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/*
american fuzzy lop++ - high-performance binary-only instrumentation
-------------------------------------------------------------------
Originally written by Andrew Griffiths <agriffiths@google.com> and
Michal Zalewski <lcamtuf@google.com>
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 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"
static void afl_compcov_log_16(target_ulong cur_loc, target_ulong arg1,
target_ulong arg2) {
register uintptr_t idx = cur_loc;
if ((arg1 & 0xff00) == (arg2 & 0xff00)) { INC_AFL_AREA(idx); }
}
static void afl_compcov_log_32(target_ulong cur_loc, target_ulong arg1,
target_ulong arg2) {
register uintptr_t idx = cur_loc;
if ((arg1 & 0xff000000) == (arg2 & 0xff000000)) {
INC_AFL_AREA(idx +2);
if ((arg1 & 0xff0000) == (arg2 & 0xff0000)) {
INC_AFL_AREA(idx + 1);
if ((arg1 & 0xff00) == (arg2 & 0xff00)) { INC_AFL_AREA(idx); }
}
}
}
static void afl_compcov_log_64(target_ulong cur_loc, target_ulong arg1,
target_ulong arg2) {
register uintptr_t idx = cur_loc;
if ((arg1 & 0xff00000000000000) == (arg2 & 0xff00000000000000)) {
INC_AFL_AREA(idx +6);
if ((arg1 & 0xff000000000000) == (arg2 & 0xff000000000000)) {
INC_AFL_AREA(idx + 5);
if ((arg1 & 0xff0000000000) == (arg2 & 0xff0000000000)) {
INC_AFL_AREA(idx + 4);
if ((arg1 & 0xff00000000) == (arg2 & 0xff00000000)) {
INC_AFL_AREA(idx + 3);
if ((arg1 & 0xff000000) == (arg2 & 0xff000000)) {
INC_AFL_AREA(idx + 2);
if ((arg1 & 0xff0000) == (arg2 & 0xff0000)) {
INC_AFL_AREA(idx + 1);
if ((arg1 & 0xff00) == (arg2 & 0xff00)) {
INC_AFL_AREA(idx);
}
}
}
}
}
}
}
}
static void afl_gen_compcov(target_ulong cur_loc, TCGv_i64 arg1, TCGv_i64 arg2,
TCGMemOp ot, int is_imm) {
void *func;
if (!afl_compcov_level || cur_loc > afl_end_code || cur_loc < afl_start_code)
return;
if (!is_imm && afl_compcov_level < 2) return;
switch (ot) {
case MO_64: func = &afl_compcov_log_64; break;
case MO_32: func = &afl_compcov_log_32; break;
case MO_16: func = &afl_compcov_log_16; break;
default: return;
}
cur_loc = (cur_loc >> 4) ^ (cur_loc << 8);
cur_loc &= MAP_SIZE - 7;
if (cur_loc >= afl_inst_rms) return;
tcg_gen_afl_compcov_log_call(func, cur_loc, arg1, arg2);
}
#define I386_RESTORE_STATE_FOR_PERSISTENT \
do { \
\
if (persistent_save_gpr) { \
\
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_save_gpr = gen_new_label(); \
TCGLabel *lbl_finish_restore_gpr = gen_new_label(); \
tcg_gen_brcond_tl(TCG_COND_EQ, first_pass, one, lbl_save_gpr); \
\
for (i = 0; i < CPU_NB_REGS; ++i) { \
\
gpr_sv = tcg_const_ptr(&persistent_saved_gpr[i]); \
tcg_gen_ld_tl(gpr_sv, cpu_regs[i], 0); \
\
} \
\
tcg_gen_br(lbl_finish_restore_gpr); \
\
gen_set_label(lbl_save_gpr); \
\
for (i = 0; i < CPU_NB_REGS; ++i) { \
\
gpr_sv = tcg_const_ptr(&persistent_saved_gpr[i]); \
tcg_gen_st_tl(cpu_regs[i], gpr_sv, 0); \
\
} \
\
gen_set_label(lbl_finish_restore_gpr); \
tcg_temp_free(first_pass); \
\
} \
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[R_ESP], cpu_regs[R_ESP], stack_off); \
tcg_temp_free(stack_off); \
\
} \
\
} while (0)
#define AFL_QEMU_TARGET_i386_SNIPPET \
if (is_persistent) { \
\
if (s->pc == afl_persistent_addr) { \
\
I386_RESTORE_STATE_FOR_PERSISTENT; \
\
if (afl_persistent_ret_addr == 0) { \
\
TCGv_ptr paddr = tcg_const_ptr(afl_persistent_addr); \
tcg_gen_st_tl(paddr, cpu_regs[R_ESP], persisent_retaddr_offset); \
\
} \
tcg_gen_afl_call0(&afl_persistent_loop); \
\
} else if (afl_persistent_ret_addr && s->pc == afl_persistent_ret_addr) { \
\
gen_jmp_im(s, afl_persistent_addr); \
gen_eob(s); \
\
} \
\
}
|
