xref: /linux/kernel/bpf/core.c (revision 35f301dd4551fa731db4834f915e8351838f6f19)
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/prandom.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->ext_mutex);
135 	mutex_init(&fp->aux->dst_mutex);
136 
137 	return fp;
138 }
139 
bpf_prog_alloc(unsigned int size,gfp_t gfp_extra_flags)140 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
141 {
142 	gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
143 	struct bpf_prog *prog;
144 	int cpu;
145 
146 	prog = bpf_prog_alloc_no_stats(size, gfp_extra_flags);
147 	if (!prog)
148 		return NULL;
149 
150 	prog->stats = alloc_percpu_gfp(struct bpf_prog_stats, gfp_flags);
151 	if (!prog->stats) {
152 		free_percpu(prog->active);
153 		kfree(prog->aux);
154 		vfree(prog);
155 		return NULL;
156 	}
157 
158 	for_each_possible_cpu(cpu) {
159 		struct bpf_prog_stats *pstats;
160 
161 		pstats = per_cpu_ptr(prog->stats, cpu);
162 		u64_stats_init(&pstats->syncp);
163 	}
164 	return prog;
165 }
166 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
167 
bpf_prog_alloc_jited_linfo(struct bpf_prog * prog)168 int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog)
169 {
170 	if (!prog->aux->nr_linfo || !prog->jit_requested)
171 		return 0;
172 
173 	prog->aux->jited_linfo = kvcalloc(prog->aux->nr_linfo,
174 					  sizeof(*prog->aux->jited_linfo),
175 					  bpf_memcg_flags(GFP_KERNEL | __GFP_NOWARN));
176 	if (!prog->aux->jited_linfo)
177 		return -ENOMEM;
178 
179 	return 0;
180 }
181 
bpf_prog_jit_attempt_done(struct bpf_prog * prog)182 void bpf_prog_jit_attempt_done(struct bpf_prog *prog)
183 {
184 	if (prog->aux->jited_linfo &&
185 	    (!prog->jited || !prog->aux->jited_linfo[0])) {
186 		kvfree(prog->aux->jited_linfo);
187 		prog->aux->jited_linfo = NULL;
188 	}
189 
190 	kfree(prog->aux->kfunc_tab);
191 	prog->aux->kfunc_tab = NULL;
192 }
193 
194 /* The jit engine is responsible to provide an array
195  * for insn_off to the jited_off mapping (insn_to_jit_off).
196  *
197  * The idx to this array is the insn_off.  Hence, the insn_off
198  * here is relative to the prog itself instead of the main prog.
199  * This array has one entry for each xlated bpf insn.
200  *
201  * jited_off is the byte off to the end of the jited insn.
202  *
203  * Hence, with
204  * insn_start:
205  *      The first bpf insn off of the prog.  The insn off
206  *      here is relative to the main prog.
207  *      e.g. if prog is a subprog, insn_start > 0
208  * linfo_idx:
209  *      The prog's idx to prog->aux->linfo and jited_linfo
210  *
211  * jited_linfo[linfo_idx] = prog->bpf_func
212  *
213  * For i > linfo_idx,
214  *
215  * jited_linfo[i] = prog->bpf_func +
216  *	insn_to_jit_off[linfo[i].insn_off - insn_start - 1]
217  */
bpf_prog_fill_jited_linfo(struct bpf_prog * prog,const u32 * insn_to_jit_off)218 void bpf_prog_fill_jited_linfo(struct bpf_prog *prog,
219 			       const u32 *insn_to_jit_off)
220 {
221 	u32 linfo_idx, insn_start, insn_end, nr_linfo, i;
222 	const struct bpf_line_info *linfo;
223 	void **jited_linfo;
224 
225 	if (!prog->aux->jited_linfo || prog->aux->func_idx > prog->aux->func_cnt)
226 		/* Userspace did not provide linfo */
227 		return;
228 
229 	linfo_idx = prog->aux->linfo_idx;
230 	linfo = &prog->aux->linfo[linfo_idx];
231 	insn_start = linfo[0].insn_off;
232 	insn_end = insn_start + prog->len;
233 
234 	jited_linfo = &prog->aux->jited_linfo[linfo_idx];
235 	jited_linfo[0] = prog->bpf_func;
236 
237 	nr_linfo = prog->aux->nr_linfo - linfo_idx;
238 
239 	for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++)
240 		/* The verifier ensures that linfo[i].insn_off is
241 		 * strictly increasing
242 		 */
243 		jited_linfo[i] = prog->bpf_func +
244 			insn_to_jit_off[linfo[i].insn_off - insn_start - 1];
245 }
246 
bpf_prog_realloc(struct bpf_prog * fp_old,unsigned int size,gfp_t gfp_extra_flags)247 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
248 				  gfp_t gfp_extra_flags)
249 {
250 	gfp_t gfp_flags = bpf_memcg_flags(GFP_KERNEL | __GFP_ZERO | gfp_extra_flags);
251 	struct bpf_prog *fp;
252 	u32 pages;
253 
254 	size = round_up(size, PAGE_SIZE);
255 	pages = size / PAGE_SIZE;
256 	if (pages <= fp_old->pages)
257 		return fp_old;
258 
259 	fp = __vmalloc(size, gfp_flags);
260 	if (fp) {
261 		memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
262 		fp->pages = pages;
263 		fp->aux->prog = fp;
264 
265 		/* We keep fp->aux from fp_old around in the new
266 		 * reallocated structure.
267 		 */
268 		fp_old->aux = NULL;
269 		fp_old->stats = NULL;
270 		fp_old->active = NULL;
271 		__bpf_prog_free(fp_old);
272 	}
273 
274 	return fp;
275 }
276 
__bpf_prog_free(struct bpf_prog * fp)277 void __bpf_prog_free(struct bpf_prog *fp)
278 {
279 	if (fp->aux) {
280 		mutex_destroy(&fp->aux->used_maps_mutex);
281 		mutex_destroy(&fp->aux->dst_mutex);
282 		kfree(fp->aux->poke_tab);
283 		kfree(fp->aux);
284 	}
285 	free_percpu(fp->stats);
286 	free_percpu(fp->active);
287 	vfree(fp);
288 }
289 
bpf_prog_calc_tag(struct bpf_prog * fp)290 int bpf_prog_calc_tag(struct bpf_prog *fp)
291 {
292 	const u32 bits_offset = SHA1_BLOCK_SIZE - sizeof(__be64);
293 	u32 raw_size = bpf_prog_tag_scratch_size(fp);
294 	u32 digest[SHA1_DIGEST_WORDS];
295 	u32 ws[SHA1_WORKSPACE_WORDS];
296 	u32 i, bsize, psize, blocks;
297 	struct bpf_insn *dst;
298 	bool was_ld_map;
299 	u8 *raw, *todo;
300 	__be32 *result;
301 	__be64 *bits;
302 
303 	raw = vmalloc(raw_size);
304 	if (!raw)
305 		return -ENOMEM;
306 
307 	sha1_init(digest);
308 	memset(ws, 0, sizeof(ws));
309 
310 	/* We need to take out the map fd for the digest calculation
311 	 * since they are unstable from user space side.
312 	 */
313 	dst = (void *)raw;
314 	for (i = 0, was_ld_map = false; i < fp->len; i++) {
315 		dst[i] = fp->insnsi[i];
316 		if (!was_ld_map &&
317 		    dst[i].code == (BPF_LD | BPF_IMM | BPF_DW) &&
318 		    (dst[i].src_reg == BPF_PSEUDO_MAP_FD ||
319 		     dst[i].src_reg == BPF_PSEUDO_MAP_VALUE)) {
320 			was_ld_map = true;
321 			dst[i].imm = 0;
322 		} else if (was_ld_map &&
323 			   dst[i].code == 0 &&
324 			   dst[i].dst_reg == 0 &&
325 			   dst[i].src_reg == 0 &&
326 			   dst[i].off == 0) {
327 			was_ld_map = false;
328 			dst[i].imm = 0;
329 		} else {
330 			was_ld_map = false;
331 		}
332 	}
333 
334 	psize = bpf_prog_insn_size(fp);
335 	memset(&raw[psize], 0, raw_size - psize);
336 	raw[psize++] = 0x80;
337 
338 	bsize  = round_up(psize, SHA1_BLOCK_SIZE);
339 	blocks = bsize / SHA1_BLOCK_SIZE;
340 	todo   = raw;
341 	if (bsize - psize >= sizeof(__be64)) {
342 		bits = (__be64 *)(todo + bsize - sizeof(__be64));
343 	} else {
344 		bits = (__be64 *)(todo + bsize + bits_offset);
345 		blocks++;
346 	}
347 	*bits = cpu_to_be64((psize - 1) << 3);
348 
349 	while (blocks--) {
350 		sha1_transform(digest, todo, ws);
351 		todo += SHA1_BLOCK_SIZE;
352 	}
353 
354 	result = (__force __be32 *)digest;
355 	for (i = 0; i < SHA1_DIGEST_WORDS; i++)
356 		result[i] = cpu_to_be32(digest[i]);
357 	memcpy(fp->tag, result, sizeof(fp->tag));
358 
359 	vfree(raw);
360 	return 0;
361 }
362 
bpf_adj_delta_to_imm(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)363 static int bpf_adj_delta_to_imm(struct bpf_insn *insn, u32 pos, s32 end_old,
364 				s32 end_new, s32 curr, const bool probe_pass)
365 {
366 	const s64 imm_min = S32_MIN, imm_max = S32_MAX;
367 	s32 delta = end_new - end_old;
368 	s64 imm = insn->imm;
369 
370 	if (curr < pos && curr + imm + 1 >= end_old)
371 		imm += delta;
372 	else if (curr >= end_new && curr + imm + 1 < end_new)
373 		imm -= delta;
374 	if (imm < imm_min || imm > imm_max)
375 		return -ERANGE;
376 	if (!probe_pass)
377 		insn->imm = imm;
378 	return 0;
379 }
380 
bpf_adj_delta_to_off(struct bpf_insn * insn,u32 pos,s32 end_old,s32 end_new,s32 curr,const bool probe_pass)381 static int bpf_adj_delta_to_off(struct bpf_insn *insn, u32 pos, s32 end_old,
382 				s32 end_new, s32 curr, const bool probe_pass)
383 {
384 	s64 off_min, off_max, off;
385 	s32 delta = end_new - end_old;
386 
387 	if (insn->code == (BPF_JMP32 | BPF_JA)) {
388 		off = insn->imm;
389 		off_min = S32_MIN;
390 		off_max = S32_MAX;
391 	} else {
392 		off = insn->off;
393 		off_min = S16_MIN;
394 		off_max = S16_MAX;
395 	}
396 
397 	if (curr < pos && curr + off + 1 >= end_old)
398 		off += delta;
399 	else if (curr >= end_new && curr + off + 1 < end_new)
400 		off -= delta;
401 	if (off < off_min || off > off_max)
402 		return -ERANGE;
403 	if (!probe_pass) {
404 		if (insn->code == (BPF_JMP32 | BPF_JA))
405 			insn->imm = off;
406 		else
407 			insn->off = off;
408 	}
409 	return 0;
410 }
411 
bpf_adj_branches(struct bpf_prog * prog,u32 pos,s32 end_old,s32 end_new,const bool probe_pass)412 static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, s32 end_old,
413 			    s32 end_new, const bool probe_pass)
414 {
415 	u32 i, insn_cnt = prog->len + (probe_pass ? end_new - end_old : 0);
416 	struct bpf_insn *insn = prog->insnsi;
417 	int ret = 0;
418 
419 	for (i = 0; i < insn_cnt; i++, insn++) {
420 		u8 code;
421 
422 		/* In the probing pass we still operate on the original,
423 		 * unpatched image in order to check overflows before we
424 		 * do any other adjustments. Therefore skip the patchlet.
425 		 */
426 		if (probe_pass && i == pos) {
427 			i = end_new;
428 			insn = prog->insnsi + end_old;
429 		}
430 		if (bpf_pseudo_func(insn)) {
431 			ret = bpf_adj_delta_to_imm(insn, pos, end_old,
432 						   end_new, i, probe_pass);
433 			if (ret)
434 				return ret;
435 			continue;
436 		}
437 		code = insn->code;
438 		if ((BPF_CLASS(code) != BPF_JMP &&
439 		     BPF_CLASS(code) != BPF_JMP32) ||
440 		    BPF_OP(code) == BPF_EXIT)
441 			continue;
442 		/* Adjust offset of jmps if we cross patch boundaries. */
443 		if (BPF_OP(code) == BPF_CALL) {
444 			if (insn->src_reg != BPF_PSEUDO_CALL)
445 				continue;
446 			ret = bpf_adj_delta_to_imm(insn, pos, end_old,
447 						   end_new, i, probe_pass);
448 		} else {
449 			ret = bpf_adj_delta_to_off(insn, pos, end_old,
450 						   end_new, i, probe_pass);
451 		}
452 		if (ret)
453 			break;
454 	}
455 
456 	return ret;
457 }
458 
bpf_adj_linfo(struct bpf_prog * prog,u32 off,u32 delta)459 static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta)
460 {
461 	struct bpf_line_info *linfo;
462 	u32 i, nr_linfo;
463 
464 	nr_linfo = prog->aux->nr_linfo;
465 	if (!nr_linfo || !delta)
466 		return;
467 
468 	linfo = prog->aux->linfo;
469 
470 	for (i = 0; i < nr_linfo; i++)
471 		if (off < linfo[i].insn_off)
472 			break;
473 
474 	/* Push all off < linfo[i].insn_off by delta */
475 	for (; i < nr_linfo; i++)
476 		linfo[i].insn_off += delta;
477 }
478 
bpf_patch_insn_single(struct bpf_prog * prog,u32 off,const struct bpf_insn * patch,u32 len)479 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
480 				       const struct bpf_insn *patch, u32 len)
481 {
482 	u32 insn_adj_cnt, insn_rest, insn_delta = len - 1;
483 	const u32 cnt_max = S16_MAX;
484 	struct bpf_prog *prog_adj;
485 	int err;
486 
487 	/* Since our patchlet doesn't expand the image, we're done. */
488 	if (insn_delta == 0) {
489 		memcpy(prog->insnsi + off, patch, sizeof(*patch));
490 		return prog;
491 	}
492 
493 	insn_adj_cnt = prog->len + insn_delta;
494 
495 	/* Reject anything that would potentially let the insn->off
496 	 * target overflow when we have excessive program expansions.
497 	 * We need to probe here before we do any reallocation where
498 	 * we afterwards may not fail anymore.
499 	 */
500 	if (insn_adj_cnt > cnt_max &&
501 	    (err = bpf_adj_branches(prog, off, off + 1, off + len, true)))
502 		return ERR_PTR(err);
503 
504 	/* Several new instructions need to be inserted. Make room
505 	 * for them. Likely, there's no need for a new allocation as
506 	 * last page could have large enough tailroom.
507 	 */
508 	prog_adj = bpf_prog_realloc(prog, bpf_prog_size(insn_adj_cnt),
509 				    GFP_USER);
510 	if (!prog_adj)
511 		return ERR_PTR(-ENOMEM);
512 
513 	prog_adj->len = insn_adj_cnt;
514 
515 	/* Patching happens in 3 steps:
516 	 *
517 	 * 1) Move over tail of insnsi from next instruction onwards,
518 	 *    so we can patch the single target insn with one or more
519 	 *    new ones (patching is always from 1 to n insns, n > 0).
520 	 * 2) Inject new instructions at the target location.
521 	 * 3) Adjust branch offsets if necessary.
522 	 */
523 	insn_rest = insn_adj_cnt - off - len;
524 
525 	memmove(prog_adj->insnsi + off + len, prog_adj->insnsi + off + 1,
526 		sizeof(*patch) * insn_rest);
527 	memcpy(prog_adj->insnsi + off, patch, sizeof(*patch) * len);
528 
529 	/* We are guaranteed to not fail at this point, otherwise
530 	 * the ship has sailed to reverse to the original state. An
531 	 * overflow cannot happen at this point.
