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Diffstat (limited to 'instrumentation/afl-compiler-rt.o.c')
| -rw-r--r-- | instrumentation/afl-compiler-rt.o.c | 1254 |
1 files changed, 1254 insertions, 0 deletions
diff --git a/instrumentation/afl-compiler-rt.o.c b/instrumentation/afl-compiler-rt.o.c new file mode 100644 index 00000000..a3d75b15 --- /dev/null +++ b/instrumentation/afl-compiler-rt.o.c @@ -0,0 +1,1254 @@ +/* + american fuzzy lop++ - instrumentation bootstrap + ------------------------------------------------ + + Copyright 2015, 2016 Google Inc. All rights reserved. + Copyright 2019-2020 AFLplusplus Project. 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 + + +*/ + +#ifdef __ANDROID__ + #include "android-ashmem.h" +#endif +#include "config.h" +#include "types.h" +#include "cmplog.h" +#include "llvm-ngram-coverage.h" + +#include <stdio.h> +#include <stdlib.h> +#include <signal.h> +#include <unistd.h> +#include <string.h> +#include <assert.h> +#include <stdint.h> +#include <stddef.h> +#include <limits.h> +#include <errno.h> + +#include <sys/mman.h> +#include <sys/shm.h> +#include <sys/wait.h> +#include <sys/types.h> + +#include "llvm/Config/llvm-config.h" + +#ifdef __linux__ + #include "snapshot-inl.h" +#endif + +/* This is a somewhat ugly hack for the experimental 'trace-pc-guard' mode. + Basically, we need to make sure that the forkserver is initialized after + the LLVM-generated runtime initialization pass, not before. */ + +#ifndef MAP_FIXED_NOREPLACE + #ifdef MAP_EXCL + #define MAP_FIXED_NOREPLACE MAP_EXCL | MAP_FIXED + #else + #define MAP_FIXED_NOREPLACE MAP_FIXED + #endif +#endif + +#define CTOR_PRIO 3 + +#include <sys/mman.h> +#include <fcntl.h> + +/* Globals needed by the injected instrumentation. The __afl_area_initial region + is used for instrumentation output before __afl_map_shm() has a chance to + run. It will end up as .comm, so it shouldn't be too wasteful. */ + +#if MAP_SIZE <= 65536 + #define MAP_INITIAL_SIZE 256000 +#else + #define MAP_INITIAL_SIZE MAP_SIZE +#endif + +u8 __afl_area_initial[MAP_INITIAL_SIZE]; +u8 * __afl_area_ptr = __afl_area_initial; +u8 * __afl_dictionary; +u8 * __afl_fuzz_ptr; +u32 __afl_fuzz_len_dummy; +u32 *__afl_fuzz_len = &__afl_fuzz_len_dummy; + +u32 __afl_final_loc; +u32 __afl_map_size = MAP_SIZE; +u32 __afl_dictionary_len; +u64 __afl_map_addr; + +#ifdef __ANDROID__ +PREV_LOC_T __afl_prev_loc[NGRAM_SIZE_MAX]; +u32 __afl_prev_ctx; +u32 __afl_cmp_counter; +#else +__thread PREV_LOC_T __afl_prev_loc[NGRAM_SIZE_MAX]; +__thread u32 __afl_prev_ctx; +__thread u32 __afl_cmp_counter; +#endif + +int __afl_sharedmem_fuzzing __attribute__((weak)); + +struct cmp_map *__afl_cmp_map; + +/* Running in persistent mode? */ + +static u8 is_persistent; + +/* Are we in sancov mode? */ + +static u8 _is_sancov; + +/* Uninspired gcc plugin instrumentation */ + +void __afl_trace(const u32 x) { + +#if 1 /* enable for neverZero feature. */ + __afl_area_ptr[__afl_prev_loc[0] ^ x] += + 1 + ((u8)(1 + __afl_area_ptr[__afl_prev_loc[0] ^ x]) == 0); +#else + ++__afl_area_ptr[__afl_prev_loc[0] ^ x]; +#endif + + __afl_prev_loc[0] = (x >> 1); + return; + +} + +/* Error reporting to forkserver controller */ + +void send_forkserver_error(int error) { + + u32 status; + if (!error || error > 0xffff) return; + status = (FS_OPT_ERROR | FS_OPT_SET_ERROR(error)); + if (write(FORKSRV_FD + 1, (char *)&status, 4) != 4) return; + +} + +/* SHM fuzzing setup. */ + +static void __afl_map_shm_fuzz() { + + char *id_str = getenv(SHM_FUZZ_ENV_VAR); + + if (id_str) { + + u8 *map = NULL; + +#ifdef USEMMAP + const char * shm_file_path = id_str; + int shm_fd = -1; + unsigned char *shm_base = NULL; + + /* create the shared memory segment as if it was a file */ + shm_fd = shm_open(shm_file_path, O_RDWR, 0600); + if (shm_fd == -1) { + + fprintf(stderr, "shm_open() failed for fuzz\n"); + send_forkserver_error(FS_ERROR_SHM_OPEN); + exit(1); + + } + + map = + (u8 *)mmap(0, MAX_FILE + sizeof(u32), PROT_READ, MAP_SHARED, shm_fd, 0); + +#else + u32 shm_id = atoi(id_str); + map = (u8 *)shmat(shm_id, NULL, 0); + +#endif + + /* Whooooops. */ + + if (!map || map == (void *)-1) { + + perror("Could not access fuzzign shared memory"); + exit(1); + + } + + __afl_fuzz_len = (u32 *)map; + __afl_fuzz_ptr = map + sizeof(u32); + + if (getenv("AFL_DEBUG")) { + + fprintf(stderr, "DEBUG: successfully got fuzzing shared memory\n"); + + } + + } else { + + fprintf(stderr, "Error: variable for fuzzing shared memory is not set\n"); + exit(1); + + } + +} + +/* SHM setup. */ + +static void __afl_map_shm(void) { + + // we we are not running in afl ensure the map exists + if (!__afl_area_ptr) { __afl_area_ptr = __afl_area_initial; } + + char *id_str = getenv(SHM_ENV_VAR); + + if (__afl_final_loc) { + + if (__afl_final_loc % 8) + __afl_final_loc = (((__afl_final_loc + 7) >> 3) << 3); + __afl_map_size = __afl_final_loc; + + if (__afl_final_loc > MAP_SIZE) { + + char *ptr; + u32 val = 0; + if ((ptr = getenv("AFL_MAP_SIZE")) != NULL) val = atoi(ptr); + if (val < __afl_final_loc) { + + if (__afl_final_loc > FS_OPT_MAX_MAPSIZE) { + + if (!getenv("AFL_QUIET")) + fprintf(stderr, + "Error: AFL++ tools *require* to set AFL_MAP_SIZE to %u " + "to be able to run this instrumented program!\n", + __afl_final_loc); + + if (id_str) { + + send_forkserver_error(FS_ERROR_MAP_SIZE); + exit(-1); + + } + + } else { + + if (!getenv("AFL_QUIET")) + fprintf(stderr, + "Warning: AFL++ tools will need to set AFL_MAP_SIZE to %u " + "to be able to run this instrumented program!\n", + __afl_final_loc); + + } + + } + + } + + } + + /* If we're running under AFL, attach to the appropriate region, replacing the + early-stage __afl_area_initial region that is needed to allow some really + hacky .init code to work correctly in projects such as OpenSSL. */ + + if (getenv("AFL_DEBUG")) + fprintf(stderr, + "DEBUG: id_str %s, __afl_area_ptr %p, __afl_area_initial %p, " + "__afl_map_addr 0x%llx, MAP_SIZE %u, __afl_final_loc %u, " + "max_size_forkserver %u/0x%x\n", + id_str == NULL ? "<null>" : id_str, __afl_area_ptr, + __afl_area_initial, __afl_map_addr, MAP_SIZE, __afl_final_loc, + FS_OPT_MAX_MAPSIZE, FS_OPT_MAX_MAPSIZE); + + if (id_str) { + + if (__afl_area_ptr && __afl_area_ptr != __afl_area_initial) { + + if (__afl_map_addr) + munmap((void *)__afl_map_addr, __afl_final_loc); + else + free(__afl_area_ptr); + __afl_area_ptr = __afl_area_initial; + + } + +#ifdef USEMMAP + const char * shm_file_path = id_str; + int shm_fd = -1; + unsigned char *shm_base = NULL; + + /* create the shared memory segment as if it was a file */ + shm_fd = shm_open(shm_file_path, O_RDWR, 0600); + if (shm_fd == -1) { + + fprintf(stderr, "shm_open() failed\n"); + send_forkserver_error(FS_ERROR_SHM_OPEN); + exit(1); + + } + + /* map the shared memory segment to the address space of the process */ + if (__afl_map_addr) { + + shm_base = + mmap((void *)__afl_map_addr, __afl_map_size, PROT_READ | PROT_WRITE, + MAP_FIXED_NOREPLACE | MAP_SHARED, shm_fd, 0); + + } else { + + shm_base = mmap(0, __afl_map_size, PROT_READ | PROT_WRITE, MAP_SHARED, + shm_fd, 0); + + } + + if (shm_base == MAP_FAILED) { + + close(shm_fd); + shm_fd = -1; + + fprintf(stderr, "mmap() failed\n"); + if (__afl_map_addr) + send_forkserver_error(FS_ERROR_MAP_ADDR); + else + send_forkserver_error(FS_ERROR_MMAP); + exit(2); + + } + + __afl_area_ptr = shm_base; +#else + u32 shm_id = atoi(id_str); + + __afl_area_ptr = shmat(shm_id, (void *)__afl_map_addr, 0); + +#endif + + /* Whooooops. */ + + if (__afl_area_ptr == (void *)-1) { + + if (__afl_map_addr) + send_forkserver_error(FS_ERROR_MAP_ADDR); + else + send_forkserver_error(FS_ERROR_SHMAT); + _exit(1); + + } + + /* Write something into the bitmap so that even with low AFL_INST_RATIO, + our parent doesn't give up on us. */ + + __afl_area_ptr[0] = 1; + + } else if ((!__afl_area_ptr || __afl_area_ptr == __afl_area_initial) && + + __afl_map_addr) { + + __afl_area_ptr = + mmap((void *)__afl_map_addr, __afl_map_size, PROT_READ | PROT_WRITE, + MAP_FIXED_NOREPLACE | MAP_SHARED | MAP_ANONYMOUS, -1, 0); + + if (__afl_area_ptr == MAP_FAILED) { + + fprintf(stderr, "can not acquire mmap for address %p\n", + (void *)__afl_map_addr); + exit(1); + + } + + } else if (_is_sancov && __afl_area_ptr != __afl_area_initial) { + + free(__afl_area_ptr); + __afl_area_ptr = NULL; + if (__afl_final_loc > MAP_INITIAL_SIZE) + __afl_area_ptr = malloc(__afl_final_loc); + if (!__afl_area_ptr) __afl_area_ptr = __afl_area_initial; + + } + + id_str = getenv(CMPLOG_SHM_ENV_VAR); + + if (getenv("AFL_DEBUG")) { + + fprintf(stderr, "DEBUG: cmplog id_str %s\n", + id_str == NULL ? "<null>" : id_str); + + } + + if (id_str) { + +#ifdef USEMMAP + const char * shm_file_path = id_str; + int shm_fd = -1; + unsigned char *shm_base = NULL; + + /* create the shared memory segment as if it was a file */ + shm_fd = shm_open(shm_file_path, O_RDWR, 0600); + if (shm_fd == -1) { + + fprintf(stderr, "shm_open() failed\n"); + exit(1); + + } + + /* map the shared memory segment to the address space of the process */ + shm_base = mmap(0, sizeof(struct cmp_map), PROT_READ | PROT_WRITE, + MAP_SHARED, shm_fd, 0); + if (shm_base == MAP_FAILED) { + + close(shm_fd); + shm_fd = -1; + + fprintf(stderr, "mmap() failed\n"); + exit(2); + + } + + __afl_cmp_map = shm_base; +#else + u32 shm_id = atoi(id_str); + + __afl_cmp_map = shmat(shm_id, NULL, 0); +#endif + + if (__afl_cmp_map == (void *)-1) _exit(1); + + } + +} + +#ifdef __linux__ +static void __afl_start_snapshots(void) { + + static u8 tmp[4] = {0, 0, 0, 0}; + s32 child_pid; + u32 status = 0; + u32 already_read_first = 0; + u32 was_killed; + + u8 child_stopped = 0; + + void (*old_sigchld_handler)(int) = 0; // = signal(SIGCHLD, SIG_DFL); + + /* Phone home and tell the parent that we're OK. If parent isn't there, + assume we're not running in forkserver mode and just execute program. */ + + status |= (FS_OPT_ENABLED | FS_OPT_SNAPSHOT); + if (__afl_sharedmem_fuzzing != 0) status |= FS_OPT_SHDMEM_FUZZ; + if (__afl_map_size <= FS_OPT_MAX_MAPSIZE) + status |= (FS_OPT_SET_MAPSIZE(__afl_map_size) | FS_OPT_MAPSIZE); + if (__afl_dictionary_len && __afl_dictionary) status |= FS_OPT_AUTODICT; + memcpy(tmp, &status, 4); + + if (write(FORKSRV_FD + 1, tmp, 4) != 4) return; + + if (__afl_sharedmem_fuzzing || (__afl_dictionary_len && __afl_dictionary)) { + + if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); + + if (getenv("AFL_DEBUG")) { + + fprintf(stderr, "target forkserver recv: %08x\n", was_killed); + + } + + if ((was_killed & (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) == + (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) { + + __afl_map_shm_fuzz(); + + } + + if ((was_killed & (FS_OPT_ENABLED | FS_OPT_AUTODICT)) == + (FS_OPT_ENABLED | FS_OPT_AUTODICT)) { + + // great lets pass the dictionary through the forkserver FD + u32 len = __afl_dictionary_len, offset = 0; + s32 ret; + + if (write(FORKSRV_FD + 1, &len, 4) != 4) { + + write(2, "Error: could not send dictionary len\n", + strlen("Error: could not send dictionary len\n")); + _exit(1); + + } + + while (len != 0) { + + ret = write(FORKSRV_FD + 1, __afl_dictionary + offset, len); + + if (ret < 1) { + + write(2, "Error: could not send dictionary\n", + strlen("Error: could not send dictionary\n")); + _exit(1); + + } + + len -= ret; + offset += ret; + + } + + } else { + + // uh this forkserver does not understand extended option passing + // or does not want the dictionary + if (!__afl_fuzz_ptr) already_read_first = 1; + + } + + } + + while (1) { + + int status; + + if (already_read_first) { + + already_read_first = 0; + + } else { + + /* Wait for parent by reading from the pipe. Abort if read fails. */ + if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); + + } + + #ifdef _AFL_DOCUMENT_MUTATIONS + if (__afl_fuzz_ptr) { + + static uint32_t counter = 0; + char fn[32]; + sprintf(fn, "%09u:forkserver", counter); + s32 fd_doc = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0600); + if (fd_doc >= 0) { + + if (write(fd_doc, __afl_fuzz_ptr, *__afl_fuzz_len) != *__afl_fuzz_len) { + + fprintf(stderr, "write of mutation file failed: %s\n", fn); + unlink(fn); + + } + + close(fd_doc); + + } + + counter++; + + } + + #endif + + /* If we stopped the child in persistent mode, but there was a race + condition and afl-fuzz already issued SIGKILL, write off the old + process. */ + + if (child_stopped && was_killed) { + + child_stopped = 0; + if (waitpid(child_pid, &status, 0) < 0) _exit(1); + + } + + if (!child_stopped) { + + /* Once woken up, create a clone of our process. */ + + child_pid = fork(); + if (child_pid < 0) _exit(1); + + /* In child process: close fds, resume execution. */ + + if (!child_pid) { + + //(void)nice(-20); // does not seem to improve + + signal(SIGCHLD, old_sigchld_handler); + + close(FORKSRV_FD); + close(FORKSRV_FD + 1); + + if (!afl_snapshot_take(AFL_SNAPSHOT_MMAP | AFL_SNAPSHOT_FDS | + AFL_SNAPSHOT_REGS | AFL_SNAPSHOT_EXIT)) { + + raise(SIGSTOP); + + } + + __afl_area_ptr[0] = 1; + memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T)); + + return; + + } + + } else { + + /* Special handling for persistent mode: if the child is alive but + currently stopped, simply restart it with SIGCONT. */ + + kill(child_pid, SIGCONT); + child_stopped = 0; + + } + + /* In parent process: write PID to pipe, then wait for child. */ + + if (write(FORKSRV_FD + 1, &child_pid, 4) != 4) _exit(1); + + if (waitpid(child_pid, &status, WUNTRACED) < 0) _exit(1); + + /* In persistent mode, the child stops itself with SIGSTOP to indicate + a successful run. In this case, we want to wake it up without forking + again. */ + + if (WIFSTOPPED(status)) child_stopped = 1; + + /* Relay wait status to pipe, then loop back. */ + + if (write(FORKSRV_FD + 1, &status, 4) != 4) _exit(1); + + } + +} + +#endif + +/* Fork server logic. */ + +static void __afl_start_forkserver(void) { + +#ifdef __linux__ + if (/*!is_persistent &&*/ !