Fix llvm-special-case-list-fuzzer regexp exception

Summary:
Original oss-fuzz report:
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=3727#c2

The minimized test case that causes this failure:
5b 5b 5b 3d 47 53 00 5b  3d 5d 5b 5d 0a     [[[=GS.[=][].

Note the string "=GS\x00". The failure happens because the code is
searching the string against an array of known collated names. "GS\x00"
is a hit, but since len takes into account an extra NUL byte, indexing
into cp->name[len] goes one byte past it's allocated memory. Fix this to
use a strlen(cp->name) comparison to account for NUL bytes in the input.

Reviewers: pcc

Reviewed By: pcc

Subscribers: hctim, kcc

Differential Revision: https://reviews.llvm.org/D39380

llvm-svn: 316786

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/unittests/Support/RegexTest.cpp b/llvm/unittests/Support/RegexTest.cpp
index 5e3ce39f005..7e44a3c0614 100644
--- a/llvm/unittests/Support/RegexTest.cpp
+++ b/llvm/unittests/Support/RegexTest.cpp
@@ -171,4 +171,12 @@ TEST_F(RegexTest, MatchInvalid) {
   EXPECT_FALSE(r1.match("X"));
 }
 
+// https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=3727
+TEST_F(RegexTest, OssFuzz3727Regression) {
+  // Wrap in a StringRef so the NUL byte doesn't terminate the string
+  Regex r(StringRef("[[[=GS\x00[=][", 10));
+  std::string Error;
+  EXPECT_FALSE(r.isValid(Error));
+}
+
 }