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
2214 #define DEFINE_BPF_PROG_RUN(stack_size) \
2215 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
2216 { \
2217 	u64 stack[stack_size / sizeof(u64)]; \
2218 	u64 regs[MAX_BPF_EXT_REG] = {}; \
2219 \
2220 	kmsan_unpoison_memory(stack, sizeof(stack)); \
2221 	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2222 	ARG1 = (u64) (unsigned long) ctx; \
2223 	return ___bpf_prog_run(regs, insn); \
2224 }
2225 
2226 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
2227 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
2228 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
2229 				      const struct bpf_insn *insn) \
2230 { \
2231 	u64 stack[stack_size / sizeof(u64)]; \
2232 	u64 regs[MAX_BPF_EXT_REG]; \
2233 \
2234 	kmsan_unpoison_memory(stack, sizeof(stack)); \
2235 	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2236 	BPF_R1 = r1; \
2237 	BPF_R2 = r2; \
2238 	BPF_R3 = r3; \
2239 	BPF_R4 = r4; \
2240 	BPF_R5 = r5; \
2241 	return ___bpf_prog_run(regs, insn); \
2242 }
2243 
2244 #define EVAL1(FN, X) FN(X)
2245 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
2246 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
2247 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
2248 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
2249 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
2250 
2251 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
2252 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
2253 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
2254 
2255 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
2256 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
2257 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
2258 
2259 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
2260 
2261 static unsigned int (*interpreters[])(const void *ctx,
2262 				      const struct bpf_insn *insn) = {
2263 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2264 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2265 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2266 };
2267 #undef PROG_NAME_LIST
2268 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
2269 static __maybe_unused
2270 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
2271 			   const struct bpf_insn *insn) = {
2272 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2273 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2274 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2275 };
2276 #undef PROG_NAME_LIST
2277 
2278 #ifdef CONFIG_BPF_SYSCALL
bpf_patch_call_args(struct bpf_insn * insn,u32 stack_depth)2279 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
2280 {
2281 	stack_depth = max_t(u32, stack_depth, 1);
2282 	insn->off = (s16) insn->imm;
2283 	insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
2284 		__bpf_call_base_args;
2285 	insn->code = BPF_JMP | BPF_CALL_ARGS;
2286 }
2287 #endif
2288 #else
__bpf_prog_ret0_warn(const void * ctx,const struct bpf_insn * insn)2289 static unsigned int __bpf_prog_ret0_warn(const void *ctx,
2290 					 const struct bpf_insn *insn)
2291 {
2292 	/* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
2293 	 * is not working properly, so warn about it!
2294 	 */
2295 	WARN_ON_ONCE(1);
2296 	return 0;
2297 }
2298 #endif
2299 
bpf_prog_map_compatible(struct bpf_map * map,const struct bpf_prog * fp)2300 bool bpf_prog_map_compatible(struct bpf_map *map,
2301 			     const struct bpf_prog *fp)
2302 {
2303 	enum bpf_prog_type prog_type = resolve_prog_type(fp);
2304 	bool ret;
2305 	struct bpf_prog_aux *aux = fp->aux;
2306 
2307 	if (fp->kprobe_override)
2308 		return false;
2309 
2310 	/* XDP programs inserted into maps are not guaranteed to run on
2311 	 * a particular netdev (and can run outside driver context entirely
2312 	 * in the case of devmap and cpumap). Until device checks
2313 	 * are implemented, prohibit adding dev-bound programs to program maps.
2314 	 */
2315 	if (bpf_prog_is_dev_bound(aux))
2316 		return false;
2317 
2318 	spin_lock(&map->owner.lock);
2319 	if (!map->owner.type) {
2320 		/* There's no owner yet where we could check for
2321 		 * compatibility.
