[PATCH] Fix buffer overflow in Lexer

[Kostya Serebryany]

Hi rnk,

Fix PR22407, where the Lexer overflows the buffer when parsing
 #include<\
(end of file after slash)

http://reviews.llvm.org/D9489

Files:
  lib/Lex/Lexer.cpp
  test/Lexer/eof-include.c

Index: lib/Lex/Lexer.cpp
===================================================================
--- lib/Lex/Lexer.cpp
+++ lib/Lex/Lexer.cpp
@@ -1854,7 +1854,7 @@
   char C = getAndAdvanceChar(CurPtr, Result);
   while (C != '>') {
     // Skip escaped characters.
-    if (C == '\\') {
+    if (C == '\\' && CurPtr < BufferEnd) {
       // Skip the escaped character.
       getAndAdvanceChar(CurPtr, Result);
     } else if (C == '\n' || C == '\r' ||             // Newline.
Index: test/Lexer/eof-include.c
===================================================================
--- /dev/null
+++ test/Lexer/eof-include.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 %s -verify
+// vim: set binary noeol:
+
+// This file intentionally ends without a \n on the last line.  Make sure your
+// editor doesn't add one.
+
+// expected-error@+1{{expected "FILENAME" or <FILENAME>}}
+#include <\
\ No newline at end of file

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Index: lib/Lex/Lexer.cpp
===================================================================
--- lib/Lex/Lexer.cpp
+++ lib/Lex/Lexer.cpp
@@ -1854,7 +1854,7 @@
   char C = getAndAdvanceChar(CurPtr, Result);
   while (C != '>') {
     // Skip escaped characters.
-    if (C == '\\') {
+    if (C == '\\' && CurPtr < BufferEnd) {
       // Skip the escaped character.
       getAndAdvanceChar(CurPtr, Result);
     } else if (C == '\n' || C == '\r' ||             // Newline.
Index: test/Lexer/eof-include.c
===================================================================
--- /dev/null
+++ test/Lexer/eof-include.c
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 %s -verify
+// vim: set binary noeol:
+
+// This file intentionally ends without a \n on the last line.  Make sure your
+// editor doesn't add one.
+
+// expected-error@+1{{expected "FILENAME" or <FILENAME>}}
+#include <\
\ No newline at end of file

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