532 	 */
533 	BUG_ON(bpf_adj_branches(prog_adj, off, off + 1, off + len, false));
534 
535 	bpf_adj_linfo(prog_adj, off, insn_delta);
536 
537 	return prog_adj;
538 }
539 
bpf_remove_insns(struct bpf_prog * prog,u32 off,u32 cnt)540 int bpf_remove_insns(struct bpf_prog *prog, u32 off, u32 cnt)
541 {
542 	int err;
543 
544 	/* Branch offsets can't overflow when program is shrinking, no need
545 	 * to call bpf_adj_branches(..., true) here
546 	 */
547 	memmove(prog->insnsi + off, prog->insnsi + off + cnt,
548 		sizeof(struct bpf_insn) * (prog->len - off - cnt));
549 	prog->len -= cnt;
550 
551 	err = bpf_adj_branches(prog, off, off + cnt, off, false);
552 	WARN_ON_ONCE(err);
553 	return err;
554 }
555 
bpf_prog_kallsyms_del_subprogs(struct bpf_prog * fp)556 static void bpf_prog_kallsyms_del_subprogs(struct bpf_prog *fp)
557 {
558 	int i;
559 
560 	for (i = 0; i < fp->aux->real_func_cnt; i++)
561 		bpf_prog_kallsyms_del(fp->aux->func[i]);
562 }
563 
bpf_prog_kallsyms_del_all(struct bpf_prog * fp)564 void bpf_prog_kallsyms_del_all(struct bpf_prog *fp)
565 {
566 	bpf_prog_kallsyms_del_subprogs(fp);
567 	bpf_prog_kallsyms_del(fp);
568 }
569 
570 #ifdef CONFIG_BPF_JIT
571 /* All BPF JIT sysctl knobs here. */
572 int bpf_jit_enable   __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
573 int bpf_jit_kallsyms __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_DEFAULT_ON);
574 int bpf_jit_harden   __read_mostly;
575 long bpf_jit_limit   __read_mostly;
576 long bpf_jit_limit_max __read_mostly;
577 
578 static void
bpf_prog_ksym_set_addr(struct bpf_prog * prog)579 bpf_prog_ksym_set_addr(struct bpf_prog *prog)
580 {
581 	WARN_ON_ONCE(!bpf_prog_ebpf_jited(prog));
582 
583 	prog->aux->ksym.start = (unsigned long) prog->bpf_func;
584 	prog->aux->ksym.end   = prog->aux->ksym.start + prog->jited_len;
585 }
586 
587 static void
bpf_prog_ksym_set_name(struct bpf_prog * prog)588 bpf_prog_ksym_set_name(struct bpf_prog *prog)
589 {
590 	char *sym = prog->aux->ksym.name;
591 	const char *end = sym + KSYM_NAME_LEN;
592 	const struct btf_type *type;
593 	const char *func_name;
594 
595 	BUILD_BUG_ON(sizeof("bpf_prog_") +
596 		     sizeof(prog->tag) * 2 +
597 		     /* name has been null terminated.
598 		      * We should need +1 for the '_' preceding
599 		      * the name.  However, the null character
600 		      * is double counted between the name and the
601 		      * sizeof("bpf_prog_") above, so we omit
602 		      * the +1 here.
603 		      */
604 		     sizeof(prog->aux->name) > KSYM_NAME_LEN);
605 
606 	sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_");
607 	sym  = bin2hex(sym, prog->tag, sizeof(prog->tag));
608 
609 	/* prog->aux->name will be ignored if full btf name is available */
610 	if (prog->aux->func_info_cnt && prog->aux->func_idx < prog->aux->func_info_cnt) {
611 		type = btf_type_by_id(prog->aux->btf,
612 				      prog->aux->func_info[prog->aux->func_idx].type_id);
613 		func_name = btf_name_by_offset(prog->aux->btf, type->name_off);
614 		snprintf(sym, (size_t)(end - sym), "_%s", func_name);
615 		return;
616 	}
617 
618 	if (prog->aux->name[0])
619 		snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name);
620 	else
621 		*sym = 0;
622 }
623 
bpf_get_ksym_start(struct latch_tree_node * n)624 static unsigned long bpf_get_ksym_start(struct latch_tree_node *n)
625 {
626 	return container_of(n, struct bpf_ksym, tnode)->start;
627 }
628 
bpf_tree_less(struct latch_tree_node * a,struct latch_tree_node * b)629 static __always_inline bool bpf_tree_less(struct latch_tree_node *a,
630 					  struct latch_tree_node *b)
631 {
632 	return bpf_get_ksym_start(a) < bpf_get_ksym_start(b);
633 }
634 
bpf_tree_comp(void * key,struct latch_tree_node * n)635 static __always_inline int bpf_tree_comp(void *key, struct latch_tree_node *n)
636 {
637 	unsigned long val = (unsigned long)key;
638 	const struct bpf_ksym *ksym;
639 
640 	ksym = container_of(n, struct bpf_ksym, tnode);
641 
642 	if (val < ksym->start)
643 		return -1;
644 	/* Ensure that we detect return addresses as part of the program, when
645 	 * the final instruction is a call for a program part of the stack
646 	 * trace. Therefore, do val > ksym->end instead of val >= ksym->end.
647 	 */
648 	if (val > ksym->end)
649 		return  1;
650 
651 	return 0;
652 }
653 
654 static const struct latch_tree_ops bpf_tree_ops = {
655 	.less	= bpf_tree_less,
656 	.comp	= bpf_tree_comp,
657 };
658 
659 static DEFINE_SPINLOCK(bpf_lock);
660 static LIST_HEAD(bpf_kallsyms);
661 static struct latch_tree_root bpf_tree __cacheline_aligned;
662 
bpf_ksym_add(struct bpf_ksym * ksym)663 void bpf_ksym_add(struct bpf_ksym *ksym)
664 {
665 	spin_lock_bh(&bpf_lock);
666 	WARN_ON_ONCE(!list_empty(&ksym->lnode));
667 	list_add_tail_rcu(&ksym->lnode, &bpf_kallsyms);
668 	latch_tree_insert(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
669 	spin_unlock_bh(&bpf_lock);
670 }
671 
__bpf_ksym_del(struct bpf_ksym * ksym)672 static void __bpf_ksym_del(struct bpf_ksym *ksym)
673 {
674 	if (list_empty(&ksym->lnode))
675 		return;
676 
677 	latch_tree_erase(&ksym->tnode, &bpf_tree, &bpf_tree_ops);
678 	list_del_rcu(&ksym->lnode);
679 }
680 
bpf_ksym_del(struct bpf_ksym * ksym)681 void bpf_ksym_del(struct bpf_ksym *ksym)
682 {
683 	spin_lock_bh(&bpf_lock);
684 	__bpf_ksym_del(ksym);
685 	spin_unlock_bh(&bpf_lock);
686 }
687 
bpf_prog_kallsyms_candidate(const struct bpf_prog * fp)688 static bool bpf_prog_kallsyms_candidate(const struct bpf_prog *fp)
689 {
690 	return fp->jited && !bpf_prog_was_classic(fp);
691 }
692 
bpf_prog_kallsyms_add(struct bpf_prog * fp)693 void bpf_prog_kallsyms_add(struct bpf_prog *fp)
694 {
695 	if (!bpf_prog_kallsyms_candidate(fp) ||
696 	    !bpf_token_capable(fp->aux->token, CAP_BPF))
697 		return;
698 
699 	bpf_prog_ksym_set_addr(fp);
700 	bpf_prog_ksym_set_name(fp);
701 	fp->aux->ksym.prog = true;
702 
703 	bpf_ksym_add(&fp->aux->ksym);
704 
705 #ifdef CONFIG_FINEIBT
706 	/*
707 	 * When FineIBT, code in the __cfi_foo() symbols can get executed
708 	 * and hence unwinder needs help.
709 	 */
710 	if (cfi_mode != CFI_FINEIBT)
711 		return;
712 
713 	snprintf(fp->aux->ksym_prefix.name, KSYM_NAME_LEN,
714 		 "__cfi_%s", fp->aux->ksym.name);
715 
716 	fp->aux->ksym_prefix.start = (unsigned long) fp->bpf_func - 16;
717 	fp->aux->ksym_prefix.end   = (unsigned long) fp->bpf_func;
718 
719 	bpf_ksym_add(&fp->aux->ksym_prefix);
720 #endif
721 }
722 
bpf_prog_kallsyms_del(struct bpf_prog * fp)723 void bpf_prog_kallsyms_del(struct bpf_prog *fp)
724 {
725 	if (!bpf_prog_kallsyms_candidate(fp))
726 		return;
727 
728 	bpf_ksym_del(&fp->aux->ksym);
729 #ifdef CONFIG_FINEIBT
730 	if (cfi_mode != CFI_FINEIBT)
731 		return;
732 	bpf_ksym_del(&fp->aux->ksym_prefix);
733 #endif
734 }
735 
bpf_ksym_find(unsigned long addr)736 static struct bpf_ksym *bpf_ksym_find(unsigned long addr)
737 {
738 	struct latch_tree_node *n;
739 
740 	n = latch_tree_find((void *)addr, &bpf_tree, &bpf_tree_ops);
741 	return n ? container_of(n, struct bpf_ksym, tnode) : NULL;
742 }
743 
__bpf_address_lookup(unsigned long addr,unsigned long * size,unsigned long * off,char * sym)744 int __bpf_address_lookup(unsigned long addr, unsigned long *size,
745 				 unsigned long *off, char *sym)
746 {
747 	struct bpf_ksym *ksym;
748 	int ret = 0;
749 
750 	rcu_read_lock();
751 	ksym = bpf_ksym_find(addr);
752 	if (ksym) {
753 		unsigned long symbol_start = ksym->start;
754 		unsigned long symbol_end = ksym->end;
755 
756 		ret = strscpy(sym, ksym->name, KSYM_NAME_LEN);
757 
758 		if (size)
759 			*size = symbol_end - symbol_start;
760 		if (off)
761 			*off  = addr - symbol_start;
762 	}
763 	rcu_read_unlock();
764 
765 	return ret;
766 }
767 
is_bpf_text_address(unsigned long addr)768 bool is_bpf_text_address(unsigned long addr)
769 {
770 	bool ret;
771 
772 	rcu_read_lock();
773 	ret = bpf_ksym_find(addr) != NULL;
774 	rcu_read_unlock();
775 
776 	return ret;
777 }
778 
bpf_prog_ksym_find(unsigned long addr)779 struct bpf_prog *bpf_prog_ksym_find(unsigned long addr)
780 {
781 	struct bpf_ksym *ksym = bpf_ksym_find(addr);
782 
783 	return ksym && ksym->prog ?
784 	       container_of(ksym, struct bpf_prog_aux, ksym)->prog :
785 	       NULL;
786 }
787 
search_bpf_extables(unsigned long addr)788 const struct exception_table_entry *search_bpf_extables(unsigned long addr)
789 {
790 	const struct exception_table_entry *e = NULL;
791 	struct bpf_prog *prog;
792 
793 	rcu_read_lock();
794 	prog = bpf_prog_ksym_find(addr);
795 	if (!prog)
796 		goto out;
797 	if (!prog->aux->num_exentries)
798 		goto out;
799 
800 	e = search_extable(prog->aux->extable, prog->aux->num_exentries, addr);
801 out:
802 	rcu_read_unlock();
803 	return e;
804 }
805 
bpf_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * sym)806 int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
807 		    char *sym)
808 {
809 	struct bpf_ksym *ksym;
810 	unsigned int it = 0;
811 	int ret = -ERANGE;
812 
813 	if (!bpf_jit_kallsyms_enabled())
814 		return ret;
815 
816 	rcu_read_lock();
817 	list_for_each_entry_rcu(ksym, &bpf_kallsyms, lnode) {
818 		if (it++ != symnum)
819 			continue;
820 
821 		strscpy(sym, ksym->name, KSYM_NAME_LEN);
822 
823 		*value = ksym->start;
824 		*type  = BPF_SYM_ELF_TYPE;
825 
826 		ret = 0;
827 		break;
828 	}
829 	rcu_read_unlock();
830 
831 	return ret;
832 }
833 
bpf_jit_add_poke_descriptor(struct bpf_prog * prog,struct bpf_jit_poke_descriptor * poke)834 int bpf_jit_add_poke_descriptor(struct bpf_prog *prog,
835 				struct bpf_jit_poke_descriptor *poke)
836 {
837 	struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
838 	static const u32 poke_tab_max = 1024;
839 	u32 slot = prog->aux->size_poke_tab;
840 	u32 size = slot + 1;
841 
842 	if (size > poke_tab_max)
843 		return -ENOSPC;
844 	if (poke->tailcall_target || poke->tailcall_target_stable ||
845 	    poke->tailcall_bypass || poke->adj_off || poke->bypass_addr)
846 		return -EINVAL;
847 
848 	switch (poke->reason) {
849 	case BPF_POKE_REASON_TAIL_CALL:
850 		if (!poke->tail_call.map)
851 			return -EINVAL;
852 		break;
853 	default:
854 		return -EINVAL;
855 	}
856 
857 	tab = krealloc_array(tab, size, sizeof(*poke), GFP_KERNEL);
858 	if (!tab)
859 		return -ENOMEM;
860 
861 	memcpy(&tab[slot], poke, sizeof(*poke));
862 	prog->aux->size_poke_tab = size;
863 	prog->aux->poke_tab = tab;
864 
865 	return slot;
866 }
867 
868 /*
869  * BPF program pack allocator.
870  *
871  * Most BPF programs are pretty small. Allocating a hole page for each
872  * program is sometime a waste. Many small bpf program also adds pressure
873  * to instruction TLB. To solve this issue, we introduce a BPF program pack
874  * allocator. The prog_pack allocator uses HPAGE_PMD_SIZE page (2MB on x86)
875  * to host BPF programs.
876  */
877 #define BPF_PROG_CHUNK_SHIFT	6
878 #define BPF_PROG_CHUNK_SIZE	(1 << BPF_PROG_CHUNK_SHIFT)
879 #define BPF_PROG_CHUNK_MASK	(~(BPF_PROG_CHUNK_SIZE - 1))
880 
881 struct bpf_prog_pack {
882 	struct list_head list;
883 	void *ptr;
884 	unsigned long bitmap[];
885 };
886 
bpf_jit_fill_hole_with_zero(void * area,unsigned int size)887 void bpf_jit_fill_hole_with_zero(void *area, unsigned int size)
888 {
889 	memset(area, 0, size);
890 }
891 
892 #define BPF_PROG_SIZE_TO_NBITS(size)	(round_up(size, BPF_PROG_CHUNK_SIZE) / BPF_PROG_CHUNK_SIZE)
893 
894 static DEFINE_MUTEX(pack_mutex);
895 static LIST_HEAD(pack_list);
896 
897 /* PMD_SIZE is not available in some special config, e.g. ARCH=arm with
898  * CONFIG_MMU=n. Use PAGE_SIZE in these cases.
899  */
900 #ifdef PMD_SIZE
901 /* PMD_SIZE is really big for some archs. It doesn't make sense to
902  * reserve too much memory in one allocation. Hardcode BPF_PROG_PACK_SIZE to
903  * 2MiB * num_possible_nodes(). On most architectures PMD_SIZE will be
904  * greater than or equal to 2MB.