2322 		 */
2323 		map->owner.type  = prog_type;
2324 		map->owner.jited = fp->jited;
2325 		map->owner.xdp_has_frags = aux->xdp_has_frags;
2326 		map->owner.attach_func_proto = aux->attach_func_proto;
2327 		ret = true;
2328 	} else {
2329 		ret = map->owner.type  == prog_type &&
2330 		      map->owner.jited == fp->jited &&
2331 		      map->owner.xdp_has_frags == aux->xdp_has_frags;
2332 		if (ret &&
2333 		    map->owner.attach_func_proto != aux->attach_func_proto) {
2334 			switch (prog_type) {
2335 			case BPF_PROG_TYPE_TRACING:
2336 			case BPF_PROG_TYPE_LSM:
2337 			case BPF_PROG_TYPE_EXT:
2338 			case BPF_PROG_TYPE_STRUCT_OPS:
2339 				ret = false;
2340 				break;
2341 			default:
2342 				break;
2343 			}
2344 		}
2345 	}
2346 	spin_unlock(&map->owner.lock);
2347 
2348 	return ret;
2349 }
2350 
bpf_check_tail_call(const struct bpf_prog * fp)2351 static int bpf_check_tail_call(const struct bpf_prog *fp)
2352 {
2353 	struct bpf_prog_aux *aux = fp->aux;
2354 	int i, ret = 0;
2355 
2356 	mutex_lock(&aux->used_maps_mutex);
2357 	for (i = 0; i < aux->used_map_cnt; i++) {
2358 		struct bpf_map *map = aux->used_maps[i];
2359 
2360 		if (!map_type_contains_progs(map))
2361 			continue;
2362 
2363 		if (!bpf_prog_map_compatible(map, fp)) {
2364 			ret = -EINVAL;
2365 			goto out;
2366 		}
2367 	}
2368 
2369 out:
2370 	mutex_unlock(&aux->used_maps_mutex);
2371 	return ret;
2372 }
2373 
bpf_prog_select_func(struct bpf_prog * fp)2374 static void bpf_prog_select_func(struct bpf_prog *fp)
2375 {
2376 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
2377 	u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
2378 
2379 	fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
2380 #else
2381 	fp->bpf_func = __bpf_prog_ret0_warn;
2382 #endif
2383 }
2384 
2385 /**
2386  *	bpf_prog_select_runtime - select exec runtime for BPF program
2387  *	@fp: bpf_prog populated with BPF program
2388  *	@err: pointer to error variable
2389  *
2390  * Try to JIT eBPF program, if JIT is not available, use interpreter.
2391  * The BPF program will be executed via bpf_prog_run() function.
2392  *
2393  * Return: the &fp argument along with &err set to 0 for success or
2394  * a negative errno code on failure
2395  */
bpf_prog_select_runtime(struct bpf_prog * fp,int * err)2396 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
2397 {
2398 	/* In case of BPF to BPF calls, verifier did all the prep
2399 	 * work with regards to JITing, etc.
2400 	 */
2401 	bool jit_needed = false;
2402 
2403 	if (fp->bpf_func)
2404 		goto finalize;
2405 
2406 	if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) ||
2407 	    bpf_prog_has_kfunc_call(fp))
2408 		jit_needed = true;
2409 
2410 	bpf_prog_select_func(fp);
2411 
2412 	/* eBPF JITs can rewrite the program in case constant
2413 	 * blinding is active. However, in case of error during
2414 	 * blinding, bpf_int_jit_compile() must always return a
2415 	 * valid program, which in this case would simply not
2416 	 * be JITed, but falls back to the interpreter.
2417 	 */
2418 	if (!bpf_prog_is_offloaded(fp->aux)) {
2419 		*err = bpf_prog_alloc_jited_linfo(fp);
2420 		if (*err)
2421 			return fp;
2422 
2423 		fp = bpf_int_jit_compile(fp);
2424 		bpf_prog_jit_attempt_done(fp);
2425 		if (!fp->jited && jit_needed) {
2426 			*err = -ENOTSUPP;
2427 			return fp;
2428 		}
2429 	} else {
2430 		*err = bpf_prog_offload_compile(fp);
2431 		if (*err)
2432 			return fp;
2433 	}
2434 
2435 finalize:
2436 	*err = bpf_prog_lock_ro(fp);
2437 	if (*err)
2438 		return fp;
2439 
2440 	/* The tail call compatibility check can only be done at
2441 	 * this late stage as we need to determine, if we deal
2442 	 * with JITed or non JITed program concatenations and not
2443 	 * all eBPF JITs might immediately support all features.
