[Bitcode] Diagnose errors instead of asserting from bad input

Eventually we can make some of these pass the error along to the caller.

Reports a fatal error if:
We find an invalid abbrev record
We try to get an invalid abbrev number
We can't fill the current word due to an EOF

Fixed an invalid bitcode test to check for output with FileCheck

Bugs found with afl-fuzz

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@226986 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/Bitcode/BitstreamReader.h b/include/llvm/Bitcode/BitstreamReader.h
index 865a3e6..bc3e48a 100644 (file)
--- a/include/llvm/Bitcode/BitstreamReader.h
+++ b/include/llvm/Bitcode/BitstreamReader.h
@@ -315,7 +315,8 @@ public:
   }
 
   void fillCurWord() {
-    assert(Size == 0 || NextChar < (unsigned)Size);
+    if (Size != 0 && NextChar >= (unsigned)Size)
+      report_fatal_error("Unexpected end of file");
 
     // Read the next word from the stream.
     uint8_t Array[sizeof(word_t)] = {0};
@@ -490,11 +491,11 @@ private:
   //===--------------------------------------------------------------------===//
 
 public:
-
   /// Return the abbreviation for the specified AbbrevId.
   const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
-    unsigned AbbrevNo = AbbrevID-bitc::FIRST_APPLICATION_ABBREV;
-    assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!");
+    unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
+    if (AbbrevNo >= CurAbbrevs.size())
+      report_fatal_error("Invalid abbrev number");
     return CurAbbrevs[AbbrevNo].get();
   }
 

diff --git a/lib/Bitcode/Reader/BitstreamReader.cpp b/lib/Bitcode/Reader/BitstreamReader.cpp
index 5e3232e..9d5fab9 100644 (file)
--- a/lib/Bitcode/Reader/BitstreamReader.cpp
+++ b/lib/Bitcode/Reader/BitstreamReader.cpp
@@ -170,8 +170,12 @@ unsigned BitstreamCursor::readRecord(unsigned AbbrevID,
   unsigned Code;
   if (CodeOp.isLiteral())
     Code = CodeOp.getLiteralValue();
-  else
+  else {
+    if (CodeOp.getEncoding() == BitCodeAbbrevOp::Array ||
+        CodeOp.getEncoding() == BitCodeAbbrevOp::Blob)
+      report_fatal_error("Abbreviation starts with an Array or a Blob");
     Code = readAbbreviatedField(*this, CodeOp);
+  }
 
   for (unsigned i = 1, e = Abbv->getNumOperandInfos(); i != e; ++i) {
     const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);

diff --git a/test/Bitcode/Inputs/invalid-abbrev.bc b/test/Bitcode/Inputs/invalid-abbrev.bc
new file mode 100644 (file)
index 0000000..4e8f394
Binary files /dev/null and b/test/Bitcode/Inputs/invalid-abbrev.bc differ

diff --git a/test/Bitcode/Inputs/invalid-bad-abbrev-number.bc b/test/Bitcode/Inputs/invalid-bad-abbrev-number.bc
new file mode 100644 (file)
index 0000000..e4e1fb3
--- /dev/null
+++ b/test/Bitcode/Inputs/invalid-bad-abbrev-number.bc
@@ -0,0 +1 @@
+BCÀÞ!0000000\ 6000
\ No newline at end of file

diff --git a/test/Bitcode/Inputs/invalid-unexpected-eof.bc b/test/Bitcode/Inputs/invalid-unexpected-eof.bc
new file mode 100644 (file)
index 0000000..a487393
--- /dev/null
+++ b/test/Bitcode/Inputs/invalid-unexpected-eof.bc
@@ -0,0 +1 @@
+BCÀÞ!\f000000\v00000000000000
\ No newline at end of file

diff --git a/test/Bitcode/invalid.test b/test/Bitcode/invalid.test
index 5f88da4..19ef326 100644 (file)
--- a/test/Bitcode/invalid.test
+++ b/test/Bitcode/invalid.test
@@ -1 +1,13 @@
-RUN: not llvm-dis -disable-output %p/Inputs/invalid-pr20485.bc
+RUN: not llvm-dis -disable-output %p/Inputs/invalid-pr20485.bc 2>&1 | \
+RUN:   FileCheck --check-prefix=INVALID-ENCODING %s
+RUN: not llvm-dis -disable-output %p/Inputs/invalid-abbrev.bc 2>&1 | \
+RUN:   FileCheck --check-prefix=BAD-ABBREV %s
+RUN: not llvm-dis -disable-output %p/Inputs/invalid-unexpected-eof.bc 2>&1 | \
+RUN:   FileCheck --check-prefix=UNEXPECTED-EOF %s
+RUN: not llvm-dis -disable-output %p/Inputs/invalid-bad-abbrev-number.bc 2>&1 | \
+RUN:   FileCheck --check-prefix=BAD-ABBREV-NUMBER %s
+
+INVALID-ENCODING: Invalid encoding
+BAD-ABBREV: Abbreviation starts with an Array or a Blob
+UNEXPECTED-EOF: Unexpected end of file
+BAD-ABBREV-NUMBER: Invalid abbrev number