diff options
| -rw-r--r-- | include/afl-persistent-replay.h (renamed from include/persistent_replay.h) | 86 | ||||
| -rw-r--r-- | include/afl-record-compat.h | 67 | ||||
| -rw-r--r-- | include/config.h | 6 | ||||
| -rw-r--r-- | instrumentation/README.persistent_mode.md | 20 | ||||
| -rw-r--r-- | instrumentation/afl-compiler-rt.o.c | 87 | ||||
| -rw-r--r-- | utils/persistent_mode/Makefile | 1 | ||||
| -rw-r--r-- | utils/replay_record/Makefile | 8 | ||||
| -rw-r--r-- | utils/replay_record/persistent_demo_replay.c | 148 |
8 files changed, 287 insertions, 136 deletions
diff --git a/include/persistent_replay.h b/include/afl-persistent-replay.h index 58b22fb4..9e60ff9c 100644 --- a/include/persistent_replay.h +++ b/include/afl-persistent-replay.h @@ -10,6 +10,10 @@ #include <sys/stat.h> #include <fcntl.h> +#ifndef PATH_MAX + #define PATH_MAX 4096 +#endif + static unsigned short int is_replay_record; static unsigned int replay_record; static unsigned int replay_record_cnt; @@ -23,7 +27,7 @@ static char **record_arg = NULL; static int select_files(const struct dirent *dirbuf) { - char fn[4096]; + char fn[PATH_MAX]; if (dirbuf->d_name[0] == '.') { @@ -123,85 +127,5 @@ __attribute__((constructor)) static void __afl_record_replay_init( } -/* only used if explictly included for compatibility - compiling without afl-cc */ - -#ifdef AFL_COMPAT - - #ifndef PATH_MAX - #define PATH_MAX 4096 - #endif - - #define FUZZ_BUF_SIZE 1024000 - - // extern ssize_t read(int fildes, void *buf, size_t nbyte); - - // extern int __afl_persistent_loop(unsigned int max_cnt); - // extern unsigned char fuzz_buf[]; - - #ifndef __AFL_HAVE_MANUAL_CONTROL - #define __AFL_HAVE_MANUAL_CONTROL - #endif - - #define __AFL_FUZZ_TESTCASE_LEN (read(0, fuzz_buf, FUZZ_BUF_SIZE)) - #define __AFL_FUZZ_TESTCASE_BUF fuzz_buf - #define __AFL_FUZZ_INIT() void sync(void); - #define __AFL_INIT() sync() - #define __AFL_LOOP(x) __afl_persistent_loop(x) - -unsigned char fuzz_buf[FUZZ_BUF_SIZE]; - -int __afl_persistent_loop(unsigned int max_cnt) { - - static unsigned int cycle_cnt = 1; - static unsigned short int inited = 0; - char tcase[PATH_MAX]; - - if (is_replay_record) { - - if (!inited) { - - cycle_cnt = replay_record_cnt; - inited = 1; - - } - - snprintf(tcase, PATH_MAX, "%s/%s", - replay_record_dir ? replay_record_dir : "./", - record_list[replay_record_cnt - cycle_cnt]->d_name); - - #ifdef AFL_PERSISTENT_REPLAY_ARGPARSE - if (record_arg) { - - *record_arg = tcase; - - } else - - #endif // AFL_PERSISTENT_REPLAY_ARGPARSE - { - - int fd = open(tcase, O_RDONLY); - dup2(fd, 0); - close(fd); - - } - - } else { - - if (!inited) { - - cycle_cnt = max_cnt; - inited = 1; - - } - - } - - return cycle_cnt--; - -} - -#endif // AFL_COMPAT - #endif // _HAVE_PERSISTENT_REPLAY_H diff --git a/include/afl-record-compat.h b/include/afl-record-compat.h new file mode 100644 index 00000000..2c79595d --- /dev/null +++ b/include/afl-record-compat.h @@ -0,0 +1,67 @@ +#ifndef _HAVE_AFL_COMPAT_H +#define _HAVE_AFL_COMPAT_H + +#include <afl-persistent-replay.h> + +#define FUZZ_BUF_SIZE 1024000 + +// extern ssize_t read(int fildes, void *buf, size_t nbyte); + +// extern int __afl_persistent_loop(unsigned int max_cnt); +// extern unsigned char fuzz_buf[]; + +#ifndef __AFL_HAVE_MANUAL_CONTROL + #define __AFL_HAVE_MANUAL_CONTROL +#endif + +#define __AFL_FUZZ_TESTCASE_LEN (read(0, fuzz_buf, FUZZ_BUF_SIZE)) +#define __AFL_FUZZ_TESTCASE_BUF fuzz_buf +#define __AFL_FUZZ_INIT() void sync(void); +#define __AFL_INIT() sync() +#define __AFL_LOOP(x) __afl_persistent_loop(x) + +unsigned char fuzz_buf[FUZZ_BUF_SIZE]; + +int __afl_persistent_loop(unsigned int max_cnt) { + + static unsigned int cycle_cnt = 1; + static unsigned short int inited = 0; + char tcase[PATH_MAX]; + + if (is_replay_record) { + + if (!inited) { + + cycle_cnt = replay_record_cnt; + inited = 1; + + } + + snprintf(tcase, PATH_MAX, "%s/%s", + replay_record_dir ? replay_record_dir : "./", + record_list[replay_record_cnt - cycle_cnt]->d_name); + +#ifdef AFL_PERSISTENT_REPLAY_ARGPARSE + if (record_arg) { + + *record_arg = tcase; + + } else + +#endif // AFL_PERSISTENT_REPLAY_ARGPARSE + { + + int fd = open(tcase, O_RDONLY); + dup2(fd, 0); + close(fd); + + } + + } + + return --cycle_cnt; + +} + +#endif // _HAVE_AFL_COMPAT_H + diff --git a/include/config.h b/include/config.h index d44cda9c..a5b6eba1 100644 --- a/include/config.h +++ b/include/config.h @@ -83,13 +83,11 @@ will be kept and written to the crash/ directory as RECORD:... files. Note that every crash will be written, not only unique ones! */ -#define AFL_PERSISTENT_RECORD - -/* Adds support in compiler-rt to replay persistent records */ -#define AFL_PERSISTENT_REPLAY +// #define AFL_PERSISTENT_RECORD /* Adds support in compiler-rt to replay persistent records in @@-style * harnesses */ + // #define AFL_PERSISTENT_REPLAY_ARGPARSE /* console output colors: There are three ways to configure its behavior diff --git a/instrumentation/README.persistent_mode.md b/instrumentation/README.persistent_mode.md index b5d982b0..8e4f6ae4 100644 --- a/instrumentation/README.persistent_mode.md +++ b/instrumentation/README.persistent_mode.md @@ -201,26 +201,28 @@ And that is all! If your software under test requires keeping a state between persistent loop iterations (i.e., a stateful network stack), you can use the `AFL_PERSISTENT_RECORD` variable as described in the [environment variables documentation](../docs/env_variables.md). -To easily replay a crashing, or hanging record, you can use the persistent replay functionality by compiling AFL++ after uncommenting the `AFL_PERSISTENT_REPLAY` define in [config.h](../include/config.h). - -You can then run the test binary specifying the record number via the AFL_PERSISTENT_REPLAY environment variable (i.e., `RECORD:XXXXX`` -> `AFL_PERSISTENT_REPLAY=XXXXX`). +When `AFL_PERSISTENT_RECORD` is enabled, replay functionality is also included in the compiler-rt library. To replay a specific record, assign the record number to the AFL_PERSISTENT_REPLAY environment variable (i.e., `RECORD:XXXXX`` -> `AFL_PERSISTENT_REPLAY=XXXXX`), and run the test binary as you would normally do. The directory where the record files live can be specified via the `AFL_PERSISTENT_DIR` environment varilable, otherwise by default it will be considered the current directory (`./`). -If your harness reads the input files from arguments using the special `@@` argument you will need to define `AFL_PERSISTENT_ARGPARSE` in `config.h`, or before including the `persistent_replay.h` header file as show before. +If your harness reads the input files from arguments using the special `@@` argument you will need to include support by enabling `AFL_PERSISTENT_ARGPARSE` in `config.h`. + In order to offer transparent support to harnesses using the `@@` command line argument, arguments are parsed by the `__afl_record_replay_init` init function. Since not all systems support passing arguments to initializers, this functionality is disabled by default, it's recommendable to use the `__AFL_FUZZ_TESTCASE_BUF/__AFL_FUZZ_TESTCASE_LEN` shared memory mechanism instead. -### 7) Drop in replay functionality +## 7) Drop-in persistent loop replay replacement -To use the replay functionality without having to use `afl-cc` you can just define `AFL_COMPAT` and include the [include/persistent_replay.h](../include/persistent_replay.h) self contained header file that provides a drop-in replacement for the persistent loop mechanism. +To use the replay functionality without having to use `afl-cc`, include the [include/record_compat.h](../include/afl-record_compat.h) header file. Together with the [include/afl-persistent-replay.h](../include/afl-persistent-replay.h) header included in it, `afl-record-compat.h` provides a drop-in replacement for the persistent loop mechanism. ```c #ifndef __AFL_FUZZ_TESTCASE_LEN - #define AFL_COMPAT // #define AFL_PERSISTENT_REPLAY_ARGPARSE - #include "persistent_replay.h" + #include "afl-record-compat.h" #endif __AFL_FUZZ_INIT(); ``` -A simple example is provided in [persistent_demo_new.c](../utils/persistent_mode/persistent_demo_new.c).
