1/*
2 * Linux Socket Filter Data Structures
3 */
4#ifndef __LINUX_FILTER_H__
5#define __LINUX_FILTER_H__
6
7#include <stdarg.h>
8
9#include <linux/atomic.h>
10#include <linux/compat.h>
11#include <linux/skbuff.h>
12#include <linux/linkage.h>
13#include <linux/printk.h>
14#include <linux/workqueue.h>
15#include <linux/sched.h>
16#include <net/sch_generic.h>
17
18#include <asm/cacheflush.h>
19
20#include <uapi/linux/filter.h>
21#include <uapi/linux/bpf.h>
22
23struct sk_buff;
24struct sock;
25struct seccomp_data;
26struct bpf_prog_aux;
27
28/* ArgX, context and stack frame pointer register positions. Note,
29 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
30 * calls in BPF_CALL instruction.
31 */
32#define BPF_REG_ARG1	BPF_REG_1
33#define BPF_REG_ARG2	BPF_REG_2
34#define BPF_REG_ARG3	BPF_REG_3
35#define BPF_REG_ARG4	BPF_REG_4
36#define BPF_REG_ARG5	BPF_REG_5
37#define BPF_REG_CTX	BPF_REG_6
38#define BPF_REG_FP	BPF_REG_10
39
40/* Additional register mappings for converted user programs. */
41#define BPF_REG_A	BPF_REG_0
42#define BPF_REG_X	BPF_REG_7
43#define BPF_REG_TMP	BPF_REG_8
44
45/* BPF program can access up to 512 bytes of stack space. */
46#define MAX_BPF_STACK	512
47
48/* Helper macros for filter block array initializers. */
49
50/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
51
52#define BPF_ALU64_REG(OP, DST, SRC)				\
53	((struct bpf_insn) {					\
54		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\
55		.dst_reg = DST,					\
56		.src_reg = SRC,					\
57		.off   = 0,					\
58		.imm   = 0 })
59
60#define BPF_ALU32_REG(OP, DST, SRC)				\
61	((struct bpf_insn) {					\
62		.code  = BPF_ALU | BPF_OP(OP) | BPF_X,		\
63		.dst_reg = DST,					\
64		.src_reg = SRC,					\
65		.off   = 0,					\
66		.imm   = 0 })
67
68/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
69
70#define BPF_ALU64_IMM(OP, DST, IMM)				\
71	((struct bpf_insn) {					\
72		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,	\
73		.dst_reg = DST,					\
74		.src_reg = 0,					\
75		.off   = 0,					\
76		.imm   = IMM })
77
78#define BPF_ALU32_IMM(OP, DST, IMM)				\
79	((struct bpf_insn) {					\
80		.code  = BPF_ALU | BPF_OP(OP) | BPF_K,		\
81		.dst_reg = DST,					\
82		.src_reg = 0,					\
83		.off   = 0,					\
84		.imm   = IMM })
85
86/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
87
88#define BPF_ENDIAN(TYPE, DST, LEN)				\
89	((struct bpf_insn) {					\
90		.code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),	\
91		.dst_reg = DST,					\
92		.src_reg = 0,					\
93		.off   = 0,					\
94		.imm   = LEN })
95
96/* Short form of mov, dst_reg = src_reg */
97
98#define BPF_MOV64_REG(DST, SRC)					\
99	((struct bpf_insn) {					\
100		.code  = BPF_ALU64 | BPF_MOV | BPF_X,		\
101		.dst_reg = DST,					\
102		.src_reg = SRC,					\
103		.off   = 0,					\
104		.imm   = 0 })
105
106#define BPF_MOV32_REG(DST, SRC)					\
107	((struct bpf_insn) {					\
108		.code  = BPF_ALU | BPF_MOV | BPF_X,		\
109		.dst_reg = DST,					\
110		.src_reg = SRC,					\
111		.off   = 0,					\
112		.imm   = 0 })
113
114/* Short form of mov, dst_reg = imm32 */
115
116#define BPF_MOV64_IMM(DST, IMM)					\
117	((struct bpf_insn) {					\
118		.code  = BPF_ALU64 | BPF_MOV | BPF_K,		\
119		.dst_reg = DST,					\
120		.src_reg = 0,					\
121		.off   = 0,					\
122		.imm   = IMM })
123
124#define BPF_MOV32_IMM(DST, IMM)					\
125	((struct bpf_insn) {					\
126		.code  = BPF_ALU | BPF_MOV | BPF_K,		\
127		.dst_reg = DST,					\
128		.src_reg = 0,					\
129		.off   = 0,					\
130		.imm   = IMM })
131
132/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
133#define BPF_LD_IMM64(DST, IMM)					\
134	BPF_LD_IMM64_RAW(DST, 0, IMM)
135
136#define BPF_LD_IMM64_RAW(DST, SRC, IMM)				\
137	((struct bpf_insn) {					\
138		.code  = BPF_LD | BPF_DW | BPF_IMM,		\
