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fix oob reads, code-format

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This commit is contained in:
van Hauser
2020-07-30 17:09:22 +02:00
parent 1ba48a5ba0
commit ea9ba53cdb
5 changed files with 146 additions and 104 deletions
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80
examples/aflpp_driver/aflpp_driver.c
View File

@ -14,12 +14,15 @@ cat << EOF > test_fuzzer.cc
#include <stddef.h> #include <stddef.h>
#include <stdint.h> #include <stdint.h>
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
if (size > 0 && data[0] == 'H') if (size > 0 && data[0] == 'H')
if (size > 1 && data[1] == 'I') if (size > 1 && data[1] == 'I')
if (size > 2 && data[2] == '!') if (size > 2 && data[2] == '!')
__builtin_trap(); __builtin_trap();
return 0; return 0;
} }
EOF EOF
# Build your target with -fsanitize-coverage=trace-pc-guard using fresh clang. # Build your target with -fsanitize-coverage=trace-pc-guard using fresh clang.
clang -g -fsanitize-coverage=trace-pc-guard test_fuzzer.cc -c clang -g -fsanitize-coverage=trace-pc-guard test_fuzzer.cc -c
@ -122,98 +125,121 @@ static FILE *output_file;
// Experimental feature to use afl_driver without AFL's deferred mode. // Experimental feature to use afl_driver without AFL's deferred mode.
// Needs to run before __afl_auto_init. // Needs to run before __afl_auto_init.
__attribute__((constructor(0))) static void __decide_deferred_forkserver(void) { __attribute__((constructor(0))) static void __decide_deferred_forkserver(void) {
if (getenv("AFL_DRIVER_DONT_DEFER")) { if (getenv("AFL_DRIVER_DONT_DEFER")) {
if (unsetenv("__AFL_DEFER_FORKSRV")) { if (unsetenv("__AFL_DEFER_FORKSRV")) {
perror("Failed to unset __AFL_DEFER_FORKSRV"); perror("Failed to unset __AFL_DEFER_FORKSRV");
abort(); abort();
} }
} }
} }
// If the user asks us to duplicate stderr, then do it. // If the user asks us to duplicate stderr, then do it.
static void maybe_duplicate_stderr() { static void maybe_duplicate_stderr() {
char *stderr_duplicate_filename = char *stderr_duplicate_filename =
getenv("AFL_DRIVER_STDERR_DUPLICATE_FILENAME"); getenv("AFL_DRIVER_STDERR_DUPLICATE_FILENAME");
if (!stderr_duplicate_filename) if (!stderr_duplicate_filename) return;
return;
FILE *stderr_duplicate_stream = FILE *stderr_duplicate_stream =
freopen(stderr_duplicate_filename, "a+", stderr); freopen(stderr_duplicate_filename, "a+", stderr);
if (!stderr_duplicate_stream) { if (!stderr_duplicate_stream) {
fprintf( fprintf(
stderr, stderr,
"Failed to duplicate stderr to AFL_DRIVER_STDERR_DUPLICATE_FILENAME"); "Failed to duplicate stderr to AFL_DRIVER_STDERR_DUPLICATE_FILENAME");
abort(); abort();
} }
output_file = stderr_duplicate_stream; output_file = stderr_duplicate_stream;
} }
// Most of these I/O functions were inspired by/copied from libFuzzer's code. // Most of these I/O functions were inspired by/copied from libFuzzer's code.
static void discard_output(int fd) { static void discard_output(int fd) {