2444 	 */
2445 	*err = bpf_check_tail_call(fp);
2446 
2447 	return fp;
2448 }
2449 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
2450 
__bpf_prog_ret1(const void * ctx,const struct bpf_insn * insn)2451 static unsigned int __bpf_prog_ret1(const void *ctx,
2452 				    const struct bpf_insn *insn)
2453 {
2454 	return 1;
2455 }
2456 
2457 static struct bpf_prog_dummy {
2458 	struct bpf_prog prog;
2459 } dummy_bpf_prog = {
2460 	.prog = {
2461 		.bpf_func = __bpf_prog_ret1,
2462 	},
2463 };
2464 
2465 struct bpf_empty_prog_array bpf_empty_prog_array = {
2466 	.null_prog = NULL,
2467 };
2468 EXPORT_SYMBOL(bpf_empty_prog_array);
2469 
bpf_prog_array_alloc(u32 prog_cnt,gfp_t flags)2470 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
2471 {
2472 	struct bpf_prog_array *p;
2473 
2474 	if (prog_cnt)
2475 		p = kzalloc(struct_size(p, items, prog_cnt + 1), flags);
2476 	else
2477 		p = &bpf_empty_prog_array.hdr;
2478 
2479 	return p;
2480 }
2481 
bpf_prog_array_free(struct bpf_prog_array * progs)2482 void bpf_prog_array_free(struct bpf_prog_array *progs)
2483 {
2484 	if (!progs || progs == &bpf_empty_prog_array.hdr)
2485 		return;
2486 	kfree_rcu(progs, rcu);
2487 }
2488 
__bpf_prog_array_free_sleepable_cb(struct rcu_head * rcu)2489 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu)
2490 {
2491 	struct bpf_prog_array *progs;
2492 
2493 	/* If RCU Tasks Trace grace period implies RCU grace period, there is
2494 	 * no need to call kfree_rcu(), just call kfree() directly.
2495 	 */
2496 	progs = container_of(rcu, struct bpf_prog_array, rcu);
2497 	if (rcu_trace_implies_rcu_gp())
2498 		kfree(progs);
2499 	else
2500 		kfree_rcu(progs, rcu);
2501 }
2502 
bpf_prog_array_free_sleepable(struct bpf_prog_array * progs)2503 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs)
2504 {
2505 	if (!progs || progs == &bpf_empty_prog_array.hdr)
2506 		return;
2507 	call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb);
2508 }
2509 
bpf_prog_array_length(struct bpf_prog_array * array)2510 int bpf_prog_array_length(struct bpf_prog_array *array)
2511 {
2512 	struct bpf_prog_array_item *item;
2513 	u32 cnt = 0;
2514 
2515 	for (item = array->items; item->prog; item++)
2516 		if (item->prog != &dummy_bpf_prog.prog)
2517 			cnt++;
2518 	return cnt;
2519 }
2520 
bpf_prog_array_is_empty(struct bpf_prog_array * array)2521 bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
2522 {
2523 	struct bpf_prog_array_item *item;
2524 
2525 	for (item = array->items; item->prog; item++)
2526 		if (item->prog != &dummy_bpf_prog.prog)
2527 			return false;
2528 	return true;
2529 }
2530 
bpf_prog_array_copy_core(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt)2531 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
2532 				     u32 *prog_ids,
2533 				     u32 request_cnt)
2534 {
2535 	struct bpf_prog_array_item *item;
2536 	int i = 0;
2537 
2538 	for (item = array->items; item->prog; item++) {
2539 		if (item->prog == &dummy_bpf_prog.prog)
2540 			continue;
2541 		prog_ids[i] = item->prog->aux->id;
2542 		if (++i == request_cnt) {
2543 			item++;
2544 			break;
2545 		}
2546 	}
2547 
2548 	return !!(item->prog);
2549 }
2550 
bpf_prog_array_copy_to_user(struct bpf_prog_array * array,__u32 __user * prog_ids,u32 cnt)2551 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
2552 				__u32 __user *prog_ids, u32 cnt)
2553 {
2554 	unsigned long err = 0;
2555 	bool nospc;
2556 	u32 *ids;
2557 
2558 	/* users of this function are doing:
2559 	 * cnt = bpf_prog_array_length();
2560 	 * if (cnt > 0)
2561 	 *     bpf_prog_array_copy_to_user(..., cnt);
2562 	 * so below kcalloc doesn't need extra cnt > 0 check.