139		.dst_reg = DST,					\
140		.src_reg = SRC,					\
141		.off   = 0,					\
142		.imm   = (__u32) (IMM) }),			\
143	((struct bpf_insn) {					\
144		.code  = 0, /* zero is reserved opcode */	\
145		.dst_reg = 0,					\
146		.src_reg = 0,					\
147		.off   = 0,					\
148		.imm   = ((__u64) (IMM)) >> 32 })
149
150/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
151#define BPF_LD_MAP_FD(DST, MAP_FD)				\
152	BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
153
154/* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
155
156#define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)			\
157	((struct bpf_insn) {					\
158		.code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),	\
159		.dst_reg = DST,					\
160		.src_reg = SRC,					\
161		.off   = 0,					\
162		.imm   = IMM })
163
164#define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)			\
165	((struct bpf_insn) {					\
166		.code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),	\
167		.dst_reg = DST,					\
168		.src_reg = SRC,					\
169		.off   = 0,					\
170		.imm   = IMM })
171
172/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
173
174#define BPF_LD_ABS(SIZE, IMM)					\
175	((struct bpf_insn) {					\
176		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,	\
177		.dst_reg = 0,					\
178		.src_reg = 0,					\
179		.off   = 0,					\
180		.imm   = IMM })
181
182/* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
183
184#define BPF_LD_IND(SIZE, SRC, IMM)				\
185	((struct bpf_insn) {					\
186		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,	\
187		.dst_reg = 0,					\
188		.src_reg = SRC,					\
189		.off   = 0,					\
190		.imm   = IMM })
191
192/* Memory load, dst_reg = *(uint *) (src_reg + off16) */
193
194#define BPF_LDX_MEM(SIZE, DST, SRC, OFF)			\
195	((struct bpf_insn) {					\
196		.code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,	\
197		.dst_reg = DST,					\
198		.src_reg = SRC,					\
199		.off   = OFF,					\
200		.imm   = 0 })
201
202/* Memory store, *(uint *) (dst_reg + off16) = src_reg */
203
204#define BPF_STX_MEM(SIZE, DST, SRC, OFF)			\
205	((struct bpf_insn) {					\
206		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,	\
207		.dst_reg = DST,					\
208		.src_reg = SRC,					\
209		.off   = OFF,					\
210		.imm   = 0 })
211
212/* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
213
214#define BPF_STX_XADD(SIZE, DST, SRC, OFF)			\
215	((struct bpf_insn) {					\
216		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,	\
217		.dst_reg = DST,					\
218		.src_reg = SRC,					\
219		.off   = OFF,					\
220		.imm   = 0 })
221
222/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
223
224#define BPF_ST_MEM(SIZE, DST, OFF, IMM)				\
225	((struct bpf_insn) {					\
226		.code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,	\
227		.dst_reg = DST,					\
228		.src_reg = 0,					\
229		.off   = OFF,					\
230		.imm   = IMM })
231
232/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
233
234#define BPF_JMP_REG(OP, DST, SRC, OFF)				\
235	((struct bpf_insn) {					\
236		.code  = BPF_JMP | BPF_OP(OP) | BPF_X,		\
237		.dst_reg = DST,					\
238		.src_reg = SRC,					\
239		.off   = OFF,					\
240		.imm   = 0 })
241
242/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
243
244#define BPF_JMP_IMM(OP, DST, IMM, OFF)				\
245	((struct bpf_insn) {					\
246		.code  = BPF_JMP | BPF_OP(OP) | BPF_K,		\
247		.dst_reg = DST,					\
248		.src_reg = 0,					\
249		.off   = OFF,					\
250		.imm   = IMM })
251
252/* Function call */
253
254#define BPF_EMIT_CALL(FUNC)					\
255	((struct bpf_insn) {					\
256		.code  = BPF_JMP | BPF_CALL,			\
257		.dst_reg = 0,					\
258		.src_reg = 0,					\
259		.off   = 0,					\
260		.imm   = ((FUNC) - __bpf_call_base) })
261
262/* Raw code statement block */
263
