bpf.h - platform/external/minijail - Gitiles

 /* bpf.h
  * Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  *
  * Berkeley Packet Filter functions.
  */

 #ifndef BPF_H
 #define BPF_H

 #include <asm/bitsperlong.h>   /* for __BITS_PER_LONG */
 #include <endian.h>
 #include <linux/audit.h>
 #include <linux/filter.h>
 #include <stddef.h>
 #include <sys/user.h>

 #ifdef __cplusplus
 extern "C" {
 #endif

 #include "arch.h"

 #if __BITS_PER_LONG == 32 || defined(__ILP32__)
 #define BITS32
 #elif __BITS_PER_LONG == 64
 #define BITS64
 #endif

 /* Constants for comparison operators. */
 #define MIN_OPERATOR 128
 enum {
 	EQ = MIN_OPERATOR,
 	NE,
 	LT,
 	LE,
 	GT,
 	GE,
 	SET,
 	IN
 };

 /*
  * BPF return values and data structures,
  * since they're not yet in the kernel.
  * TODO(crbug.com/1147037): Replace this with an #include.
  */

 #define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the entire process */
 #define SECCOMP_RET_KILL_THREAD	 0x00000000U /* kill the thread */
 #define SECCOMP_RET_KILL	 SECCOMP_RET_KILL_THREAD
 #define SECCOMP_RET_TRAP	 0x00030000U /* return SIGSYS */
 #define SECCOMP_RET_ERRNO	 0x00050000U /* return -1 and set errno */
 #define SECCOMP_RET_LOG		 0x7ffc0000U /* allow after logging */
 #define SECCOMP_RET_ALLOW	 0x7fff0000U /* allow */

 #define SECCOMP_RET_DATA	 0x0000ffffU /* mask for return value */

 struct seccomp_data {
 	int nr;
 	__u32 arch;
 	__u64 instruction_pointer;
 	__u64 args[6];
 };

 #define syscall_nr (offsetof(struct seccomp_data, nr))
 #define arch_nr (offsetof(struct seccomp_data, arch))

 /* Size-dependent defines. */
 #if defined(BITS32)
 /*
  * On 32 bits, comparisons take 2 instructions: 1 for loading the argument,
  * 1 for the actual comparison.
  */
 #define BPF_LOAD_ARG_LEN		1U
 #define BPF_COMP_LEN			1U
 #define BPF_SHORT_GT_GE_COMP_LEN	1U
 #define BPF_GT_GE_COMP_LEN		1U
 #define BPF_ARG_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_COMP_LEN)
 #define BPF_ARG_SHORT_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_SHORT_GT_GE_COMP_LEN)
 #define BPF_ARG_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_GT_GE_COMP_LEN)

 #define bpf_comp_jeq bpf_comp_jeq32
 #define bpf_comp_jgt bpf_comp_jgt32
 #define bpf_comp_jge bpf_comp_jge32
 #define bpf_comp_jset bpf_comp_jset32

 #define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)])

 #elif defined(BITS64)
 /*
  * On 64 bits, comparisons take 7-8 instructions: 4 for loading the argument,
  * and 3-4 for the actual comparison.
  */
 #define BPF_LOAD_ARG_LEN		4U
 #define BPF_COMP_LEN			3U
 #define BPF_SHORT_GT_GE_COMP_LEN	3U
 #define BPF_GT_GE_COMP_LEN		4U
 #define BPF_ARG_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_COMP_LEN)
 #define BPF_ARG_SHORT_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_SHORT_GT_GE_COMP_LEN)
 #define BPF_ARG_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_GT_GE_COMP_LEN)

 #define bpf_comp_jeq bpf_comp_jeq64
 #define bpf_comp_jgt bpf_comp_jgt64
 #define bpf_comp_jge bpf_comp_jge64
 #define bpf_comp_jset bpf_comp_jset64

 /* Ensure that we load the logically correct offset. */
 #if defined(__LITTLE_ENDIAN__) || __BYTE_ORDER == __LITTLE_ENDIAN
 #define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)])
 #define HI_ARG(idx) offsetof(struct seccomp_data, args[(idx)]) + sizeof(__u32)
 #else
 #error "Unsupported endianness"
 #endif

 #else
 #error "Unknown bit width"

