kernel/bpf/disasm.c - linux - Git at Google

 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
  * Copyright (c) 2016 Facebook
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of version 2 of the GNU General Public
  * License as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful, but
  * WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  * General Public License for more details.
  */

 #include <linux/bpf.h>

 #include "disasm.h"

 #define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
 static const char * const func_id_str[] = {
 	__BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
 };
 #undef __BPF_FUNC_STR_FN

 static const char *__func_get_name(const struct bpf_insn_cbs *cbs,
 				   const struct bpf_insn *insn,
 				   char *buff, size_t len)
 {
 	BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);

 	if (insn->src_reg != BPF_PSEUDO_CALL &&
 	    insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID &&
 	    func_id_str[insn->imm])
 		return func_id_str[insn->imm];

 	if (cbs && cbs->cb_call)
 		return cbs->cb_call(cbs->private_data, insn);

 	if (insn->src_reg == BPF_PSEUDO_CALL)
 		snprintf(buff, len, "%+d", insn->imm);

 	return buff;
 }

 static const char *__func_imm_name(const struct bpf_insn_cbs *cbs,
 				   const struct bpf_insn *insn,
 				   u64 full_imm, char *buff, size_t len)
 {
 	if (cbs && cbs->cb_imm)
 		return cbs->cb_imm(cbs->private_data, insn, full_imm);

 	snprintf(buff, len, "0x%llx", (unsigned long long)full_imm);
 	return buff;
 }

 const char *func_id_name(int id)
 {
 	if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
 		return func_id_str[id];
 	else
 		return "unknown";
 }

 const char *const bpf_class_string[8] = {
 	[BPF_LD]    = "ld",
 	[BPF_LDX]   = "ldx",
 	[BPF_ST]    = "st",
 	[BPF_STX]   = "stx",
 	[BPF_ALU]   = "alu",
 	[BPF_JMP]   = "jmp",
 	[BPF_JMP32] = "jmp32",
 	[BPF_ALU64] = "alu64",
 };

 const char *const bpf_alu_string[16] = {
 	[BPF_ADD >> 4]  = "+=",
 	[BPF_SUB >> 4]  = "-=",
 	[BPF_MUL >> 4]  = "*=",
 	[BPF_DIV >> 4]  = "/=",
 	[BPF_OR  >> 4]  = "|=",
 	[BPF_AND >> 4]  = "&=",
 	[BPF_LSH >> 4]  = "<<=",
 	[BPF_RSH >> 4]  = ">>=",
 	[BPF_NEG >> 4]  = "neg",
 	[BPF_MOD >> 4]  = "%=",
 	[BPF_XOR >> 4]  = "^=",
 	[BPF_MOV >> 4]  = "=",
 	[BPF_ARSH >> 4] = "s>>=",
 	[BPF_END >> 4]  = "endian",
 };

 static const char *const bpf_ldst_string[] = {
 	[BPF_W >> 3]  = "u32",
 	[BPF_H >> 3]  = "u16",
 	[BPF_B >> 3]  = "u8",
 	[BPF_DW >> 3] = "u64",
 };

 static const char *const bpf_jmp_string[16] = {
 	[BPF_JA >> 4]   = "jmp",
 	[BPF_JEQ >> 4]  = "==",
 	[BPF_JGT >> 4]  = ">",
 	[BPF_JLT >> 4]  = "<",
 	[BPF_JGE >> 4]  = ">=",
 	[BPF_JLE >> 4]  = "<=",
 	[BPF_JSET >> 4] = "&",
 	[BPF_JNE >> 4]  = "!=",
 	[BPF_JSGT >> 4] = "s>",
 	[BPF_JSLT >> 4] = "s<",
 	[BPF_JSGE >> 4] = "s>=",
 	[BPF_JSLE >> 4] = "s<=",
 	[BPF_CALL >> 4] = "call",
 	[BPF_EXIT >> 4] = "exit",
 };

 static void print_bpf_end_insn(bpf_insn_print_t verbose,
 			       void *private_data,
 			       const struct bpf_insn *insn)
 {
 	verbose(private_data, "(%02x) r%d = %s%d r%d\n",
 		insn->code, insn->dst_reg,
 		BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
 		insn->imm, insn->dst_reg);
 }