264#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)			\
265	((struct bpf_insn) {					\
266		.code  = CODE,					\
267		.dst_reg = DST,					\
268		.src_reg = SRC,					\
269		.off   = OFF,					\
270		.imm   = IMM })
271
272/* Program exit */
273
274#define BPF_EXIT_INSN()						\
275	((struct bpf_insn) {					\
276		.code  = BPF_JMP | BPF_EXIT,			\
277		.dst_reg = 0,					\
278		.src_reg = 0,					\
279		.off   = 0,					\
280		.imm   = 0 })
281
282/* Internal classic blocks for direct assignment */
283
284#define __BPF_STMT(CODE, K)					\
285	((struct sock_filter) BPF_STMT(CODE, K))
286
287#define __BPF_JUMP(CODE, K, JT, JF)				\
288	((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
289
290#define bytes_to_bpf_size(bytes)				\
291({								\
292	int bpf_size = -EINVAL;					\
293								\
294	if (bytes == sizeof(u8))				\
295		bpf_size = BPF_B;				\
296	else if (bytes == sizeof(u16))				\
297		bpf_size = BPF_H;				\
298	else if (bytes == sizeof(u32))				\
299		bpf_size = BPF_W;				\
300	else if (bytes == sizeof(u64))				\
301		bpf_size = BPF_DW;				\
302								\
303	bpf_size;						\
304})
305
306#ifdef CONFIG_COMPAT
307/* A struct sock_filter is architecture independent. */
308struct compat_sock_fprog {
309	u16		len;
310	compat_uptr_t	filter;	/* struct sock_filter * */
311};
312#endif
313
314struct sock_fprog_kern {
315	u16			len;
316	struct sock_filter	*filter;
317};
318
319struct bpf_binary_header {
320	unsigned int pages;
321	u8 image[];
322};
323
324struct bpf_prog {
325	u16			pages;		/* Number of allocated pages */
326	kmemcheck_bitfield_begin(meta);
327	u16			jited:1,	/* Is our filter JIT'ed? */
328				gpl_compatible:1, /* Is filter GPL compatible? */
329				cb_access:1,	/* Is control block accessed? */
330				dst_needed:1;	/* Do we need dst entry? */
331	kmemcheck_bitfield_end(meta);
332	u32			len;		/* Number of filter blocks */
333	enum bpf_prog_type	type;		/* Type of BPF program */
334	struct bpf_prog_aux	*aux;		/* Auxiliary fields */
335	struct sock_fprog_kern	*orig_prog;	/* Original BPF program */
336	unsigned int		(*bpf_func)(const struct sk_buff *skb,
337					    const struct bpf_insn *filter);
338	/* Instructions for interpreter */
339	union {
340		struct sock_filter	insns[0];
341		struct bpf_insn		insnsi[0];
342	};
343};
344
345struct sk_filter {
346	atomic_t	refcnt;
347	struct rcu_head	rcu;
348	struct bpf_prog	*prog;
349};
350
351#define BPF_PROG_RUN(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)
352
353static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
354				       struct sk_buff *skb)
355{
356	u8 *cb_data = qdisc_skb_cb(skb)->data;
357	u8 saved_cb[QDISC_CB_PRIV_LEN];
358	u32 res;
359
360	BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
361		     QDISC_CB_PRIV_LEN);
362
363	if (unlikely(prog->cb_access)) {
364		memcpy(saved_cb, cb_data, sizeof(saved_cb));
365		memset(cb_data, 0, sizeof(saved_cb));
366	}
367
368	res = BPF_PROG_RUN(prog, skb);
369
370	if (unlikely(prog->cb_access))
371		memcpy(cb_data, saved_cb, sizeof(saved_cb));
372
373	return res;
374}
375
376static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
377					struct sk_buff *skb)
378{
379	u8 *cb_data = qdisc_skb_cb(skb)->data;
380
381	if (unlikely(prog->cb_access))
382		memset(cb_data, 0, QDISC_CB_PRIV_LEN);
383	return BPF_PROG_RUN(prog, skb);
384}
385
386static inline unsigned int bpf_prog_size(unsigned int proglen)
387{
388	return max(sizeof(struct bpf_prog),
389		   offsetof(struct bpf_prog, insns[proglen]));
390}
391
392static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
393{
394	/* When classic BPF programs have been loaded and the arch
395	 * does not have a classic BPF JIT (anymore), they have been
396	 * converted via bpf_migrate_filter() to eBPF and thus always
397	 * have an unspec program type.