905  */
906 #define BPF_PROG_PACK_SIZE (SZ_2M * num_possible_nodes())
907 #else
908 #define BPF_PROG_PACK_SIZE PAGE_SIZE
909 #endif
910 
911 #define BPF_PROG_CHUNK_COUNT (BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE)
912 
alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)913 static struct bpf_prog_pack *alloc_new_pack(bpf_jit_fill_hole_t bpf_fill_ill_insns)
914 {
915 	struct bpf_prog_pack *pack;
916 	int err;
917 
918 	pack = kzalloc(struct_size(pack, bitmap, BITS_TO_LONGS(BPF_PROG_CHUNK_COUNT)),
919 		       GFP_KERNEL);
920 	if (!pack)
921 		return NULL;
922 	pack->ptr = bpf_jit_alloc_exec(BPF_PROG_PACK_SIZE);
923 	if (!pack->ptr)
924 		goto out;
925 	bpf_fill_ill_insns(pack->ptr, BPF_PROG_PACK_SIZE);
926 	bitmap_zero(pack->bitmap, BPF_PROG_PACK_SIZE / BPF_PROG_CHUNK_SIZE);
927 
928 	set_vm_flush_reset_perms(pack->ptr);
929 	err = set_memory_rox((unsigned long)pack->ptr,
930 			     BPF_PROG_PACK_SIZE / PAGE_SIZE);
931 	if (err)
932 		goto out;
933 	list_add_tail(&pack->list, &pack_list);
934 	return pack;
935 
936 out:
937 	bpf_jit_free_exec(pack->ptr);
938 	kfree(pack);
939 	return NULL;
940 }
941 
bpf_prog_pack_alloc(u32 size,bpf_jit_fill_hole_t bpf_fill_ill_insns)942 void *bpf_prog_pack_alloc(u32 size, bpf_jit_fill_hole_t bpf_fill_ill_insns)
943 {
944 	unsigned int nbits = BPF_PROG_SIZE_TO_NBITS(size);
945 	struct bpf_prog_pack *pack;
946 	unsigned long pos;
947 	void *ptr = NULL;
948 
949 	mutex_lock(&pack_mutex);
950 	if (size > BPF_PROG_PACK_SIZE) {
951 		size = round_up(size, PAGE_SIZE);
952 		ptr = bpf_jit_alloc_exec(size);
953 		if (ptr) {
954 			int err;
955 
956 			bpf_fill_ill_insns(ptr, size);
957 			set_vm_flush_reset_perms(ptr);
958 			err = set_memory_rox((unsigned long)ptr,
959 					     size / PAGE_SIZE);
960 			if (err) {
961 				bpf_jit_free_exec(ptr);
962 				ptr = NULL;
963 			}
964 		}
965 		goto out;
966 	}
967 	list_for_each_entry(pack, &pack_list, list) {
968 		pos = bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
969 						 nbits, 0);
970 		if (pos < BPF_PROG_CHUNK_COUNT)
971 			goto found_free_area;
972 	}
973 
974 	pack = alloc_new_pack(bpf_fill_ill_insns);
975 	if (!pack)
976 		goto out;
977 
978 	pos = 0;
979 
980 found_free_area:
981 	bitmap_set(pack->bitmap, pos, nbits);
982 	ptr = (void *)(pack->ptr) + (pos << BPF_PROG_CHUNK_SHIFT);
983 
984 out:
985 	mutex_unlock(&pack_mutex);
986 	return ptr;
987 }
988 
bpf_prog_pack_free(void * ptr,u32 size)989 void bpf_prog_pack_free(void *ptr, u32 size)
990 {
991 	struct bpf_prog_pack *pack = NULL, *tmp;
992 	unsigned int nbits;
993 	unsigned long pos;
994 
995 	mutex_lock(&pack_mutex);
996 	if (size > BPF_PROG_PACK_SIZE) {
997 		bpf_jit_free_exec(ptr);
998 		goto out;
999 	}
1000 
1001 	list_for_each_entry(tmp, &pack_list, list) {
1002 		if (ptr >= tmp->ptr && (tmp->ptr + BPF_PROG_PACK_SIZE) > ptr) {
1003 			pack = tmp;
1004 			break;
1005 		}
1006 	}
1007 
1008 	if (WARN_ONCE(!pack, "bpf_prog_pack bug\n"))
1009 		goto out;
1010 
1011 	nbits = BPF_PROG_SIZE_TO_NBITS(size);
1012 	pos = ((unsigned long)ptr - (unsigned long)pack->ptr) >> BPF_PROG_CHUNK_SHIFT;
1013 
1014 	WARN_ONCE(bpf_arch_text_invalidate(ptr, size),
1015 		  "bpf_prog_pack bug: missing bpf_arch_text_invalidate?\n");
1016 
1017 	bitmap_clear(pack->bitmap, pos, nbits);
1018 	if (bitmap_find_next_zero_area(pack->bitmap, BPF_PROG_CHUNK_COUNT, 0,
1019 				       BPF_PROG_CHUNK_COUNT, 0) == 0) {
1020 		list_del(&pack->list);
1021 		bpf_jit_free_exec(pack->ptr);
1022 		kfree(pack);
1023 	}
1024 out:
1025 	mutex_unlock(&pack_mutex);
1026 }
1027 
1028 static atomic_long_t bpf_jit_current;
1029 
1030 /* Can be overridden by an arch's JIT compiler if it has a custom,
1031  * dedicated BPF backend memory area, or if neither of the two
1032  * below apply.
1033  */
bpf_jit_alloc_exec_limit(void)1034 u64 __weak bpf_jit_alloc_exec_limit(void)
1035 {
1036 #if defined(MODULES_VADDR)
1037 	return MODULES_END - MODULES_VADDR;
1038 #else
1039 	return VMALLOC_END - VMALLOC_START;
1040 #endif
1041 }
1042 
bpf_jit_charge_init(void)1043 static int __init bpf_jit_charge_init(void)
1044 {
1045 	/* Only used as heuristic here to derive limit. */
1046 	bpf_jit_limit_max = bpf_jit_alloc_exec_limit();
1047 	bpf_jit_limit = min_t(u64, round_up(bpf_jit_limit_max >> 1,
1048 					    PAGE_SIZE), LONG_MAX);
1049 	return 0;
1050 }
1051 pure_initcall(bpf_jit_charge_init);
1052 
bpf_jit_charge_modmem(u32 size)1053 int bpf_jit_charge_modmem(u32 size)
1054 {
1055 	if (atomic_long_add_return(size, &bpf_jit_current) > READ_ONCE(bpf_jit_limit)) {
1056 		if (!bpf_capable()) {
1057 			atomic_long_sub(size, &bpf_jit_current);
1058 			return -EPERM;
1059 		}
1060 	}
1061 
1062 	return 0;
1063 }
1064 
bpf_jit_uncharge_modmem(u32 size)1065 void bpf_jit_uncharge_modmem(u32 size)
1066 {
1067 	atomic_long_sub(size, &bpf_jit_current);
1068 }
1069 
bpf_jit_alloc_exec(unsigned long size)1070 void *__weak bpf_jit_alloc_exec(unsigned long size)
1071 {
1072 	return execmem_alloc(EXECMEM_BPF, size);
1073 }
1074 
bpf_jit_free_exec(void * addr)1075 void __weak bpf_jit_free_exec(void *addr)
1076 {
1077 	execmem_free(addr);
1078 }
1079 
1080 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)1081 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
1082 		     unsigned int alignment,
1083 		     bpf_jit_fill_hole_t bpf_fill_ill_insns)
1084 {
1085 	struct bpf_binary_header *hdr;
1086 	u32 size, hole, start;
1087 
1088 	WARN_ON_ONCE(!is_power_of_2(alignment) ||
1089 		     alignment > BPF_IMAGE_ALIGNMENT);
1090 
1091 	/* Most of BPF filters are really small, but if some of them
1092 	 * fill a page, allow at least 128 extra bytes to insert a
1093 	 * random section of illegal instructions.
1094 	 */
1095 	size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
1096 
1097 	if (bpf_jit_charge_modmem(size))
1098 		return NULL;
1099 	hdr = bpf_jit_alloc_exec(size);
1100 	if (!hdr) {
1101 		bpf_jit_uncharge_modmem(size);
1102 		return NULL;
1103 	}
1104 
1105 	/* Fill space with illegal/arch-dep instructions. */
1106 	bpf_fill_ill_insns(hdr, size);
1107 
1108 	hdr->size = size;
1109 	hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
1110 		     PAGE_SIZE - sizeof(*hdr));
1111 	start = get_random_u32_below(hole) & ~(alignment - 1);
1112 
1113 	/* Leave a random number of instructions before BPF code. */
1114 	*image_ptr = &hdr->image[start];
1115 
1116 	return hdr;
1117 }
1118 
bpf_jit_binary_free(struct bpf_binary_header * hdr)1119 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
1120 {
1121 	u32 size = hdr->size;
1122 
1123 	bpf_jit_free_exec(hdr);
1124 	bpf_jit_uncharge_modmem(size);
1125 }
1126 
1127 /* Allocate jit binary from bpf_prog_pack allocator.
1128  * Since the allocated memory is RO+X, the JIT engine cannot write directly
1129  * to the memory. To solve this problem, a RW buffer is also allocated at
1130  * as the same time. The JIT engine should calculate offsets based on the
1131  * RO memory address, but write JITed program to the RW buffer. Once the
1132  * JIT engine finishes, it calls bpf_jit_binary_pack_finalize, which copies
1133  * the JITed program to the RO memory.
1134  */
1135 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)1136 bpf_jit_binary_pack_alloc(unsigned int proglen, u8 **image_ptr,
1137 			  unsigned int alignment,
1138 			  struct bpf_binary_header **rw_header,
1139 			  u8 **rw_image,
1140 			  bpf_jit_fill_hole_t bpf_fill_ill_insns)
1141 {
1142 	struct bpf_binary_header *ro_header;
1143 	u32 size, hole, start;
1144 
1145 	WARN_ON_ONCE(!is_power_of_2(alignment) ||
1146 		     alignment > BPF_IMAGE_ALIGNMENT);
1147 
1148 	/* add 16 bytes for a random section of illegal instructions */
1149 	size = round_up(proglen + sizeof(*ro_header) + 16, BPF_PROG_CHUNK_SIZE);
1150 
1151 	if (bpf_jit_charge_modmem(size))
1152 		return NULL;
1153 	ro_header = bpf_prog_pack_alloc(size, bpf_fill_ill_insns);
1154 	if (!ro_header) {
1155 		bpf_jit_uncharge_modmem(size);
1156 		return NULL;
1157 	}
1158 
1159 	*rw_header = kvmalloc(size, GFP_KERNEL);
1160 	if (!*rw_header) {
1161 		bpf_prog_pack_free(ro_header, size);
1162 		bpf_jit_uncharge_modmem(size);
1163 		return NULL;
1164 	}
1165 
1166 	/* Fill space with illegal/arch-dep instructions. */
1167 	bpf_fill_ill_insns(*rw_header, size);
1168 	(*rw_header)->size = size;
1169 
1170 	hole = min_t(unsigned int, size - (proglen + sizeof(*ro_header)),
1171 		     BPF_PROG_CHUNK_SIZE - sizeof(*ro_header));
1172 	start = get_random_u32_below(hole) & ~(alignment - 1);
1173 
1174 	*image_ptr = &ro_header->image[start];
1175 	*rw_image = &(*rw_header)->image[start];
1176 
1177 	return ro_header;
1178 }
1179 
1180 /* 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)1181 int bpf_jit_binary_pack_finalize(struct bpf_binary_header *ro_header,
1182 				 struct bpf_binary_header *rw_header)
1183 {
1184 	void *ptr;
1185 
1186 	ptr = bpf_arch_text_copy(ro_header, rw_header, rw_header->size);
1187 
1188 	kvfree(rw_header);
1189 
1190 	if (IS_ERR(ptr)) {
1191 		bpf_prog_pack_free(ro_header, ro_header->size);
1192 		return PTR_ERR(ptr);
1193 	}
1194 	return 0;
1195 }
1196 
1197 /* bpf_jit_binary_pack_free is called in two different scenarios:
1198  *   1) when the program is freed after;
1199  *   2) when the JIT engine fails (before bpf_jit_binary_pack_finalize).
1200  * For case 2), we need to free both the RO memory and the RW buffer.
1201  *
1202  * bpf_jit_binary_pack_free requires proper ro_header->size. However,
1203  * bpf_jit_binary_pack_alloc does not set it. Therefore, ro_header->size
1204  * must be set with either bpf_jit_binary_pack_finalize (normal path) or
1205  * bpf_arch_text_copy (when jit fails).
1206  */
bpf_jit_binary_pack_free(struct bpf_binary_header * ro_header,struct bpf_binary_header * rw_header)1207 void bpf_jit_binary_pack_free(struct bpf_binary_header *ro_header,
1208 			      struct bpf_binary_header *rw_header)
1209 {
1210 	u32 size = ro_header->size;
1211 
1212 	bpf_prog_pack_free(ro_header, size);
1213 	kvfree(rw_header);
1214 	bpf_jit_uncharge_modmem(size);
1215 }
1216 
1217 struct bpf_binary_header *
bpf_jit_binary_pack_hdr(const struct bpf_prog * fp)1218 bpf_jit_binary_pack_hdr(const struct bpf_prog *fp)
1219 {
1220 	unsigned long real_start = (unsigned long)fp->bpf_func;
1221 	unsigned long addr;
1222 
1223 	addr = real_start & BPF_PROG_CHUNK_MASK;
1224 	return (void *)addr;
1225 }
1226 
1227 static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog * fp)1228 bpf_jit_binary_hdr(const struct bpf_prog *fp)
1229 {
1230 	unsigned long real_start = (unsigned long)fp->bpf_func;
1231 	unsigned long addr;
1232 
1233 	addr = real_start & PAGE_MASK;
1234 	return (void *)addr;
1235 }
1236 
1237 /* This symbol is only overridden by archs that have different
1238  * requirements than the usual eBPF JITs, f.e. when they only
1239  * implement cBPF JIT, do not set images read-only, etc.
1240  */
bpf_jit_free(struct bpf_prog * fp)1241 void __weak bpf_jit_free(struct bpf_prog *fp)
1242 {
1243 	if (fp->jited) {
1244 		struct bpf_binary_header *hdr = bpf_jit_binary_hdr(fp);
1245 
1246 		bpf_jit_binary_free(hdr);
1247 		WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
1248 	}
1249 
1250 	bpf_prog_unlock_free(fp);
1251 }
1252 
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)1253 int bpf_jit_get_func_addr(const struct bpf_prog *prog,
1254 			  const struct bpf_insn *insn, bool extra_pass,
1255 			  u64 *func_addr, bool *func_addr_fixed)
1256 {
1257 	s16 off = insn->off;
1258 	s32 imm = insn->imm;
1259 	u8 *addr;
1260 	int err;
1261 
1262 	*func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL;
1263 	if (!*func_addr_fixed) {
1264 		/* Place-holder address till the last pass has collected
1265 		 * all addresses for JITed subprograms in which case we
1266 		 * can pick them up from prog->aux.
1267 		 */
1268 		if (!extra_pass)
1269 			addr = NULL;
1270 		else if (prog->aux->func &&
1271 			 off >= 0 && off < prog->aux->real_func_cnt)
1272 			addr = (u8 *)prog->aux->func[off]->bpf_func;
1273 		else
1274 			return -EINVAL;
1275 	} else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
1276 		   bpf_jit_supports_far_kfunc_call()) {
1277 		err = bpf_get_kfunc_addr(prog, insn->imm, insn->off, &addr);
1278 		if (err)
1279 			return err;
1280 	} else {
1281 		/* Address of a BPF helper call. Since part of the core
1282 		 * kernel, it's always at a fixed location. __bpf_call_base
1283 		 * and the helper with imm relative to it are both in core
1284 		 * kernel.