 void print_bpf_insn(const struct bpf_insn_cbs *cbs,
 		    const struct bpf_insn *insn,
 		    bool allow_ptr_leaks)
 {
 	const bpf_insn_print_t verbose = cbs->cb_print;
 	u8 class = BPF_CLASS(insn->code);

 	if (class == BPF_ALU || class == BPF_ALU64) {
 		if (BPF_OP(insn->code) == BPF_END) {
 			if (class == BPF_ALU64)
 				verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
 			else
 				print_bpf_end_insn(verbose, cbs->private_data, insn);
 		} else if (BPF_OP(insn->code) == BPF_NEG) {
 			verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
 				insn->code, class == BPF_ALU ? 'w' : 'r',
 				insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
 				insn->dst_reg);
 		} else if (BPF_SRC(insn->code) == BPF_X) {
 			verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
 				insn->code, class == BPF_ALU ? 'w' : 'r',
 				insn->dst_reg,
 				bpf_alu_string[BPF_OP(insn->code) >> 4],
 				class == BPF_ALU ? 'w' : 'r',
 				insn->src_reg);
 		} else {
 			verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
 				insn->code, class == BPF_ALU ? 'w' : 'r',
 				insn->dst_reg,
 				bpf_alu_string[BPF_OP(insn->code) >> 4],
 				insn->imm);
 		}
 	} else if (class == BPF_STX) {
 		if (BPF_MODE(insn->code) == BPF_MEM)
 			verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = r%d\n",
 				insn->code,
 				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
 				insn->dst_reg,
 				insn->off, insn->src_reg);
 		else if (BPF_MODE(insn->code) == BPF_XADD)
 			verbose(cbs->private_data, "(%02x) lock *(%s *)(r%d %+d) += r%d\n",
 				insn->code,
 				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
 				insn->dst_reg, insn->off,
 				insn->src_reg);
 		else
 			verbose(cbs->private_data, "BUG_%02x\n", insn->code);
 	} else if (class == BPF_ST) {
 		if (BPF_MODE(insn->code) != BPF_MEM) {
 			verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
 			return;
 		}
 		verbose(cbs->private_data, "(%02x) *(%s *)(r%d %+d) = %d\n",
 			insn->code,
 			bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
 			insn->dst_reg,
 			insn->off, insn->imm);
 	} else if (class == BPF_LDX) {
 		if (BPF_MODE(insn->code) != BPF_MEM) {
 			verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
 			return;
 		}
 		verbose(cbs->private_data, "(%02x) r%d = *(%s *)(r%d %+d)\n",
 			insn->code, insn->dst_reg,
 			bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
 			insn->src_reg, insn->off);
 	} else if (class == BPF_LD) {
 		if (BPF_MODE(insn->code) == BPF_ABS) {
 			verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[%d]\n",
 				insn->code,
 				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
 				insn->imm);
 		} else if (BPF_MODE(insn->code) == BPF_IND) {
 			verbose(cbs->private_data, "(%02x) r0 = *(%s *)skb[r%d + %d]\n",
 				insn->code,
 				bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
 				insn->src_reg, insn->imm);
 		} else if (BPF_MODE(insn->code) == BPF_IMM &&
 			   BPF_SIZE(insn->code) == BPF_DW) {
 			/* At this point, we already made sure that the second
 			 * part of the ldimm64 insn is accessible.
 			 */
 			u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
 			bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD ||
 				      insn->src_reg == BPF_PSEUDO_MAP_VALUE;
 			char tmp[64];

 			if (is_ptr && !allow_ptr_leaks)
 				imm = 0;

 			verbose(cbs->private_data, "(%02x) r%d = %s\n",
 				insn->code, insn->dst_reg,
 				__func_imm_name(cbs, insn, imm,
 						tmp, sizeof(tmp)));
 		} else {
 			verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
 			return;
 		}
 	} else if (class == BPF_JMP32 || class == BPF_JMP) {
 		u8 opcode = BPF_OP(insn->code);

 		if (opcode == BPF_CALL) {
 			char tmp[64];

