497 lines
		
	
	
		
			9.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			497 lines
		
	
	
		
			9.9 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Copyright (C) 2015 Josh Poimboeuf <jpoimboe@redhat.com>
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|  *
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|  * This program is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU General Public License
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|  * as published by the Free Software Foundation; either version 2
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|  * of the License, or (at your option) any later version.
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|  *
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|  * This program is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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|  * GNU General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU General Public License
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|  * along with this program; if not, see <http://www.gnu.org/licenses/>.
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|  */
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| 
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| #include <stdio.h>
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| #include <stdlib.h>
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| 
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| #define unlikely(cond) (cond)
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| #include <asm/insn.h>
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| #include "lib/inat.c"
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| #include "lib/insn.c"
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| 
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| #include "../../elf.h"
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| #include "../../arch.h"
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| #include "../../warn.h"
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| 
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| static unsigned char op_to_cfi_reg[][2] = {
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| 	{CFI_AX, CFI_R8},
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| 	{CFI_CX, CFI_R9},
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| 	{CFI_DX, CFI_R10},
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| 	{CFI_BX, CFI_R11},
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| 	{CFI_SP, CFI_R12},
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| 	{CFI_BP, CFI_R13},
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| 	{CFI_SI, CFI_R14},
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| 	{CFI_DI, CFI_R15},
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| };
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| 
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| static int is_x86_64(struct elf *elf)
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| {
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| 	switch (elf->ehdr.e_machine) {
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| 	case EM_X86_64:
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| 		return 1;
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| 	case EM_386:
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| 		return 0;
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| 	default:
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| 		WARN("unexpected ELF machine type %d", elf->ehdr.e_machine);
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| 		return -1;
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| 	}
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| }
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| 
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| bool arch_callee_saved_reg(unsigned char reg)
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| {
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| 	switch (reg) {
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| 	case CFI_BP:
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| 	case CFI_BX:
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| 	case CFI_R12:
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| 	case CFI_R13:
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| 	case CFI_R14:
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| 	case CFI_R15:
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| 		return true;
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| 
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| 	case CFI_AX:
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| 	case CFI_CX:
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| 	case CFI_DX:
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| 	case CFI_SI:
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| 	case CFI_DI:
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| 	case CFI_SP:
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| 	case CFI_R8:
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| 	case CFI_R9:
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| 	case CFI_R10:
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| 	case CFI_R11:
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| 	case CFI_RA:
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| 	default:
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| 		return false;
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| 	}
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| }
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| 
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| int arch_decode_instruction(struct elf *elf, struct section *sec,
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| 			    unsigned long offset, unsigned int maxlen,
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| 			    unsigned int *len, unsigned char *type,
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| 			    unsigned long *immediate, struct stack_op *op)
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| {
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| 	struct insn insn;
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| 	int x86_64, sign;
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| 	unsigned char op1, op2, rex = 0, rex_b = 0, rex_r = 0, rex_w = 0,
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| 		      rex_x = 0, modrm = 0, modrm_mod = 0, modrm_rm = 0,
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| 		      modrm_reg = 0, sib = 0;
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| 
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| 	x86_64 = is_x86_64(elf);
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| 	if (x86_64 == -1)
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| 		return -1;
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| 
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| 	insn_init(&insn, sec->data->d_buf + offset, maxlen, x86_64);
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| 	insn_get_length(&insn);
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| 
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| 	if (!insn_complete(&insn)) {
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| 		WARN_FUNC("can't decode instruction", sec, offset);
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| 		return -1;
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| 	}
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| 
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| 	*len = insn.length;
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| 	*type = INSN_OTHER;
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| 
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| 	if (insn.vex_prefix.nbytes)
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| 		return 0;
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| 
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| 	op1 = insn.opcode.bytes[0];
