81 lines
2.6 KiB
C
81 lines
2.6 KiB
C
/*
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american fuzzy lop++ - unicorn instrumentation
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----------------------------------------------
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Originally written by Andrew Griffiths <agriffiths@google.com> and
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Michal Zalewski
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Adapted for afl-unicorn by Dominik Maier <mail@dmnk.co>
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CompareCoverage and NeverZero counters by Andrea Fioraldi
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<andreafioraldi@gmail.com>
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Copyright 2015, 2016, 2017 Google Inc. All rights reserved.
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Copyright 2019 AFLplusplus Project. All rights reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at:
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http://www.apache.org/licenses/LICENSE-2.0
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This code is a shim patched into the separately-distributed source
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code of Unicorn 1.0.1. It leverages the built-in QEMU tracing functionality
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to implement AFL-style instrumentation and to take care of the remaining
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parts of the AFL fork server logic.
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The resulting libunicorn binary is essentially a standalone instrumentation
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tool; for an example of how to leverage it for other purposes, you can
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have a look at afl-showmap.c.
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*/
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#include "config.h"
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#include "types.h"
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/* These are executed on code generation. Execution is in afl-unicorn-tcg-runtime-inl.h */
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/* Roughly afl_gen_maybe_log -> gen_afl_maybe_log -> emit HELPER(afl_maybe_log) -> call afl_maybe_log */
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static void afl_gen_maybe_log(TCGContext *s, uint64_t cur_loc) {
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if (!s->uc->afl_area_ptr) return;
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/* "Hash" */
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cur_loc = (cur_loc >> 4) ^ (cur_loc << 8);
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cur_loc &= MAP_SIZE - 7;
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/* Implement probabilistic instrumentation by looking at scrambled block
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address. This keeps the instrumented locations stable across runs. */
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if (cur_loc >= s->uc->afl_inst_rms) return;
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gen_afl_maybe_log(s, cur_loc);
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}
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// Currently only arm32 and x86. We undefine it for others to silence unused func compiler warnings.
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#if defined(ARCH_HAS_COMPCOV)
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static void afl_gen_compcov(TCGContext *s, uint64_t cur_loc, TCGv arg1,
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TCGv arg2, TCGMemOp ot, int is_imm) {
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if (!s->uc->afl_compcov_level || !s->uc->afl_area_ptr) return;
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if (!is_imm && s->uc->afl_compcov_level < 2) return;
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cur_loc = (cur_loc >> 4) ^ (cur_loc << 8);
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cur_loc &= MAP_SIZE - 7;
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if (cur_loc >= s->uc->afl_inst_rms) return;
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switch (ot) {
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case MO_64: gen_afl_compcov_log_64(s, cur_loc, (TCGv_i64)arg1, (TCGv_i64)arg2); break;
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case MO_32: gen_afl_compcov_log_32(s, cur_loc, (TCGv_i32)arg1, (TCGv_i32)arg2); break;
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case MO_16: gen_afl_compcov_log_16(s, cur_loc, (TCGv_i32)arg1, (TCGv_i32)arg2); break;
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default: return;
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}
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}
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#endif |