2563 	 */
2564 	ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
2565 	if (!ids)
2566 		return -ENOMEM;
2567 	nospc = bpf_prog_array_copy_core(array, ids, cnt);
2568 	err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
2569 	kfree(ids);
2570 	if (err)
2571 		return -EFAULT;
2572 	if (nospc)
2573 		return -ENOSPC;
2574 	return 0;
2575 }
2576 
bpf_prog_array_delete_safe(struct bpf_prog_array * array,struct bpf_prog * old_prog)2577 void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
2578 				struct bpf_prog *old_prog)
2579 {
2580 	struct bpf_prog_array_item *item;
2581 
2582 	for (item = array->items; item->prog; item++)
2583 		if (item->prog == old_prog) {
2584 			WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
2585 			break;
2586 		}
2587 }
2588 
2589 /**
2590  * bpf_prog_array_delete_safe_at() - Replaces the program at the given
2591  *                                   index into the program array with
2592  *                                   a dummy no-op program.
2593  * @array: a bpf_prog_array
2594  * @index: the index of the program to replace
2595  *
2596  * Skips over dummy programs, by not counting them, when calculating
2597  * the position of the program to replace.
2598  *
2599  * Return:
2600  * * 0		- Success
2601  * * -EINVAL	- Invalid index value. Must be a non-negative integer.
2602  * * -ENOENT	- Index out of range
2603  */
bpf_prog_array_delete_safe_at(struct bpf_prog_array * array,int index)2604 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
2605 {
2606 	return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
2607 }
2608 
2609 /**
2610  * bpf_prog_array_update_at() - Updates the program at the given index
2611  *                              into the program array.
2612  * @array: a bpf_prog_array
2613  * @index: the index of the program to update
2614  * @prog: the program to insert into the array
2615  *
2616  * Skips over dummy programs, by not counting them, when calculating
2617  * the position of the program to update.
2618  *
2619  * Return:
2620  * * 0		- Success
2621  * * -EINVAL	- Invalid index value. Must be a non-negative integer.
2622  * * -ENOENT	- Index out of range
2623  */
bpf_prog_array_update_at(struct bpf_prog_array * array,int index,struct bpf_prog * prog)2624 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
2625 			     struct bpf_prog *prog)
2626 {
2627 	struct bpf_prog_array_item *item;
2628 
2629 	if (unlikely(index < 0))
2630 		return -EINVAL;
2631 
2632 	for (item = array->items; item->prog; item++) {
2633 		if (item->prog == &dummy_bpf_prog.prog)
2634 			continue;
2635 		if (!index) {
2636 			WRITE_ONCE(item->prog, prog);
2637 			return 0;
2638 		}
2639 		index--;
2640 	}
2641 	return -ENOENT;
2642 }
2643 
bpf_prog_array_copy(struct bpf_prog_array * old_array,struct bpf_prog * exclude_prog,struct bpf_prog * include_prog,u64 bpf_cookie,struct bpf_prog_array ** new_array)2644 int bpf_prog_array_copy(struct bpf_prog_array *old_array,
2645 			struct bpf_prog *exclude_prog,
2646 			struct bpf_prog *include_prog,
2647 			u64 bpf_cookie,
2648 			struct bpf_prog_array **new_array)
2649 {
2650 	int new_prog_cnt, carry_prog_cnt = 0;
2651 	struct bpf_prog_array_item *existing, *new;
2652 	struct bpf_prog_array *array;
2653 	bool found_exclude = false;
2654 
2655 	/* Figure out how many existing progs we need to carry over to
2656 	 * the new array.