 			if (insn->src_reg == BPF_PSEUDO_CALL) {
 				verbose(cbs->private_data, "(%02x) call pc%s\n",
 					insn->code,
 					__func_get_name(cbs, insn,
 							tmp, sizeof(tmp)));
 			} else {
 				strcpy(tmp, "unknown");
 				verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
 					__func_get_name(cbs, insn,
 							tmp, sizeof(tmp)),
 					insn->imm);
 			}
 		} else if (insn->code == (BPF_JMP | BPF_JA)) {
 			verbose(cbs->private_data, "(%02x) goto pc%+d\n",
 				insn->code, insn->off);
 		} else if (insn->code == (BPF_JMP | BPF_EXIT)) {
 			verbose(cbs->private_data, "(%02x) exit\n", insn->code);
 		} else if (BPF_SRC(insn->code) == BPF_X) {
 			verbose(cbs->private_data,
 				"(%02x) if %c%d %s %c%d goto pc%+d\n",
 				insn->code, class == BPF_JMP32 ? 'w' : 'r',
 				insn->dst_reg,
 				bpf_jmp_string[BPF_OP(insn->code) >> 4],
 				class == BPF_JMP32 ? 'w' : 'r',
 				insn->src_reg, insn->off);
 		} else {
 			verbose(cbs->private_data,
 				"(%02x) if %c%d %s 0x%x goto pc%+d\n",
 				insn->code, class == BPF_JMP32 ? 'w' : 'r',
 				insn->dst_reg,
 				bpf_jmp_string[BPF_OP(insn->code) >> 4],
 				insn->imm, insn->off);
 		}
 	} else {
 		verbose(cbs->private_data, "(%02x) %s\n",
 			insn->code, bpf_class_string[class]);
 	}
 }
	/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
	* Copyright (c) 2016 Facebook
	*
	* This program is free software; you can redistribute it and/or
	* modify it under the terms of version 2 of the GNU General Public
	* License as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful, but
	* WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* General Public License for more details.
	*/

	#include <linux/bpf.h>

	#include "disasm.h"

	#define __BPF_FUNC_STR_FN(x) [BPF_FUNC_ ## x] = __stringify(bpf_ ## x)
	static const char * const func_id_str[] = {
	__BPF_FUNC_MAPPER(__BPF_FUNC_STR_FN)
	};
	#undef __BPF_FUNC_STR_FN

	static const char __func_get_name(const struct bpf_insn_cbs cbs,
	const struct bpf_insn *insn,
	char *buff, size_t len)
	{
	BUILD_BUG_ON(ARRAY_SIZE(func_id_str) != __BPF_FUNC_MAX_ID);

	if (insn->src_reg != BPF_PSEUDO_CALL &&
	insn->imm >= 0 && insn->imm < __BPF_FUNC_MAX_ID &&
	func_id_str[insn->imm])
	return func_id_str[insn->imm];

	if (cbs && cbs->cb_call)
	return cbs->cb_call(cbs->private_data, insn);

	if (insn->src_reg == BPF_PSEUDO_CALL)
	snprintf(buff, len, "%+d", insn->imm);

	return buff;
	}

	static const char __func_imm_name(const struct bpf_insn_cbs cbs,
	const struct bpf_insn *insn,
	u64 full_imm, char *buff, size_t len)
	{
	if (cbs && cbs->cb_imm)
	return cbs->cb_imm(cbs->private_data, insn, full_imm);

	snprintf(buff, len, "0x%llx", (unsigned long long)full_imm);
	return buff;
	}

	const char *func_id_name(int id)
	{
	if (id >= 0 && id < __BPF_FUNC_MAX_ID && func_id_str[id])
	return func_id_str[id];
	else
	return "unknown";
	}

	const char *const bpf_class_string[8] = {
	[BPF_LD] = "ld",
	[BPF_LDX] = "ldx",
	[BPF_ST] = "st",
	[BPF_STX] = "stx",
	[BPF_ALU] = "alu",
	[BPF_JMP] = "jmp",
	[BPF_JMP32] = "jmp32",
	[BPF_ALU64] = "alu64",
	};

