ensure afl-cc only allows available compiler modes

src/afl-cc.c

@@ -167,7 +167,7 @@ typedef struct aflcc_state {
 
   u8 cmplog_mode;
 
-  u8 have_instr_env, have_gcc, have_llvm, have_gcc_plugin, have_lto,
+  u8 have_instr_env, have_gcc, have_clang, have_llvm, have_gcc_plugin, have_lto,
       have_optimized_pcguard, have_instr_list;
 
   u8 fortify_set, asan_set, x_set, bit_mode, preprocessor_only, have_unroll,
@@ -504,13 +504,20 @@ void find_built_deps(aflcc_state_t *aflcc) {
 
   char *ptr = NULL;
 
+#if defined(__x86_64__)
   if ((ptr = find_object(aflcc, "as")) != NULL) {
 
+  #ifndef __APPLE__
+    // on OSX clang masquerades as GCC
     aflcc->have_gcc = 1;
+  #endif
+    aflcc->have_clang = 1;
     ck_free(ptr);
 
   }
 
+#endif
+
   if ((ptr = find_object(aflcc, "SanitizerCoveragePCGUARD.so")) != NULL) {
 
     aflcc->have_optimized_pcguard = 1;
@@ -604,12 +611,18 @@ void compiler_mode_by_callname(aflcc_state_t *aflcc) {
 
     aflcc->compiler_mode = GCC_PLUGIN;
 
+#if defined(__x86_64__)
+
   } else if (strncmp(aflcc->callname, "afl-gcc", 7) == 0 ||
 
              strncmp(aflcc->callname, "afl-g++", 7) == 0) {
 
     aflcc->compiler_mode = GCC;
 
+#endif
+
+#if defined(__x86_64__)
+
   } else if (strcmp(aflcc->callname, "afl-clang") == 0 ||
 
              strcmp(aflcc->callname, "afl-clang++") == 0) {
@@ -618,6 +631,8 @@ void compiler_mode_by_callname(aflcc_state_t *aflcc) {
 
   }
 
+#endif
+
 }
 
 void compiler_mode_by_environ(aflcc_state_t *aflcc) {
@@ -660,14 +675,22 @@ void compiler_mode_by_environ(aflcc_state_t *aflcc) {
 
       aflcc->compiler_mode = GCC_PLUGIN;
 
+#if defined(__x86_64__)
+
     } else if (strcasecmp(ptr, "GCC") == 0) {
 
       aflcc->compiler_mode = GCC;
 
+#endif
+
+#if defined(__x86_64__)
+
     } else if (strcasecmp(ptr, "CLANG") == 0) {
 
       aflcc->compiler_mode = CLANG;
 
+#endif
+
     } else
 
       FATAL("Unknown AFL_CC_COMPILER mode: %s\n", ptr);
@@ -751,14 +774,22 @@ void compiler_mode_by_cmdline(aflcc_state_t *aflcc, int argc, char **argv) {
 
         aflcc->compiler_mode = GCC_PLUGIN;
 
+#if defined(__x86_64__)
+
       } else if (strcasecmp(ptr, "GCC") == 0) {
 
         aflcc->compiler_mode = GCC;
 
+#endif
+
+#if defined(__x86_64__)
+
       } else if (strncasecmp(ptr, "CLANG", 5) == 0) {
 
         aflcc->compiler_mode = CLANG;
 
+#endif
+
       } else
 
         FATAL("Unknown --afl-... compiler mode: %s\n", argv[i]);
@@ -929,6 +960,7 @@ static void instrument_mode_new_environ(aflcc_state_t *aflcc) {
 
     }
 
+#if defined(__x86_64__)
     if (strcasecmp(ptr2, "gcc") == 0) {
 
       if (!aflcc->instrument_mode || aflcc->instrument_mode == INSTRUMENT_GCC)
@@ -943,6 +975,9 @@ static void instrument_mode_new_environ(aflcc_state_t *aflcc) {
 