1285 		 */
1286 		addr = (u8 *)__bpf_call_base + imm;
1287 	}
1288 
1289 	*func_addr = (unsigned long)addr;
1290 	return 0;
1291 }
1292 
bpf_jit_blind_insn(const struct bpf_insn * from,const struct bpf_insn * aux,struct bpf_insn * to_buff,bool emit_zext)1293 static int bpf_jit_blind_insn(const struct bpf_insn *from,
1294 			      const struct bpf_insn *aux,
1295 			      struct bpf_insn *to_buff,
1296 			      bool emit_zext)
1297 {
1298 	struct bpf_insn *to = to_buff;
1299 	u32 imm_rnd = get_random_u32();
1300 	s16 off;
1301 
1302 	BUILD_BUG_ON(BPF_REG_AX  + 1 != MAX_BPF_JIT_REG);
1303 	BUILD_BUG_ON(MAX_BPF_REG + 1 != MAX_BPF_JIT_REG);
1304 
1305 	/* Constraints on AX register:
1306 	 *
1307 	 * AX register is inaccessible from user space. It is mapped in
1308 	 * all JITs, and used here for constant blinding rewrites. It is
1309 	 * typically "stateless" meaning its contents are only valid within
1310 	 * the executed instruction, but not across several instructions.
1311 	 * There are a few exceptions however which are further detailed
1312 	 * below.
1313 	 *
1314 	 * Constant blinding is only used by JITs, not in the interpreter.
1315 	 * The interpreter uses AX in some occasions as a local temporary
1316 	 * register e.g. in DIV or MOD instructions.
1317 	 *
1318 	 * In restricted circumstances, the verifier can also use the AX
1319 	 * register for rewrites as long as they do not interfere with
1320 	 * the above cases!
1321 	 */
1322 	if (from->dst_reg == BPF_REG_AX || from->src_reg == BPF_REG_AX)
1323 		goto out;
1324 
1325 	if (from->imm == 0 &&
1326 	    (from->code == (BPF_ALU   | BPF_MOV | BPF_K) ||
1327 	     from->code == (BPF_ALU64 | BPF_MOV | BPF_K))) {
1328 		*to++ = BPF_ALU64_REG(BPF_XOR, from->dst_reg, from->dst_reg);
1329 		goto out;
1330 	}
1331 
1332 	switch (from->code) {
1333 	case BPF_ALU | BPF_ADD | BPF_K:
1334 	case BPF_ALU | BPF_SUB | BPF_K:
1335 	case BPF_ALU | BPF_AND | BPF_K:
1336 	case BPF_ALU | BPF_OR  | BPF_K:
1337 	case BPF_ALU | BPF_XOR | BPF_K:
1338 	case BPF_ALU | BPF_MUL | BPF_K:
1339 	case BPF_ALU | BPF_MOV | BPF_K:
1340 	case BPF_ALU | BPF_DIV | BPF_K:
1341 	case BPF_ALU | BPF_MOD | BPF_K:
1342 		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1343 		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1344 		*to++ = BPF_ALU32_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1345 		break;
1346 
1347 	case BPF_ALU64 | BPF_ADD | BPF_K:
1348 	case BPF_ALU64 | BPF_SUB | BPF_K:
1349 	case BPF_ALU64 | BPF_AND | BPF_K:
1350 	case BPF_ALU64 | BPF_OR  | BPF_K:
1351 	case BPF_ALU64 | BPF_XOR | BPF_K:
1352 	case BPF_ALU64 | BPF_MUL | BPF_K:
1353 	case BPF_ALU64 | BPF_MOV | BPF_K:
1354 	case BPF_ALU64 | BPF_DIV | BPF_K:
1355 	case BPF_ALU64 | BPF_MOD | BPF_K:
1356 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1357 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1358 		*to++ = BPF_ALU64_REG_OFF(from->code, from->dst_reg, BPF_REG_AX, from->off);
1359 		break;
1360 
1361 	case BPF_JMP | BPF_JEQ  | BPF_K:
1362 	case BPF_JMP | BPF_JNE  | BPF_K:
1363 	case BPF_JMP | BPF_JGT  | BPF_K:
1364 	case BPF_JMP | BPF_JLT  | BPF_K:
1365 	case BPF_JMP | BPF_JGE  | BPF_K:
1366 	case BPF_JMP | BPF_JLE  | BPF_K:
1367 	case BPF_JMP | BPF_JSGT | BPF_K:
1368 	case BPF_JMP | BPF_JSLT | BPF_K:
1369 	case BPF_JMP | BPF_JSGE | BPF_K:
1370 	case BPF_JMP | BPF_JSLE | BPF_K:
1371 	case BPF_JMP | BPF_JSET | BPF_K:
1372 		/* Accommodate for extra offset in case of a backjump. */
1373 		off = from->off;
1374 		if (off < 0)
1375 			off -= 2;
1376 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1377 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1378 		*to++ = BPF_JMP_REG(from->code, from->dst_reg, BPF_REG_AX, off);
1379 		break;
1380 
1381 	case BPF_JMP32 | BPF_JEQ  | BPF_K:
1382 	case BPF_JMP32 | BPF_JNE  | BPF_K:
1383 	case BPF_JMP32 | BPF_JGT  | BPF_K:
1384 	case BPF_JMP32 | BPF_JLT  | BPF_K:
1385 	case BPF_JMP32 | BPF_JGE  | BPF_K:
1386 	case BPF_JMP32 | BPF_JLE  | BPF_K:
1387 	case BPF_JMP32 | BPF_JSGT | BPF_K:
1388 	case BPF_JMP32 | BPF_JSLT | BPF_K:
1389 	case BPF_JMP32 | BPF_JSGE | BPF_K:
1390 	case BPF_JMP32 | BPF_JSLE | BPF_K:
1391 	case BPF_JMP32 | BPF_JSET | BPF_K:
1392 		/* Accommodate for extra offset in case of a backjump. */
1393 		off = from->off;
1394 		if (off < 0)
1395 			off -= 2;
1396 		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1397 		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1398 		*to++ = BPF_JMP32_REG(from->code, from->dst_reg, BPF_REG_AX,
1399 				      off);
1400 		break;
1401 
1402 	case BPF_LD | BPF_IMM | BPF_DW:
1403 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[1].imm);
1404 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1405 		*to++ = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
1406 		*to++ = BPF_ALU64_REG(BPF_MOV, aux[0].dst_reg, BPF_REG_AX);
1407 		break;
1408 	case 0: /* Part 2 of BPF_LD | BPF_IMM | BPF_DW. */
1409 		*to++ = BPF_ALU32_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ aux[0].imm);
1410 		*to++ = BPF_ALU32_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1411 		if (emit_zext)
1412 			*to++ = BPF_ZEXT_REG(BPF_REG_AX);
1413 		*to++ = BPF_ALU64_REG(BPF_OR,  aux[0].dst_reg, BPF_REG_AX);
1414 		break;
1415 
1416 	case BPF_ST | BPF_MEM | BPF_DW:
1417 	case BPF_ST | BPF_MEM | BPF_W:
1418 	case BPF_ST | BPF_MEM | BPF_H:
1419 	case BPF_ST | BPF_MEM | BPF_B:
1420 		*to++ = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, imm_rnd ^ from->imm);
1421 		*to++ = BPF_ALU64_IMM(BPF_XOR, BPF_REG_AX, imm_rnd);
1422 		*to++ = BPF_STX_MEM(from->code, from->dst_reg, BPF_REG_AX, from->off);
1423 		break;
1424 	}
1425 out:
1426 	return to - to_buff;
1427 }
1428 
bpf_prog_clone_create(struct bpf_prog * fp_other,gfp_t gfp_extra_flags)1429 static struct bpf_prog *bpf_prog_clone_create(struct bpf_prog *fp_other,
1430 					      gfp_t gfp_extra_flags)
1431 {
1432 	gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | gfp_extra_flags;
1433 	struct bpf_prog *fp;
1434 
1435 	fp = __vmalloc(fp_other->pages * PAGE_SIZE, gfp_flags);
1436 	if (fp != NULL) {
1437 		/* aux->prog still points to the fp_other one, so
1438 		 * when promoting the clone to the real program,
1439 		 * this still needs to be adapted.
1440 		 */
1441 		memcpy(fp, fp_other, fp_other->pages * PAGE_SIZE);
1442 	}
1443 
1444 	return fp;
1445 }
1446 
bpf_prog_clone_free(struct bpf_prog * fp)1447 static void bpf_prog_clone_free(struct bpf_prog *fp)
1448 {
1449 	/* aux was stolen by the other clone, so we cannot free
1450 	 * it from this path! It will be freed eventually by the
1451 	 * other program on release.
1452 	 *
1453 	 * At this point, we don't need a deferred release since
1454 	 * clone is guaranteed to not be locked.
1455 	 */
1456 	fp->aux = NULL;
1457 	fp->stats = NULL;
1458 	fp->active = NULL;
1459 	__bpf_prog_free(fp);
1460 }
1461 
bpf_jit_prog_release_other(struct bpf_prog * fp,struct bpf_prog * fp_other)1462 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other)
1463 {
1464 	/* We have to repoint aux->prog to self, as we don't
1465 	 * know whether fp here is the clone or the original.
1466 	 */
1467 	fp->aux->prog = fp;
1468 	bpf_prog_clone_free(fp_other);
1469 }
1470 
bpf_jit_blind_constants(struct bpf_prog * prog)1471 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
1472 {
1473 	struct bpf_insn insn_buff[16], aux[2];
1474 	struct bpf_prog *clone, *tmp;
1475 	int insn_delta, insn_cnt;
1476 	struct bpf_insn *insn;
1477 	int i, rewritten;
1478 
1479 	if (!prog->blinding_requested || prog->blinded)
1480 		return prog;
1481 
1482 	clone = bpf_prog_clone_create(prog, GFP_USER);
1483 	if (!clone)
1484 		return ERR_PTR(-ENOMEM);
1485 
1486 	insn_cnt = clone->len;
1487 	insn = clone->insnsi;
1488 
1489 	for (i = 0; i < insn_cnt; i++, insn++) {
1490 		if (bpf_pseudo_func(insn)) {
1491 			/* ld_imm64 with an address of bpf subprog is not
1492 			 * a user controlled constant. Don't randomize it,
1493 			 * since it will conflict with jit_subprogs() logic.
1494 			 */
1495 			insn++;
1496 			i++;
1497 			continue;
1498 		}
1499 
1500 		/* We temporarily need to hold the original ld64 insn
1501 		 * so that we can still access the first part in the
1502 		 * second blinding run.
1503 		 */
1504 		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
1505 		    insn[1].code == 0)
1506 			memcpy(aux, insn, sizeof(aux));
1507 
1508 		rewritten = bpf_jit_blind_insn(insn, aux, insn_buff,
1509 						clone->aux->verifier_zext);
1510 		if (!rewritten)
1511 			continue;
1512 
1513 		tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
1514 		if (IS_ERR(tmp)) {
1515 			/* Patching may have repointed aux->prog during
1516 			 * realloc from the original one, so we need to
1517 			 * fix it up here on error.
1518 			 */
1519 			bpf_jit_prog_release_other(prog, clone);
1520 			return tmp;
1521 		}
1522 
1523 		clone = tmp;
1524 		insn_delta = rewritten - 1;
1525 
1526 		/* Walk new program and skip insns we just inserted. */
1527 		insn = clone->insnsi + i + insn_delta;
1528 		insn_cnt += insn_delta;
1529 		i        += insn_delta;
1530 	}
1531 
1532 	clone->blinded = 1;
1533 	return clone;
1534 }
1535 #endif /* CONFIG_BPF_JIT */
1536 
1537 /* Base function for offset calculation. Needs to go into .text section,
1538  * therefore keeping it non-static as well; will also be used by JITs
1539  * anyway later on, so do not let the compiler omit it. This also needs
1540  * to go into kallsyms for correlation from e.g. bpftool, so naming
1541  * must not change.