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| 	op2 = insn.opcode.bytes[1];
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| 
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| 	if (insn.rex_prefix.nbytes) {
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| 		rex = insn.rex_prefix.bytes[0];
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| 		rex_w = X86_REX_W(rex) >> 3;
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| 		rex_r = X86_REX_R(rex) >> 2;
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| 		rex_x = X86_REX_X(rex) >> 1;
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| 		rex_b = X86_REX_B(rex);
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| 	}
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| 
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| 	if (insn.modrm.nbytes) {
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| 		modrm = insn.modrm.bytes[0];
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| 		modrm_mod = X86_MODRM_MOD(modrm);
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| 		modrm_reg = X86_MODRM_REG(modrm);
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| 		modrm_rm = X86_MODRM_RM(modrm);
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| 	}
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| 
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| 	if (insn.sib.nbytes)
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| 		sib = insn.sib.bytes[0];
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| 
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| 	switch (op1) {
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| 
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| 	case 0x1:
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| 	case 0x29:
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| 		if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) {
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| 
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| 			/* add/sub reg, %rsp */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_ADD;
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| 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = CFI_SP;
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| 		}
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| 		break;
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| 
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| 	case 0x50 ... 0x57:
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| 
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| 		/* push reg */
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| 		*type = INSN_STACK;
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| 		op->src.type = OP_SRC_REG;
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| 		op->src.reg = op_to_cfi_reg[op1 & 0x7][rex_b];
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| 		op->dest.type = OP_DEST_PUSH;
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| 
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| 		break;
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| 
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| 	case 0x58 ... 0x5f:
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| 
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| 		/* pop reg */
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| 		*type = INSN_STACK;
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| 		op->src.type = OP_SRC_POP;
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| 		op->dest.type = OP_DEST_REG;
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| 		op->dest.reg = op_to_cfi_reg[op1 & 0x7][rex_b];
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| 
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| 		break;
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| 
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| 	case 0x68:
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| 	case 0x6a:
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| 		/* push immediate */
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| 		*type = INSN_STACK;
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| 		op->src.type = OP_SRC_CONST;
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| 		op->dest.type = OP_DEST_PUSH;
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| 		break;
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| 
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| 	case 0x70 ... 0x7f:
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| 		*type = INSN_JUMP_CONDITIONAL;
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| 		break;
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| 
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| 	case 0x81:
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| 	case 0x83:
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| 		if (rex != 0x48)
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| 			break;
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| 
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| 		if (modrm == 0xe4) {
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| 			/* and imm, %rsp */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_AND;
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| 			op->src.reg = CFI_SP;
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| 			op->src.offset = insn.immediate.value;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = CFI_SP;
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| 			break;
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| 		}
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| 
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| 		if (modrm == 0xc4)
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| 			sign = 1;
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| 		else if (modrm == 0xec)
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| 			sign = -1;
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| 		else
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| 			break;
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| 
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| 		/* add/sub imm, %rsp */
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| 		*type = INSN_STACK;
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| 		op->src.type = OP_SRC_ADD;
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| 		op->src.reg = CFI_SP;
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| 		op->src.offset = insn.immediate.value * sign;
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| 		op->dest.type = OP_DEST_REG;
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| 		op->dest.reg = CFI_SP;
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| 		break;
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| 
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| 	case 0x89:
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| 		if (rex_w && !rex_r && modrm_mod == 3 && modrm_reg == 4) {
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| 
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| 			/* mov %rsp, reg */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_REG;
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| 			op->src.reg = CFI_SP;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = op_to_cfi_reg[modrm_rm][rex_b];
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| 			break;
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| 		}
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| 
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| 		if (rex_w && !rex_b && modrm_mod == 3 && modrm_rm == 4) {
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| 
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| 			/* mov reg, %rsp */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_REG;
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| 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = CFI_SP;
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| 			break;
