Index: third_party/afl/src/llvm_mode/afl-llvm-rt.o.c |
diff --git a/third_party/afl/src/llvm_mode/afl-llvm-rt.o.c b/third_party/afl/src/llvm_mode/afl-llvm-rt.o.c |
new file mode 100644 |
index 0000000000000000000000000000000000000000..8f3f303d54881020d1abe984fa3bb6ab0809402e |
--- /dev/null |
+++ b/third_party/afl/src/llvm_mode/afl-llvm-rt.o.c |
@@ -0,0 +1,283 @@ |
+/* |
+ american fuzzy lop - LLVM instrumentation bootstrap |
+ --------------------------------------------------- |
+ |
+ Written by Laszlo Szekeres <lszekeres@google.com> and |
+ Michal Zalewski <lcamtuf@google.com> |
+ |
+ LLVM integration design comes from Laszlo Szekeres. |
+ |
+ Copyright 2015, 2016 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 code is the rewrite of afl-as.h's main_payload. |
+ |
+*/ |
+ |
+#include "../config.h" |
+#include "../types.h" |
+ |
+#include <stdio.h> |
+#include <stdlib.h> |
+#include <signal.h> |
+#include <unistd.h> |
+#include <assert.h> |
+ |
+#include <sys/mman.h> |
+#include <sys/shm.h> |
+#include <sys/wait.h> |
+#include <sys/types.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. */ |
+ |
+u8 __afl_area_initial[MAP_SIZE]; |
+u8* __afl_area_ptr = __afl_area_initial; |
+ |
+__thread u32 __afl_prev_loc; |
+ |
+ |
+/* 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) { |
+ |
+ u32 shm_id = atoi(id_str); |
+ |
+ __afl_area_ptr = shmat(shm_id, NULL, 0); |
+ |
+ /* 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; |
+ |
+ } |
+ |
+} |
+ |
+ |
+/* Fork server logic. */ |
+ |
+static void __afl_start_forkserver(void) { |
+ |
+ static u8 tmp[4]; |
+ s32 child_pid; |
+ |
+ u8 child_stopped = 0; |
+ |
+ /* 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) { |
+ |
+ 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) { |
+ |
+ cycle_cnt = max_cnt; |
+ first_pass = 0; |
+ return 1; |
+ |
+ } |
+ |
+ if (is_persistent && --cycle_cnt) { |
+ |
+ raise(SIGSTOP); |
+ return 1; |
+ |
+ } else 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; |
+ |
+ } |
+ |
+} |
+ |
+ |
+static void __afl_trace_pc_init(void); |
+ |
+ |
+/* Proper initialization routine. */ |
+ |
+__attribute__((constructor(0))) void __afl_auto_init(void) { |
+ |
+ is_persistent = !!getenv(PERSIST_ENV_VAR); |
+ |
+ __afl_trace_pc_init(); |
+ |
+ if (getenv(DEFER_ENV_VAR)) return; |
+ |
+ __afl_manual_init(); |
+ |
+} |
+ |
+ |
+/* The following stuff deals with support for -fsanitize-coverage=bb,trace-pc. |
+ It remains non-operational in the traditional, plugin-backed LLVM mode. |
+ For more info about 'trace-pc', see README.llvm. |
+ |
+ The first function (__sanitizer_cov_trace_pc) is called back on every |
+ basic block. Since LLVM is not giving us any stable IDs for the blocks, |
+ we use 12 least significant bits of the return address (which should be |
+ stable even with ASLR; more significant bits may vary across runs). |
+ |
+ Since MAP_SIZE is usually larger than 12 bits, we "pad" it by combining |
+ left-shifted __afl_prev_loc. This gives us a theoretical maximum of 24 |
+ bits, although instruction alignment likely reduces this somewhat. */ |
+ |
+ |
+static u32 inst_ratio_scaled = MIN(4096, MAP_SIZE); |
+ |
+void __sanitizer_cov_trace_pc(void) { |
+ |
+ u32 cur = ((u32)__builtin_return_address(0)) & MIN(4095, MAP_SIZE - 1); |
+ |
+ if (cur > inst_ratio_scaled) return; |
+ |
+ __afl_area_ptr[cur ^ __afl_prev_loc]++; |
+ |
+#if MAP_SIZE_POW2 > 12 |
+ __afl_prev_loc = cur << (MAP_SIZE_POW2 - 12); |
+#else |
+ __afl_prev_loc = cur >> 1; |
+#endif /* ^MAP_SIZE_POW2 > 12 */ |
+ |
+} |
+ |
+ |
+/* Init callback. Unfortunately, LLVM does not support compile-time |
+ instrumentation density scaling, at least not just yet. This means |
+ taking some performance hit by checking inst_ratio_scaled at runtime. */ |
+ |
+static void __afl_trace_pc_init(void) { |
+ |
+ u8* x = getenv("AFL_INST_RATIO"); |
+ |
+ if (!x) return; |
+ |
+ inst_ratio_scaled = atoi(x); |
+ |
+ if (!inst_ratio_scaled || inst_ratio_scaled > 100) { |
+ fprintf(stderr, "[-] ERROR: Invalid AFL_INST_RATIO (must be 1-100).\n"); |
+ abort(); |
+ } |
+ |
+ inst_ratio_scaled = inst_ratio_scaled * MIN(4096, MAP_SIZE) / 100; |
+ |
+} |
+ |
+ |
+/* Work around a short-lived bug in LLVM with -fsanitize-coverage=trace-pc. */ |
+ |
+void __sanitizer_cov_module_init(void) __attribute__((weak)); |
+void __sanitizer_cov_module_init(void) { } |
+ |