Check special-case-list regex before insertion.

Summary:
Checks that the supplied regex to SpecialCaseList::Matcher::insert(..) is non-empty.

Reported by OSS-fuzz: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=3688

Verified that this fixes the provided assertion failure (built with {asan, fuzzer}):
```
mitchp@mitchp2:~/llvm-build/git-fuzz$ ninja llvm-special-case-list-fuzzer[12/12] Linking CXX executable bin/llvm-special-case-list-fuzzer
mitchp@mitchp2:~/llvm-build/git-fuzz$ bin/llvm-special-case-list-fuzzer ~/Downloads/clusterfuzz-testcase-6748633157337088
INFO: Seed: 1697404507
INFO: Loaded 1 modules   (18581 inline 8-bit counters): 18581 [0x9e9f60, 0x9ee7f5),
INFO: Loaded 1 PC tables (18581 PCs): 18581 [0x9ee7f8,0xa37148),
bin/llvm-special-case-list-fuzzer: Running 1 inputs 1 time(s) each.
Running: /usr/local/google/home/mitchp/Downloads/clusterfuzz-testcase-6748633157337088
Executed /usr/local/google/home/mitchp/Downloads/clusterfuzz-testcase-6748633157337088 in 0 ms
***
*** NOTE: fuzzing was not performed, you have only
***       executed the target code on a fixed set of inputs.
***
mitchp@mitchp2:~/llvm-build/git-fuzz$

```

Reviewers: kcc, vsk

Reviewed By: vsk

Subscribers: vsk, llvm-commits, vlad.tsyrklevich

Differential Revision: https://reviews.llvm.org/D39212

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316537 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Support/SpecialCaseList.cpp b/lib/Support/SpecialCaseList.cpp
index 25222b0..a659a2a 100644 (file)
--- a/lib/Support/SpecialCaseList.cpp
+++ b/lib/Support/SpecialCaseList.cpp
@@ -28,6 +28,11 @@ namespace llvm {
 
 bool SpecialCaseList::Matcher::insert(std::string Regexp,
                                       std::string &REError) {
+  if (Regexp.empty()) {
+    REError = "Supplied regexp was blank";
+    return false;
+  }
+
   if (Regex::isLiteralERE(Regexp)) {
     Strings.insert(Regexp);
     return true;

diff --git a/unittests/Support/SpecialCaseListTest.cpp b/unittests/Support/SpecialCaseListTest.cpp
index 0aa8452..9e1223b 100644 (file)
--- a/unittests/Support/SpecialCaseListTest.cpp
+++ b/unittests/Support/SpecialCaseListTest.cpp
@@ -67,6 +67,9 @@ TEST_F(SpecialCaseListTest, SectionRegexErrorHandling) {
 
   EXPECT_EQ(makeSpecialCaseList("[[]", Error), nullptr);
   EXPECT_TRUE(((StringRef)Error).startswith("malformed regex for section [: "));
+
+  EXPECT_EQ(makeSpecialCaseList("src:=", Error), nullptr);
+  EXPECT_TRUE(((StringRef)Error).endswith("Supplied regexp was blank"));
 }
 
 TEST_F(SpecialCaseListTest, Section) {