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author | van Hauser <vh@thc.org> | 2020-08-14 13:23:14 +0200 |
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committer | GitHub <noreply@github.com> | 2020-08-14 13:23:14 +0200 |
commit | a7537b5511ad767d2240cf2dc6d3e261daa676f9 (patch) | |
tree | 2cd8418efff844e634425e050ef716301adfd84b /afl_driver.cpp | |
parent | 15e799f7ae666418e75c6a79db833c5316b21f97 (diff) | |
parent | 83281503b3f1d4109c6f7a6af62a2133d55f1150 (diff) | |
download | afl++-a7537b5511ad767d2240cf2dc6d3e261daa676f9.tar.gz |
Merge branch 'debug' into dev
Diffstat (limited to 'afl_driver.cpp')
-rw-r--r-- | afl_driver.cpp | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/afl_driver.cpp b/afl_driver.cpp new file mode 100644 index 00000000..7d6a6fd4 --- /dev/null +++ b/afl_driver.cpp @@ -0,0 +1,191 @@ +#include <assert.h> +#include <errno.h> +#include <stdarg.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +// Platform detection. Copied from FuzzerInternal.h +#ifdef __linux__ +#define LIBFUZZER_LINUX 1 +#define LIBFUZZER_APPLE 0 +#define LIBFUZZER_NETBSD 0 +#define LIBFUZZER_FREEBSD 0 +#define LIBFUZZER_OPENBSD 0 +#elif __APPLE__ +#define LIBFUZZER_LINUX 0 +#define LIBFUZZER_APPLE 1 +#define LIBFUZZER_NETBSD 0 +#define LIBFUZZER_FREEBSD 0 +#define LIBFUZZER_OPENBSD 0 +#elif __NetBSD__ +#define LIBFUZZER_LINUX 0 +#define LIBFUZZER_APPLE 0 +#define LIBFUZZER_NETBSD 1 +#define LIBFUZZER_FREEBSD 0 +#define LIBFUZZER_OPENBSD 0 +#elif __FreeBSD__ +#define LIBFUZZER_LINUX 0 +#define LIBFUZZER_APPLE 0 +#define LIBFUZZER_NETBSD 0 +#define LIBFUZZER_FREEBSD 1 +#define LIBFUZZER_OPENBSD 0 +#elif __OpenBSD__ +#define LIBFUZZER_LINUX 0 +#define LIBFUZZER_APPLE 0 +#define LIBFUZZER_NETBSD 0 +#define LIBFUZZER_FREEBSD 0 +#define LIBFUZZER_OPENBSD 1 +#else +#error "Support for your platform has not been implemented" +#endif + +// libFuzzer interface is thin, so we don't include any libFuzzer headers. +int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size); +__attribute__((weak)) int LLVMFuzzerInitialize(int *argc, char ***argv); + +// Notify AFL about persistent mode. +static volatile char AFL_PERSISTENT[] = "##SIG_AFL_PERSISTENT##"; +int __afl_persistent_loop(unsigned int); +static volatile char suppress_warning2 = AFL_PERSISTENT[0]; + +// Notify AFL about deferred forkserver. +static volatile char AFL_DEFER_FORKSVR[] = "##SIG_AFL_DEFER_FORKSRV##"; +void __afl_manual_init(); +static volatile char suppress_warning1 = AFL_DEFER_FORKSVR[0]; + +// Input buffer. +static const size_t kMaxAflInputSize = 1024000; +static uint8_t AflInputBuf[kMaxAflInputSize]; + +// Use this optionally defined function to output sanitizer messages even if +// user asks to close stderr. +__attribute__((weak)) void __sanitizer_set_report_fd(void *); + +// Keep track of where stderr content is being written to, so that +// dup_and_close_stderr can use the correct one. +static FILE *output_file = stderr; + +// Experimental feature to use afl_driver without AFL's deferred mode. +// Needs to run before __afl_auto_init. +__attribute__((constructor(0))) static void __decide_deferred_forkserver(void) { + if (getenv("AFL_DRIVER_DONT_DEFER")) { + if (unsetenv("__AFL_DEFER_FORKSRV")) { + perror("Failed to unset __AFL_DEFER_FORKSRV"); + abort(); + } + } +} + +// If