 #endif

 /* Common jump targets. */
 #define NEXT 0
 #define SKIP 1
 #define SKIPN(_n) (_n)

 /* Support for labels in BPF programs. */
 #define JUMP_JT 0xff
 #define JUMP_JF 0xff
 #define LABEL_JT 0xfe
 #define LABEL_JF 0xfe

 #define MAX_BPF_LABEL_LEN 32

 #define BPF_LABELS_MAX 512U	/* Each syscall could have an argument block. */
 struct bpf_labels {
 	size_t count;
 	struct __bpf_label {
 		const char *label;
 		unsigned int location;
 	} labels[BPF_LABELS_MAX];
 };

 /* BPF instruction manipulation functions and macros. */
 static inline size_t set_bpf_instr(struct sock_filter *instr,
 				   unsigned short code, unsigned int k,
 				   unsigned char jt, unsigned char jf)
 {
 	instr->code = code;
 	instr->k = k;
 	instr->jt = jt;
 	instr->jf = jf;
 	return 1U;
 }

 #define set_bpf_stmt(_block, _code, _k) \
 	set_bpf_instr((_block), (_code), (_k), 0, 0)

 #define set_bpf_jump(_block, _code, _k, _jt, _jf) \
 	set_bpf_instr((_block), (_code), (_k), (_jt), (_jf))

 #define set_bpf_lbl(_block, _lbl_id) \
 	set_bpf_jump((_block), BPF_JMP+BPF_JA, (_lbl_id), \
 			LABEL_JT, LABEL_JF)

 #define set_bpf_jump_lbl(_block, _lbl_id) \
 	set_bpf_jump((_block), BPF_JMP+BPF_JA, (_lbl_id), \
 			JUMP_JT, JUMP_JF)

 #define set_bpf_ret_kill(_block) \
 	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_KILL)

 #define set_bpf_ret_kill_process(_block) \
 	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_KILL_PROCESS)

 #define set_bpf_ret_trap(_block) \
 	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_TRAP)

 #define set_bpf_ret_errno(_block, _errno) \
 	set_bpf_stmt((_block), BPF_RET+BPF_K, \
 		SECCOMP_RET_ERRNO | ((_errno) & SECCOMP_RET_DATA))

 #define set_bpf_ret_log(_block) \
 	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_LOG)

 #define set_bpf_ret_allow(_block) \
 	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_ALLOW)

 #define bpf_load_syscall_nr(_filter) \
 	set_bpf_stmt((_filter), BPF_LD+BPF_W+BPF_ABS, syscall_nr)

 /* BPF label functions. */
 int bpf_resolve_jumps(struct bpf_labels *labels,
 		struct sock_filter *filter, size_t count);
 int bpf_label_id(struct bpf_labels *labels, const char *label);
 void free_label_strings(struct bpf_labels *labels);

 /* BPF helper functions. */
 size_t bpf_load_arg(struct sock_filter *filter, int argidx);
 size_t bpf_comp_jeq(struct sock_filter *filter, unsigned long c,
 		    unsigned char jt, unsigned char jf);
 size_t bpf_comp_jgt(struct sock_filter *filter, unsigned long c,
 		    unsigned char jt, unsigned char jf);
 size_t bpf_comp_jge(struct sock_filter *filter, unsigned long c,
 		    unsigned char jt, unsigned char jf);
 size_t bpf_comp_jset(struct sock_filter *filter, unsigned long mask,
 		     unsigned char jt, unsigned char jf);
 size_t bpf_comp_jin(struct sock_filter *filter, unsigned long mask,
 		    unsigned char jt, unsigned char jf);

 /* Functions called by syscall_filter.c */
 #define ARCH_VALIDATION_LEN 3U
 #define ALLOW_SYSCALL_LEN 2U

 size_t bpf_arg_comp(struct sock_filter **pfilter,
 		int op, int argidx, unsigned long c, unsigned int label_id);
 size_t bpf_validate_arch(struct sock_filter *filter);
 size_t bpf_allow_syscall(struct sock_filter *filter, int nr);
 size_t bpf_allow_syscall_args(struct sock_filter *filter,
 		int nr, unsigned int id);

 #ifdef __cplusplus
 }; /* extern "C" */
 #endif

 #endif /* BPF_H */
	/* bpf.h
	* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
	* Use of this source code is governed by a BSD-style license that can be
	* found in the LICENSE file.
	*
	* Berkeley Packet Filter functions.
	*/