1542  */
__bpf_call_base(u64 r1,u64 r2,u64 r3,u64 r4,u64 r5)1543 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
1544 {
1545 	return 0;
1546 }
1547 EXPORT_SYMBOL_GPL(__bpf_call_base);
1548 
1549 /* All UAPI available opcodes. */
1550 #define BPF_INSN_MAP(INSN_2, INSN_3)		\
1551 	/* 32 bit ALU operations. */		\
1552 	/*   Register based. */			\
1553 	INSN_3(ALU, ADD,  X),			\
1554 	INSN_3(ALU, SUB,  X),			\
1555 	INSN_3(ALU, AND,  X),			\
1556 	INSN_3(ALU, OR,   X),			\
1557 	INSN_3(ALU, LSH,  X),			\
1558 	INSN_3(ALU, RSH,  X),			\
1559 	INSN_3(ALU, XOR,  X),			\
1560 	INSN_3(ALU, MUL,  X),			\
1561 	INSN_3(ALU, MOV,  X),			\
1562 	INSN_3(ALU, ARSH, X),			\
1563 	INSN_3(ALU, DIV,  X),			\
1564 	INSN_3(ALU, MOD,  X),			\
1565 	INSN_2(ALU, NEG),			\
1566 	INSN_3(ALU, END, TO_BE),		\
1567 	INSN_3(ALU, END, TO_LE),		\
1568 	/*   Immediate based. */		\
1569 	INSN_3(ALU, ADD,  K),			\
1570 	INSN_3(ALU, SUB,  K),			\
1571 	INSN_3(ALU, AND,  K),			\
1572 	INSN_3(ALU, OR,   K),			\
1573 	INSN_3(ALU, LSH,  K),			\
1574 	INSN_3(ALU, RSH,  K),			\
1575 	INSN_3(ALU, XOR,  K),			\
1576 	INSN_3(ALU, MUL,  K),			\
1577 	INSN_3(ALU, MOV,  K),			\
1578 	INSN_3(ALU, ARSH, K),			\
1579 	INSN_3(ALU, DIV,  K),			\
1580 	INSN_3(ALU, MOD,  K),			\
1581 	/* 64 bit ALU operations. */		\
1582 	/*   Register based. */			\
1583 	INSN_3(ALU64, ADD,  X),			\
1584 	INSN_3(ALU64, SUB,  X),			\
1585 	INSN_3(ALU64, AND,  X),			\
1586 	INSN_3(ALU64, OR,   X),			\
1587 	INSN_3(ALU64, LSH,  X),			\
1588 	INSN_3(ALU64, RSH,  X),			\
1589 	INSN_3(ALU64, XOR,  X),			\
1590 	INSN_3(ALU64, MUL,  X),			\
1591 	INSN_3(ALU64, MOV,  X),			\
1592 	INSN_3(ALU64, ARSH, X),			\
1593 	INSN_3(ALU64, DIV,  X),			\
1594 	INSN_3(ALU64, MOD,  X),			\
1595 	INSN_2(ALU64, NEG),			\
1596 	INSN_3(ALU64, END, TO_LE),		\
1597 	/*   Immediate based. */		\
1598 	INSN_3(ALU64, ADD,  K),			\
1599 	INSN_3(ALU64, SUB,  K),			\
1600 	INSN_3(ALU64, AND,  K),			\
1601 	INSN_3(ALU64, OR,   K),			\
1602 	INSN_3(ALU64, LSH,  K),			\
1603 	INSN_3(ALU64, RSH,  K),			\
1604 	INSN_3(ALU64, XOR,  K),			\
1605 	INSN_3(ALU64, MUL,  K),			\
1606 	INSN_3(ALU64, MOV,  K),			\
1607 	INSN_3(ALU64, ARSH, K),			\
1608 	INSN_3(ALU64, DIV,  K),			\
1609 	INSN_3(ALU64, MOD,  K),			\
1610 	/* Call instruction. */			\
1611 	INSN_2(JMP, CALL),			\
1612 	/* Exit instruction. */			\
1613 	INSN_2(JMP, EXIT),			\
1614 	/* 32-bit Jump instructions. */		\
1615 	/*   Register based. */			\
1616 	INSN_3(JMP32, JEQ,  X),			\
1617 	INSN_3(JMP32, JNE,  X),			\
1618 	INSN_3(JMP32, JGT,  X),			\
1619 	INSN_3(JMP32, JLT,  X),			\
1620 	INSN_3(JMP32, JGE,  X),			\
1621 	INSN_3(JMP32, JLE,  X),			\
1622 	INSN_3(JMP32, JSGT, X),			\
1623 	INSN_3(JMP32, JSLT, X),			\
1624 	INSN_3(JMP32, JSGE, X),			\
1625 	INSN_3(JMP32, JSLE, X),			\
1626 	INSN_3(JMP32, JSET, X),			\
1627 	/*   Immediate based. */		\
1628 	INSN_3(JMP32, JEQ,  K),			\
1629 	INSN_3(JMP32, JNE,  K),			\
1630 	INSN_3(JMP32, JGT,  K),			\
1631 	INSN_3(JMP32, JLT,  K),			\
1632 	INSN_3(JMP32, JGE,  K),			\
1633 	INSN_3(JMP32, JLE,  K),			\
1634 	INSN_3(JMP32, JSGT, K),			\
1635 	INSN_3(JMP32, JSLT, K),			\
1636 	INSN_3(JMP32, JSGE, K),			\
1637 	INSN_3(JMP32, JSLE, K),			\
1638 	INSN_3(JMP32, JSET, K),			\
1639 	/* Jump instructions. */		\
1640 	/*   Register based. */			\
1641 	INSN_3(JMP, JEQ,  X),			\
1642 	INSN_3(JMP, JNE,  X),			\
1643 	INSN_3(JMP, JGT,  X),			\
1644 	INSN_3(JMP, JLT,  X),			\
1645 	INSN_3(JMP, JGE,  X),			\
1646 	INSN_3(JMP, JLE,  X),			\
1647 	INSN_3(JMP, JSGT, X),			\
1648 	INSN_3(JMP, JSLT, X),			\
1649 	INSN_3(JMP, JSGE, X),			\
1650 	INSN_3(JMP, JSLE, X),			\
1651 	INSN_3(JMP, JSET, X),			\
1652 	/*   Immediate based. */		\
1653 	INSN_3(JMP, JEQ,  K),			\
1654 	INSN_3(JMP, JNE,  K),			\
1655 	INSN_3(JMP, JGT,  K),			\
1656 	INSN_3(JMP, JLT,  K),			\
1657 	INSN_3(JMP, JGE,  K),			\
1658 	INSN_3(JMP, JLE,  K),			\
1659 	INSN_3(JMP, JSGT, K),			\
1660 	INSN_3(JMP, JSLT, K),			\
1661 	INSN_3(JMP, JSGE, K),			\
1662 	INSN_3(JMP, JSLE, K),			\
1663 	INSN_3(JMP, JSET, K),			\
1664 	INSN_2(JMP, JA),			\
1665 	INSN_2(JMP32, JA),			\
1666 	/* Store instructions. */		\
1667 	/*   Register based. */			\
1668 	INSN_3(STX, MEM,  B),			\
1669 	INSN_3(STX, MEM,  H),			\
1670 	INSN_3(STX, MEM,  W),			\
1671 	INSN_3(STX, MEM,  DW),			\
1672 	INSN_3(STX, ATOMIC, W),			\
1673 	INSN_3(STX, ATOMIC, DW),		\
1674 	/*   Immediate based. */		\
1675 	INSN_3(ST, MEM, B),			\
1676 	INSN_3(ST, MEM, H),			\
1677 	INSN_3(ST, MEM, W),			\
1678 	INSN_3(ST, MEM, DW),			\
1679 	/* Load instructions. */		\
1680 	/*   Register based. */			\
1681 	INSN_3(LDX, MEM, B),			\
1682 	INSN_3(LDX, MEM, H),			\
1683 	INSN_3(LDX, MEM, W),			\
1684 	INSN_3(LDX, MEM, DW),			\
1685 	INSN_3(LDX, MEMSX, B),			\
1686 	INSN_3(LDX, MEMSX, H),			\
1687 	INSN_3(LDX, MEMSX, W),			\
1688 	/*   Immediate based. */		\
1689 	INSN_3(LD, IMM, DW)
1690 
bpf_opcode_in_insntable(u8 code)1691 bool bpf_opcode_in_insntable(u8 code)
1692 {
1693 #define BPF_INSN_2_TBL(x, y)    [BPF_##x | BPF_##y] = true
1694 #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
1695 	static const bool public_insntable[256] = {
1696 		[0 ... 255] = false,
1697 		/* Now overwrite non-defaults ... */
1698 		BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
1699 		/* UAPI exposed, but rewritten opcodes. cBPF carry-over. */
1700 		[BPF_LD | BPF_ABS | BPF_B] = true,
1701 		[BPF_LD | BPF_ABS | BPF_H] = true,
1702 		[BPF_LD | BPF_ABS | BPF_W] = true,
1703 		[BPF_LD | BPF_IND | BPF_B] = true,
1704 		[BPF_LD | BPF_IND | BPF_H] = true,
1705 		[BPF_LD | BPF_IND | BPF_W] = true,
1706 		[BPF_JMP | BPF_JCOND] = true,
1707 	};
1708 #undef BPF_INSN_3_TBL
1709 #undef BPF_INSN_2_TBL
1710 	return public_insntable[code];
1711 }
1712 
1713 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
1714 /**
1715  *	___bpf_prog_run - run eBPF program on a given context
1716  *	@regs: is the array of MAX_BPF_EXT_REG eBPF pseudo-registers
1717  *	@insn: is the array of eBPF instructions
1718  *
1719  * Decode and execute eBPF instructions.
1720  *
1721  * Return: whatever value is in %BPF_R0 at program exit
1722  */
___bpf_prog_run(u64 * regs,const struct bpf_insn * insn)1723 static u64 ___bpf_prog_run(u64 *regs, const struct bpf_insn *insn)
1724 {
1725 #define BPF_INSN_2_LBL(x, y)    [BPF_##x | BPF_##y] = &&x##_##y
1726 #define BPF_INSN_3_LBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = &&x##_##y##_##z
1727 	static const void * const jumptable[256] __annotate_jump_table = {
1728 		[0 ... 255] = &&default_label,
1729 		/* Now overwrite non-defaults ... */
1730 		BPF_INSN_MAP(BPF_INSN_2_LBL, BPF_INSN_3_LBL),
1731 		/* Non-UAPI available opcodes. */
1732 		[BPF_JMP | BPF_CALL_ARGS] = &&JMP_CALL_ARGS,
1733 		[BPF_JMP | BPF_TAIL_CALL] = &&JMP_TAIL_CALL,
1734 		[BPF_ST  | BPF_NOSPEC] = &&ST_NOSPEC,
1735 		[BPF_LDX | BPF_PROBE_MEM | BPF_B] = &&LDX_PROBE_MEM_B,
1736 		[BPF_LDX | BPF_PROBE_MEM | BPF_H] = &&LDX_PROBE_MEM_H,
1737 		[BPF_LDX | BPF_PROBE_MEM | BPF_W] = &&LDX_PROBE_MEM_W,
1738 		[BPF_LDX | BPF_PROBE_MEM | BPF_DW] = &&LDX_PROBE_MEM_DW,
1739 		[BPF_LDX | BPF_PROBE_MEMSX | BPF_B] = &&LDX_PROBE_MEMSX_B,
1740 		[BPF_LDX | BPF_PROBE_MEMSX | BPF_H] = &&LDX_PROBE_MEMSX_H,
1741 		[BPF_LDX | BPF_PROBE_MEMSX | BPF_W] = &&LDX_PROBE_MEMSX_W,
1742 	};
1743 #undef BPF_INSN_3_LBL
1744 #undef BPF_INSN_2_LBL
1745 	u32 tail_call_cnt = 0;
1746 
1747 #define CONT	 ({ insn++; goto select_insn; })
1748 #define CONT_JMP ({ insn++; goto select_insn; })
1749 
1750 select_insn:
1751 	goto *jumptable[insn->code];
1752 
1753 	/* Explicitly mask the register-based shift amounts with 63 or 31
1754 	 * to avoid undefined behavior. Normally this won't affect the
1755 	 * generated code, for example, in case of native 64 bit archs such
1756 	 * as x86-64 or arm64, the compiler is optimizing the AND away for
1757 	 * the interpreter. In case of JITs, each of the JIT backends compiles
1758 	 * the BPF shift operations to machine instructions which produce
1759 	 * implementation-defined results in such a case; the resulting
1760 	 * contents of the register may be arbitrary, but program behaviour
1761 	 * as a whole remains defined. In other words, in case of JIT backends,
1762 	 * the AND must /not/ be added to the emitted LSH/RSH/ARSH translation.
1763 	 */
1764 	/* ALU (shifts) */
1765 #define SHT(OPCODE, OP)					\
1766 	ALU64_##OPCODE##_X:				\
1767 		DST = DST OP (SRC & 63);		\
1768 		CONT;					\
1769 	ALU_##OPCODE##_X:				\
1770 		DST = (u32) DST OP ((u32) SRC & 31);	\
1771 		CONT;					\
1772 	ALU64_##OPCODE##_K:				\
1773 		DST = DST OP IMM;			\
1774 		CONT;					\
1775 	ALU_##OPCODE##_K:				\
1776 		DST = (u32) DST OP (u32) IMM;		\
1777 		CONT;
1778 	/* ALU (rest) */
1779 #define ALU(OPCODE, OP)					\
1780 	ALU64_##OPCODE##_X:				\
1781 		DST = DST OP SRC;			\
1782 		CONT;					\
1783 	ALU_##OPCODE##_X:				\
1784 		DST = (u32) DST OP (u32) SRC;		\
1785 		CONT;					\
1786 	ALU64_##OPCODE##_K:				\
1787 		DST = DST OP IMM;			\
1788 		CONT;					\
1789 	ALU_##OPCODE##_K:				\
1790 		DST = (u32) DST OP (u32) IMM;		\
1791 		CONT;
1792 	ALU(ADD,  +)
1793 	ALU(SUB,  -)
1794 	ALU(AND,  &)
1795 	ALU(OR,   |)
1796 	ALU(XOR,  ^)
1797 	ALU(MUL,  *)
1798 	SHT(LSH, <<)
1799 	SHT(RSH, >>)
1800 #undef SHT
1801 #undef ALU
1802 	ALU_NEG:
1803 		DST = (u32) -DST;
1804 		CONT;
1805 	ALU64_NEG:
1806 		DST = -DST;
1807 		CONT;
1808 	ALU_MOV_X:
1809 		switch (OFF) {
1810 		case 0:
1811 			DST = (u32) SRC;
1812 			break;
1813 		case 8:
1814 			DST = (u32)(s8) SRC;
1815 			break;
1816 		case 16:
1817 			DST = (u32)(s16) SRC;
1818 			break;
1819 		}
1820 		CONT;
1821 	ALU_MOV_K:
1822 		DST = (u32) IMM;
1823 		CONT;
1824 	ALU64_MOV_X:
1825 		switch (OFF) {
1826 		case 0:
1827 			DST = SRC;
1828 			break;
1829 		case 8:
1830 			DST = (s8) SRC;
1831 			break;
1832 		case 16:
1833 			DST = (s16) SRC;
1834 			break;
1835 		case 32:
1836 			DST = (s32) SRC;
1837 			break;
1838 		}
1839 		CONT;
1840 	ALU64_MOV_K:
1841 		DST = IMM;
1842 		CONT;
1843 	LD_IMM_DW:
1844 		DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
1845 		insn++;
1846 		CONT;
1847 	ALU_ARSH_X:
1848 		DST = (u64) (u32) (((s32) DST) >> (SRC & 31));
1849 		CONT;
1850 	ALU_ARSH_K:
1851 		DST = (u64) (u32) (((s32) DST) >> IMM);
1852 		CONT;
1853 	ALU64_ARSH_X:
1854 		(*(s64 *) &DST) >>= (SRC & 63);
1855 		CONT;
1856 	ALU64_ARSH_K:
1857 		(*(s64 *) &DST) >>= IMM;
1858 		CONT;
1859 	ALU64_MOD_X:
1860 		switch (OFF) {
1861 		case 0:
1862 			div64_u64_rem(DST, SRC, &AX);
1863 			DST = AX;
1864 			break;
1865 		case 1:
1866 			AX = div64_s64(DST, SRC);
1867 			DST = DST - AX * SRC;
1868 			break;
1869 		}
1870 		CONT;
1871 	ALU_MOD_X:
1872 		switch (OFF) {
1873 		case 0:
1874 			AX = (u32) DST;
1875 			DST = do_div(AX, (u32) SRC);
1876 			break;
1877 		case 1:
1878 			AX = abs((s32)DST);
1879 			AX = do_div(AX, abs((s32)SRC));
1880 			if ((s32)DST < 0)
1881 				DST = (u32)-AX;
1882 			else
1883 				DST = (u32)AX;
1884 			break;
1885 		}
1886 		CONT;
1887 	ALU64_MOD_K:
1888 		switch (OFF) {
1889 		case 0:
1890 			div64_u64_rem(DST, IMM, &AX);
1891 			DST = AX;
1892 			break;
1893 		case 1:
1894 			AX = div64_s64(DST, IMM);
1895 			DST = DST - AX * IMM;
1896 			break;
1897 		}
1898 		CONT;
1899 	ALU_MOD_K:
1900 		switch (OFF) {
1901 		case 0:
1902 			AX = (u32) DST;
1903 			DST = do_div(AX, (u32) IMM);
1904 			break;
1905 		case 1:
1906 			AX = abs((s32)DST);
1907 			AX = do_div(AX, abs((s32)IMM));
1908 			if ((s32)DST < 0)
1909 				DST = (u32)-AX;
1910 			else
1911 				DST = (u32)AX;
1912 			break;
1913 		}
1914 		CONT;
1915 	ALU64_DIV_X:
1916 		switch (OFF) {
1917 		case 0:
1918 			DST = div64_u64(DST, SRC);
1919 			break;
1920 		case 1:
1921 			DST = div64_s64(DST, SRC);
1922 			break;
1923 		}
1924 		CONT;
1925 	ALU_DIV_X:
1926 		switch (OFF) {
1927 		case 0:
1928 			AX = (u32) DST;
1929 			do_div(AX, (u32) SRC);
1930 			DST = (u32) AX;
1931 			break;
1932 		case 1:
1933 			AX = abs((s32)DST);
1934 			do_div(AX, abs((s32)SRC));
1935 			if (((s32)DST < 0) == ((s32)SRC < 0))
1936 				DST = (u32)AX;
1937 			else
1938 				DST = (u32)-AX;
1939 			break;
1940 		}
1941 		CONT;
1942 	ALU64_DIV_K:
1943 		switch (OFF) {
1944 		case 0:
1945 			DST = div64_u64(DST, IMM);
1946 			break;
1947 		case 1:
1948 			DST = div64_s64(DST, IMM);
1949 			break;
1950 		}
1951 		CONT;
1952 	ALU_DIV_K:
1953 		switch (OFF) {
1954 		case 0:
1955 			AX = (u32) DST;
1956 			do_div(AX, (u32) IMM);
1957 			DST = (u32) AX;
1958 			break;
1959 		case 1:
1960 			AX = abs((s32)DST);
1961 			do_div(AX, abs((s32)IMM));
1962 			if (((s32)DST < 0) == ((s32)IMM < 0))
1963 				DST = (u32)AX;
1964 			else
1965 				DST = (u32)-AX;
1966 			break;
1967 		}
1968 		CONT;
1969 	ALU_END_TO_BE:
1970 		switch (IMM) {
1971 		case 16:
1972 			DST = (__force u16) cpu_to_be16(DST);
1973 			break;
1974 		case 32:
1975 			DST = (__force u32) cpu_to_be32(DST);
1976 			break;
1977 		case 64:
1978 			DST = (__force u64) cpu_to_be64(DST);
1979 			break;
1980 		}
1981 		CONT;
1982 	ALU_END_TO_LE:
1983 		switch (IMM) {
1984 		case 16:
1985 			DST = (__force u16) cpu_to_le16(DST);
1986 			break;
1987 		case 32:
1988 			DST = (__force u32) cpu_to_le32(DST);
1989 			break;
1990 		case 64:
1991 			DST = (__force u64) cpu_to_le64(DST);
1992 			break;
1993 		}
1994 		CONT;
1995 	ALU64_END_TO_LE:
1996 		switch (IMM) {
1997 		case 16:
1998 			DST = (__force u16) __swab16(DST);
1999 			break;
2000 		case 32:
2001 			DST = (__force u32) __swab32(DST);
2002 			break;
2003 		case 64:
2004 			DST = (__force u64) __swab64(DST);
2005 			break;
2006 		}
2007 		CONT;
2008 
2009 	/* CALL */
2010 	JMP_CALL:
2011 		/* Function call scratches BPF_R1-BPF_R5 registers,
2012 		 * preserves BPF_R6-BPF_R9, and stores return value
2013 		 * into BPF_R0.