2657 	 */
2658 	if (old_array) {
2659 		existing = old_array->items;
2660 		for (; existing->prog; existing++) {
2661 			if (existing->prog == exclude_prog) {
2662 				found_exclude = true;
2663 				continue;
2664 			}
2665 			if (existing->prog != &dummy_bpf_prog.prog)
2666 				carry_prog_cnt++;
2667 			if (existing->prog == include_prog)
2668 				return -EEXIST;
2669 		}
2670 	}
2671 
2672 	if (exclude_prog && !found_exclude)
2673 		return -ENOENT;
2674 
2675 	/* How many progs (not NULL) will be in the new array? */
2676 	new_prog_cnt = carry_prog_cnt;
2677 	if (include_prog)
2678 		new_prog_cnt += 1;
2679 
2680 	/* Do we have any prog (not NULL) in the new array? */
2681 	if (!new_prog_cnt) {
2682 		*new_array = NULL;
2683 		return 0;
2684 	}
2685 
2686 	/* +1 as the end of prog_array is marked with NULL */
2687 	array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
2688 	if (!array)
2689 		return -ENOMEM;
2690 	new = array->items;
2691 
2692 	/* Fill in the new prog array */
2693 	if (carry_prog_cnt) {
2694 		existing = old_array->items;
2695 		for (; existing->prog; existing++) {
2696 			if (existing->prog == exclude_prog ||
2697 			    existing->prog == &dummy_bpf_prog.prog)
2698 				continue;
2699 
2700 			new->prog = existing->prog;
2701 			new->bpf_cookie = existing->bpf_cookie;
2702 			new++;
2703 		}
2704 	}
2705 	if (include_prog) {
2706 		new->prog = include_prog;
2707 		new->bpf_cookie = bpf_cookie;
2708 		new++;
2709 	}
2710 	new->prog = NULL;
2711 	*new_array = array;
2712 	return 0;
2713 }
2714 
bpf_prog_array_copy_info(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt,u32 * prog_cnt)2715 int bpf_prog_array_copy_info(struct bpf_prog_array *array,
2716 			     u32 *prog_ids, u32 request_cnt,
2717 			     u32 *prog_cnt)
2718 {
2719 	u32 cnt = 0;
2720 
2721 	if (array)
2722 		cnt = bpf_prog_array_length(array);
2723 
2724 	*prog_cnt = cnt;
2725 
2726 	/* return early if user requested only program count or nothing to copy */
2727 	if (!request_cnt || !cnt)
2728 		return 0;
2729 
2730 	/* this function is called under trace/bpf_trace.c: bpf_event_mutex */
2731 	return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
2732 								     : 0;
2733 }
2734 
__bpf_free_used_maps(struct bpf_prog_aux * aux,struct bpf_map ** used_maps,u32 len)2735 void __bpf_free_used_maps(struct bpf_prog_aux *aux,
2736 			  struct bpf_map **used_maps, u32 len)
2737 {
2738 	struct bpf_map *map;
2739 	bool sleepable;
2740 	u32 i;
2741 
2742 	sleepable = aux->prog->sleepable;
2743 	for (i = 0; i < len; i++) {
2744 		map = used_maps[i];
2745 		if (map->ops->map_poke_untrack)
2746 			map->ops->map_poke_untrack(map, aux);
2747 		if (sleepable)
2748 			atomic64_dec(&map->sleepable_refcnt);
2749 		bpf_map_put(map);
2750 	}
2751 }
2752 
bpf_free_used_maps(struct bpf_prog_aux * aux)2753 static void bpf_free_used_maps(struct bpf_prog_aux *aux)
2754 {
2755 	__bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
2756 	kfree(aux->used_maps);
2757 }
2758 