	#ifndef BPF_H
	#define BPF_H

	#include <asm/bitsperlong.h> /* for __BITS_PER_LONG */
	#include <endian.h>
	#include <linux/audit.h>
	#include <linux/filter.h>
	#include <stddef.h>
	#include <sys/user.h>

	#ifdef __cplusplus
	extern "C" {
	#endif

	#include "arch.h"

	#if __BITS_PER_LONG == 32 \|\| defined(__ILP32__)
	#define BITS32
	#elif __BITS_PER_LONG == 64
	#define BITS64
	#endif

	/* Constants for comparison operators. */
	#define MIN_OPERATOR 128
	enum {
	EQ = MIN_OPERATOR,
	NE,
	LT,
	LE,
	GT,
	GE,
	SET,
	IN
	};

	/*
	* BPF return values and data structures,
	* since they're not yet in the kernel.
	* TODO(crbug.com/1147037): Replace this with an #include.
	*/

	#define SECCOMP_RET_KILL_PROCESS 0x80000000U /* kill the entire process */
	#define SECCOMP_RET_KILL_THREAD 0x00000000U /* kill the thread */
	#define SECCOMP_RET_KILL SECCOMP_RET_KILL_THREAD
	#define SECCOMP_RET_TRAP 0x00030000U /* return SIGSYS */
	#define SECCOMP_RET_ERRNO 0x00050000U /* return -1 and set errno */
	#define SECCOMP_RET_LOG 0x7ffc0000U /* allow after logging */
	#define SECCOMP_RET_ALLOW 0x7fff0000U /* allow */

	#define SECCOMP_RET_DATA 0x0000ffffU /* mask for return value */

	struct seccomp_data {
	int nr;
	__u32 arch;
	__u64 instruction_pointer;
	__u64 args[6];
	};

	#define syscall_nr (offsetof(struct seccomp_data, nr))
	#define arch_nr (offsetof(struct seccomp_data, arch))

	/* Size-dependent defines. */
	#if defined(BITS32)
	/*
	* On 32 bits, comparisons take 2 instructions: 1 for loading the argument,
	* 1 for the actual comparison.
	*/
	#define BPF_LOAD_ARG_LEN 1U
	#define BPF_COMP_LEN 1U
	#define BPF_SHORT_GT_GE_COMP_LEN 1U
	#define BPF_GT_GE_COMP_LEN 1U
	#define BPF_ARG_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_COMP_LEN)
	#define BPF_ARG_SHORT_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_SHORT_GT_GE_COMP_LEN)
	#define BPF_ARG_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_GT_GE_COMP_LEN)

	#define bpf_comp_jeq bpf_comp_jeq32
	#define bpf_comp_jgt bpf_comp_jgt32
	#define bpf_comp_jge bpf_comp_jge32
	#define bpf_comp_jset bpf_comp_jset32

	#define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)])

	#elif defined(BITS64)
	/*
	* On 64 bits, comparisons take 7-8 instructions: 4 for loading the argument,
	* and 3-4 for the actual comparison.
	*/
	#define BPF_LOAD_ARG_LEN 4U
	#define BPF_COMP_LEN 3U
	#define BPF_SHORT_GT_GE_COMP_LEN 3U
	#define BPF_GT_GE_COMP_LEN 4U
	#define BPF_ARG_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_COMP_LEN)
	#define BPF_ARG_SHORT_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_SHORT_GT_GE_COMP_LEN)
	#define BPF_ARG_GT_GE_COMP_LEN (BPF_LOAD_ARG_LEN + BPF_GT_GE_COMP_LEN)

	#define bpf_comp_jeq bpf_comp_jeq64
	#define bpf_comp_jgt bpf_comp_jgt64
	#define bpf_comp_jge bpf_comp_jge64
	#define bpf_comp_jset bpf_comp_jset64

	/* Ensure that we load the logically correct offset. */
	#if defined(__LITTLE_ENDIAN__) \|\| __BYTE_ORDER == __LITTLE_ENDIAN
	#define LO_ARG(idx) offsetof(struct seccomp_data, args[(idx)])
	#define HI_ARG(idx) offsetof(struct seccomp_data, args[(idx)]) + sizeof(__u32)
	#else
	#error "Unsupported endianness"
	#endif

