commit 0b8763eae21d5d8952d401cf8e4dd7e4fe9b401d
author Karl Schimpf <kschimpf@google.com> Tue Sep 22 10:41:11 2015 -0700
committer Karl Schimpf <kschimpf@google.com> Tue Sep 22 10:41:11 2015 -0700
tree 4353308d043b722127fea83421df0137ba02778d
parent 55f2e6d308e8a05dad706a6dd9c18a8f103e63c8

Fix pnacl-sz to not accept files containing multiple modules.

Previous code checked, after the fact, that there weren't multiple
modules in the block. However, the code for TopLevelParser assumes
that there is only on module block, allowing it to more efficiently
test internal state. To fix the problem, modified
TopLevelParser::ParseBlock to fail, and not attempt to parse the second
block if the file contains more than one block.

BUG= https://code.google.com/p/nativeclient/issues/detail?id=4260
R=stichnot@chromium.org

Review URL: https://codereview.chromium.org/1362643002 .

src/PNaClTranslator.cpp

diff --git a/src/PNaClTranslator.cpp b/src/PNaClTranslator.cpp
index 449332a..3380c9e 100644
--- a/src/PNaClTranslator.cpp
+++ b/src/PNaClTranslator.cpp
@@ -338,6 +338,9 @@
       return getGlobalVariableByID(Index - NumFunctionIds);
   }
 
+  /// Returns true if a module block has been parsed.
+  bool parsedModuleBlock() const { return ParsedModuleBlock; }
+
   /// Returns the list of parsed global variable declarations. Releases
   /// ownership of the current list of global variables. Note: only returns
   /// non-null pointer on first call. All successive calls return a null
@@ -374,6 +377,8 @@
   Ice::FuncSigType UndefinedFuncSigType;
   // The block parser currently being applied. Used for error reporting.
   BlockParserBaseClass *BlockParser = nullptr;
+  // Defines if a module block has already been parsed.
+  bool ParsedModuleBlock = false;
 
   bool ParseBlock(unsigned BlockID) override;
 
@@ -3220,8 +3225,12 @@
 
 bool TopLevelParser::ParseBlock(unsigned BlockID) {
   if (BlockID == naclbitc::MODULE_BLOCK_ID) {
+    if (ParsedModuleBlock)
+      Fatal("Input can't contain more than one module");
     ModuleParser Parser(BlockID, this);
-    return Parser.ParseThisBlock();
+    bool ParseFailed = Parser.ParseThisBlock();
+    ParsedModuleBlock = true;
+    return ParseFailed;
   }
   // Generate error message by using default block implementation.
   BlockParserBaseClass Parser(BlockID, this);
@@ -3248,14 +3257,13 @@
   // need a hook to tell the IceBrowserCompileServer to unblock its
   // QueueStreamer.
   // https://code.google.com/p/nativeclient/issues/detail?id=4163
-  Ostream &ErrStream = getContext()->getStrError();
   // Read header and verify it is good.
   NaClBitcodeHeader Header;
   if (Header.Read(MemObj.get())) {
     llvm::report_fatal_error("Invalid PNaCl bitcode header");
   }
   if (!Header.IsSupported()) {
-    ErrStream << Header.Unsupported();
+    getContext()->getStrError() << Header.Unsupported();
     if (!Header.IsReadable()) {
       llvm::report_fatal_error("Invalid PNaCl bitcode header");
     }
@@ -3266,25 +3274,20 @@
   NaClBitstreamCursor InputStream(InputStreamFile);
 
   TopLevelParser Parser(*this, InputStream, ErrorStatus);
-  int TopLevelBlocks = 0;
   while (!InputStream.AtEndOfStream()) {
     if (Parser.Parse()) {
       ErrorStatus.assign(EC_Bitcode);
       return;
     }
-    ++TopLevelBlocks;
   }
 
-  if (TopLevelBlocks != 1) {
-    ErrStream << IRFilename
-              << ": Contains more than one module. Found: " << TopLevelBlocks
-              << "\n";
-    llvm::report_fatal_error("Bitcode has more than one module");
+  if (!Parser.parsedModuleBlock()) {
+    std::string Buffer;
+    raw_string_ostream StrBuf(Buffer);
+    StrBuf << IRFilename << ": Does not contain a module!";
+    llvm::report_fatal_error(StrBuf.str());
   }
   if (InputStreamFile.getBitcodeBytes().getExtent() % 4 != 0) {
-    ErrStream
-        << IRFilename
-        << ": Bitcode stream should be a multiple of 4 bytes in length.\n";
     llvm::report_fatal_error("Bitcode stream should be a multiple of 4 bytes");
   }
 }