     }
 
+#endif
+
+#if defined(__x86_64__)
     if (strcasecmp(ptr2, "clang") == 0) {
 
       if (!aflcc->instrument_mode || aflcc->instrument_mode == INSTRUMENT_CLANG)
@@ -957,6 +992,8 @@ static void instrument_mode_new_environ(aflcc_state_t *aflcc) {
 
     }
 
+#endif
+
     if (strncasecmp(ptr2, "ctx-", strlen("ctx-")) == 0 ||
         strncasecmp(ptr2, "kctx-", strlen("c-ctx-")) == 0 ||
         strncasecmp(ptr2, "k-ctx-", strlen("k-ctx-")) == 0) {
@@ -1130,12 +1167,9 @@ void mode_final_checkout(aflcc_state_t *aflcc, int argc, char **argv) {
     else if (aflcc->have_gcc_plugin)
       aflcc->compiler_mode = GCC_PLUGIN;
     else if (aflcc->have_gcc)
-#ifdef __APPLE__
-      // on OSX clang masquerades as GCC
-      aflcc->compiler_mode = CLANG;
-#else
       aflcc->compiler_mode = GCC;
-#endif
+    else if (aflcc->have_clang)
+      aflcc->compiler_mode = CLANG;
     else if (aflcc->have_lto)
       aflcc->compiler_mode = LTO;
     else
@@ -1143,6 +1177,38 @@ void mode_final_checkout(aflcc_state_t *aflcc, int argc, char **argv) {
 
   }
 
+  switch (aflcc->compiler_mode) {
+
+    case GCC:
+      if (!aflcc->have_gcc) FATAL("afl-gcc not available on your platform!");
+      break;
+    case CLANG:
+      if (!aflcc->have_clang)
+        FATAL("afl-clang not available on your platform!");
+      break;
+    case LLVM:
+      if (!aflcc->have_llvm)
+        FATAL(
+            "LLVM mode is not available, please install LLVM 13+ and recompile "
+            "AFL++");
+      break;
+    case GCC_PLUGIN:
+      if (!aflcc->have_gcc_plugin)
+        FATAL(
+            "GCC_PLUGIN mode is not available, install gcc plugin support and "
+            "recompile AFL++");
+      break;
+    case LTO:
+      if (!aflcc->have_lto)
+        FATAL(
+            "LTO mode is not available, please install LLVM 13+ and lld of the "
+            "same version and recompile AFL++");
+      break;
+    default:
+      FATAL("no compiler mode available");
+
+  }
+
   if (aflcc->compiler_mode == GCC) { aflcc->instrument_mode = INSTRUMENT_GCC; }
 
   if (aflcc->compiler_mode == CLANG) {
@@ -1618,8 +1684,6 @@ static u8 fsanitize_fuzzer_comma(char *string) {
   } while (!ende);
 
   strcpy(string, new);
-  // fprintf(stderr, "string: %s\n", string);
-  // fprintf(stderr, "new: %s\n", new);
 
   ck_free(tmp);
   ck_free(new);
@@ -2503,7 +2567,11 @@ static void maybe_usage(aflcc_state_t *aflcc, int argc, char **argv) {
         aflcc->compiler_mode == LTO ? " [SELECTED]" : "",
         aflcc->have_gcc_plugin ? "AVAILABLE" : "unavailable!",
         aflcc->compiler_mode == GCC_PLUGIN ? " [SELECTED]" : "",
-        aflcc->have_gcc ? "AVAILABLE" : "unavailable!",
+        aflcc->have_gcc && aflcc->have_clang
+            ? "AVAILABLE"
+            : (aflcc->have_gcc
+                   ? "GCC ONLY "
+                   : (aflcc->have_clang ? "CLANG ONLY" : "unavailable!")),
         (aflcc->compiler_mode == GCC || aflcc->compiler_mode == CLANG)
             ? " [SELECTED]"
             : "");