upstream commit

add a fuzz_matches_original() function to the fuzzer to
 detect fuzz cases that are identical to the original data. Hacky
 implementation, but very useful when you need the fuzz to be different, e.g.
 when verifying signature

2 files changed, 18 insertions, 2 deletions

diff --git a/regress/unittests/test_helper/fuzz.c b/regress/unittests/test_helper/fuzz.c
index 93cff6969..06fb247ef 100644
--- a/regress/unittests/test_helper/fuzz.c
+++ b/regress/unittests/test_helper/fuzz.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: fuzz.c,v 1.6 2015/01/18 19:50:55 djm Exp $    */
+/*      $OpenBSD: fuzz.c,v 1.7 2015/01/18 19:52:44 djm Exp $    */
 /*
  * Copyright (c) 2011 Damien Miller <djm@mindrot.org>
  *
@@ -378,6 +378,14 @@ fuzz_next(struct fuzz *fuzz)
 }
 
 int
+fuzz_matches_original(struct fuzz *fuzz)
+{
+        if (fuzz_len(fuzz) != fuzz->slen)
+                return 0;
+        return memcmp(fuzz_ptr(fuzz), fuzz->seed, fuzz->slen) == 0;
+}
+
+int
 fuzz_done(struct fuzz *fuzz)
 {
         FUZZ_DBG(("fuzz = %p, strategies = 0x%lx", fuzz,
diff --git a/regress/unittests/test_helper/test_helper.h b/regress/unittests/test_helper/test_helper.h
index 48c888ac3..1d9c66986 100644
--- a/regress/unittests/test_helper/test_helper.h
+++ b/regress/unittests/test_helper/test_helper.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: test_helper.h,v 1.5 2015/01/15 07:36:28 djm Exp $     */
+/*      $OpenBSD: test_helper.h,v 1.6 2015/01/18 19:52:44 djm Exp $     */
 /*
  * Copyright (c) 2011 Damien Miller <djm@mindrot.org>
  *
@@ -283,6 +283,13 @@ void fuzz_cleanup(struct fuzz *fuzz);
 /* Prepare the next fuzz case in the series */
 void fuzz_next(struct fuzz *fuzz);
 
+/*
+ * Check whether this fuzz case is identical to the original
+ * This is slow, but useful if the caller needs to ensure that all tests
+ * generated change the input (e.g. when fuzzing signatures).
+ */
+int fuzz_matches_original(struct fuzz *fuzz);
+
 /* Determine whether the current fuzz sequence is exhausted (nonzero = yes) */
 int fuzz_done(struct fuzz *fuzz);
 
@@ -292,4 +299,5 @@ u_char *fuzz_ptr(struct fuzz *fuzz);
 
 /* Dump the current fuzz case to stderr */
 void fuzz_dump(struct fuzz *fuzz);
+
 #endif /* _TEST_HELPER_H */