added AFL_IGNORE_UNKNOWN_ENVS

docs/Changelog.md

@@ -61,7 +61,8 @@ sending a mail to <afl-users+subscribe@googlegroups.com>.
     - Added a new example harness to compare python, c, and rust bindings
   - afl-cmin and afl-showmap now support the -f option
   - changed default: no memory limit for afl-cmin and afl-cmin.bash
-  - warn on any _AFL and __AFL env vars
+  - warn on any _AFL and __AFL env vars.
+  - set AFL_IGNORE_UNKNOWN_ENVS to not warn on unknown AFL_... env vars.
   - added dummy Makefile to instrumentation/
   - Updated utils/afl_frida to be 5% faster, 7% on x86_x64
   - Added AFL_KILL_SIGNAL env variable (thanks @v-p-b)

docs/env_variables.md

@@ -5,6 +5,10 @@
   users or for some types of custom fuzzing setups. See [README.md](README.md) for the general
   instruction manual.
 
+  Note that most tools will warn on any unknown AFL environment variables.
+  This is for warning on typos that can happen. If you want to disable this
+  check then set the `AFL_IGNORE_UNKNOWN_ENVS` environment variable.
+
 ## 1) Settings for all compilers
 
 Starting with afl++ 3.0 there is only one compiler: afl-cc
@@ -18,7 +22,6 @@ To select the different instrumentation modes this can be done by
 `MODE` can be one of `LTO` (afl-clang-lto*), `LLVM` (afl-clang-fast*), `GCC_PLUGIN`
 (afl-g*-fast) or `GCC` (afl-gcc/afl-g++).
 
-
 Because (with the exception of the --afl-MODE command line option) the
 compile-time tools do not accept afl specific command-line options, they
 make fairly broad use of environmental variables instead:

include/envs.h

@@ -61,6 +61,7 @@ static char *afl_environment_variables[] = {
     "AFL_FORKSRV_INIT_TMOUT",
     "AFL_HARDEN",
     "AFL_I_DONT_CARE_ABOUT_MISSING_CRASHES",
+    "AFL_IGNORE_UNKNOWN_ENVS",
     "AFL_IMPORT_FIRST",
     "AFL_INST_LIBS",
     "AFL_INST_RATIO",

src/afl-cc.c

@@ -1587,6 +1587,7 @@ int main(int argc, char **argv, char **envp) {
           "libtokencap.so)\n"
           "  AFL_PATH: path to instrumenting pass and runtime  "
           "(afl-compiler-rt.*o)\n"
+          "  AFL_IGNORE_UNKNOWN_ENVS: don't warn on unknown env vars\n"
           "  AFL_INST_RATIO: percentage of branches to instrument\n"
           "  AFL_QUIET: suppress verbose output\n"
           "  AFL_HARDEN: adds code hardening to catch memory bugs\n"

src/afl-common.c

@@ -523,7 +523,7 @@ void check_environment_vars(char **envp) {
   if (be_quiet) { return; }
 
   int   index = 0, issue_detected = 0;
-  char *env, *val;
+  char *env, *val, *ignore = getenv("AFL_IGNORE_UNKNOWN_ENVS");
   while ((env = envp[index++]) != NULL) {
 
     if (strncmp(env, "ALF_", 4) == 0 || strncmp(env, "_ALF", 4) == 0 ||
@@ -582,7 +582,7 @@ void check_environment_vars(char **envp) {
 
       }
 
-      if (match == 0) {
+      if (match == 0 && !ignore) {
 
         WARNF("Mistyped AFL environment variable: %s", env);
         issue_detected = 1;

src/afl-fuzz.c

@@ -198,6 +198,7 @@ static void usage(u8 *argv0, int more_help) {
       "AFL_FORKSRV_INIT_TMOUT: time spent waiting for forkserver during startup (in milliseconds)\n"
       "AFL_HANG_TMOUT: override timeout value (in milliseconds)\n"
       "AFL_I_DONT_CARE_ABOUT_MISSING_CRASHES: don't warn about core dump handlers\n"
+      "AFL_IGNORE_UNKNOWN_ENVS: don't warn on unknown env vars\n"
       "AFL_IMPORT_FIRST: sync and import test cases from other fuzzer instances first\n"
       "AFL_KILL_SIGNAL: Signal ID delivered to child processes on timeout, etc. (default: SIGKILL)\n"
       "AFL_MAP_SIZE: the shared memory size for that target. must be >= the size\n"

src/afl-showmap.c

@@ -1168,8 +1168,9 @@ int main(int argc, char **argv_orig, char **envp) {
 
     }
 
-    stdin_file = at_file ? strdup(at_file) : (char *)
-        alloc_printf("%s/.afl-showmap-temp-%u", use_dir, (u32)getpid());
+    stdin_file = at_file ? strdup(at_file)
+                         : (char *)alloc_printf("%s/.afl-showmap-temp-%u",
+                                                use_dir, (u32)getpid());
     unlink(stdin_file);
     atexit(at_exit_handler);
     fsrv->out_file = stdin_file;