__afl_cmp_map && !getenv("AFL_NO_SNAPSHOT") && + afl_snapshot_init() >= 0) { + + __afl_start_snapshots(); + return; + + } + +#endif + + u8 tmp[4] = {0, 0, 0, 0}; + s32 child_pid; + u32 status = 0; + u32 already_read_first = 0; + u32 was_killed; + + u8 child_stopped = 0; + + void (*old_sigchld_handler)(int) = 0; // = signal(SIGCHLD, SIG_DFL); + + if (__afl_map_size <= FS_OPT_MAX_MAPSIZE) + status |= (FS_OPT_SET_MAPSIZE(__afl_map_size) | FS_OPT_MAPSIZE); + if (__afl_dictionary_len && __afl_dictionary) status |= FS_OPT_AUTODICT; + if (__afl_sharedmem_fuzzing != 0) status |= FS_OPT_SHDMEM_FUZZ; + if (status) status |= (FS_OPT_ENABLED); + memcpy(tmp, &status, 4); + + /* Phone home and tell the parent that we're OK. If parent isn't there, + assume we're not running in forkserver mode and just execute program. */ + + if (write(FORKSRV_FD + 1, tmp, 4) != 4) return; + + if (__afl_sharedmem_fuzzing || (__afl_dictionary_len && __afl_dictionary)) { + + if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); + + if (getenv("AFL_DEBUG")) { + + fprintf(stderr, "target forkserver recv: %08x\n", was_killed); + + } + + if ((was_killed & (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) == + (FS_OPT_ENABLED | FS_OPT_SHDMEM_FUZZ)) { + + __afl_map_shm_fuzz(); + + } + + if ((was_killed & (FS_OPT_ENABLED | FS_OPT_AUTODICT)) == + (FS_OPT_ENABLED | FS_OPT_AUTODICT)) { + + // great lets pass the dictionary through the forkserver FD + u32 len = __afl_dictionary_len, offset = 0; + s32 ret; + + if (write(FORKSRV_FD + 1, &len, 4) != 4) { + + write(2, "Error: could not send dictionary len\n", + strlen("Error: could not send dictionary len\n")); + _exit(1); + + } + + while (len != 0) { + + ret = write(FORKSRV_FD + 1, __afl_dictionary + offset, len); + + if (ret < 1) { + + write(2, "Error: could not send dictionary\n", + strlen("Error: could not send dictionary\n")); + _exit(1); + + } + + len -= ret; + offset += ret; + + } + + } else { + + // uh this forkserver does not understand extended option passing + // or does not want the dictionary + if (!__afl_fuzz_ptr) already_read_first = 1; + + } + + } + + while (1) { + + int status; + + /* Wait for parent by reading from the pipe. Abort if read fails. */ + + if (already_read_first) { + + already_read_first = 0; + + } else { + + if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); + + } + +#ifdef _AFL_DOCUMENT_MUTATIONS + if (__afl_fuzz_ptr) { + + static uint32_t counter = 0; + char fn[32]; + sprintf(fn, "%09u:forkserver", counter); + s32 fd_doc = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0600); + if (fd_doc >= 0) { + + if (write(fd_doc, __afl_fuzz_ptr, *__afl_fuzz_len) != *__afl_fuzz_len) { + + fprintf(stderr, "write of mutation file failed: %s\n", fn); + unlink(fn); + + } + + close(fd_doc); + + } + + counter++; + + } + +#endif + + /* If we stopped the child in persistent mode, but there was a race + condition and afl-fuzz already issued SIGKILL, write off the old + process. */ + + if (child_stopped && was_killed) { + + child_stopped = 0; + if (waitpid(child_pid, &status, 0) < 0) _exit(1); + + } + + if (!child_stopped) { + + /* Once woken up, create a clone of our process. */ + + child_pid = fork(); + if (child_pid < 0) _exit(1); + + /* In child process: close fds, resume execution. */ + + if (!child_pid) { + + //(void)nice(-20); + + signal(SIGCHLD, old_sigchld_handler); + + close(FORKSRV_FD); + close(FORKSRV_FD + 1); + return; + + } + + } else { + + /* Special handling for persistent mode: if the child is alive but + currently stopped, simply restart it with SIGCONT. */ + + kill(child_pid, SIGCONT); + child_stopped = 0; + + } + + /* In parent process: write PID to pipe, then wait for child. */ + + if (write(FORKSRV_FD + 1, &child_pid, 4) != 4) _exit(1); + + if (waitpid(child_pid, &status, is_persistent ? WUNTRACED : 0) < 