2014 		 */
2015 		BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
2016 						       BPF_R4, BPF_R5);
2017 		CONT;
2018 
2019 	JMP_CALL_ARGS:
2020 		BPF_R0 = (__bpf_call_base_args + insn->imm)(BPF_R1, BPF_R2,
2021 							    BPF_R3, BPF_R4,
2022 							    BPF_R5,
2023 							    insn + insn->off + 1);
2024 		CONT;
2025 
2026 	JMP_TAIL_CALL: {
2027 		struct bpf_map *map = (struct bpf_map *) (unsigned long) BPF_R2;
2028 		struct bpf_array *array = container_of(map, struct bpf_array, map);
2029 		struct bpf_prog *prog;
2030 		u32 index = BPF_R3;
2031 
2032 		if (unlikely(index >= array->map.max_entries))
2033 			goto out;
2034 
2035 		if (unlikely(tail_call_cnt >= MAX_TAIL_CALL_CNT))
2036 			goto out;
2037 
2038 		tail_call_cnt++;
2039 
2040 		prog = READ_ONCE(array->ptrs[index]);
2041 		if (!prog)
2042 			goto out;
2043 
2044 		/* ARG1 at this point is guaranteed to point to CTX from
2045 		 * the verifier side due to the fact that the tail call is
2046 		 * handled like a helper, that is, bpf_tail_call_proto,
2047 		 * where arg1_type is ARG_PTR_TO_CTX.
2048 		 */
2049 		insn = prog->insnsi;
2050 		goto select_insn;
2051 out:
2052 		CONT;
2053 	}
2054 	JMP_JA:
2055 		insn += insn->off;
2056 		CONT;
2057 	JMP32_JA:
2058 		insn += insn->imm;
2059 		CONT;
2060 	JMP_EXIT:
2061 		return BPF_R0;
2062 	/* JMP */
2063 #define COND_JMP(SIGN, OPCODE, CMP_OP)				\
2064 	JMP_##OPCODE##_X:					\
2065 		if ((SIGN##64) DST CMP_OP (SIGN##64) SRC) {	\
2066 			insn += insn->off;			\
2067 			CONT_JMP;				\
2068 		}						\
2069 		CONT;						\
2070 	JMP32_##OPCODE##_X:					\
2071 		if ((SIGN##32) DST CMP_OP (SIGN##32) SRC) {	\
2072 			insn += insn->off;			\
2073 			CONT_JMP;				\
2074 		}						\
2075 		CONT;						\
2076 	JMP_##OPCODE##_K:					\
2077 		if ((SIGN##64) DST CMP_OP (SIGN##64) IMM) {	\
2078 			insn += insn->off;			\
2079 			CONT_JMP;				\
2080 		}						\
2081 		CONT;						\
2082 	JMP32_##OPCODE##_K:					\
2083 		if ((SIGN##32) DST CMP_OP (SIGN##32) IMM) {	\
2084 			insn += insn->off;			\
2085 			CONT_JMP;				\
2086 		}						\
2087 		CONT;
2088 	COND_JMP(u, JEQ, ==)
2089 	COND_JMP(u, JNE, !=)
2090 	COND_JMP(u, JGT, >)
2091 	COND_JMP(u, JLT, <)
2092 	COND_JMP(u, JGE, >=)
2093 	COND_JMP(u, JLE, <=)
2094 	COND_JMP(u, JSET, &)
2095 	COND_JMP(s, JSGT, >)
2096 	COND_JMP(s, JSLT, <)
2097 	COND_JMP(s, JSGE, >=)
2098 	COND_JMP(s, JSLE, <=)
2099 #undef COND_JMP
2100 	/* ST, STX and LDX*/
2101 	ST_NOSPEC:
2102 		/* Speculation barrier for mitigating Speculative Store Bypass.
2103 		 * In case of arm64, we rely on the firmware mitigation as
2104 		 * controlled via the ssbd kernel parameter. Whenever the
2105 		 * mitigation is enabled, it works for all of the kernel code
2106 		 * with no need to provide any additional instructions here.
2107 		 * In case of x86, we use 'lfence' insn for mitigation. We
2108 		 * reuse preexisting logic from Spectre v1 mitigation that
2109 		 * happens to produce the required code on x86 for v4 as well.
2110 		 */
2111 		barrier_nospec();
2112 		CONT;
2113 #define LDST(SIZEOP, SIZE)						\
2114 	STX_MEM_##SIZEOP:						\
2115 		*(SIZE *)(unsigned long) (DST + insn->off) = SRC;	\
2116 		CONT;							\
2117 	ST_MEM_##SIZEOP:						\
2118 		*(SIZE *)(unsigned long) (DST + insn->off) = IMM;	\
2119 		CONT;							\
2120 	LDX_MEM_##SIZEOP:						\
2121 		DST = *(SIZE *)(unsigned long) (SRC + insn->off);	\
2122 		CONT;							\
2123 	LDX_PROBE_MEM_##SIZEOP:						\
2124 		bpf_probe_read_kernel_common(&DST, sizeof(SIZE),	\
2125 			      (const void *)(long) (SRC + insn->off));	\
2126 		DST = *((SIZE *)&DST);					\
2127 		CONT;
2128 
2129 	LDST(B,   u8)
2130 	LDST(H,  u16)
2131 	LDST(W,  u32)
2132 	LDST(DW, u64)
2133 #undef LDST
2134 
2135 #define LDSX(SIZEOP, SIZE)						\
2136 	LDX_MEMSX_##SIZEOP:						\
2137 		DST = *(SIZE *)(unsigned long) (SRC + insn->off);	\
2138 		CONT;							\
2139 	LDX_PROBE_MEMSX_##SIZEOP:					\
2140 		bpf_probe_read_kernel_common(&DST, sizeof(SIZE),		\
2141 				      (const void *)(long) (SRC + insn->off));	\
2142 		DST = *((SIZE *)&DST);					\
2143 		CONT;
2144 
2145 	LDSX(B,   s8)
2146 	LDSX(H,  s16)
2147 	LDSX(W,  s32)
2148 #undef LDSX
2149 
2150 #define ATOMIC_ALU_OP(BOP, KOP)						\
2151 		case BOP:						\
2152 			if (BPF_SIZE(insn->code) == BPF_W)		\
2153 				atomic_##KOP((u32) SRC, (atomic_t *)(unsigned long) \
2154 					     (DST + insn->off));	\
2155 			else						\
2156 				atomic64_##KOP((u64) SRC, (atomic64_t *)(unsigned long) \
2157 					       (DST + insn->off));	\
2158 			break;						\
2159 		case BOP | BPF_FETCH:					\
2160 			if (BPF_SIZE(insn->code) == BPF_W)		\
2161 				SRC = (u32) atomic_fetch_##KOP(		\
2162 					(u32) SRC,			\
2163 					(atomic_t *)(unsigned long) (DST + insn->off)); \
2164 			else						\
2165 				SRC = (u64) atomic64_fetch_##KOP(	\
2166 					(u64) SRC,			\
2167 					(atomic64_t *)(unsigned long) (DST + insn->off)); \
2168 			break;
2169 
2170 	STX_ATOMIC_DW:
2171 	STX_ATOMIC_W:
2172 		switch (IMM) {
2173 		ATOMIC_ALU_OP(BPF_ADD, add)
2174 		ATOMIC_ALU_OP(BPF_AND, and)
2175 		ATOMIC_ALU_OP(BPF_OR, or)
2176 		ATOMIC_ALU_OP(BPF_XOR, xor)
2177 #undef ATOMIC_ALU_OP
2178 
2179 		case BPF_XCHG:
2180 			if (BPF_SIZE(insn->code) == BPF_W)
2181 				SRC = (u32) atomic_xchg(
2182 					(atomic_t *)(unsigned long) (DST + insn->off),
2183 					(u32) SRC);
2184 			else
2185 				SRC = (u64) atomic64_xchg(
2186 					(atomic64_t *)(unsigned long) (DST + insn->off),
2187 					(u64) SRC);
2188 			break;
2189 		case BPF_CMPXCHG:
2190 			if (BPF_SIZE(insn->code) == BPF_W)
2191 				BPF_R0 = (u32) atomic_cmpxchg(
2192 					(atomic_t *)(unsigned long) (DST + insn->off),
2193 					(u32) BPF_R0, (u32) SRC);
2194 			else
2195 				BPF_R0 = (u64) atomic64_cmpxchg(
2196 					(atomic64_t *)(unsigned long) (DST + insn->off),
2197 					(u64) BPF_R0, (u64) SRC);
2198 			break;
2199 
2200 		default:
2201 			goto default_label;
2202 		}
2203 		CONT;
2204 
2205 	default_label:
2206 		/* If we ever reach this, we have a bug somewhere. Die hard here
2207 		 * instead of just returning 0; we could be somewhere in a subprog,
2208 		 * so execution could continue otherwise which we do /not/ want.
2209 		 *
2210 		 * Note, verifier whitelists all opcodes in bpf_opcode_in_insntable().
2211 		 */
2212 		pr_warn("BPF interpreter: unknown opcode %02x (imm: 0x%x)\n",
2213 			insn->code, insn->imm);
2214 		BUG_ON(1);
2215 		return 0;
2216 }
2217 
2218 #define PROG_NAME(stack_size) __bpf_prog_run##stack_size
2219 #define DEFINE_BPF_PROG_RUN(stack_size) \
2220 static unsigned int PROG_NAME(stack_size)(const void *ctx, const struct bpf_insn *insn) \
2221 { \
2222 	u64 stack[stack_size / sizeof(u64)]; \
2223 	u64 regs[MAX_BPF_EXT_REG] = {}; \
2224 \
2225 	kmsan_unpoison_memory(stack, sizeof(stack)); \
2226 	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2227 	ARG1 = (u64) (unsigned long) ctx; \
2228 	return ___bpf_prog_run(regs, insn); \
2229 }
2230 
2231 #define PROG_NAME_ARGS(stack_size) __bpf_prog_run_args##stack_size
2232 #define DEFINE_BPF_PROG_RUN_ARGS(stack_size) \
2233 static u64 PROG_NAME_ARGS(stack_size)(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5, \
2234 				      const struct bpf_insn *insn) \
2235 { \
2236 	u64 stack[stack_size / sizeof(u64)]; \
2237 	u64 regs[MAX_BPF_EXT_REG]; \
2238 \
2239 	kmsan_unpoison_memory(stack, sizeof(stack)); \
2240 	FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)]; \
2241 	BPF_R1 = r1; \
2242 	BPF_R2 = r2; \
2243 	BPF_R3 = r3; \
2244 	BPF_R4 = r4; \
2245 	BPF_R5 = r5; \
2246 	return ___bpf_prog_run(regs, insn); \
2247 }
2248 
2249 #define EVAL1(FN, X) FN(X)
2250 #define EVAL2(FN, X, Y...) FN(X) EVAL1(FN, Y)
2251 #define EVAL3(FN, X, Y...) FN(X) EVAL2(FN, Y)
2252 #define EVAL4(FN, X, Y...) FN(X) EVAL3(FN, Y)
2253 #define EVAL5(FN, X, Y...) FN(X) EVAL4(FN, Y)
2254 #define EVAL6(FN, X, Y...) FN(X) EVAL5(FN, Y)
2255 
2256 EVAL6(DEFINE_BPF_PROG_RUN, 32, 64, 96, 128, 160, 192);
2257 EVAL6(DEFINE_BPF_PROG_RUN, 224, 256, 288, 320, 352, 384);
2258 EVAL4(DEFINE_BPF_PROG_RUN, 416, 448, 480, 512);
2259 
2260 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 32, 64, 96, 128, 160, 192);
2261 EVAL6(DEFINE_BPF_PROG_RUN_ARGS, 224, 256, 288, 320, 352, 384);
2262 EVAL4(DEFINE_BPF_PROG_RUN_ARGS, 416, 448, 480, 512);
2263 
2264 #define PROG_NAME_LIST(stack_size) PROG_NAME(stack_size),
2265 
2266 static unsigned int (*interpreters[])(const void *ctx,
2267 				      const struct bpf_insn *insn) = {
2268 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2269 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2270 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2271 };
2272 #undef PROG_NAME_LIST
2273 #define PROG_NAME_LIST(stack_size) PROG_NAME_ARGS(stack_size),
2274 static __maybe_unused
2275 u64 (*interpreters_args[])(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5,
2276 			   const struct bpf_insn *insn) = {
2277 EVAL6(PROG_NAME_LIST, 32, 64, 96, 128, 160, 192)
2278 EVAL6(PROG_NAME_LIST, 224, 256, 288, 320, 352, 384)
2279 EVAL4(PROG_NAME_LIST, 416, 448, 480, 512)
2280 };
2281 #undef PROG_NAME_LIST
2282 
2283 #ifdef CONFIG_BPF_SYSCALL
bpf_patch_call_args(struct bpf_insn * insn,u32 stack_depth)2284 void bpf_patch_call_args(struct bpf_insn *insn, u32 stack_depth)
2285 {
2286 	stack_depth = max_t(u32, stack_depth, 1);
2287 	insn->off = (s16) insn->imm;
2288 	insn->imm = interpreters_args[(round_up(stack_depth, 32) / 32) - 1] -
2289 		__bpf_call_base_args;
2290 	insn->code = BPF_JMP | BPF_CALL_ARGS;
2291 }
2292 #endif
2293 #else
__bpf_prog_ret0_warn(const void * ctx,const struct bpf_insn * insn)2294 static unsigned int __bpf_prog_ret0_warn(const void *ctx,
2295 					 const struct bpf_insn *insn)
2296 {
2297 	/* If this handler ever gets executed, then BPF_JIT_ALWAYS_ON
2298 	 * is not working properly, so warn about it!
2299 	 */
2300 	WARN_ON_ONCE(1);
2301 	return 0;
2302 }
2303 #endif
2304 
bpf_prog_map_compatible(struct bpf_map * map,const struct bpf_prog * fp)2305 bool bpf_prog_map_compatible(struct bpf_map *map,
2306 			     const struct bpf_prog *fp)
2307 {
2308 	enum bpf_prog_type prog_type = resolve_prog_type(fp);
2309 	bool ret;
2310 	struct bpf_prog_aux *aux = fp->aux;
2311 
2312 	if (fp->kprobe_override)
2313 		return false;
2314 
2315 	/* XDP programs inserted into maps are not guaranteed to run on
2316 	 * a particular netdev (and can run outside driver context entirely
2317 	 * in the case of devmap and cpumap). Until device checks
2318 	 * are implemented, prohibit adding dev-bound programs to program maps.
2319 	 */
2320 	if (bpf_prog_is_dev_bound(aux))
2321 		return false;
2322 
2323 	spin_lock(&map->owner.lock);
2324 	if (!map->owner.type) {
2325 		/* There's no owner yet where we could check for
2326 		 * compatibility.