FILE *temp = fopen("/dev/null", "w"); FILE *temp = fopen("/dev/null", "w");
if (!temp) if (!temp) abort();
abort();
dup2(fileno(temp), fd); dup2(fileno(temp), fd);
fclose(temp); fclose(temp);
} }
static void close_stdout() { discard_output(STDOUT_FILENO); } static void close_stdout() {
discard_output(STDOUT_FILENO);
}
// Prevent the targeted code from writing to "stderr" but allow sanitizers and // Prevent the targeted code from writing to "stderr" but allow sanitizers and
// this driver to do so. // this driver to do so.
static void dup_and_close_stderr() { static void dup_and_close_stderr() {
int output_fileno = fileno(output_file); int output_fileno = fileno(output_file);
int output_fd = dup(output_fileno); int output_fd = dup(output_fileno);
if (output_fd <= 0) if (output_fd <= 0) abort();
abort();
FILE *new_output_file = fdopen(output_fd, "w"); FILE *new_output_file = fdopen(output_fd, "w");
if (!new_output_file) if (!new_output_file) abort();
abort(); if (!__sanitizer_set_report_fd) return;
if (!__sanitizer_set_report_fd)
return;
__sanitizer_set_report_fd((void *)output_fd); __sanitizer_set_report_fd((void *)output_fd);
discard_output(output_fileno); discard_output(output_fileno);
} }
// Close stdout and/or stderr if user asks for it. // Close stdout and/or stderr if user asks for it.
static void maybe_close_fd_mask() { static void maybe_close_fd_mask() {
char *fd_mask_str = getenv("AFL_DRIVER_CLOSE_FD_MASK"); char *fd_mask_str = getenv("AFL_DRIVER_CLOSE_FD_MASK");
if (!fd_mask_str) if (!fd_mask_str) return;
return;
int fd_mask = atoi(fd_mask_str); int fd_mask = atoi(fd_mask_str);
if (fd_mask & 2) if (fd_mask & 2) dup_and_close_stderr();
dup_and_close_stderr(); if (fd_mask & 1) close_stdout();
if (fd_mask & 1)
close_stdout();
} }
// Define LLVMFuzzerMutate to avoid link failures for targets that use it // Define LLVMFuzzerMutate to avoid link failures for targets that use it
// with libFuzzer's LLVMFuzzerCustomMutator. // with libFuzzer's LLVMFuzzerCustomMutator.
size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) { size_t LLVMFuzzerMutate(uint8_t *Data, size_t Size, size_t MaxSize) {
// assert(false && "LLVMFuzzerMutate should not be called from afl_driver"); // assert(false && "LLVMFuzzerMutate should not be called from afl_driver");
return 0; return 0;
} }
// Execute any files provided as parameters. // Execute any files provided as parameters.
static int ExecuteFilesOnyByOne(int argc, char **argv) { static int ExecuteFilesOnyByOne(int argc, char **argv) {
unsigned char *buf = malloc(MAX_FILE); unsigned char *buf = malloc(MAX_FILE);
for (int i = 1; i < argc; i++) { for (int i = 1; i < argc; i++) {
int fd = open(argv[i], O_RDONLY); int fd = open(argv[i], O_RDONLY);
if (fd == -1) continue; if (fd == -1) continue;
ssize_t length = read(fd, buf, MAX_FILE); ssize_t length = read(fd, buf, MAX_FILE);
if (length > 0) { if (length > 0) {
printf("Reading %zu bytes from %s\n", length, argv[i]); printf("Reading %zu bytes from %s\n", length, argv[i]);
LLVMFuzzerTestOneInput(buf, length); LLVMFuzzerTestOneInput(buf, length);