\ No newline at end of file +A simple example is provided in [persistent_demo_replay.c](../utils/replay_record/persistent_demo_replay.c). + +Be aware that the [afl-record-compat.h](../include/afl-record-compat.h) header should only be included in a single compilation unit, or you will end up with clobbered functions and variables. + +If you need a cleaner solution, you'll have to move the functions and variables defined in [include/record_compat.h](../include/afl-record-compat.h) and [include/afl-persistent-replay.h](../include/afl-persistent-replay.h) in a C file, and add the relevant declarations to a header file. After including the new header file, the compilation unit resulting from compiling the C file can then be linked with your program.
\ No newline at end of file diff --git a/instrumentation/afl-compiler-rt.o.c b/instrumentation/afl-compiler-rt.o.c index 037caaf0..4c5d4e79 100644 --- a/instrumentation/afl-compiler-rt.o.c +++ b/instrumentation/afl-compiler-rt.o.c @@ -83,8 +83,8 @@ #include <sys/mman.h> #include <fcntl.h> -#ifdef AFL_PERSISTENT_REPLAY - #include "persistent_replay.h" +#ifdef AFL_PERSISTENT_RECORD + #include "afl-persistent-replay.h" #endif /* Globals needed by the injected instrumentation. The __afl_area_initial region @@ -1342,68 +1342,73 @@ int __afl_persistent_loop(unsigned int max_cnt) { static u8 first_pass = 1; static u32 cycle_cnt; -#ifdef AFL_PERSISTENT_REPLAY +#ifdef AFL_PERSISTENT_RECORD + char tcase[PATH_MAX]; +#endif - #ifndef PATH_MAX - #define PATH_MAX 4096 - #endif + if (first_pass) { - static u8 inited = 0; - char tcase[PATH_MAX]; + /* Make sure that every iteration of __AFL_LOOP() starts with a clean slate. + On subsequent calls, the parent will take care of that, but on the first + iteration, it's our job to erase any trace of whatever happened + before the loop. */ - if (unlikely(is_replay_record)) { + memset(__afl_area_ptr, 0, __afl_map_size); + __afl_area_ptr[0] = 1; + memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T)); - if (!inited) { + first_pass = 0; + __afl_selective_coverage_temp = 1; + +#ifdef AFL_PERSISTENT_RECORD + if (unlikely(is_replay_record)) { cycle_cnt = replay_record_cnt; - inited = 1; + goto persistent_record; - } + } else - snprintf(tcase, PATH_MAX, "%s/%s", - replay_record_dir ? replay_record_dir : "./", - record_list[replay_record_cnt - cycle_cnt]->d_name); +#endif + { - #ifdef AFL_PERSISTENT_REPLAY_ARGPARSE - if (record_arg) { + cycle_cnt = max_cnt; - *record_arg = tcase; + } - } else + return 1; - #endif // AFL_PERSISTENT_REPLAY_ARGPARSE - { + } else if (--cycle_cnt) { - int fd = open(tcase, O_RDONLY); - dup2(fd, 0); - close(fd); +#ifdef AFL_PERSISTENT_RECORD + if (unlikely(is_replay_record)) { - } + persistent_record: - return cycle_cnt--; + snprintf(tcase, PATH_MAX, "%s/%s", + replay_record_dir ? replay_record_dir : "./", + record_list[replay_record_cnt - cycle_cnt]->d_name); - } else + #ifdef AFL_PERSISTENT_REPLAY_ARGPARSE + if (unlikely(record_arg)) { -#endif + *record_arg = tcase; - if (first_pass) { + } else - /* Make sure that every iteration of __AFL_LOOP() starts with a clean slate. - On subsequent calls, the parent will take care of that, but on the first - iteration, it's our job to erase any trace of whatever happened - before the loop. */ + #endif // AFL_PERSISTENT_REPLAY_ARGPARSE + { - memset(__afl_area_ptr, 0, __afl_map_size); - __afl_area_ptr[0] = 1; - memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T)); + int fd = open(tcase, O_RDONLY); + dup2(fd, 0); + close(fd); - cycle_cnt = max_cnt; - first_pass = 0; - __afl_selective_coverage_temp = 1; + } - return 1; + return 1; - } else if (--cycle_cnt) { + } + +#endif raise(SIGSTOP); diff --git a/utils/persistent_mode/Makefile b/utils/persistent_mode/Makefile index 64de82a7..498aa3f8 100644 --- a/utils/persistent_mode/Makefile +++ b/utils/persistent_mode/Makefile @@ -1,7 +1,6 @@ all: ../../afl-clang-fast -o persistent_demo persistent_demo.c ../../afl-clang-fast -o persistent_demo_new persistent_demo_new.c - gcc -g -I ../../include -o