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| 		}
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| 
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| 		/* fallthrough */
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| 	case 0x88:
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| 		if (!rex_b &&
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| 		    (modrm_mod == 1 || modrm_mod == 2) && modrm_rm == 5) {
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| 
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| 			/* mov reg, disp(%rbp) */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_REG;
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| 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
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| 			op->dest.type = OP_DEST_REG_INDIRECT;
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| 			op->dest.reg = CFI_BP;
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| 			op->dest.offset = insn.displacement.value;
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| 
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| 		} else if (rex_w && !rex_b && modrm_rm == 4 && sib == 0x24) {
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| 
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| 			/* mov reg, disp(%rsp) */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_REG;
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| 			op->src.reg = op_to_cfi_reg[modrm_reg][rex_r];
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| 			op->dest.type = OP_DEST_REG_INDIRECT;
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| 			op->dest.reg = CFI_SP;
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| 			op->dest.offset = insn.displacement.value;
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| 		}
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| 
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| 		break;
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| 
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| 	case 0x8b:
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| 		if (rex_w && !rex_b && modrm_mod == 1 && modrm_rm == 5) {
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| 
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| 			/* mov disp(%rbp), reg */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_REG_INDIRECT;
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| 			op->src.reg = CFI_BP;
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| 			op->src.offset = insn.displacement.value;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];
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| 
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| 		} else if (rex_w && !rex_b && sib == 0x24 &&
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| 			   modrm_mod != 3 && modrm_rm == 4) {
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| 
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| 			/* mov disp(%rsp), reg */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_REG_INDIRECT;
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| 			op->src.reg = CFI_SP;
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| 			op->src.offset = insn.displacement.value;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];
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| 		}
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| 
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| 		break;
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| 
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| 	case 0x8d:
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| 		if (sib == 0x24 && rex_w && !rex_b && !rex_x) {
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| 
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| 			*type = INSN_STACK;
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| 			if (!insn.displacement.value) {
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| 				/* lea (%rsp), reg */
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| 				op->src.type = OP_SRC_REG;
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| 			} else {
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| 				/* lea disp(%rsp), reg */
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| 				op->src.type = OP_SRC_ADD;
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| 				op->src.offset = insn.displacement.value;
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| 			}
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| 			op->src.reg = CFI_SP;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = op_to_cfi_reg[modrm_reg][rex_r];
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| 
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| 		} else if (rex == 0x48 && modrm == 0x65) {
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| 
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| 			/* lea disp(%rbp), %rsp */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_ADD;
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| 			op->src.reg = CFI_BP;
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| 			op->src.offset = insn.displacement.value;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = CFI_SP;
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| 
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| 		} else if (rex == 0x49 && modrm == 0x62 &&
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| 			   insn.displacement.value == -8) {
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| 
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| 			/*
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| 			 * lea -0x8(%r10), %rsp
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| 			 *
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| 			 * Restoring rsp back to its original value after a
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| 			 * stack realignment.
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| 			 */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_ADD;
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| 			op->src.reg = CFI_R10;
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| 			op->src.offset = -8;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = CFI_SP;
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| 
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| 		} else if (rex == 0x49 && modrm == 0x65 &&
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| 			   insn.displacement.value == -16) {
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| 
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| 			/*
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| 			 * lea -0x10(%r13), %rsp
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| 			 *
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| 			 * Restoring rsp back to its original value after a
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| 			 * stack realignment.
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| 			 */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_ADD;
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| 			op->src.reg = CFI_R13;
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| 			op->src.offset = -16;
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| 			op->dest.type = OP_DEST_REG;
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| 			op->dest.reg = CFI_SP;
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| 		}
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| 
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| 		break;
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| 
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| 	case 0x8f:
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| 		/* pop to mem */
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| 		*type = INSN_STACK;
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| 		op->src.type = OP_SRC_POP;
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| 		op->dest.type = OP_DEST_MEM;