the user asks us to duplicate stderr, then do it. +static void maybe_duplicate_stderr() { + char *stderr_duplicate_filename = + getenv("AFL_DRIVER_STDERR_DUPLICATE_FILENAME"); + + if (!stderr_duplicate_filename) + return; + + FILE *stderr_duplicate_stream = + freopen(stderr_duplicate_filename, "a+", stderr); + + if (!stderr_duplicate_stream) { + fprintf( + stderr, + "Failed to duplicate stderr to AFL_DRIVER_STDERR_DUPLICATE_FILENAME"); + abort(); + } + output_file = stderr_duplicate_stream; +} + +// Most of these I/O functions were inspired by/copied from libFuzzer's code. +static void discard_output(int fd) { + FILE *temp = fopen("/dev/null", "w"); + if (!temp) + abort(); + dup2(fileno(temp), fd); + fclose(temp); +} + +static void close_stdout() { discard_output(STDOUT_FILENO); } + +// Prevent the targeted code from writing to "stderr" but allow sanitizers and +// this driver to do so. +static void dup_and_close_stderr() { + int output_fileno = fileno(output_file); + int output_fd = dup(output_fileno); + if (output_fd <= 0) + abort(); + FILE *new_output_file = fdopen(output_fd, "w"); + if (!new_output_file) + abort(); + if (!__sanitizer_set_report_fd) + return; + __sanitizer_set_report_fd(reinterpret_cast<void *>(output_fd)); + discard_output(output_fileno); +} + +// Close stdout and/or stderr if user asks for it. +static void maybe_close_fd_mask() { + char *fd_mask_str = getenv("AFL_DRIVER_CLOSE_FD_MASK"); + if (!fd_mask_str) + return; + int fd_mask = atoi(fd_mask_str); + if (fd_mask & 2) + dup_and_close_stderr(); + if (fd_mask & 1) + close_stdout(); +} + +// Define LLVMFuzzerMutate to avoid link failures for targets that use it +// with libFuzzer's LLVMFuzzerCustomMutator. +size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) { + assert(false && "LLVMFuzzerMutate should not be called from afl_driver"); + return 0; +} + +int main(int argc, char **argv) { + printf( + "======================= INFO =========================\n" + "This binary is built for AFL-fuzz.\n" + "To run the target function on individual input(s) execute this:\n" + " %s < INPUT_FILE\n" + "To fuzz with afl-fuzz execute this:\n" + " afl-fuzz [afl-flags] %s [-N]\n" + "afl-fuzz will run N iterations before " + "re-spawning the process (default: 1000)\n" + "======================================================\n", + argv[0], argv[0]); + + maybe_duplicate_stderr(); + maybe_close_fd_mask(); + if (LLVMFuzzerInitialize) + LLVMFuzzerInitialize(&argc, &argv); + // Do any other expensive one-time initialization here. + + int N = 100000; + if (argc == 2 && argv[1][0] == '-') + N = atoi(argv[1] + 1); + else if(argc == 2 && (N = atoi(argv[1])) > 0) + printf("WARNING: using the deprecated call style `%s %d`\n", argv[0], N); + + assert(N > 0); + + if (!getenv("AFL_DRIVER_DONT_DEFER")) + __afl_manual_init(); + + // Call LLVMFuzzerTestOneInput here so that coverage caused by initialization + // on the first execution of LLVMFuzzerTestOneInput is ignored. + uint8_t dummy_input[1] = {0}; + LLVMFuzzerTestOneInput(dummy_input, 1); + + while (__afl_persistent_loop(N)) { + ssize_t n_read = read(0, AflInputBuf, kMaxAflInputSize); + if (n_read > 0) { + LLVMFuzzerTestOneInput(AflInputBuf, n_read); + } + } + + printf("%s: successfully executed input(s)\n", argv[0]); +} |