2327 		 */
2328 		map->owner.type  = prog_type;
2329 		map->owner.jited = fp->jited;
2330 		map->owner.xdp_has_frags = aux->xdp_has_frags;
2331 		map->owner.attach_func_proto = aux->attach_func_proto;
2332 		ret = true;
2333 	} else {
2334 		ret = map->owner.type  == prog_type &&
2335 		      map->owner.jited == fp->jited &&
2336 		      map->owner.xdp_has_frags == aux->xdp_has_frags;
2337 		if (ret &&
2338 		    map->owner.attach_func_proto != aux->attach_func_proto) {
2339 			switch (prog_type) {
2340 			case BPF_PROG_TYPE_TRACING:
2341 			case BPF_PROG_TYPE_LSM:
2342 			case BPF_PROG_TYPE_EXT:
2343 			case BPF_PROG_TYPE_STRUCT_OPS:
2344 				ret = false;
2345 				break;
2346 			default:
2347 				break;
2348 			}
2349 		}
2350 	}
2351 	spin_unlock(&map->owner.lock);
2352 
2353 	return ret;
2354 }
2355 
bpf_check_tail_call(const struct bpf_prog * fp)2356 static int bpf_check_tail_call(const struct bpf_prog *fp)
2357 {
2358 	struct bpf_prog_aux *aux = fp->aux;
2359 	int i, ret = 0;
2360 
2361 	mutex_lock(&aux->used_maps_mutex);
2362 	for (i = 0; i < aux->used_map_cnt; i++) {
2363 		struct bpf_map *map = aux->used_maps[i];
2364 
2365 		if (!map_type_contains_progs(map))
2366 			continue;
2367 
2368 		if (!bpf_prog_map_compatible(map, fp)) {
2369 			ret = -EINVAL;
2370 			goto out;
2371 		}
2372 	}
2373 
2374 out:
2375 	mutex_unlock(&aux->used_maps_mutex);
2376 	return ret;
2377 }
2378 
bpf_prog_select_func(struct bpf_prog * fp)2379 static void bpf_prog_select_func(struct bpf_prog *fp)
2380 {
2381 #ifndef CONFIG_BPF_JIT_ALWAYS_ON
2382 	u32 stack_depth = max_t(u32, fp->aux->stack_depth, 1);
2383 
2384 	fp->bpf_func = interpreters[(round_up(stack_depth, 32) / 32) - 1];
2385 #else
2386 	fp->bpf_func = __bpf_prog_ret0_warn;
2387 #endif
2388 }
2389 
2390 /**
2391  *	bpf_prog_select_runtime - select exec runtime for BPF program
2392  *	@fp: bpf_prog populated with BPF program
2393  *	@err: pointer to error variable
2394  *
2395  * Try to JIT eBPF program, if JIT is not available, use interpreter.
2396  * The BPF program will be executed via bpf_prog_run() function.
2397  *
2398  * Return: the &fp argument along with &err set to 0 for success or
2399  * a negative errno code on failure
2400  */
bpf_prog_select_runtime(struct bpf_prog * fp,int * err)2401 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err)
2402 {
2403 	/* In case of BPF to BPF calls, verifier did all the prep
2404 	 * work with regards to JITing, etc.
2405 	 */
2406 	bool jit_needed = false;
2407 
2408 	if (fp->bpf_func)
2409 		goto finalize;
2410 
2411 	if (IS_ENABLED(CONFIG_BPF_JIT_ALWAYS_ON) ||
2412 	    bpf_prog_has_kfunc_call(fp))
2413 		jit_needed = true;
2414 
2415 	bpf_prog_select_func(fp);
2416 
2417 	/* eBPF JITs can rewrite the program in case constant
2418 	 * blinding is active. However, in case of error during
2419 	 * blinding, bpf_int_jit_compile() must always return a
2420 	 * valid program, which in this case would simply not
2421 	 * be JITed, but falls back to the interpreter.
2422 	 */
2423 	if (!bpf_prog_is_offloaded(fp->aux)) {
2424 		*err = bpf_prog_alloc_jited_linfo(fp);
2425 		if (*err)
2426 			return fp;
2427 
2428 		fp = bpf_int_jit_compile(fp);
2429 		bpf_prog_jit_attempt_done(fp);
2430 		if (!fp->jited && jit_needed) {
2431 			*err = -ENOTSUPP;
2432 			return fp;
2433 		}
2434 	} else {
2435 		*err = bpf_prog_offload_compile(fp);
2436 		if (*err)
2437 			return fp;
2438 	}
2439 
2440 finalize:
2441 	*err = bpf_prog_lock_ro(fp);
2442 	if (*err)
2443 		return fp;
2444 
2445 	/* The tail call compatibility check can only be done at
2446 	 * this late stage as we need to determine, if we deal
2447 	 * with JITed or non JITed program concatenations and not
2448 	 * all eBPF JITs might immediately support all features.
2449 	 */
2450 	*err = bpf_check_tail_call(fp);
2451 
2452 	return fp;
2453 }
2454 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
2455 
__bpf_prog_ret1(const void * ctx,const struct bpf_insn * insn)2456 static unsigned int __bpf_prog_ret1(const void *ctx,
2457 				    const struct bpf_insn *insn)
2458 {
2459 	return 1;
2460 }
2461 
2462 static struct bpf_prog_dummy {
2463 	struct bpf_prog prog;
2464 } dummy_bpf_prog = {
2465 	.prog = {
2466 		.bpf_func = __bpf_prog_ret1,
2467 	},
2468 };
2469 
2470 struct bpf_empty_prog_array bpf_empty_prog_array = {
2471 	.null_prog = NULL,
2472 };
2473 EXPORT_SYMBOL(bpf_empty_prog_array);
2474 
bpf_prog_array_alloc(u32 prog_cnt,gfp_t flags)2475 struct bpf_prog_array *bpf_prog_array_alloc(u32 prog_cnt, gfp_t flags)
2476 {
2477 	struct bpf_prog_array *p;
2478 
2479 	if (prog_cnt)
2480 		p = kzalloc(struct_size(p, items, prog_cnt + 1), flags);
2481 	else
2482 		p = &bpf_empty_prog_array.hdr;
2483 
2484 	return p;
2485 }
2486 
bpf_prog_array_free(struct bpf_prog_array * progs)2487 void bpf_prog_array_free(struct bpf_prog_array *progs)
2488 {
2489 	if (!progs || progs == &bpf_empty_prog_array.hdr)
2490 		return;
2491 	kfree_rcu(progs, rcu);
2492 }
2493 
__bpf_prog_array_free_sleepable_cb(struct rcu_head * rcu)2494 static void __bpf_prog_array_free_sleepable_cb(struct rcu_head *rcu)
2495 {
2496 	struct bpf_prog_array *progs;
2497 
2498 	/* If RCU Tasks Trace grace period implies RCU grace period, there is
2499 	 * no need to call kfree_rcu(), just call kfree() directly.
2500 	 */
2501 	progs = container_of(rcu, struct bpf_prog_array, rcu);
2502 	if (rcu_trace_implies_rcu_gp())
2503 		kfree(progs);
2504 	else
2505 		kfree_rcu(progs, rcu);
2506 }
2507 
bpf_prog_array_free_sleepable(struct bpf_prog_array * progs)2508 void bpf_prog_array_free_sleepable(struct bpf_prog_array *progs)
2509 {
2510 	if (!progs || progs == &bpf_empty_prog_array.hdr)
2511 		return;
2512 	call_rcu_tasks_trace(&progs->rcu, __bpf_prog_array_free_sleepable_cb);
2513 }
2514 
bpf_prog_array_length(struct bpf_prog_array * array)2515 int bpf_prog_array_length(struct bpf_prog_array *array)
2516 {
2517 	struct bpf_prog_array_item *item;
2518 	u32 cnt = 0;
2519 
2520 	for (item = array->items; item->prog; item++)
2521 		if (item->prog != &dummy_bpf_prog.prog)
2522 			cnt++;
2523 	return cnt;
2524 }
2525 
bpf_prog_array_is_empty(struct bpf_prog_array * array)2526 bool bpf_prog_array_is_empty(struct bpf_prog_array *array)
2527 {
2528 	struct bpf_prog_array_item *item;
2529 
2530 	for (item = array->items; item->prog; item++)
2531 		if (item->prog != &dummy_bpf_prog.prog)
2532 			return false;
2533 	return true;
2534 }
2535 
bpf_prog_array_copy_core(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt)2536 static bool bpf_prog_array_copy_core(struct bpf_prog_array *array,
2537 				     u32 *prog_ids,
2538 				     u32 request_cnt)
2539 {
2540 	struct bpf_prog_array_item *item;
2541 	int i = 0;
2542 
2543 	for (item = array->items; item->prog; item++) {
2544 		if (item->prog == &dummy_bpf_prog.prog)
2545 			continue;
2546 		prog_ids[i] = item->prog->aux->id;
2547 		if (++i == request_cnt) {
2548 			item++;
2549 			break;
2550 		}
2551 	}
2552 
2553 	return !!(item->prog);
2554 }
2555 
bpf_prog_array_copy_to_user(struct bpf_prog_array * array,__u32 __user * prog_ids,u32 cnt)2556 int bpf_prog_array_copy_to_user(struct bpf_prog_array *array,
2557 				__u32 __user *prog_ids, u32 cnt)
2558 {
2559 	unsigned long err = 0;
2560 	bool nospc;
2561 	u32 *ids;
2562 
2563 	/* users of this function are doing:
2564 	 * cnt = bpf_prog_array_length();
2565 	 * if (cnt > 0)
2566 	 *     bpf_prog_array_copy_to_user(..., cnt);
2567 	 * so below kcalloc doesn't need extra cnt > 0 check.
2568 	 */
2569 	ids = kcalloc(cnt, sizeof(u32), GFP_USER | __GFP_NOWARN);
2570 	if (!ids)
2571 		return -ENOMEM;
2572 	nospc = bpf_prog_array_copy_core(array, ids, cnt);
2573 	err = copy_to_user(prog_ids, ids, cnt * sizeof(u32));
2574 	kfree(ids);
2575 	if (err)
2576 		return -EFAULT;
2577 	if (nospc)
2578 		return -ENOSPC;
2579 	return 0;
2580 }
2581 
bpf_prog_array_delete_safe(struct bpf_prog_array * array,struct bpf_prog * old_prog)2582 void bpf_prog_array_delete_safe(struct bpf_prog_array *array,
2583 				struct bpf_prog *old_prog)
2584 {
2585 	struct bpf_prog_array_item *item;
2586 
2587 	for (item = array->items; item->prog; item++)
2588 		if (item->prog == old_prog) {
2589 			WRITE_ONCE(item->prog, &dummy_bpf_prog.prog);
2590 			break;
2591 		}
2592 }
2593 
2594 /**
2595  * bpf_prog_array_delete_safe_at() - Replaces the program at the given
2596  *                                   index into the program array with
2597  *                                   a dummy no-op program.
2598  * @array: a bpf_prog_array
2599  * @index: the index of the program to replace
2600  *
2601  * Skips over dummy programs, by not counting them, when calculating
2602  * the position of the program to replace.
2603  *
2604  * Return:
2605  * * 0		- Success
2606  * * -EINVAL	- Invalid index value. Must be a non-negative integer.
2607  * * -ENOENT	- Index out of range
2608  */
bpf_prog_array_delete_safe_at(struct bpf_prog_array * array,int index)2609 int bpf_prog_array_delete_safe_at(struct bpf_prog_array *array, int index)
2610 {
2611 	return bpf_prog_array_update_at(array, index, &dummy_bpf_prog.prog);
2612 }
2613 
2614 /**
2615  * bpf_prog_array_update_at() - Updates the program at the given index
2616  *                              into the program array.
2617  * @array: a bpf_prog_array
2618  * @index: the index of the program to update
2619  * @prog: the program to insert into the array
2620  *
2621  * Skips over dummy programs, by not counting them, when calculating
2622  * the position of the program to update.
2623  *
2624  * Return:
2625  * * 0		- Success
2626  * * -EINVAL	- Invalid index value. Must be a non-negative integer.
2627  * * -ENOENT	- Index out of range
2628  */
bpf_prog_array_update_at(struct bpf_prog_array * array,int index,struct bpf_prog * prog)2629 int bpf_prog_array_update_at(struct bpf_prog_array *array, int index,
2630 			     struct bpf_prog *prog)
2631 {
2632 	struct bpf_prog_array_item *item;
2633 
2634 	if (unlikely(index < 0))
2635 		return -EINVAL;
2636 
2637 	for (item = array->items; item->prog; item++) {
2638 		if (item->prog == &dummy_bpf_prog.prog)
2639 			continue;
2640 		if (!index) {
2641 			WRITE_ONCE(item->prog, prog);
2642 			return 0;
2643 		}
2644 		index--;
2645 	}
2646 	return -ENOENT;
2647 }
2648 
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)2649 int bpf_prog_array_copy(struct bpf_prog_array *old_array,
2650 			struct bpf_prog *exclude_prog,
2651 			struct bpf_prog *include_prog,
2652 			u64 bpf_cookie,
2653 			struct bpf_prog_array **new_array)
2654 {
2655 	int new_prog_cnt, carry_prog_cnt = 0;
2656 	struct bpf_prog_array_item *existing, *new;
2657 	struct bpf_prog_array *array;
2658 	bool found_exclude = false;
2659 
2660 	/* Figure out how many existing progs we need to carry over to
2661 	 * the new array.
