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/*
american fuzzy lop++ - high-performance binary-only instrumentation
-------------------------------------------------------------------
Originally written by Andrew Griffiths <agriffiths@google.com> and
Michal Zalewski
TCG instrumentation and block chaining support by Andrea Biondo
<andrea.biondo965@gmail.com>
QEMU 3.1.1 port, TCG thread-safety, CompareCoverage and NeverZero
counters by Andrea Fioraldi <andreafioraldi@gmail.com>
Copyright 2015, 2016, 2017 Google Inc. All rights reserved.
Copyright 2019-2020 AFLplusplus Project. All rights reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at:
http://www.apache.org/licenses/LICENSE-2.0
This code is a shim patched into the separately-distributed source
code of QEMU 3.1.0. It leverages the built-in QEMU tracing functionality
to implement AFL-style instrumentation and to take care of the remaining
parts of the AFL fork server logic.
The resulting QEMU binary is essentially a standalone instrumentation
tool; for an example of how to leverage it for other purposes, you can
have a look at afl-showmap.c.
*/
#include "afl-qemu-common.h"
#include "tcg.h"
#include "tcg-op.h"
#if TCG_TARGET_REG_BITS == 64
# define _DEFAULT_MO MO_64
#else
# define _DEFAULT_MO MO_32
#endif
static void afl_gen_compcov(target_ulong cur_loc, TCGv arg1, TCGv arg2,
TCGMemOp ot, int is_imm) {
if (cur_loc > afl_end_code || cur_loc < afl_start_code) return;
if (__afl_cmp_map) {
cur_loc = (cur_loc >> 4) ^ (cur_loc << 8);
cur_loc &= CMP_MAP_W - 1;
TCGv cur_loc_v = tcg_const_tl(cur_loc);
switch (ot & MO_SIZE) {
case MO_64:
gen_helper_afl_cmplog_64(cur_loc_v, arg1, arg2);
break;
case MO_32:
gen_helper_afl_cmplog_32(cur_loc_v, arg1, arg2);
break;
case MO_16:
gen_helper_afl_cmplog_16(cur_loc_v, arg1, arg2);
break;
case MO_8:
gen_helper_afl_cmplog_8(cur_loc_v, arg1, arg2);
break;
default:
break;
}
tcg_temp_free(cur_loc_v);
} else if (afl_compcov_level) {
if (!is_imm && afl_compcov_level < 2) return;
cur_loc = (cur_loc >> 4) ^ (cur_loc << 8);
cur_loc &= MAP_SIZE - 7;
TCGv cur_loc_v = tcg_const_tl(cur_loc);
if (cur_loc >= afl_inst_rms) return;
switch (ot & MO_SIZE) {
case MO_64:
gen_helper_afl_compcov_64(cur_loc_v, arg1, arg2);
break;
case MO_32:
gen_helper_afl_compcov_32(cur_loc_v, arg1, arg2);
break;
case MO_16:
gen_helper_afl_compcov_16(cur_loc_v, arg1, arg2);
break;
default:
break;
}
tcg_temp_free(cur_loc_v);
}
}
/* Routines for debug */
/*
static void log_x86_saved_gpr(void) {
static const char reg_names[CPU_NB_REGS][4] = {
#ifdef TARGET_X86_64
[R_EAX] = "rax",
[R_EBX] = "rbx",
[R_ECX] = "rcx",
[R_EDX] = "rdx",
[R_ESI] = "rsi",
[R_EDI] = "rdi",
[R_EBP] = "rbp",
[R_ESP] = "rsp",
[8] = "r8",
[9] = "r9",
[10] = "r10",
[11] = "r11",
[12] = "r12",
[13] = "r13",
[14] = "r14",
[15] = "r15",
#else
[R_EAX] = "eax",
[R_EBX] = "ebx",
[R_ECX] = "ecx",
[R_EDX] = "edx",
[R_ESI] = "esi",
[R_EDI] = "edi",
[R_EBP] = "ebp",
[R_ESP] = "esp",
#endif
};
int i;
for (i = 0; i < CPU_NB_REGS; ++i) {
fprintf(stderr, "%s = %lx\n", reg_names[i], persistent_saved_gpr[i]);
}
}
static void log_x86_sp_content(void) {
fprintf(stderr, ">> SP = %lx -> %lx\n", persistent_saved_gpr[R_ESP],
*(unsigned long*)persistent_saved_gpr[R_ESP]);