persistent_demo_new_compat persistent_demo_new.c AFL_DONT_OPTIMIZE=1 ../../afl-clang-fast -o test-instr test-instr.c document: diff --git a/utils/replay_record/Makefile b/utils/replay_record/Makefile new file mode 100644 index 00000000..0d1cba92 --- /dev/null +++ b/utils/replay_record/Makefile @@ -0,0 +1,8 @@ +all: + test `grep '//[\s\t ]*#define[\s\t ]*AFL_PERSISTENT_RECORD' ../../include/config.h | wc -l` -eq 0 || (echo "AFL_PERSISTENT_RECORD must be enabled in config.h"; exit 1) + ../../afl-clang-fast -o persistent_demo_replay persistent_demo_replay.c + ${CC} -I ../../include -o persistent_demo_replay_compat persistent_demo_replay.c + ${CC} -g -I ../../include -DAFL_PERSISTENT_REPLAY_ARGPARSE -o persistent_demo_replay_argparse persistent_demo_replay.c + +clean: + rm -f persistent_demo_replay persistent_demo_replay_argparse persistent_demo_replay_compat diff --git a/utils/replay_record/persistent_demo_replay.c b/utils/replay_record/persistent_demo_replay.c new file mode 100644 index 00000000..6f6648f1 --- /dev/null +++ b/utils/replay_record/persistent_demo_replay.c @@ -0,0 +1,148 @@ +/* + american fuzzy lop++ - persistent mode example + -------------------------------------------- + + Originally written by Michal Zalewski + + Copyright 2015 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 file demonstrates the high-performance "persistent mode" that may be + suitable for fuzzing certain fast and well-behaved libraries, provided that + they are stateless or that their internal state can be easily reset + across runs. + + To make this work, the library and this shim need to be compiled in LLVM + mode using afl-clang-fast (other compiler wrappers will *not* work). + + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <signal.h> +#include <string.h> +#include <limits.h> + +#ifdef AFL_PERSISTENT_REPLAY_ARGPARSE + #include <sys/stat.h> + #include <fcntl.h> +#endif + +/* this lets the source compile without afl-clang-fast/lto */ +#ifndef __AFL_FUZZ_TESTCASE_LEN + #include "afl-record-compat.h" +#endif + +__AFL_FUZZ_INIT(); + +/* Main entry point. */ + +/* To ensure checks are not optimized out it is recommended to disable + code optimization for the fuzzer harness main() */ +#pragma clang optimize off +#pragma GCC optimize("O0") + +int main(int argc, char **argv) { + + ssize_t len; /* how much input did we read? */ + unsigned char *buf; /* test case buffer pointer */ + +#ifdef AFL_PERSISTENT_REPLAY_ARGPARSE + int fd; + + if (argc < 2) { printf("Need an input file!"); } +#endif + + /* The number passed to __AFL_LOOP() controls the maximum number of + iterations before the loop exits and the program is allowed to + terminate normally. This limits the impact of accidental memory leaks + and similar hiccups. */ + + __AFL_INIT(); + +#ifdef AFL_PERSISTENT_REPLAY_ARGPARSE + buf = malloc(1000); +#else + buf = __AFL_FUZZ_TESTCASE_BUF; // this must be assigned before __AFL_LOOP! +#endif + + while (__AFL_LOOP(UINT_MAX)) { // increase if you have good stability + +#ifdef AFL_PERSISTENT_REPLAY_ARGPARSE + fd = open(argv[1], O_RDONLY); + len = read(fd, buf, 1000); + close(fd); +#else + len = __AFL_FUZZ_TESTCASE_LEN; // do not use the macro directly in a call! +#endif + + // fprintf(stderr, "input: %zd \"%s\"\n", len, buf); + + /* do we have enough data? */ + if (len < 8) continue; + + if (strcmp((char *)buf, "thisisateststring") == 0) printf("teststring\n"); + + if (buf[0] == 'f') { + + printf("one\n"); + if (buf[1] == 'o') { + + printf("two\n"); + if (buf[2] == 'o') { + + printf("three\n"); + if (buf[3] == '!') { + + printf("four\n"); + if (buf[4] == '!') { + + printf("five\n"); + if (buf[5] == '!') { + + printf("six\n"); + abort(); + + } else { + + if (buf[5] == 'O') { + + // hang + while (1) { + + continue; + + }; + + } + + } + + } + + } + + } + + } + + } + + /*** END PLACEHOLDER CODE ***/ + + } + + /* Once the loop is exited, terminate normally - AFL will restart the process + when this happens, with a clean slate when it comes to allocated memory, + leftover file descriptors, etc. */ + + return 0; + +} + |