2662 	 */
2663 	if (old_array) {
2664 		existing = old_array->items;
2665 		for (; existing->prog; existing++) {
2666 			if (existing->prog == exclude_prog) {
2667 				found_exclude = true;
2668 				continue;
2669 			}
2670 			if (existing->prog != &dummy_bpf_prog.prog)
2671 				carry_prog_cnt++;
2672 			if (existing->prog == include_prog)
2673 				return -EEXIST;
2674 		}
2675 	}
2676 
2677 	if (exclude_prog && !found_exclude)
2678 		return -ENOENT;
2679 
2680 	/* How many progs (not NULL) will be in the new array? */
2681 	new_prog_cnt = carry_prog_cnt;
2682 	if (include_prog)
2683 		new_prog_cnt += 1;
2684 
2685 	/* Do we have any prog (not NULL) in the new array? */
2686 	if (!new_prog_cnt) {
2687 		*new_array = NULL;
2688 		return 0;
2689 	}
2690 
2691 	/* +1 as the end of prog_array is marked with NULL */
2692 	array = bpf_prog_array_alloc(new_prog_cnt + 1, GFP_KERNEL);
2693 	if (!array)
2694 		return -ENOMEM;
2695 	new = array->items;
2696 
2697 	/* Fill in the new prog array */
2698 	if (carry_prog_cnt) {
2699 		existing = old_array->items;
2700 		for (; existing->prog; existing++) {
2701 			if (existing->prog == exclude_prog ||
2702 			    existing->prog == &dummy_bpf_prog.prog)
2703 				continue;
2704 
2705 			new->prog = existing->prog;
2706 			new->bpf_cookie = existing->bpf_cookie;
2707 			new++;
2708 		}
2709 	}
2710 	if (include_prog) {
2711 		new->prog = include_prog;
2712 		new->bpf_cookie = bpf_cookie;
2713 		new++;
2714 	}
2715 	new->prog = NULL;
2716 	*new_array = array;
2717 	return 0;
2718 }
2719 
bpf_prog_array_copy_info(struct bpf_prog_array * array,u32 * prog_ids,u32 request_cnt,u32 * prog_cnt)2720 int bpf_prog_array_copy_info(struct bpf_prog_array *array,
2721 			     u32 *prog_ids, u32 request_cnt,
2722 			     u32 *prog_cnt)
2723 {
2724 	u32 cnt = 0;
2725 
2726 	if (array)
2727 		cnt = bpf_prog_array_length(array);
2728 
2729 	*prog_cnt = cnt;
2730 
2731 	/* return early if user requested only program count or nothing to copy */
2732 	if (!request_cnt || !cnt)
2733 		return 0;
2734 
2735 	/* this function is called under trace/bpf_trace.c: bpf_event_mutex */
2736 	return bpf_prog_array_copy_core(array, prog_ids, request_cnt) ? -ENOSPC
2737 								     : 0;
2738 }
2739 
__bpf_free_used_maps(struct bpf_prog_aux * aux,struct bpf_map ** used_maps,u32 len)2740 void __bpf_free_used_maps(struct bpf_prog_aux *aux,
2741 			  struct bpf_map **used_maps, u32 len)
2742 {
2743 	struct bpf_map *map;
2744 	bool sleepable;
2745 	u32 i;
2746 
2747 	sleepable = aux->prog->sleepable;
2748 	for (i = 0; i < len; i++) {
2749 		map = used_maps[i];
2750 		if (map->ops->map_poke_untrack)
2751 			map->ops->map_poke_untrack(map, aux);
2752 		if (sleepable)
2753 			atomic64_dec(&map->sleepable_refcnt);
2754 		bpf_map_put(map);
2755 	}
2756 }
2757 
bpf_free_used_maps(struct bpf_prog_aux * aux)2758 static void bpf_free_used_maps(struct bpf_prog_aux *aux)
2759 {
2760 	__bpf_free_used_maps(aux, aux->used_maps, aux->used_map_cnt);
2761 	kfree(aux->used_maps);
2762 }
2763 
__bpf_free_used_btfs(struct btf_mod_pair * used_btfs,u32 len)2764 void __bpf_free_used_btfs(struct btf_mod_pair *used_btfs, u32 len)
2765 {
2766 #ifdef CONFIG_BPF_SYSCALL
2767 	struct btf_mod_pair *btf_mod;
2768 	u32 i;
2769 
2770 	for (i = 0; i < len; i++) {
2771 		btf_mod = &used_btfs[i];
2772 		if (btf_mod->module)
2773 			module_put(btf_mod->module);
2774 		btf_put(btf_mod->btf);
2775 	}
2776 #endif
2777 }
2778 
bpf_free_used_btfs(struct bpf_prog_aux * aux)2779 static void bpf_free_used_btfs(struct bpf_prog_aux *aux)
2780 {
2781 	__bpf_free_used_btfs(aux->used_btfs, aux->used_btf_cnt);
2782 	kfree(aux->used_btfs);
2783 }
2784 
bpf_prog_free_deferred(struct work_struct * work)2785 static void bpf_prog_free_deferred(struct work_struct *work)
2786 {
2787 	struct bpf_prog_aux *aux;
2788 	int i;
2789 
2790 	aux = container_of(work, struct bpf_prog_aux, work);
2791 #ifdef CONFIG_BPF_SYSCALL
2792 	bpf_free_kfunc_btf_tab(aux->kfunc_btf_tab);
2793 #endif
2794 #ifdef CONFIG_CGROUP_BPF
2795 	if (aux->cgroup_atype != CGROUP_BPF_ATTACH_TYPE_INVALID)
2796 		bpf_cgroup_atype_put(aux->cgroup_atype);
2797 #endif
2798 	bpf_free_used_maps(aux);
2799 	bpf_free_used_btfs(aux);
2800 	if (bpf_prog_is_dev_bound(aux))
2801 		bpf_prog_dev_bound_destroy(aux->prog);
2802 #ifdef CONFIG_PERF_EVENTS
2803 	if (aux->prog->has_callchain_buf)
2804 		put_callchain_buffers();
2805 #endif
2806 	if (aux->dst_trampoline)
2807 		bpf_trampoline_put(aux->dst_trampoline);
2808 	for (i = 0; i < aux->real_func_cnt; i++) {
2809 		/* We can just unlink the subprog poke descriptor table as
2810 		 * it was originally linked to the main program and is also
2811 		 * released along with it.
2812 		 */
2813 		aux->func[i]->aux->poke_tab = NULL;
2814 		bpf_jit_free(aux->func[i]);
2815 	}
2816 	if (aux->real_func_cnt) {
2817 		kfree(aux->func);
2818 		bpf_prog_unlock_free(aux->prog);
2819 	} else {
2820 		bpf_jit_free(aux->prog);
2821 	}
2822 }
2823 
bpf_prog_free(struct bpf_prog * fp)2824 void bpf_prog_free(struct bpf_prog *fp)
2825 {
2826 	struct bpf_prog_aux *aux = fp->aux;
2827 
2828 	if (aux->dst_prog)
2829 		bpf_prog_put(aux->dst_prog);
2830 	bpf_token_put(aux->token);
2831 	INIT_WORK(&aux->work, bpf_prog_free_deferred);
2832 	schedule_work(&aux->work);
2833 }
2834 EXPORT_SYMBOL_GPL(bpf_prog_free);
2835 
2836 /* RNG for unprivileged user space with separated state from prandom_u32(). */
2837 static DEFINE_PER_CPU(struct rnd_state, bpf_user_rnd_state);
2838 
bpf_user_rnd_init_once(void)2839 void bpf_user_rnd_init_once(void)
2840 {
2841 	prandom_init_once(&bpf_user_rnd_state);
2842 }
2843 
BPF_CALL_0(bpf_user_rnd_u32)2844 BPF_CALL_0(bpf_user_rnd_u32)
2845 {
2846 	/* Should someone ever have the rather unwise idea to use some
2847 	 * of the registers passed into this function, then note that
2848 	 * this function is called from native eBPF and classic-to-eBPF
2849 	 * transformations. Register assignments from both sides are
2850 	 * different, f.e. classic always sets fn(ctx, A, X) here.
2851 	 */
2852 	struct rnd_state *state;
2853 	u32 res;
2854 
2855 	state = &get_cpu_var(bpf_user_rnd_state);
2856 	res = prandom_u32_state(state);
2857 	put_cpu_var(bpf_user_rnd_state);
2858 
2859 	return res;
2860 }
2861 
BPF_CALL_0(bpf_get_raw_cpu_id)2862 BPF_CALL_0(bpf_get_raw_cpu_id)
2863 {
2864 	return raw_smp_processor_id();
2865 }
2866 
2867 /* Weak definitions of helper functions in case we don't have bpf syscall. */
2868 const struct bpf_func_proto bpf_map_lookup_elem_proto __weak;
2869 const struct bpf_func_proto bpf_map_update_elem_proto __weak;
2870 const struct bpf_func_proto bpf_map_delete_elem_proto __weak;
2871 const struct bpf_func_proto bpf_map_push_elem_proto __weak;
2872 const struct bpf_func_proto bpf_map_pop_elem_proto __weak;
2873 const struct bpf_func_proto bpf_map_peek_elem_proto __weak;
2874 const struct bpf_func_proto bpf_map_lookup_percpu_elem_proto __weak;
2875 const struct bpf_func_proto bpf_spin_lock_proto __weak;
2876 const struct bpf_func_proto bpf_spin_unlock_proto __weak;
2877 const struct bpf_func_proto bpf_jiffies64_proto __weak;
2878 
2879 const struct bpf_func_proto bpf_get_prandom_u32_proto __weak;
2880 const struct bpf_func_proto bpf_get_smp_processor_id_proto __weak;
2881 const struct bpf_func_proto bpf_get_numa_node_id_proto __weak;
2882 const struct bpf_func_proto bpf_ktime_get_ns_proto __weak;
2883 const struct bpf_func_proto bpf_ktime_get_boot_ns_proto __weak;
2884 const struct bpf_func_proto bpf_ktime_get_coarse_ns_proto __weak;
2885 const struct bpf_func_proto bpf_ktime_get_tai_ns_proto __weak;
2886 
2887 const struct bpf_func_proto bpf_get_current_pid_tgid_proto __weak;
2888 const struct bpf_func_proto bpf_get_current_uid_gid_proto __weak;
2889 const struct bpf_func_proto bpf_get_current_comm_proto __weak;
2890 const struct bpf_func_proto bpf_get_current_cgroup_id_proto __weak;
2891 const struct bpf_func_proto bpf_get_current_ancestor_cgroup_id_proto __weak;
2892 const struct bpf_func_proto bpf_get_local_storage_proto __weak;
2893 const struct bpf_func_proto bpf_get_ns_current_pid_tgid_proto __weak;
2894 const struct bpf_func_proto bpf_snprintf_btf_proto __weak;
2895 const struct bpf_func_proto bpf_seq_printf_btf_proto __weak;
2896 const struct bpf_func_proto bpf_set_retval_proto __weak;
2897 const struct bpf_func_proto bpf_get_retval_proto __weak;
2898 
bpf_get_trace_printk_proto(void)2899 const struct bpf_func_proto * __weak bpf_get_trace_printk_proto(void)
2900 {
2901 	return NULL;
2902 }
2903 
bpf_get_trace_vprintk_proto(void)2904 const struct bpf_func_proto * __weak bpf_get_trace_vprintk_proto(void)
2905 {
2906 	return NULL;
2907 }
2908 
2909 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)2910 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
2911 		 void *ctx, u64 ctx_size, bpf_ctx_copy_t ctx_copy)
2912 {
2913 	return -ENOTSUPP;
2914 }
2915 EXPORT_SYMBOL_GPL(bpf_event_output);
2916 
2917 /* Always built-in helper functions. */
2918 const struct bpf_func_proto bpf_tail_call_proto = {
2919 	.func		= NULL,
2920 	.gpl_only	= false,
2921 	.ret_type	= RET_VOID,
2922 	.arg1_type	= ARG_PTR_TO_CTX,
2923 	.arg2_type	= ARG_CONST_MAP_PTR,
2924 	.arg3_type	= ARG_ANYTHING,
2925 };
2926 
2927 /* Stub for JITs that only support cBPF. eBPF programs are interpreted.
2928  * It is encouraged to implement bpf_int_jit_compile() instead, so that
2929  * eBPF and implicitly also cBPF can get JITed!
2930  */
bpf_int_jit_compile(struct bpf_prog * prog)2931 struct bpf_prog * __weak bpf_int_jit_compile(struct bpf_prog *prog)
2932 {
2933 	return prog;
2934 }
2935 
2936 /* Stub for JITs that support eBPF. All cBPF code gets transformed into
2937  * eBPF by the kernel and is later compiled by bpf_int_jit_compile().
2938  */
bpf_jit_compile(struct bpf_prog * prog)2939 void __weak bpf_jit_compile(struct bpf_prog *prog)
2940 {
2941 }
2942 
bpf_helper_changes_pkt_data(enum bpf_func_id func_id)2943 bool __weak bpf_helper_changes_pkt_data(enum bpf_func_id func_id)
2944 {
2945 	return false;
2946 }
2947 
2948 /* Return TRUE if the JIT backend wants verifier to enable sub-register usage
2949  * analysis code and wants explicit zero extension inserted by verifier.
2950  * Otherwise, return FALSE.
2951  *
2952  * The verifier inserts an explicit zero extension after BPF_CMPXCHGs even if
2953  * you don't override this. JITs that don't want these extra insns can detect
2954  * them using insn_is_zext.
2955  */
bpf_jit_needs_zext(void)2956 bool __weak bpf_jit_needs_zext(void)
2957 {
2958 	return false;
2959 }
2960 
2961 /* Return true if the JIT inlines the call to the helper corresponding to
2962  * the imm.
2963  *
2964  * The verifier will not patch the insn->imm for the call to the helper if
2965  * this returns true.
2966  */
bpf_jit_inlines_helper_call(s32 imm)2967 bool __weak bpf_jit_inlines_helper_call(s32 imm)
2968 {
2969 	return false;
2970 }
2971 
2972 /* Return TRUE if the JIT backend supports mixing bpf2bpf and tailcalls. */
bpf_jit_supports_subprog_tailcalls(void)2973 bool __weak bpf_jit_supports_subprog_tailcalls(void)
2974 {
2975 	return false;
2976 }
2977 
bpf_jit_supports_percpu_insn(void)2978 bool __weak bpf_jit_supports_percpu_insn(void)
2979 {
2980 	return false;
2981 }
2982 
bpf_jit_supports_kfunc_call(void)2983 bool __weak bpf_jit_supports_kfunc_call(void)
2984 {
2985 	return false;
2986 }
2987 
bpf_jit_supports_far_kfunc_call(void)2988 bool __weak bpf_jit_supports_far_kfunc_call(void)
2989 {
2990 	return false;
2991 }
2992 
bpf_jit_supports_arena(void)2993 bool __weak bpf_jit_supports_arena(void)
2994 {
2995 	return false;
2996 }
2997 
bpf_jit_supports_insn(struct bpf_insn * insn,bool in_arena)2998 bool __weak bpf_jit_supports_insn(struct bpf_insn *insn, bool in_arena)
2999 {
3000 	return false;
3001 }
3002 
bpf_arch_uaddress_limit(void)3003 u64 __weak bpf_arch_uaddress_limit(void)
3004 {
3005 #if defined(CONFIG_64BIT) && defined(CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE)
3006 	return TASK_SIZE;
3007 #else
3008 	return 0;
3009 #endif
3010 }
3011 
3012 /* Return TRUE if the JIT backend satisfies the following two conditions:
3013  * 1) JIT backend supports atomic_xchg() on pointer-sized words.
3014  * 2) Under the specific arch, the implementation of xchg() is the same
3015  *    as atomic_xchg() on pointer-sized words.
3016  */
bpf_jit_supports_ptr_xchg(void)3017 bool __weak bpf_jit_supports_ptr_xchg(void)
3018 {
3019 	return false;
3020 }
3021 
3022 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
3023  * skb_copy_bits(), so provide a weak definition of it for NET-less config.
3024  */
skb_copy_bits(const struct sk_buff * skb,int offset,void * to,int len)3025 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
3026 			 int len)
3027 {
3028 	return -EFAULT;
3029 }
3030 
bpf_arch_text_poke(void * ip,enum bpf_text_poke_type t,void * addr1,void * addr2)3031 int __weak bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
3032 			      void *addr1, void *addr2)
3033 {
3034 	return -ENOTSUPP;
3035 }
3036 
bpf_arch_text_copy(void * dst,void * src,size_t len)3037 void * __weak bpf_arch_text_copy(void *dst, void *src, size_t len)
3038 {
3039 	return ERR_PTR(-ENOTSUPP);
3040 }
3041 
bpf_arch_text_invalidate(void * dst,size_t len)3042 int __weak bpf_arch_text_invalidate(void *dst, size_t len)
3043 {
3044 	return -ENOTSUPP;
3045 }
3046 
bpf_jit_supports_exceptions(void)3047 bool __weak bpf_jit_supports_exceptions(void)
3048 {
3049 	return false;
3050 }
3051 
bpf_jit_supports_private_stack(void)3052 bool __weak bpf_jit_supports_private_stack(void)
3053 {
3054 	return false;
3055 }
3056 
arch_bpf_stack_walk(bool (* consume_fn)(void * cookie,u64 ip,u64 sp,u64 bp),void * cookie)3057 void __weak arch_bpf_stack_walk(bool (*consume_fn)(void *cookie, u64 ip, u64 sp, u64 bp), void *cookie)
3058 {
3059 }
3060 
3061 /* for configs without MMU or 32-bit */
3062 __weak const struct bpf_map_ops arena_map_ops;
bpf_arena_get_user_vm_start(struct bpf_arena * arena)3063 __weak u64 bpf_arena_get_user_vm_start(struct bpf_arena *arena)
3064 {
3065 	return 0;
3066 }
bpf_arena_get_kern_vm_start(struct bpf_arena * arena)3067 __weak u64 bpf_arena_get_kern_vm_start(struct bpf_arena *arena)
3068 {
3069 	return 0;
3070 }
3071 
3072 #ifdef CONFIG_BPF_SYSCALL
bpf_global_ma_init(void)3073 static int __init bpf_global_ma_init(void)
3074 {
3075 	int ret;
3076 
3077 	ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false);
3078 	bpf_global_ma_set = !ret;
3079 	return ret;
3080 }
3081 late_initcall(bpf_global_ma_init);
3082 #endif
3083 
3084 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
3085 EXPORT_SYMBOL(bpf_stats_enabled_key);
3086 
3087 /* All definitions of tracepoints related to BPF. */
3088 #define CREATE_TRACE_POINTS
3089 #include <linux/bpf_trace.h>
3090 
3091 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_exception);
3092 EXPORT_TRACEPOINT_SYMBOL_GPL(xdp_bulk_tx);
3093