	const char *const bpf_alu_string[16] = {
	[BPF_ADD >> 4] = "+=",
	[BPF_SUB >> 4] = "-=",
	[BPF_MUL >> 4] = "*=",
	[BPF_DIV >> 4] = "/=",
	[BPF_OR >> 4] = "\|=",
	[BPF_AND >> 4] = "&=",
	[BPF_LSH >> 4] = "<<=",
	[BPF_RSH >> 4] = ">>=",
	[BPF_NEG >> 4] = "neg",
	[BPF_MOD >> 4] = "%=",
	[BPF_XOR >> 4] = "^=",
	[BPF_MOV >> 4] = "=",
	[BPF_ARSH >> 4] = "s>>=",
	[BPF_END >> 4] = "endian",
	};

	static const char *const bpf_ldst_string[] = {
	[BPF_W >> 3] = "u32",
	[BPF_H >> 3] = "u16",
	[BPF_B >> 3] = "u8",
	[BPF_DW >> 3] = "u64",
	};

	static const char *const bpf_jmp_string[16] = {
	[BPF_JA >> 4] = "jmp",
	[BPF_JEQ >> 4] = "==",
	[BPF_JGT >> 4] = ">",
	[BPF_JLT >> 4] = "<",
	[BPF_JGE >> 4] = ">=",
	[BPF_JLE >> 4] = "<=",
	[BPF_JSET >> 4] = "&",
	[BPF_JNE >> 4] = "!=",
	[BPF_JSGT >> 4] = "s>",
	[BPF_JSLT >> 4] = "s<",
	[BPF_JSGE >> 4] = "s>=",
	[BPF_JSLE >> 4] = "s<=",
	[BPF_CALL >> 4] = "call",
	[BPF_EXIT >> 4] = "exit",
	};

	static void print_bpf_end_insn(bpf_insn_print_t verbose,
	void *private_data,
	const struct bpf_insn *insn)
	{
	verbose(private_data, "(%02x) r%d = %s%d r%d\n",
	insn->code, insn->dst_reg,
	BPF_SRC(insn->code) == BPF_TO_BE ? "be" : "le",
	insn->imm, insn->dst_reg);
	}

	void print_bpf_insn(const struct bpf_insn_cbs *cbs,
	const struct bpf_insn *insn,
	bool allow_ptr_leaks)
	{
	const bpf_insn_print_t verbose = cbs->cb_print;
	u8 class = BPF_CLASS(insn->code);

	if (class == BPF_ALU \|\| class == BPF_ALU64) {
	if (BPF_OP(insn->code) == BPF_END) {
	if (class == BPF_ALU64)
	verbose(cbs->private_data, "BUG_alu64_%02x\n", insn->code);
	else
	print_bpf_end_insn(verbose, cbs->private_data, insn);
	} else if (BPF_OP(insn->code) == BPF_NEG) {
	verbose(cbs->private_data, "(%02x) %c%d = -%c%d\n",
	insn->code, class == BPF_ALU ? 'w' : 'r',
	insn->dst_reg, class == BPF_ALU ? 'w' : 'r',
	insn->dst_reg);
	} else if (BPF_SRC(insn->code) == BPF_X) {
	verbose(cbs->private_data, "(%02x) %c%d %s %c%d\n",
	insn->code, class == BPF_ALU ? 'w' : 'r',
	insn->dst_reg,
	bpf_alu_string[BPF_OP(insn->code) >> 4],
	class == BPF_ALU ? 'w' : 'r',
	insn->src_reg);
	} else {
	verbose(cbs->private_data, "(%02x) %c%d %s %d\n",
	insn->code, class == BPF_ALU ? 'w' : 'r',
	insn->dst_reg,
	bpf_alu_string[BPF_OP(insn->code) >> 4],
	insn->imm);
	}
	} else if (class == BPF_STX) {
	if (BPF_MODE(insn->code) == BPF_MEM)
	verbose(cbs->private_data, "(%02x) (%s )(r%d %+d) = r%d\n",
	insn->code,
	bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
	insn->dst_reg,
	insn->off, insn->src_reg);
	else if (BPF_MODE(insn->code) == BPF_XADD)
	verbose(cbs->private_data, "(%02x) lock (%s )(r%d %+d) += r%d\n",
	insn->code,
	bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
	insn->dst_reg, insn->off,
	insn->src_reg);
	else
	verbose(cbs->private_data, "BUG_%02x\n", insn->code);
	} else if (class == BPF_ST) {
	if (BPF_MODE(insn->code) != BPF_MEM) {
	verbose(cbs->private_data, "BUG_st_%02x\n", insn->code);
	return;
	}
	verbose(cbs->private_data, "(%02x) (%s )(r%d %+d) = %d\n",
	insn->code,
	bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
	insn->dst_reg,
	insn->off, insn->imm);
	} else if (class == BPF_LDX) {
	if (BPF_MODE(insn->code) != BPF_MEM) {
	verbose(cbs->private_data, "BUG_ldx_%02x\n", insn->code);
	return;
	}
	verbose(cbs->private_data, "(%02x) r%d = (%s )(r%d %+d)\n",
	insn->code, insn->dst_reg,
	bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
	insn->src_reg, insn->off);
	} else if (class == BPF_LD) {
	if (BPF_MODE(insn->code) == BPF_ABS) {
	verbose(cbs->private_data, "(%02x) r0 = (%s )skb[%d]\n",
	insn->code,
	bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
	insn->imm);
	} else if (BPF_MODE(insn->code) == BPF_IND) {
	verbose(cbs->private_data, "(%02x) r0 = (%s )skb[r%d + %d]\n",
	insn->code,
	bpf_ldst_string[BPF_SIZE(insn->code) >> 3],
	insn->src_reg, insn->imm);
	} else if (BPF_MODE(insn->code) == BPF_IMM &&
	BPF_SIZE(insn->code) == BPF_DW) {
	/* At this point, we already made sure that the second
	* part of the ldimm64 insn is accessible.
	*/
	u64 imm = ((u64)(insn + 1)->imm << 32) \| (u32)insn->imm;
	bool is_ptr = insn->src_reg == BPF_PSEUDO_MAP_FD \|\|
	insn->src_reg == BPF_PSEUDO_MAP_VALUE;
	char tmp[64];