__bpf_free_used_btfs(struct btf_mod_pair * used_btfs,u32 len)2759 void __bpf_free_used_btfs(struct btf_mod_pair *used_btfs, u32 len)
2760 {
2761 #ifdef CONFIG_BPF_SYSCALL
2762 	struct btf_mod_pair *btf_mod;
2763 	u32 i;
2764 
2765 	for (i = 0; i < len; i++) {
2766 		btf_mod = &used_btfs[i];
2767 		if (btf_mod->module)
2768 			module_put(btf_mod->module);
2769 		btf_put(btf_mod->btf);
2770 	}
2771 #endif
2772 }
2773 
bpf_free_used_btfs(struct bpf_prog_aux * aux)2774 static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
2775 {
2776 	__bpf_free_used_btfs(aux->used_btfs, aux->used_btf_cnt);
2777 	kfree(aux->used_btfs);
2778 }
2779 
bpf_prog_free_deferred(struct work_struct * work)2780 static void bpf_prog_free_deferred(struct work_struct *work)
2781 {
2782 	struct bpf_prog_aux *aux;
2783 	int i;
2784 
2785 	aux = container_of(work, struct bpf_prog_aux, work);
2786 #ifdef CONFIG_BPF_SYSCALL
2787 	bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab);
2788 #endif
2789 #ifdef CONFIG_CGROUP_BPF
2790 	if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID)
2791 		bpf_cgroup_atype_put(aux->cgroup_atype);
2792 #endif
2793 	bpf_free_used_maps(aux);
2794 	bpf_free_used_btfs(aux);
2795 	if (bpf_prog_is_dev_bound(aux))
2796 		bpf_prog_dev_bound_destroy(aux->prog);
2797 #ifdef CONFIG_PERF_EVENTS
2798 	if (aux->prog->has_callchain_buf)
2799 		put_callchain_buffers();
2800 #endif
2801 	if (aux->dst_trampoline)
2802 		bpf_trampoline_put(aux->dst_trampoline);
2803 	for (i = 0; i < aux->real_func_cnt; i++) {
2804 		/* We can just unlink the subprog poke descriptor table as
2805 		 * it was originally linked to the main program and is also
2806 		 * released along with it.
2807 		 */
2808 		aux->func[i]->aux->poke_tab = NULL;
2809 		bpf_jit_free(aux->func[i]);
2810 	}
2811 	if (aux->real_func_cnt) {
2812 		kfree(aux->func);
2813 		bpf_prog_unlock_free(aux->prog);
2814 	} else {
2815 		bpf_jit_free(aux->prog);
2816 	}
2817 }
2818 
bpf_prog_free(struct bpf_prog * fp)2819 void bpf_prog_free(struct bpf_prog *fp)
2820 {
2821 	struct bpf_prog_aux *aux = fp->aux;
2822 
2823 	if (aux->dst_prog)
2824 		bpf_prog_put(aux->dst_prog);
2825 	bpf_token_put(aux->token);
2826 	INIT_WORK(&aux->work, bpf_prog_free_deferred);
2827 	schedule_work(&aux->work);
2828 }
2829 EXPORT_SYMBOL_GPL(bpf_prog_free);
2830 
2831 /* RNG for unprivileged user space with separated state from prandom_u32(). */
2832 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
2833 
bpf_user_rnd_init_once(void)2834 void bpf_user_rnd_init_once(void)
2835 {
2836 	prandom_init_once(&bpf_user_rnd_state);
2837 }
2838 
BPF_CALL_0(bpf_user_rnd_u32)2839 BPF_CALL_0(bpf_user_rnd_u32)
2840 {
2841 	/* Should someone ever have the rather unwise idea to use some
2842 	 * of the registers passed into this function, then note that
2843 	 * this function is called from native eBPF and classic-to-eBPF
2844 	 * transformations. Register assignments from both sides are
2845 	 * different, f.e. classic always sets fn(ctx, A, X) here.
