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/*
american fuzzy lop - high-performance binary-only instrumentation
-----------------------------------------------------------------
Written by Andrew Griffiths <agriffiths@google.com> and
Michal Zalewski <lcamtuf@google.com>
Idea & design very much by Andrew Griffiths.
TCG instrumentation and block chaining support by Andrea Biondo
<andrea.biondo965@gmail.com>
QEMU 3.1.0 port and thread-safety by Andrea Fioraldi
<andreafioraldi@gmail.com>
Copyright 2015, 2016, 2017 Google Inc. 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.
*/
void afl_maybe_log(void* cur_loc);
/* Note: we convert the 64 bit args to 32 bit and do some alignment
and endian swap. Maybe it would be better to do the alignment
and endian swap in tcg_reg_alloc_call(). */
void tcg_gen_afl_maybe_log_call(target_ulong cur_loc)
{
int real_args, pi;
unsigned sizemask, flags;
TCGOp *op;
TCGTemp *arg = tcgv_ptr_temp( tcg_const_tl(cur_loc) );
flags = 0;
sizemask = dh_sizemask(void, 0) | dh_sizemask(ptr, 1);
#if defined(__sparc__) && !defined(__arch64__) \
&& !defined(CONFIG_TCG_INTERPRETER)
/* We have 64-bit values in one register, but need to pass as two
separate parameters. Split them. */
int orig_sizemask = sizemask;
TCGv_i64 retl, reth;
TCGTemp *split_args[MAX_OPC_PARAM];
retl = NULL;
reth = NULL;
if (sizemask != 0) {
real_args = 0;
int is_64bit = sizemask & (1 << 2);
if (is_64bit) {
TCGv_i64 orig = temp_tcgv_i64(arg);
TCGv_i32 h = tcg_temp_new_i32();
TCGv_i32 l = tcg_temp_new_i32();
tcg_gen_extr_i64_i32(l, h, orig);
split_args[real_args++] = tcgv_i32_temp(h);
split_args[real_args++] = tcgv_i32_temp(l);
} else {
split_args[real_args++] = arg;
}
nargs = real_args;
args = split_args;
sizemask = 0;
}
#elif defined(TCG_TARGET_EXTEND_ARGS) && TCG_TARGET_REG_BITS == 64
int is_64bit = sizemask & (1 << 2);
int is_signed = sizemask & (2 << 2);
if (!is_64bit) {
TCGv_i64 temp = tcg_temp_new_i64();
TCGv_i64 orig = temp_tcgv_i64(arg);
if (is_signed) {
tcg_gen_ext32s_i64(temp, orig);
} else {
tcg_gen_ext32u_i64(temp, orig);
}
arg = tcgv_i64_temp(temp);
}
#endif /* TCG_TARGET_EXTEND_ARGS */
op = tcg_emit_op(INDEX_op_call);
pi = 0;
TCGOP_CALLO(op) = 0;
real_args = 0;
int is_64bit = sizemask & (1 << 2);
if (TCG_TARGET_REG_BITS < 64 && is_64bit) {
#ifdef TCG_TARGET_CALL_ALIGN_ARGS
/* some targets want aligned 64 bit args */
if (real_args & 1) {
op->args[pi++] = TCG_CALL_DUMMY_ARG;
real_args++;
}
#endif
/* If stack grows up, then we will be placing successive
arguments at lower addresses, which means we need to
reverse the order compared to how we would normally
treat either big or little-endian. For those arguments
that will wind up in registers, this still works for
HPPA (the only current STACK_GROWSUP target) since the
argument registers are *also* allocated in decreasing
order. If another such target is added, this logic may
have to get more complicated to differentiate between
stack arguments and register arguments. */
#if defined(HOST_WORDS_BIGENDIAN) != defined(TCG_TARGET_STACK_GROWSUP)
op->args[pi++] = temp_arg(arg + 1);
op->args[pi++] = temp_arg(arg);
#else
op->args[pi++] = temp_arg(arg);
op->args[pi++] = temp_arg(arg + 1);
#endif
real_args += 2;
}
op->args[pi++] = temp_arg(arg);
real_args++;
op->args[pi++] = (uintptr_t)&afl_maybe_log;
op->args[pi++] = flags;
TCGOP_CALLI(op) = real_args;
/* Make sure the fields didn't overflow. */
tcg_debug_assert(TCGOP_CALLI(op) == real_args);
tcg_debug_assert(pi <= ARRAY_SIZE(op->args));
#if defined(__sparc__) && !defined(__arch64__) \
&& !defined(CONFIG_TCG_INTERPRETER)
/* Free all of the parts we allocated above. */
real_args = 0;
int is_64bit = orig_sizemask & (1 << 2);
if (is_64bit) {
tcg_temp_free_internal(args[real_args++]);
tcg_temp_free_internal(args[real_args++]);
} else {
real_args++;
}
if (orig_sizemask & 1) {
/* The 32-bit ABI returned two 32-bit pieces. Re-assemble them.
Note that describing these as TCGv_i64 eliminates an unnecessary
zero-extension that tcg_gen_concat_i32_i64 would create. */
tcg_gen_concat32_i64(temp_tcgv_i64(ret), retl, reth);
tcg_temp_free_i64(retl);
tcg_temp_free_i64(reth);
}
#elif defined(TCG_TARGET_EXTEND_ARGS) && TCG_TARGET_REG_BITS == 64
int is_64bit = sizemask & (1 << 2);
if (!is_64bit) {
tcg_temp_free_internal(arg);
}
#endif /* TCG_TARGET_EXTEND_ARGS */
}
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