1 files changed, 58 insertions, 0 deletions
diff --git a/src/c-ares/test/ares-fuzz.c b/src/c-ares/test/ares-fuzz.c
new file mode 100644
index 00000000..92761286
--- /dev/null
+++ b/src/c-ares/test/ares-fuzz.c
@@ -0,0 +1,58 @@
+/*
+ * General driver to allow command-line fuzzer (i.e. afl) to
+ * exercise the libFuzzer entrypoint.
+ */
+
+#include <sys/types.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define kMaxAflInputSize (1 << 20)
+static unsigned char afl_buffer[kMaxAflInputSize];
+
+#ifdef __AFL_LOOP
+/* If we are built with afl-clang-fast, use persistent mode */
+#define KEEP_FUZZING(count)  __AFL_LOOP(1000)
+#else
+/* If we are built with afl-clang, execute each input once */
+#define KEEP_FUZZING(count) ((count) < 1)
+#endif
+
+/* In ares-test-fuzz.c: */
+int LLVMFuzzerTestOneInput(const unsigned char *data, unsigned long size);
+
+static void ProcessFile(int fd) {
+  ssize_t count = read(fd, afl_buffer, kMaxAflInputSize);
+  /*
+   * Make a copy of the data so that it's not part of a larger
+   * buffer (where buffer overflows would go unnoticed).
+   */
+  unsigned char *copied_data = (unsigned char *)malloc(count);
+  LLVMFuzzerTestOneInput(copied_data, count);
+  free(copied_data);
+}
+
+int main(int argc, char *argv[]) {
+  if (argc == 1) {
+    int count = 0;
+    while (KEEP_FUZZING(count)) {
+      ProcessFile(fileno(stdin));
+      count++;
+    }
+  } else {
+    int ii;
+    for (ii = 1; ii < argc; ++ii) {
+      int fd = open(argv[ii], O_RDONLY);
+      if (fd < 0) {
+        fprintf(stderr, "Failed to open '%s'\n", argv[ii]);
+        continue;
+      }
+      ProcessFile(fd);
+      close(fd);
+    }
+  }
+  return 0;
+}