2846 	 */
2847 	struct rnd_state *state;
2848 	u32 res;
2849 
2850 	state = &get_cpu_var(bpf_user_rnd_state);
2851 	res = prandom_u32_state(state);
2852 	put_cpu_var(bpf_user_rnd_state);
2853 
2854 	return res;
2855 }
2856 
BPF_CALL_0(bpf_get_raw_cpu_id)2857 BPF_CALL_0(bpf_get_raw_cpu_id)
2858 {
2859 	return raw_smp_processor_id();
2860 }
2861 
2862 /* Weak definitions of helper functions in case we don't have bpf syscall. */
2863 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
2864 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
2865 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
2866 const struct bpf_func_proto bpf_map_push_elem_proto __weak;
2867 const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
2868 const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
2869 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak;
2870 const struct bpf_func_proto bpf_spin_lock_proto __weak;
2871 const struct bpf_func_proto bpf_spin_unlock_proto __weak;
2872 const struct bpf_func_proto bpf_jiffies64_proto __weak;
2873 
2874 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
2875 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
2876 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
2877 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
2878 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
2879 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak;
2880 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak;
2881 
2882 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
2883 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
2884 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
2885 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
2886 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
2887 const struct bpf_func_proto bpf_get_local_storage_proto __weak;
2888 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
2889 const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
2890 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak;
2891 const struct bpf_func_proto bpf_set_retval_proto __weak;
2892 const struct bpf_func_proto bpf_get_retval_proto __weak;
2893 
bpf_get_trace_printk_proto(void)2894 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
2895 {
2896 	return NULL;
2897 }
2898 
bpf_get_trace_vprintk_proto(void)2899 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void)
2900 {
2901 	return NULL;
2902 }
2903 
2904 u64 __weak
bpf_event_output(struct bpf_map * map,u64 flags,void * meta,u64 meta_size,void * ctx,u64 ctx_size,bpf_ctx_copy_t ctx_copy)2905 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
2906 		 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
2907 {
2908 	return -ENOTSUPP;
2909 }
2910 EXPORT_SYMBOL_GPL(bpf_event_output);
2911 
2912 /* Always built-in helper functions. */
2913 const struct bpf_func_proto bpf_tail_call_proto = {
2914 	.func		= NULL,
2915 	.gpl_only	= false,
2916 	.ret_type	= RET_VOID,
2917 	.arg1_type	= ARG_PTR_TO_CTX,
2918 	.arg2_type	= ARG_CONST_MAP_PTR,
2919 	.arg3_type	= ARG_ANYTHING,
2920 };
2921 
2922 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
2923  * It is encouraged to implement bpf_int_jit_compile() instead, so that
2924  * eBPF and implicitly also cBPF can get JITed!
2925  */
bpf_int_jit_compile(struct bpf_prog * prog)2926 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
2927 {
2928 	return prog;
2929 }
2930 
2931 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
2932  * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
2933  */
bpf_jit_compile(struct bpf_prog * prog)2934 void __weak bpf_jit_compile(struct bpf_prog *prog)
2935 {
2936 }
2937 
bpf_helper_changes_pkt_data(void * func)2938 bool __weak bpf_helper_changes_pkt_data(void *func)
2939 {
2940 	return false;
2941 }
2942 
2943 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage
2944  * analysis code and wants explicit zero extension inserted by verifier.
2945  * Otherwise, return FALSE.
2946  *
2947  * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if
2948  * you don't override this. JITs that don't want these extra insns can detect
2949  * them using insn_is_zext.
2950  */
bpf_jit_needs_zext(void)2951 bool __weak bpf_jit_needs_zext(void)
2952 {
2953 	return false;
2954 }
2955 
2956 /* Return true if the JIT inlines the call to the helper corresponding to
2957  * the imm.
2958  *
2959  * The verifier will not patch the insn->imm for the call to the helper if
2960  * this returns true.