	if (is_ptr && !allow_ptr_leaks)
	imm = 0;

	verbose(cbs->private_data, "(%02x) r%d = %s\n",
	insn->code, insn->dst_reg,
	__func_imm_name(cbs, insn, imm,
	tmp, sizeof(tmp)));
	} else {
	verbose(cbs->private_data, "BUG_ld_%02x\n", insn->code);
	return;
	}
	} else if (class == BPF_JMP32 \|\| class == BPF_JMP) {
	u8 opcode = BPF_OP(insn->code);

	if (opcode == BPF_CALL) {
	char tmp[64];

	if (insn->src_reg == BPF_PSEUDO_CALL) {
	verbose(cbs->private_data, "(%02x) call pc%s\n",
	insn->code,
	__func_get_name(cbs, insn,
	tmp, sizeof(tmp)));
	} else {
	strcpy(tmp, "unknown");
	verbose(cbs->private_data, "(%02x) call %s#%d\n", insn->code,
	__func_get_name(cbs, insn,
	tmp, sizeof(tmp)),
	insn->imm);
	}
	} else if (insn->code == (BPF_JMP \| BPF_JA)) {
	verbose(cbs->private_data, "(%02x) goto pc%+d\n",
	insn->code, insn->off);
	} else if (insn->code == (BPF_JMP \| BPF_EXIT)) {
	verbose(cbs->private_data, "(%02x) exit\n", insn->code);
	} else if (BPF_SRC(insn->code) == BPF_X) {
	verbose(cbs->private_data,
	"(%02x) if %c%d %s %c%d goto pc%+d\n",
	insn->code, class == BPF_JMP32 ? 'w' : 'r',
	insn->dst_reg,
	bpf_jmp_string[BPF_OP(insn->code) >> 4],
	class == BPF_JMP32 ? 'w' : 'r',
	insn->src_reg, insn->off);
	} else {
	verbose(cbs->private_data,
	"(%02x) if %c%d %s 0x%x goto pc%+d\n",
	insn->code, class == BPF_JMP32 ? 'w' : 'r',
	insn->dst_reg,
	bpf_jmp_string[BPF_OP(insn->code) >> 4],
	insn->imm, insn->off);
	}
	} else {
	verbose(cbs->private_data, "(%02x) %s\n",
	insn->code, bpf_class_string[class]);
	}
	}