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| 		break;
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| 
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| 	case 0x90:
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| 		*type = INSN_NOP;
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| 		break;
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| 
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| 	case 0x9c:
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| 		/* pushf */
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| 		*type = INSN_STACK;
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| 		op->src.type = OP_SRC_CONST;
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| 		op->dest.type = OP_DEST_PUSH;
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| 		break;
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| 
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| 	case 0x9d:
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| 		/* popf */
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| 		*type = INSN_STACK;
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| 		op->src.type = OP_SRC_POP;
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| 		op->dest.type = OP_DEST_MEM;
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| 		break;
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| 
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| 	case 0x0f:
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| 
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| 		if (op2 >= 0x80 && op2 <= 0x8f) {
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| 
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| 			*type = INSN_JUMP_CONDITIONAL;
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| 
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| 		} else if (op2 == 0x05 || op2 == 0x07 || op2 == 0x34 ||
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| 			   op2 == 0x35) {
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| 
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| 			/* sysenter, sysret */
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| 			*type = INSN_CONTEXT_SWITCH;
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| 
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| 		} else if (op2 == 0x0b || op2 == 0xb9) {
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| 
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| 			/* ud2 */
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| 			*type = INSN_BUG;
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| 
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| 		} else if (op2 == 0x0d || op2 == 0x1f) {
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| 
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| 			/* nopl/nopw */
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| 			*type = INSN_NOP;
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| 
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| 		} else if (op2 == 0xa0 || op2 == 0xa8) {
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| 
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| 			/* push fs/gs */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_CONST;
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| 			op->dest.type = OP_DEST_PUSH;
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| 
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| 		} else if (op2 == 0xa1 || op2 == 0xa9) {
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| 
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| 			/* pop fs/gs */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_POP;
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| 			op->dest.type = OP_DEST_MEM;
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| 		}
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| 
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| 		break;
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| 
 | |
| 	case 0xc9:
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| 		/*
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| 		 * leave
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| 		 *
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| 		 * equivalent to:
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| 		 * mov bp, sp
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| 		 * pop bp
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| 		 */
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| 		*type = INSN_STACK;
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| 		op->dest.type = OP_DEST_LEAVE;
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| 
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| 		break;
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| 
 | |
| 	case 0xe3:
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| 		/* jecxz/jrcxz */
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| 		*type = INSN_JUMP_CONDITIONAL;
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| 		break;
 | |
| 
 | |
| 	case 0xe9:
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| 	case 0xeb:
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| 		*type = INSN_JUMP_UNCONDITIONAL;
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| 		break;
 | |
| 
 | |
| 	case 0xc2:
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| 	case 0xc3:
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| 		*type = INSN_RETURN;
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| 		break;
 | |
| 
 | |
| 	case 0xca: /* retf */
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| 	case 0xcb: /* retf */
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| 	case 0xcf: /* iret */
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| 		*type = INSN_CONTEXT_SWITCH;
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| 		break;
 | |
| 
 | |
| 	case 0xe8:
 | |
| 		*type = INSN_CALL;
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| 		break;
 | |
| 
 | |
| 	case 0xff:
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| 		if (modrm_reg == 2 || modrm_reg == 3)
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| 
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| 			*type = INSN_CALL_DYNAMIC;
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| 
 | |
| 		else if (modrm_reg == 4)
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| 
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| 			*type = INSN_JUMP_DYNAMIC;
 | |
| 
 | |
| 		else if (modrm_reg == 5)
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| 
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| 			/* jmpf */
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| 			*type = INSN_CONTEXT_SWITCH;
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| 
 | |
| 		else if (modrm_reg == 6) {
 | |
| 
 | |
| 			/* push from mem */
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| 			*type = INSN_STACK;
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| 			op->src.type = OP_SRC_CONST;
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| 			op->dest.type = OP_DEST_PUSH;
 | |
| 		}
 | |
| 
 | |
| 		break;
 | |
| 
 | |
| 	default:
 | |
| 		break;
 | |
| 	}
 | |
| 
 | |
| 	*immediate = insn.immediate.nbytes ? insn.immediate.value : 0;
 | |
| 
 | |
| 	return 0;
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| }
 | |
| 
 | |
| void arch_initial_func_cfi_state(struct cfi_state *state)
 | |
| {
 | |
| 	int i;
 | |
| 
 | |
| 	for (i = 0; i < CFI_NUM_REGS; i++) {
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| 		state->regs[i].base = CFI_UNDEFINED;
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| 		state->regs[i].offset = 0;
 | |
| 	}
 | |
| 
 | |
| 	/* initial CFA (call frame address) */
 | |
| 	state->cfa.base = CFI_SP;
 | |
| 	state->cfa.offset = 8;
 | |
| 
 | |
| 	/* initial RA (return address) */
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| 	state->regs[16].base = CFI_CFA;
 | |
| 	state->regs[16].offset = -8;
 | |
| }
 | 