2961  */
bpf_jit_inlines_helper_call(s32 imm)2962 bool __weak bpf_jit_inlines_helper_call(s32 imm)
2963 {
2964 	return false;
2965 }
2966 
2967 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */
bpf_jit_supports_subprog_tailcalls(void)2968 bool __weak bpf_jit_supports_subprog_tailcalls(void)
2969 {
2970 	return false;
2971 }
2972 
bpf_jit_supports_percpu_insn(void)2973 bool __weak bpf_jit_supports_percpu_insn(void)
2974 {
2975 	return false;
2976 }
2977 
bpf_jit_supports_kfunc_call(void)2978 bool __weak bpf_jit_supports_kfunc_call(void)
2979 {
2980 	return false;
2981 }
2982 
bpf_jit_supports_far_kfunc_call(void)2983 bool __weak bpf_jit_supports_far_kfunc_call(void)
2984 {
2985 	return false;
2986 }
2987 
bpf_jit_supports_arena(void)2988 bool __weak bpf_jit_supports_arena(void)
2989 {
2990 	return false;
2991 }
2992 
bpf_jit_supports_insn(struct bpf_insn * insn,bool in_arena)2993 bool __weak bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena)
2994 {
2995 	return false;
2996 }
2997 
bpf_arch_uaddress_limit(void)2998 u64 __weak bpf_arch_uaddress_limit(void)
2999 {
3000 #if defined(CONFIG_64BIT) && defined(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE)
3001 	return TASK_SIZE;
3002 #else
3003 	return 0;
3004 #endif
3005 }
3006 
3007 /* Return TRUE if the JIT backend satisfies the following two conditions:
3008  * 1) JIT backend supports atomic_xchg() on pointer-sized words.
3009  * 2) Under the specific arch, the implementation of xchg() is the same
3010  *    as atomic_xchg() on pointer-sized words.
3011  */
bpf_jit_supports_ptr_xchg(void)3012 bool __weak bpf_jit_supports_ptr_xchg(void)
3013 {
3014 	return false;
3015 }
3016 
3017 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
3018  * skb_copy_bits(), so provide a weak definition of it for NET-less config.
3019  */
skb_copy_bits(const struct sk_buff * skb,int offset,void * to,int len)3020 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
3021 			 int len)
3022 {
3023 	return -EFAULT;
3024 }
3025 
bpf_arch_text_poke(void * ip,enum bpf_text_poke_type t,void * addr1,void * addr2)3026 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
3027 			      void *addr1, void *addr2)
3028 {
3029 	return -ENOTSUPP;
3030 }
3031 
bpf_arch_text_copy(void * dst,void * src,size_t len)3032 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len)
3033 {
3034 	return ERR_PTR(-ENOTSUPP);
3035 }
3036 
bpf_arch_text_invalidate(void * dst,size_t len)3037 int __weak bpf_arch_text_invalidate(void *dst, size_t len)
3038 {
3039 	return -ENOTSUPP;
3040 }
3041 
bpf_jit_supports_exceptions(void)3042 bool __weak bpf_jit_supports_exceptions(void)
3043 {
3044 	return false;
3045 }
3046 
arch_bpf_stack_walk(bool (* consume_fn)(void * cookie,u64 ip,u64 sp,u64 bp),void * cookie)3047 void __weak arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp), void *cookie)
3048 {
3049 }
3050 
3051 /* for configs without MMU or 32-bit */
3052 __weak const struct bpf_map_ops arena_map_ops;
bpf_arena_get_user_vm_start(struct bpf_arena * arena)3053 __weak u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena)
3054 {
3055 	return 0;
3056 }
bpf_arena_get_kern_vm_start(struct bpf_arena * arena)3057 __weak u64 bpf_arena_get_kern_vm_start(struct bpf_arena *arena)
3058 {
3059 	return 0;
3060 }
3061 
3062 #ifdef CONFIG_BPF_SYSCALL
bpf_global_ma_init(void)3063 static int __init bpf_global_ma_init(void)
3064 {
3065 	int ret;
3066 
3067 	ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false);
3068 	bpf_global_ma_set = !ret;
3069 	return ret;
3070 }
3071 late_initcall(bpf_global_ma_init);
3072 #endif
3073 
3074 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
3075 EXPORT_SYMBOL(bpf_stats_enabled_key);
3076 
3077 /* All definitions of tracepoints related to BPF. */
3078 #define CREATE_TRACE_POINTS
3079 #include <linux/bpf_trace.h>
3080 
3081 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
3082 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
3083