}*/
static void callback_to_persistent_hook(void) {
afl_persistent_hook_ptr(persistent_saved_gpr, guest_base);
}
static void gpr_saving(TCGv *cpu_regs, int regs_num) {
int i;
TCGv_ptr gpr_sv;
TCGv_ptr first_pass_ptr = tcg_const_ptr(&persistent_first_pass);
TCGv first_pass = tcg_temp_local_new();
TCGv one = tcg_const_tl(1);
tcg_gen_ld8u_tl(first_pass, first_pass_ptr, 0);
TCGLabel *lbl_restore_gpr = gen_new_label();
tcg_gen_brcond_tl(TCG_COND_NE, first_pass, one, lbl_restore_gpr);
// save GPR registers
for (i = 0; i < regs_num; ++i) {
gpr_sv = tcg_const_ptr(&persistent_saved_gpr[i]);
tcg_gen_st_tl(cpu_regs[i], gpr_sv, 0);
tcg_temp_free_ptr(gpr_sv);
}
gen_set_label(lbl_restore_gpr);
afl_gen_tcg_plain_call(&afl_persistent_loop);
if (afl_persistent_hook_ptr)
afl_gen_tcg_plain_call(callback_to_persistent_hook);
// restore GPR registers
for (i = 0; i < regs_num; ++i) {
gpr_sv = tcg_const_ptr(&persistent_saved_gpr[i]);
tcg_gen_ld_tl(cpu_regs[i], gpr_sv, 0);
tcg_temp_free_ptr(gpr_sv);
}
tcg_temp_free_ptr(first_pass_ptr);
tcg_temp_free(first_pass);
tcg_temp_free(one);
}
static void restore_state_for_persistent(TCGv *cpu_regs, int regs_num, int sp) {
if (persistent_save_gpr) {
gpr_saving(cpu_regs, regs_num);
} else if (afl_persistent_ret_addr == 0) {
TCGv_ptr stack_off_ptr = tcg_const_ptr(&persistent_stack_offset);
TCGv stack_off = tcg_temp_new();
tcg_gen_ld_tl(stack_off, stack_off_ptr, 0);
tcg_gen_sub_tl(cpu_regs[sp], cpu_regs[sp], stack_off);
tcg_temp_free(stack_off);
}
}
#define AFL_QEMU_TARGET_I386_SNIPPET \
if (is_persistent) { \
\
if (s->pc == afl_persistent_addr) { \
\
restore_state_for_persistent(cpu_regs, AFL_REGS_NUM, R_ESP); \
/*afl_gen_tcg_plain_call(log_x86_saved_gpr); \
afl_gen_tcg_plain_call(log_x86_sp_content);*/ \
\
if (afl_persistent_ret_addr == 0) { \
\
TCGv paddr = tcg_const_tl(afl_persistent_addr); \
tcg_gen_qemu_st_tl(paddr, cpu_regs[R_ESP], persisent_retaddr_offset, \
_DEFAULT_MO); \
tcg_temp_free(paddr); \
\
} \
\
if (!persistent_save_gpr) afl_gen_tcg_plain_call(&afl_persistent_loop); \
/*afl_gen_tcg_plain_call(log_x86_sp_content);*/ \
\
} else if (afl_persistent_ret_addr && s->pc == afl_persistent_ret_addr) { \
\
gen_jmp_im(s, afl_persistent_addr); \
gen_eob(s); \
\
} \
\
}
// SP = 13, LINK = 14
#define AFL_QEMU_TARGET_ARM_SNIPPET \
if (is_persistent) { \
\
if (dc->pc == afl_persistent_addr) { \
\
if (persistent_save_gpr) gpr_saving(cpu_R, AFL_REGS_NUM); \
\
if (afl_persistent_ret_addr == 0) { \
\
tcg_gen_movi_tl(cpu_R[14], afl_persistent_addr); \
\
} \
\
if (!persistent_save_gpr) afl_gen_tcg_plain_call(&afl_persistent_loop); \
\
} else if (afl_persistent_ret_addr && dc->pc == afl_persistent_ret_addr) { \
\
gen_bx_im(dc, afl_persistent_addr); \
\
} \
\
}
// SP = 31, LINK = 30
#define AFL_QEMU_TARGET_ARM64_SNIPPET \
if (is_persistent) { \
\
if (s->pc == afl_persistent_addr) { \
\
if (persistent_save_gpr) gpr_saving(cpu_X, AFL_REGS_NUM); \
\
if (afl_persistent_ret_addr == 0) { \
\
tcg_gen_movi_tl(cpu_X[30], afl_persistent_addr); \
\
} \
\
if (!persistent_save_gpr) afl_gen_tcg_plain_call(&afl_persistent_loop); \
\
} else if (afl_persistent_ret_addr && s->pc == afl_persistent_ret_addr) { \
\
gen_goto_tb(s, 0, afl_persistent_addr); \
\
} \
\
}
|
