From: Douglas Gregor <dgregor@apple.com>
Date: Mon, 31 Jan 2011 22:42:36 +0000 (+0000)
Subject: Harden Lexer::GetBeginningOfToken() against bogus source locations and
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=3de84241d90f3dd280126fdf2c4651667151c967;p=clang

Harden Lexer::GetBeginningOfToken() against bogus source locations and
the disappearance/alteration of files.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124616 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Basic/SourceManager.cpp b/lib/Basic/SourceManager.cpp
index 409851f108..e476cb2e29 100644
--- a/lib/Basic/SourceManager.cpp
+++ b/lib/Basic/SourceManager.cpp
@@ -531,12 +531,21 @@ void SourceManager::overrideFileContents(const FileEntry *SourceFile,
 
 llvm::StringRef SourceManager::getBufferData(FileID FID, bool *Invalid) const {
   bool MyInvalid = false;
-  const llvm::MemoryBuffer *Buf = getBuffer(FID, &MyInvalid);
+  const SLocEntry &SLoc = getSLocEntry(FID.ID);
+  if (!SLoc.isFile()) {
+    if (Invalid) 
+      *Invalid = true;
+    return "<<<<<INVALID SOURCE LOCATION>>>>>";
+  }
+  
+  const llvm::MemoryBuffer *Buf
+    = SLoc.getFile().getContentCache()->getBuffer(Diag, *this, SourceLocation(), 
+                                                  &MyInvalid);
   if (Invalid)
     *Invalid = MyInvalid;
 
   if (MyInvalid)
-    return "";
+    return "<<<<<INVALID SOURCE LOCATION>>>>>";
   
   return Buf->getBuffer();
 }
diff --git a/lib/Lex/Lexer.cpp b/lib/Lex/Lexer.cpp
index 5d9536f40d..7c94528c64 100644
--- a/lib/Lex/Lexer.cpp
+++ b/lib/Lex/Lexer.cpp
@@ -357,6 +357,9 @@ SourceLocation Lexer::GetBeginningOfToken(SourceLocation Loc,
                                           const SourceManager &SM,
                                           const LangOptions &LangOpts) {
   std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(Loc);
+  if (LocInfo.first.isInvalid())
+    return Loc;
+  
   bool Invalid = false;
   llvm::StringRef Buffer = SM.getBufferData(LocInfo.first, &Invalid);
   if (Invalid)
@@ -365,6 +368,9 @@ SourceLocation Lexer::GetBeginningOfToken(SourceLocation Loc,
   // Back up from the current location until we hit the beginning of a line
   // (or the buffer). We'll relex from that point.
   const char *BufStart = Buffer.data();
+  if (LocInfo.second >= Buffer.size())
+    return Loc;
+  
   const char *StrData = BufStart+LocInfo.second;
   if (StrData[0] == '\n' || StrData[0] == '\r')
     return Loc;