mirror of
https://github.com/AFLplusplus/AFLplusplus.git
synced 2025-06-13 02:28:09 +00:00
added gcc_plugin
This commit is contained in:
van Hauser
372
gcc_plugin/afl-gcc-pass.so.cc
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372
gcc_plugin/afl-gcc-pass.so.cc
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@ -0,0 +1,372 @@
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//
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// There are two TODOs in this file:
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// - dont instrument blocks that are uninterested
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// - implement whitelist feature
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//
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/*
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american fuzzy lop - GCC instrumentation pass
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---------------------------------------------
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Written by Austin Seipp <aseipp@pobox.com> with bits from
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Emese Revfy <re.emese@gmail.com>
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Updated by Thorsten Schulz <thorsten.schulz@uni-rostock.de>
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GCC integration design is based on the LLVM design, which comes
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from Laszlo Szekeres. Some of the boilerplate code below for
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afl_pass to adapt to different GCC versions was taken from Emese
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Revfy's Size Overflow plugin for GCC, licensed under the GPLv2/v3.
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(NOTE: this plugin code is under GPLv3, in order to comply with the
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GCC runtime library exception, which states that you may distribute
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"Target Code" from the compiler under a license of your choice, as
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long as the "Compilation Process" is "Eligible", and contains no
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GPL-incompatible software in GCC "during the process of
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transforming high level code to target code". In this case, the
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plugin will be used to generate "Target Code" during the
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"Compilation Process", and thus it must be GPLv3 to be "eligible".)
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Copyright (C) 2015 Austin Seipp
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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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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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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//#define BUILD_INLINE_INST
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#include "../config.h"
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#include "../debug.h"
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/* clear helper AFL types pulls in, which intervene with gcc-plugin geaders from GCC-8 */
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#ifdef likely
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#undef likely
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#endif
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#ifdef unlikely
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#undef unlikely
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <gcc-plugin.h>
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#include <plugin-version.h>
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#include <diagnostic.h>
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#include <tree.h>
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#include <tree-ssa.h>
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#include <tree-pass.h>
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#include <tree-ssa-alias.h>
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#include <basic-block.h>
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#include <gimple-expr.h>
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#include <gimple.h>
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#include <gimple-iterator.h>
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#include <version.h>
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#include <toplev.h>
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#include <intl.h>
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#include <context.h>
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#include <stringpool.h>
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#include <cgraph.h>
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#include <cfgloop.h>
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/* -------------------------------------------------------------------------- */
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/* -- AFL instrumentation pass ---------------------------------------------- */
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static int be_quiet = 0;
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static unsigned int inst_ratio = 100;
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static bool inst_ext = true; /* I reckon inline is broken / unfunctional */
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static unsigned int ext_call_instrument(function *fun) {
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/* Instrument all the things! */
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basic_block bb;
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unsigned finst_blocks = 0;
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unsigned fcnt_blocks = 0;
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FOR_ALL_BB_FN(bb, fun) {
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gimple_seq fcall;
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gimple_seq seq = NULL;
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gimple_stmt_iterator bentry;
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if (!fcnt_blocks++) continue; /* skip block 0 */
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// TODO: if the predecessor does not have to destinations
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// then skip this block :TODO
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/* Bail on this block if we trip the specified ratio */
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if (R(100) >= inst_ratio) continue;
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/* Make up cur_loc */
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unsigned int rand_loc = R(MAP_SIZE);
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tree cur_loc = build_int_cst(uint64_type_node, rand_loc);
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/* Update bitmap via external call */
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/* to quote:
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* /+ Trace a basic block with some ID +/
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* void __afl_trace(u16 x);
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*/
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tree fntype = build_function_type_list(
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void_type_node, /* return */
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uint16_type_node, /* args */
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NULL_TREE); /* done */
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tree fndecl = build_fn_decl("__afl_trace", fntype);
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TREE_STATIC(fndecl) = 1; /* Defined elsewhere */
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TREE_PUBLIC(fndecl) = 1; /* Public */
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DECL_EXTERNAL(fndecl) = 1; /* External linkage */
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DECL_ARTIFICIAL(fndecl) = 1; /* Injected by compiler */
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fcall = gimple_build_call(fndecl, 1, cur_loc); /* generate the function _call_ to above built reference, with *1* parameter -> the random const for the location */
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gimple_seq_add_stmt(&seq, fcall); /* and insert into a sequence */