printf("Execution successful.\n"); printf("Execution successful.\n");
} }
} }
free(buf); free(buf);
return 0; return 0;
} }
int main(int argc, char **argv) { int main(int argc, char **argv) {
printf( printf(
"======================= INFO =========================\n" "======================= INFO =========================\n"
"This binary is built for AFL-fuzz.\n" "This binary is built for AFL-fuzz.\n"
@ -231,26 +257,29 @@ int main(int argc, char **argv) {
output_file = stderr; output_file = stderr;
maybe_duplicate_stderr(); maybe_duplicate_stderr();
maybe_close_fd_mask(); maybe_close_fd_mask();
if (LLVMFuzzerInitialize) if (LLVMFuzzerInitialize) LLVMFuzzerInitialize(&argc, &argv);
LLVMFuzzerInitialize(&argc, &argv);
// Do any other expensive one-time initialization here. // Do any other expensive one-time initialization here.
uint8_t dummy_input[64] = {0}; uint8_t dummy_input[64] = {0};
memcpy(dummy_input, (void *)AFL_PERSISTENT, sizeof(AFL_PERSISTENT)); memcpy(dummy_input, (void *)AFL_PERSISTENT, sizeof(AFL_PERSISTENT));
memcpy(dummy_input + 32, (void*)AFL_DEFER_FORKSVR, sizeof(AFL_DEFER_FORKSVR)); memcpy(dummy_input + 32, (void *)AFL_DEFER_FORKSVR,
sizeof(AFL_DEFER_FORKSVR));
int N = INT_MAX; int N = INT_MAX;
if (argc == 2 && argv[1][0] == '-') if (argc == 2 && argv[1][0] == '-')
N = atoi(argv[1] + 1); N = atoi(argv[1] + 1);
else if (argc == 2 && (N = atoi(argv[1])) > 0) else if (argc == 2 && (N = atoi(argv[1])) > 0)
printf("WARNING: using the deprecated call style `%s %d`\n", argv[0], N); printf("WARNING: using the deprecated call style `%s %d`\n", argv[0], N);
else if (argc > 1) { else if (argc > 1) {
// if (!getenv("AFL_DRIVER_DONT_DEFER")) { // if (!getenv("AFL_DRIVER_DONT_DEFER")) {
__afl_sharedmem_fuzzing = 0; __afl_sharedmem_fuzzing = 0;
__afl_manual_init(); __afl_manual_init();
// } // }
return ExecuteFilesOnyByOne(argc, argv); return ExecuteFilesOnyByOne(argc, argv);
exit(0); exit(0);
} }
assert(N > 0); assert(N > 0);
@ -264,17 +293,26 @@ int main(int argc, char **argv) {
int num_runs = 0; int num_runs = 0;
while (__afl_persistent_loop(N)) { while (__afl_persistent_loop(N)) {
#ifdef _DEBUG #ifdef _DEBUG
fprintf(stderr, "CLIENT crc: %016llx len: %u\n", hash64(__afl_fuzz_ptr, *__afl_fuzz_len, 0xa5b35705), *__afl_fuzz_len); fprintf(stderr, "CLIENT crc: %016llx len: %u\n",
hash64(__afl_fuzz_ptr, *__afl_fuzz_len, 0xa5b35705),
*__afl_fuzz_len);
fprintf(stderr, "RECV:"); fprintf(stderr, "RECV:");
for (int i = 0; i < *__afl_fuzz_len; i++) for (int i = 0; i < *__afl_fuzz_len; i++)
fprintf(stderr, "%02x", __afl_fuzz_ptr[i]); fprintf(stderr, "%02x", __afl_fuzz_ptr[i]);
fprintf(stderr, "\n"); fprintf(stderr, "\n");
#endif #endif
if (*__afl_fuzz_len) { if (*__afl_fuzz_len) {
num_runs++; num_runs++;
LLVMFuzzerTestOneInput(__afl_fuzz_ptr, *__afl_fuzz_len); LLVMFuzzerTestOneInput(__afl_fuzz_ptr, *__afl_fuzz_len);
} }
} }
printf("%s: successfully executed %d input(s)\n", argv[0], num_runs); printf("%s: successfully executed %d input(s)\n", argv[0], num_runs);
} }