0) + _exit(1); + + /* In persistent mode, the child stops itself with SIGSTOP to indicate + a successful run. In this case, we want to wake it up without forking + again. */ + + if (WIFSTOPPED(status)) child_stopped = 1; + + /* Relay wait status to pipe, then loop back. */ + + if (write(FORKSRV_FD + 1, &status, 4) != 4) _exit(1); + + } + +} + +/* A simplified persistent mode handler, used as explained in + * README.llvm.md. */ + +int __afl_persistent_loop(unsigned int max_cnt) { + + static u8 first_pass = 1; + static u32 cycle_cnt; + + if (first_pass) { + + /* 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 (is_persistent) { + + 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)); + + } + + cycle_cnt = max_cnt; + first_pass = 0; + return 1; + + } + + if (is_persistent) { + + if (--cycle_cnt) { + + raise(SIGSTOP); + + __afl_area_ptr[0] = 1; + memset(__afl_prev_loc, 0, NGRAM_SIZE_MAX * sizeof(PREV_LOC_T)); + + return 1; + + } else { + + /* When exiting __AFL_LOOP(), make sure that the subsequent code that + follows the loop is not traced. We do that by pivoting back to the + dummy output region. */ + + __afl_area_ptr = __afl_area_initial; + + } + + } + + return 0; + +} + +/* This one can be called from user code when deferred forkserver mode + is enabled. */ + +void __afl_manual_init(void) { + + static u8 init_done; + + if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) { + + init_done = 1; + is_persistent = 0; + __afl_sharedmem_fuzzing = 0; + if (__afl_area_ptr == NULL) __afl_area_ptr = __afl_area_initial; + + if (getenv("AFL_DEBUG")) + fprintf(stderr, + "DEBUG: disabled instrumentation because of " + "AFL_DISABLE_LLVM_INSTRUMENTATION\n"); + + } + + if (!init_done) { + + __afl_start_forkserver(); + init_done = 1; + + } + +} + +/* Initialization of the forkserver - latest possible */ + +__attribute__((constructor())) void __afl_auto_init(void) { + + if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; + + if (getenv(DEFER_ENV_VAR)) return; + + __afl_manual_init(); + +} + +/* Initialization of the shmem - earliest possible because of LTO fixed mem. */ + +__attribute__((constructor(CTOR_PRIO))) void __afl_auto_early(void) { + + is_persistent = !!getenv(PERSIST_ENV_VAR); + + if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; + + __afl_map_shm(); + +} + +/* preset __afl_area_ptr #2 */ + +__attribute__((constructor(1))) void __afl_auto_second(void) { + + if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; + u8 *ptr; + + if (__afl_final_loc) { + + if (__afl_area_ptr && __afl_area_ptr != __afl_area_initial) + free(__afl_area_ptr); + + if (__afl_map_addr) + ptr = (u8 *)mmap((void *)__afl_map_addr, __afl_final_loc, + PROT_READ | PROT_WRITE, + MAP_FIXED_NOREPLACE | MAP_SHARED | MAP_ANONYMOUS, -1, 0); + else + ptr = (u8 *)malloc(__afl_final_loc); + + if (ptr && (ssize_t)ptr != -1) __afl_area_ptr = ptr; + + } + +} + +/* preset __afl_area_ptr #1 - at constructor level 0 global variables have + not been set */ + +__attribute__((constructor(0))) void __afl_auto_first(void) { + + if (getenv("AFL_DISABLE_LLVM_INSTRUMENTATION")) return; + u8 *ptr; + + ptr = (u8 *)malloc(1024000); + + if (ptr && (ssize_t)ptr != -1) __afl_area_ptr = ptr; + +} + +/* The following stuff deals with supporting -fsanitize-coverage=trace-pc-guard. + It remains non-operational in the traditional, plugin-backed LLVM mode. + For more info about 'trace-pc-guard', see README.llvm.md. + + The first function (__sanitizer_cov_trace_pc_guard) is called back on every + edge (as opposed to every basic block). */ + +void __sanitizer_cov_trace_pc_guard(uint32_t *guard) { + + // For stability analysis, if you want to know to which function unstable + // edge IDs belong - uncomment, recompile+install llvm_mode, recompile + // the target. libunwind and libbacktrace are better solutions. + // Set AFL_DEBUG_CHILD_OUTPUT=1 and run afl-fuzz with 2>file to capture + // the backtrace output + /* + uint32_t unstable[] = { ... unstable edge IDs }; + uint32_t idx; + char bt[1024]; + for (idx = 0; i < sizeof(unstable)/sizeof(uint32_t); i++) { + + if (unstable[idx] == __afl_area_ptr[*guard]) { + + int bt_size = backtrace(bt, 256); + if (bt_size > 0) { + + char **bt_syms = backtrace_symbols(bt, bt_size); + if (bt_syms) { + + fprintf(stderr, "DEBUG: edge=%u caller=%s\n", unstable[idx], + bt_syms[0]); + free(bt_syms); + + } + + } + + } + + } + + */ + +#if (LLVM_VERSION_MAJOR < 9) + + __afl_area_ptr[*guard]++; + +#else + + __afl_area_ptr[*guard] = + __afl_area_ptr[*guard] + 1 + (__afl_area_ptr[*guard] == 255 ? 1 : 0); + +#endif + +} + +/* Init callback. Populates instrumentation IDs. Note that we're using + ID of 0 as a special value to indicate non-instrumented bits. That may + still touch the bitmap, but in a fairly harmless way. */ + +void __sanitizer_cov_trace_pc_guard_init(uint32_t *start, uint32_t *stop) { + + u32 inst_ratio = 100; + char *x; + + _is_sancov = 1; + + if (getenv("AFL_DEBUG")) { + + fprintf(stderr, "Running __sanitizer_cov_trace_pc_guard_init: %p-%p\n", + start, stop); + + } + + if (start == stop || *start) return; + + x = getenv("AFL_INST_RATIO"); + if (x) inst_ratio = (u32)atoi(x); + + if (!inst_ratio || inst_ratio > 100) { + + fprintf(stderr, "[-] ERROR: Invalid AFL_INST_RATIO (must be 1-100).\n"); + abort(); + + } + + /* Make sure that the first element in the range is always set - we use that + to avoid duplicate calls (which can happen as an artifact of the underlying + implementation in LLVM). */ + + *(start++) = R(MAP_SIZE - 1) + 1; + + while (start < stop) { + + if (R(100) < inst_ratio) + *start = ++__afl_final_loc; + else + *start = 0; + + start++; + + } + +} + +///// CmpLog instrumentation + +void __cmplog_ins_hook1(uint8_t arg1, uint8_t arg2) { + + if (unlikely(!__afl_cmp_map)) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + __afl_cmp_map->headers[k].type = CMP_TYPE_INS; + + u32 hits = __afl_cmp_map->headers[k].hits; + __afl_cmp_map->headers[k].hits = hits + 1; + // if (!__afl_cmp_map->headers[k].cnt) + // __afl_cmp_map->headers[k].cnt = __afl_cmp_counter++; + + __afl_cmp_map->headers[k].shape = 0; + + hits &= CMP_MAP_H - 1; + __afl_cmp_map->log[k][hits].v0 = arg1; + __afl_cmp_map->log[k][hits].v1 = arg2; + +} + +void __cmplog_ins_hook2(uint16_t arg1, uint16_t arg2) { + + if (unlikely(!__afl_cmp_map)) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + __afl_cmp_map->headers[k].type = CMP_TYPE_INS; + + u32 hits = __afl_cmp_map->headers[k].hits; + __afl_cmp_map->headers[k].hits = hits + 1; + + __afl_cmp_map->headers[k].shape = 1; + + hits &= CMP_MAP_H - 1; + __afl_cmp_map->log[k][hits].v0 = arg1; + __afl_cmp_map->log[k][hits].v1 = arg2; + +} + +void __cmplog_ins_hook4(uint32_t arg1, uint32_t arg2) { + + if (unlikely(!__afl_cmp_map)) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + __afl_cmp_map->headers[k].type = CMP_TYPE_INS; + + u32 hits = __afl_cmp_map->headers[k].hits; + __afl_cmp_map->headers[k].hits = hits + 1; + + __afl_cmp_map->headers[k].shape = 3; + + hits &= CMP_MAP_H - 1; + __afl_cmp_map->log[k][hits].v0 = arg1; + __afl_cmp_map->log[k][hits].v1 = arg2; + +} + +void __cmplog_ins_hook8(uint64_t arg1, uint64_t arg2) { + + if (unlikely(!