	#else
	#error "Unknown bit width"

	#endif

	/* Common jump targets. */
	#define NEXT 0
	#define SKIP 1
	#define SKIPN(_n) (_n)

	/* Support for labels in BPF programs. */
	#define JUMP_JT 0xff
	#define JUMP_JF 0xff
	#define LABEL_JT 0xfe
	#define LABEL_JF 0xfe

	#define MAX_BPF_LABEL_LEN 32

	#define BPF_LABELS_MAX 512U /* Each syscall could have an argument block. */
	struct bpf_labels {
	size_t count;
	struct __bpf_label {
	const char *label;
	unsigned int location;
	} labels[BPF_LABELS_MAX];
	};

	/* BPF instruction manipulation functions and macros. */
	static inline size_t set_bpf_instr(struct sock_filter *instr,
	unsigned short code, unsigned int k,
	unsigned char jt, unsigned char jf)
	{
	instr->code = code;
	instr->k = k;
	instr->jt = jt;
	instr->jf = jf;
	return 1U;
	}

	#define set_bpf_stmt(_block, _code, _k) \
	set_bpf_instr((_block), (_code), (_k), 0, 0)

	#define set_bpf_jump(_block, _code, _k, _jt, _jf) \
	set_bpf_instr((_block), (_code), (_k), (_jt), (_jf))

	#define set_bpf_lbl(_block, _lbl_id) \
	set_bpf_jump((_block), BPF_JMP+BPF_JA, (_lbl_id), \
	LABEL_JT, LABEL_JF)

	#define set_bpf_jump_lbl(_block, _lbl_id) \
	set_bpf_jump((_block), BPF_JMP+BPF_JA, (_lbl_id), \
	JUMP_JT, JUMP_JF)

	#define set_bpf_ret_kill(_block) \
	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_KILL)

	#define set_bpf_ret_kill_process(_block) \
	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_KILL_PROCESS)

	#define set_bpf_ret_trap(_block) \
	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_TRAP)

	#define set_bpf_ret_errno(_block, _errno) \
	set_bpf_stmt((_block), BPF_RET+BPF_K, \
	SECCOMP_RET_ERRNO \| ((_errno) & SECCOMP_RET_DATA))

	#define set_bpf_ret_log(_block) \
	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_LOG)

	#define set_bpf_ret_allow(_block) \
	set_bpf_stmt((_block), BPF_RET+BPF_K, SECCOMP_RET_ALLOW)

	#define bpf_load_syscall_nr(_filter) \
	set_bpf_stmt((_filter), BPF_LD+BPF_W+BPF_ABS, syscall_nr)

	/* BPF label functions. */
	int bpf_resolve_jumps(struct bpf_labels *labels,
	struct sock_filter *filter, size_t count);
	int bpf_label_id(struct bpf_labels labels, const char label);
	void free_label_strings(struct bpf_labels *labels);

	/* BPF helper functions. */
	size_t bpf_load_arg(struct sock_filter *filter, int argidx);
	size_t bpf_comp_jeq(struct sock_filter *filter, unsigned long c,
	unsigned char jt, unsigned char jf);
	size_t bpf_comp_jgt(struct sock_filter *filter, unsigned long c,
	unsigned char jt, unsigned char jf);
	size_t bpf_comp_jge(struct sock_filter *filter, unsigned long c,
	unsigned char jt, unsigned char jf);
	size_t bpf_comp_jset(struct sock_filter *filter, unsigned long mask,
	unsigned char jt, unsigned char jf);
	size_t bpf_comp_jin(struct sock_filter *filter, unsigned long mask,
	unsigned char jt, unsigned char jf);

	/* Functions called by syscall_filter.c */
	#define ARCH_VALIDATION_LEN 3U
	#define ALLOW_SYSCALL_LEN 2U

	size_t bpf_arg_comp(struct sock_filter **pfilter,
	int op, int argidx, unsigned long c, unsigned int label_id);
	size_t bpf_validate_arch(struct sock_filter *filter);
	size_t bpf_allow_syscall(struct sock_filter *filter, int nr);
	size_t bpf_allow_syscall_args(struct sock_filter *filter,
	int nr, unsigned int id);

	#ifdef __cplusplus
	}; /* extern "C" */
	#endif

	#endif /* BPF_H */