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/* Done - grab the entry to the block and insert sequence */
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bentry = gsi_start_bb(bb);
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gsi_insert_seq_before(&bentry, seq, GSI_SAME_STMT);
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finst_blocks++;
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}
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fcnt_blocks--; /* discard the first in the count */
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/* Say something nice. */
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if (!be_quiet) {
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if (!finst_blocks)
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WARNF(G_("No instrumentation targets found in " cBRI "%s" cRST ),
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function_name(fun));
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else if (finst_blocks < fcnt_blocks)
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OKF(G_("Instrumented %2u /%2u locations in " cBRI "%s" cRST ),
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finst_blocks, fcnt_blocks,
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function_name(fun));
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else
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OKF(G_("Instrumented %2u locations in " cBRI "%s" cRST ),
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finst_blocks,
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function_name(fun));
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}
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return 0;
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}
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static unsigned int inline_instrument(function *fun) {
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#ifdef BUILD_INLINE_INST /* ifdef inline away, so I don't have to refactor it */
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/* Instrument all the things! */
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basic_block bb;
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unsigned finst_blocks = 0;
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unsigned fcnt_blocks = 0;
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/* Set up global type declarations */
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tree map_type = build_pointer_type(unsigned_char_type_node);
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tree map_ptr_g = build_decl(UNKNOWN_LOCATION, VAR_DECL, get_identifier_with_length("__afl_area_ptr",14), map_type);
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TREE_USED(map_ptr_g) = 1;
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TREE_STATIC(map_ptr_g) = 1; /* Defined elsewhere */
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DECL_EXTERNAL(map_ptr_g) = 1; /* External linkage */
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DECL_PRESERVE_P(map_ptr_g) = 1;
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DECL_ARTIFICIAL(map_ptr_g) = 1;
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rest_of_decl_compilation(map_ptr_g, 1, 0);
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tree prev_loc_g = build_decl(UNKNOWN_LOCATION, VAR_DECL, get_identifier_with_length("__afl_prev_loc",14), uint16_type_node);
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TREE_USED(prev_loc_g) = 1;
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TREE_STATIC(prev_loc_g) = 1; /* Defined elsewhere */
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DECL_EXTERNAL(prev_loc_g) = 1; /* External linkage */
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DECL_PRESERVE_P(prev_loc_g) = 1;
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DECL_ARTIFICIAL(prev_loc_g) = 1;
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rest_of_decl_compilation(prev_loc_g, 1, 0);
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FOR_ALL_BB_FN(bb, fun) {
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gimple *g;
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gimple_seq seq = NULL;
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gimple_stmt_iterator bentry;
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if (!fcnt_blocks++) continue; /* skip block 0 */
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/* Bail on this block if we trip the specified ratio */
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if (R(100) >= inst_ratio) continue;
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/* Make up cur_loc */
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unsigned int rand_loc = R(MAP_SIZE);
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tree cur_loc = build_int_cst(uint64_type_node, rand_loc);
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/* Load prev_loc, xor with cur_loc */
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tree area_off = create_tmp_var(uint64_type_node, "area_off");
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g = gimple_build_assign(area_off, BIT_XOR_EXPR, prev_loc_g, cur_loc);
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gimple_seq_add_stmt(&seq, g); // area_off = prev_loc ^ cur_loc
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/* Update bitmap */
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// tree zero = build_int_cst(unsigned_char_type_node, 0);
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tree one = build_int_cst(unsigned_char_type_node, 1);
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tree tmp1 = create_tmp_var(map_type, "tmp1");
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g = gimple_build_assign(tmp1, PLUS_EXPR, map_ptr_g, area_off);
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gimple_seq_add_stmt(&seq, g); // tmp1 = __afl_area_ptr + area_off
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SAYF(G_("%d,"), fcnt_blocks);
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tree tmp2 = create_tmp_var(unsigned_char_type_node, "tmp2");
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//tree tmp1_ptr = build_simple_mem_ref_loc(UNKNOWN_LOCATION, tmp1);
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g = gimple_build_assign(tmp2, INDIRECT_REF, tmp1);
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gimple_seq_add_stmt(&seq, g); // tmp2 = *tmp1
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tree tmp3 = create_tmp_var(unsigned_char_type_node, "tmp3");
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g = gimple_build_assign(tmp3, PLUS_EXPR, tmp2, one);
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gimple_seq_add_stmt(&seq, g); // tmp3 = tmp2 + 1
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// tree tmp4 = create_tmp_var(map_type, "tmp4");
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// g = gimple_build_assign(tmp4, PLUS_EXPR, map_ptr_g, area_off);
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// gimple_seq_add_stmt(&seq, g); // tmp4 = __afl_area_ptr + area_off
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// tree deref2 = build2(MEM_REF, map_type, tmp4, zero);
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tree deref2 = build4(ARRAY_REF, map_type, map_ptr_g, area_off, NULL, NULL);
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g = gimple_build_assign(deref2, MODIFY_EXPR, tmp3);
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gimple_seq_add_stmt(&seq, g); // *tmp4 = tmp3
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SAYF(G_("+%d,"), fcnt_blocks);
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/* Set prev_loc to cur_loc >> 1 */
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tree shifted_loc = build_int_cst(TREE_TYPE(prev_loc_g), rand_loc >> 1);
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g = gimple_build_assign(prev_loc_g, MODIFY_EXPR, shifted_loc);
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gimple_seq_add_stmt(&seq, g); // __afl_pred_loc = cur_loc >> 1
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/* Done - grab the entry to the block and insert sequence */
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bentry = gsi_start_bb(bb);
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gsi_insert_seq_before(&bentry, seq, GSI_SAME_STMT);
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inst_blocks++;
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finst_blocks++;
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}
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/* Say something nice. */
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if (!be_quiet) {