398	 */
399	return prog->type == BPF_PROG_TYPE_UNSPEC;
400}
401
402#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
403
404#ifdef CONFIG_DEBUG_SET_MODULE_RONX
405static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
406{
407	set_memory_ro((unsigned long)fp, fp->pages);
408}
409
410static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
411{
412	set_memory_rw((unsigned long)fp, fp->pages);
413}
414#else
415static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
416{
417}
418
419static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
420{
421}
422#endif /* CONFIG_DEBUG_SET_MODULE_RONX */
423
424int sk_filter(struct sock *sk, struct sk_buff *skb);
425
426int bpf_prog_select_runtime(struct bpf_prog *fp);
427void bpf_prog_free(struct bpf_prog *fp);
428
429struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
430struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
431				  gfp_t gfp_extra_flags);
432void __bpf_prog_free(struct bpf_prog *fp);
433
434static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
435{
436	bpf_prog_unlock_ro(fp);
437	__bpf_prog_free(fp);
438}
439
440typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
441				       unsigned int flen);
442
443int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
444int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
445			      bpf_aux_classic_check_t trans, bool save_orig);
446void bpf_prog_destroy(struct bpf_prog *fp);
447
448int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
449int __sk_attach_filter(struct sock_fprog *fprog, struct sock *sk,
450		       bool locked);
451int sk_attach_bpf(u32 ufd, struct sock *sk);
452int sk_detach_filter(struct sock *sk);
453int __sk_detach_filter(struct sock *sk, bool locked);
454
455int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
456		  unsigned int len);
457
458bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
459void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
460
461u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
462void bpf_int_jit_compile(struct bpf_prog *fp);
463bool bpf_helper_changes_skb_data(void *func);
464
465#ifdef CONFIG_BPF_JIT
466typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
467
468struct bpf_binary_header *
469bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
470		     unsigned int alignment,
471		     bpf_jit_fill_hole_t bpf_fill_ill_insns);
472void bpf_jit_binary_free(struct bpf_binary_header *hdr);
473
474void bpf_jit_compile(struct bpf_prog *fp);
475void bpf_jit_free(struct bpf_prog *fp);
476
477static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
478				u32 pass, void *image)
479{
480	pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
481	       proglen, pass, image, current->comm, task_pid_nr(current));
482
483	if (image)
484		print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
485			       16, 1, image, proglen, false);
486}
487#else
488static inline void bpf_jit_compile(struct bpf_prog *fp)
489{
490}
491
492static inline void bpf_jit_free(struct bpf_prog *fp)
493{
494	bpf_prog_unlock_free(fp);
495}
496#endif /* CONFIG_BPF_JIT */
497
498#define BPF_ANC		BIT(15)
499
500static inline bool bpf_needs_clear_a(const struct sock_filter *first)
501{
502	switch (first->code) {
503	case BPF_RET | BPF_K:
504	case BPF_LD | BPF_W | BPF_LEN:
505		return false;
506
507	case BPF_LD | BPF_W | BPF_ABS:
508	case BPF_LD | BPF_H | BPF_ABS:
509	case BPF_LD | BPF_B | BPF_ABS:
510		if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
511			return true;
512		return false;
513
514	default:
515		return true;
516	}
517}
518
519static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
520{
521	BUG_ON(ftest->code & BPF_ANC);
522
523	switch (ftest->code) {
524	case BPF_LD | BPF_W | BPF_ABS:
525	case BPF_LD | BPF_H | BPF_ABS:
526	case BPF_LD | BPF_B | BPF_ABS:
527#define BPF_ANCILLARY(CODE)	case SKF_AD_OFF + SKF_AD_##CODE:	\
528				return BPF_ANC | SKF_AD_##CODE
529		switch (ftest->k) {
530		BPF_ANCILLARY(PROTOCOL);
531		BPF_ANCILLARY(PKTTYPE);
532		BPF_ANCILLARY(IFINDEX);
533		BPF_ANCILLARY(NLATTR);
534		BPF_ANCILLARY(NLATTR_NEST);
535		BPF_ANCILLARY(MARK);
536		BPF_ANCILLARY(QUEUE);
537		BPF_ANCILLARY(HATYPE);
538		BPF_ANCILLARY(RXHASH);
539		BPF_ANCILLARY(CPU);
540		BPF_ANCILLARY(ALU_XOR_X);
541		BPF_ANCILLARY(VLAN_TAG);
542		BPF_ANCILLARY(VLAN_TAG_PRESENT);
543		BPF_ANCILLARY(PAY_OFFSET);
544		BPF_ANCILLARY(RANDOM);
545		BPF_ANCILLARY(VLAN_TPID);
546		}
547		/* Fallthrough. */
548	default:
549		return ftest->code;
550	}
551}
552
553void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
554					   int k, unsigned int size);
555
556static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
557				     unsigned int size, void *buffer)
558{
559	if (k >= 0)
560		return skb_header_pointer(skb, k, size, buffer);
561
562	return bpf_internal_load_pointer_neg_helper(skb, k, size);
563}
564
565static inline int bpf_tell_extensions(void)
566{
567	return SKF_AD_MAX;
568}
569
570#endif /* __LINUX_FILTER_H__ */
571