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Diffstat (limited to 'llvm_mode/afl-llvm-cmplog-rt.o.c')
-rw-r--r-- | llvm_mode/afl-llvm-cmplog-rt.o.c | 412 |
1 files changed, 412 insertions, 0 deletions
diff --git a/llvm_mode/afl-llvm-cmplog-rt.o.c b/llvm_mode/afl-llvm-cmplog-rt.o.c new file mode 100644 index 00000000..7a513c0d --- /dev/null +++ b/llvm_mode/afl-llvm-cmplog-rt.o.c @@ -0,0 +1,412 @@ +/* + american fuzzy lop++ - LLVM instrumentation bootstrap + --------------------------------------------------- + + Written by Laszlo Szekeres <lszekeres@google.com> and + Michal Zalewski + + LLVM integration design comes from Laszlo Szekeres. + + 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 + + This code is the rewrite of afl-as.h's main_payload. + +*/ + +#ifdef __ANDROID__ +#include "android-ashmem.h" +#endif +#include "config.h" +#include "types.h" +#include "cmplog.h" + +#include <stdio.h> +#include <stdlib.h> +#include <signal.h> +#include <unistd.h> +#include <string.h> +#include <assert.h> +#include <stdint.h> + +#include <sys/mman.h> +#include <sys/shm.h> +#include <sys/wait.h> +#include <sys/types.h> + +/* 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. */ + +#ifdef USE_TRACE_PC +#define CONST_PRIO 5 +#else +#define CONST_PRIO 0 +#endif /* ^USE_TRACE_PC */ + +#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. */ + +// In CmpLog, the only usage of __afl_area_ptr is to report errors +u8* __afl_area_ptr; + +struct cmp_map* __afl_cmp_map; +__thread u32 __afl_cmp_counter; + +/* Running in persistent mode? */ + +static u8 is_persistent; + +/* SHM setup. */ + +static void __afl_map_shm(void) { + + u8* id_str = getenv(SHM_ENV_VAR); + + /* 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 (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) { + + printf("shm_open() failed\n"); + exit(1); + + } + + /* map the shared memory segment to the address space of the process */ + shm_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0); + if (shm_base == MAP_FAILED) { + + close(shm_fd); + shm_fd = -1; + + printf("mmap() failed\n"); + exit(2); + + } + + __afl_area_ptr = shm_base; +#else + u32 shm_id = atoi(id_str); + + __afl_area_ptr = shmat(shm_id, NULL, 0); +#endif + + /* Whooooops. */ + + if (__afl_area_ptr == (void*)-1) _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; + + } + + id_str = getenv(CMPLOG_SHM_ENV_VAR); + + if (id_str) { + + u32 shm_id = atoi(id_str); + + __afl_cmp_map = shmat(shm_id, NULL, 0); + + if (__afl_cmp_map == (void*)-1) _exit(1); + + } + +} + +/* Fork server logic. */ + +static void __afl_start_forkserver(void) { + + static u8 tmp[4]; + s32 child_pid; + + 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. */ + + if (write(FORKSRV_FD + 1, tmp, 4) != 4) return; + + while (1) { + + u32 was_killed; + int status; + + /* Wait for parent by reading from the pipe. Abort if read fails. */ + + if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1); + + /* 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) { + + 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. */ + +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, MAP_SIZE); + __afl_area_ptr[0] = 1; + + } + + cycle_cnt = max_cnt; + first_pass = 0; + return 1; + + } + + if (is_persistent) { + + if (--cycle_cnt) { + + raise(SIGSTOP); + + __afl_area_ptr[0] = 1; + + 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 (!init_done) { + + __afl_map_shm(); + __afl_start_forkserver(); + init_done = 1; + + } + +} + +/* Proper initialization routine. */ + +__attribute__((constructor(CONST_PRIO))) void __afl_auto_init(void) { + + is_persistent = !!getenv(PERSIST_ENV_VAR); + + if (getenv(DEFER_ENV_VAR)) return; + + __afl_manual_init(); + +} + +///// CmpLog instrumentation + +void __sanitizer_cov_trace_cmp1(uint8_t Arg1, uint8_t Arg2) { + + return; + +} + +void __sanitizer_cov_trace_cmp2(uint16_t Arg1, uint16_t Arg2) { + + if (!__afl_cmp_map) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + 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 = 1; + //__afl_cmp_map->headers[k].type = CMP_TYPE_INS; + + hits &= CMP_MAP_H - 1; + __afl_cmp_map->log[k][hits].v0 = Arg1; + __afl_cmp_map->log[k][hits].v1 = Arg2; + +} + +void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2) { + + if (!__afl_cmp_map) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + 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 __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2) { + + if (!__afl_cmp_map) return; + + uintptr_t k = (uintptr_t)__builtin_return_address(0); + k = (k >> 4) ^ (k << 8); + k &= CMP_MAP_W - 1; + + 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 = __sanitizer_cov_trace_cmp1 +#pragma weak __sanitizer_cov_trace_const_cmp2 = __sanitizer_cov_trace_cmp2 +#pragma weak __sanitizer_cov_trace_const_cmp4 = __sanitizer_cov_trace_cmp4 +#pragma weak __sanitizer_cov_trace_const_cmp8 = __sanitizer_cov_trace_cmp8 +#else +void __sanitizer_cov_trace_const_cmp1(uint8_t Arg1, uint8_t Arg2) + __attribute__((alias("__sanitizer_cov_trace_cmp1"))); +void __sanitizer_cov_trace_const_cmp2(uint16_t Arg1, uint16_t Arg2) + __attribute__((alias("__sanitizer_cov_trace_cmp2"))); +void __sanitizer_cov_trace_const_cmp4(uint32_t Arg1, uint32_t Arg2) + __attribute__((alias("__sanitizer_cov_trace_cmp4"))); +void __sanitizer_cov_trace_const_cmp8(uint64_t Arg1, uint64_t Arg2) + __attribute__((alias("__sanitizer_cov_trace_cmp8"))); +#endif /* defined(__APPLE__) */ + +void __sanitizer_cov_trace_switch(uint64_t Val, uint64_t* Cases) { + + 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; + + 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]; + + } + +} + |