__afl_cmp_map)) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + __afl_cmp_map->headers[k].type = CMP_TYPE_INS; + + u32 hits = __afl_cmp_map->headers[k].hits; + __afl_cmp_map->headers[k].hits = hits + 1; + + __afl_cmp_map->headers[k].shape = 7; + + hits &= CMP_MAP_H - 1; + __afl_cmp_map->log[k][hits].v0 = arg1; + __afl_cmp_map->log[k][hits].v1 = arg2; + +} + +#if defined(__APPLE__) + #pragma weak __sanitizer_cov_trace_const_cmp1 = __cmplog_ins_hook1 + #pragma weak __sanitizer_cov_trace_const_cmp2 = __cmplog_ins_hook2 + #pragma weak __sanitizer_cov_trace_const_cmp4 = __cmplog_ins_hook4 + #pragma weak __sanitizer_cov_trace_const_cmp8 = __cmplog_ins_hook8 + + #pragma weak __sanitizer_cov_trace_cmp1 = __cmplog_ins_hook1 + #pragma weak __sanitizer_cov_trace_cmp2 = __cmplog_ins_hook2 + #pragma weak __sanitizer_cov_trace_cmp4 = __cmplog_ins_hook4 + #pragma weak __sanitizer_cov_trace_cmp8 = __cmplog_ins_hook8 +#else +void __sanitizer_cov_trace_const_cmp1(uint8_t arg1, uint8_t arg2) + __attribute__((alias("__cmplog_ins_hook1"))); +void __sanitizer_cov_trace_const_cmp2(uint16_t arg1, uint16_t arg2) + __attribute__((alias("__cmplog_ins_hook2"))); +void __sanitizer_cov_trace_const_cmp4(uint32_t arg1, uint32_t arg2) + __attribute__((alias("__cmplog_ins_hook4"))); +void __sanitizer_cov_trace_const_cmp8(uint64_t arg1, uint64_t arg2) + __attribute__((alias("__cmplog_ins_hook8"))); + +void __sanitizer_cov_trace_cmp1(uint8_t arg1, uint8_t arg2) + __attribute__((alias("__cmplog_ins_hook1"))); +void __sanitizer_cov_trace_cmp2(uint16_t arg1, uint16_t arg2) + __attribute__((alias("__cmplog_ins_hook2"))); +void __sanitizer_cov_trace_cmp4(uint32_t arg1, uint32_t arg2) + __attribute__((alias("__cmplog_ins_hook4"))); +void __sanitizer_cov_trace_cmp8(uint64_t arg1, uint64_t arg2) + __attribute__((alias("__cmplog_ins_hook8"))); +#endif /* defined(__APPLE__) */ + +void __sanitizer_cov_trace_switch(uint64_t val, uint64_t *cases) { + + if (unlikely(!__afl_cmp_map)) return; + + for (uint64_t i = 0; i < cases[0]; i++) { + + uintptr_t k = (uintptr_t)__builtin_return_address(0) + i; + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + __afl_cmp_map->headers[k].type = CMP_TYPE_INS; + + u32 hits = __afl_cmp_map->headers[k].hits; + __afl_cmp_map->headers[k].hits = hits + 1; + + __afl_cmp_map->headers[k].shape = 7; + + hits &= CMP_MAP_H - 1; + __afl_cmp_map->log[k][hits].v0 = val; + __afl_cmp_map->log[k][hits].v1 = cases[i + 2]; + + } + +} + +// POSIX shenanigan to see if an area is mapped. +// If it is mapped as X-only, we have a problem, so maybe we should add a check +// to avoid to call it on .text addresses +static int area_is_mapped(void *ptr, size_t len) { + + char *p = ptr; + char *page = (char *)((uintptr_t)p & ~(sysconf(_SC_PAGE_SIZE) - 1)); + + int r = msync(page, (p - page) + len, MS_ASYNC); + if (r < 0) return errno != ENOMEM; + return 1; + +} + +void __cmplog_rtn_hook(u8 *ptr1, u8 *ptr2) { + + if (unlikely(!__afl_cmp_map)) return; + + if (!area_is_mapped(ptr1, 32) || !area_is_mapped(ptr2, 32)) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + __afl_cmp_map->headers[k].type = CMP_TYPE_RTN; + + u32 hits = __afl_cmp_map->headers[k].hits; + __afl_cmp_map->headers[k].hits = hits + 1; + + __afl_cmp_map->headers[k].shape = 31; + + hits &= CMP_MAP_RTN_H - 1; + __builtin_memcpy(((struct cmpfn_operands *)__afl_cmp_map->log[k])[hits].v0, + ptr1, 32); + __builtin_memcpy(((struct cmpfn_operands *)__afl_cmp_map->log[k])[hits].v1, + ptr2, 32); + +} + |