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if (!finst_blocks)
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WARNF(G_("No instrumentation targets found in " cBRI "%s" cRST ),
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function_name(fun));
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else if (finst_blocks < fcnt_blocks)
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OKF(G_("Instrumented %2u /%2u locations in " cBRI "%s" cRST ),
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finst_blocks, fcnt_blocks,
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function_name(fun));
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else
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OKF(G_("Instrumented %2u locations in " cBRI "%s" cRST ),
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finst_blocks,
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function_name(fun));
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}
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#endif
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return 0;
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}
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/* -------------------------------------------------------------------------- */
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/* -- Boilerplate and initialization ---------------------------------------- */
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static const struct pass_data afl_pass_data = {
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.type = GIMPLE_PASS,
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.name = "afl-inst",
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.optinfo_flags = OPTGROUP_NONE,
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.tv_id = TV_NONE,
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.properties_required = 0,
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.properties_provided = 0,
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.properties_destroyed = 0,
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.todo_flags_start = 0,
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// NOTE(aseipp): it's very, very important to include
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// at least 'TODO_update_ssa' here so that GCC will
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// properly update the resulting SSA form, e.g., to
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// include new PHI nodes for newly added symbols or
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// names. Do not remove this. Do not taunt Happy Fun
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// Ball.
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.todo_flags_finish = TODO_update_ssa | TODO_verify_il | TODO_cleanup_cfg,
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};
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namespace {
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class afl_pass : public gimple_opt_pass {
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private:
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bool do_ext_call;
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public:
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afl_pass(bool ext_call, gcc::context *g) : gimple_opt_pass(afl_pass_data, g), do_ext_call(ext_call) {}
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virtual unsigned int execute(function *fun) {
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// TODO: implement whitelist feature here :TODO
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return do_ext_call ? ext_call_instrument(fun) : inline_instrument(fun);
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}
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}; /* class afl_pass */
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} /* anon namespace */
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static struct opt_pass *make_afl_pass(bool ext_call, gcc::context *ctxt) {
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return new afl_pass(ext_call, ctxt);
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}
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/* -------------------------------------------------------------------------- */
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/* -- Initialization -------------------------------------------------------- */
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int plugin_is_GPL_compatible = 1;
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static struct plugin_info afl_plugin_info = {
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.version = "20181200",
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.help = "AFL gcc plugin\n",
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};
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int plugin_init(struct plugin_name_args *plugin_info,
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struct plugin_gcc_version *version) {
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struct register_pass_info afl_pass_info;
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struct timeval tv;
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struct timezone tz;
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u32 rand_seed;
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/* Setup random() so we get Actually Random(TM) outputs from R() */
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gettimeofday(&tv, &tz);
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rand_seed = tv.tv_sec ^ tv.tv_usec ^ getpid();
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srandom(rand_seed);
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/* Pass information */
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afl_pass_info.pass = make_afl_pass(inst_ext, g);
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afl_pass_info.reference_pass_name = "ssa";
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afl_pass_info.ref_pass_instance_number = 1;
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afl_pass_info.pos_op = PASS_POS_INSERT_AFTER;
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if (!plugin_default_version_check(version, &gcc_version)) {
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FATAL(G_("Incompatible gcc/plugin versions!"));
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}
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/* Show a banner */
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if (isatty(2) && !getenv("AFL_QUIET")) {
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SAYF(G_(cCYA "afl-gcc-pass" cRST " initial version 1.94 by <aseipp@pobox.com>, updated to " cBRI VERSION cRST " by <thorsten.schulz@uni-rostock.de>\n"));
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} else
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be_quiet = 1;
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/* Decide instrumentation ratio */
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char* inst_ratio_str = getenv("AFL_INST_RATIO");
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if (inst_ratio_str) {
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if (sscanf(inst_ratio_str, "%u", &inst_ratio) != 1 || !inst_ratio || inst_ratio > 100)
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FATAL(G_("Bad value of AFL_INST_RATIO (must be between 1 and 100)"));
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else {
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if (!be_quiet)
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ACTF(G_("%s instrumentation at ratio of %u%% in %s mode."),
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inst_ext ? G_("Call-based") : G_("Inline"),
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inst_ratio,
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getenv("AFL_HARDEN") ? G_("hardened") : G_("non-hardened"));
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}
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}
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/* Go go gadget */
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register_callback(plugin_info->base_name, PLUGIN_INFO, NULL, &afl_plugin_info);
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register_callback(plugin_info->base_name, PLUGIN_PASS_MANAGER_SETUP, NULL, &afl_pass_info);
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return 0;
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}
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