12
examples/aflpp_driver/aflpp_driver_test.c
View File

@ -6,18 +6,20 @@
int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) { int LLVMFuzzerTestOneInput(const uint8_t *Data, size_t Size) {
fprintf(stderr, "FUNC crc: %016llx len: %lu\n", hash64((u8*)Data, (unsigned int) Size, (unsigned long long int) 0xa5b35705), Size); fprintf(stderr, "FUNC crc: %016llx len: %lu\n",
hash64((u8 *)Data, (unsigned int)Size,
(unsigned long long int)0xa5b35705),
Size);
if (Size < 5) if (Size < 5) return 0;
return 0;
if (Data[0] == 'F') if (Data[0] == 'F')
if (Data[1] == 'A') if (Data[1] == 'A')
if (Data[2] == '$') if (Data[2] == '$')
if (Data[3] == '$') if (Data[3] == '$')
if (Data[4] == '$') if (Data[4] == '$') abort();
abort();
return 0; return 0;
} }

13
src/afl-fuzz-queue.c
View File

@ -139,7 +139,8 @@ static u8 check_if_text(struct queue_entry *q) {
// non-overlong 2-byte // non-overlong 2-byte
if (((0xC2 <= buf[offset + 0] && buf[offset + 0] <= 0xDF) && if (((0xC2 <= buf[offset + 0] && buf[offset + 0] <= 0xDF) &&
(0x80 <= buf[offset + 1] && buf[offset + 1] <= 0xBF))) { (0x80 <= buf[offset + 1] && buf[offset + 1] <= 0xBF)) &&
len - offset > 1) {
offset += 2; offset += 2;
utf8++; utf8++;
@ -149,7 +150,8 @@ static u8 check_if_text(struct queue_entry *q) {
} }
// excluding overlongs // excluding overlongs
if ((buf[offset + 0] == 0xE0 && if ((len - offset > 2) &&
((buf[offset + 0] == 0xE0 &&
(0xA0 <= buf[offset + 1] && buf[offset + 1] <= 0xBF) && (0xA0 <= buf[offset + 1] && buf[offset + 1] <= 0xBF) &&
(0x80 <= buf[offset + 2] && (0x80 <= buf[offset + 2] &&
buf[offset + 2] <= 0xBF)) || // straight 3-byte buf[offset + 2] <= 0xBF)) || // straight 3-byte
@ -160,7 +162,7 @@ static u8 check_if_text(struct queue_entry *q) {
buf[offset + 2] <= 0xBF)) || // excluding surrogates buf[offset + 2] <= 0xBF)) || // excluding surrogates
(buf[offset + 0] == 0xED && (buf[offset + 0] == 0xED &&
(0x80 <= buf[offset + 1] && buf[offset + 1] <= 0x9F) && (0x80 <= buf[offset + 1] && buf[offset + 1] <= 0x9F) &&
(0x80 <= buf[offset + 2] && buf[offset + 2] <= 0xBF))) { (0x80 <= buf[offset + 2] && buf[offset + 2] <= 0xBF)))) {
offset += 3; offset += 3;
utf8++; utf8++;
@ -170,7 +172,8 @@ static u8 check_if_text(struct queue_entry *q) {
} }
// planes 1-3 // planes 1-3
if ((buf[offset + 0] == 0xF0 && if ((len - offset > 3) &&
((buf[offset + 0] == 0xF0 &&
(0x90 <= buf[offset + 1] && buf[offset + 1] <= 0xBF) && (0x90 <= buf[offset + 1] && buf[offset + 1] <= 0xBF) &&
(0x80 <= buf[offset + 2] && buf[offset + 2] <= 0xBF) && (0x80 <= buf[offset + 2] && buf[offset + 2] <= 0xBF) &&
(0x80 <= buf[offset + 3] && (0x80 <= buf[offset + 3] &&
@ -182,7 +185,7 @@ static u8 check_if_text(struct queue_entry *q) {
(buf[offset + 0] == 0xF4 && (buf[offset + 0] == 0xF4 &&
(0x80 <= buf[offset + 1] && buf[offset + 1] <= 0x8F) && (0x80 <= buf[offset + 1] && buf[offset + 1] <= 0x8F) &&
(0x80 <= buf[offset + 2] && buf[offset + 2] <= 0xBF) && (0x80 <= buf[offset + 2] && buf[offset + 2] <= 0xBF) &&
(0x80 <= buf[offset + 3] && buf[offset + 3] <= 0xBF))) { (0x80 <= buf[offset + 3] && buf[offset + 3] <= 0xBF)))) {
offset += 4; offset += 4;
utf8++; utf8++;

3
src/afl-fuzz-redqueen.c
View File

@ -269,8 +269,7 @@ static long long strntoll(const char *str, size_t sz, char **end, int base) {
long long ret; long long ret;
const char *beg = str; const char *beg = str;
for (; beg && sz && *beg == ' '; beg++, sz--) for (; beg && sz && *beg == ' '; beg++, sz--) {};
;
if (!sz || sz >= sizeof(buf)) { if (!sz || sz >= sizeof(buf)) {