[clang] 574e417 - [clang] Fix a bug that allowed some overflowing octal escape sequences

[Sergei Barannikov via cfe-commits]

Author: Sergei Barannikov
Date: 2023-02-16T15:19:24+03:00
New Revision: 574e417460cdfebb8157fbe61b6a015e44856f64

URL: https://github.com/llvm/llvm-project/commit/574e417460cdfebb8157fbe61b6a015e44856f64
DIFF: https://github.com/llvm/llvm-project/commit/574e417460cdfebb8157fbe61b6a015e44856f64.diff

LOG: [clang] Fix a bug that allowed some overflowing octal escape sequences

Reviewed By: cor3ntin

Differential Revision: https://reviews.llvm.org/D144100

Added: 
    

Modified: 
    clang/lib/Lex/LiteralSupport.cpp
    clang/test/Lexer/char-escapes-delimited.c

Removed: 
    


################################################################################
diff  --git a/clang/lib/Lex/LiteralSupport.cpp b/clang/lib/Lex/LiteralSupport.cpp
index 421a853360430..38b68bde4b516 100644
--- a/clang/lib/Lex/LiteralSupport.cpp
+++ b/clang/lib/Lex/LiteralSupport.cpp
@@ -263,7 +263,8 @@ static unsigned ProcessCharEscape(const char *ThisTokBegin,
         ThisTokBuf++;
         continue;
       }
-      if (ResultChar & 0x020000000)
+      // Check if one of the top three bits is set before shifting them out.
+      if (ResultChar & 0xE0000000)
         Overflow = true;
 
       ResultChar <<= 3;

diff  --git a/clang/test/Lexer/char-escapes-delimited.c b/clang/test/Lexer/char-escapes-delimited.c
index 8e7094bc2ca5d..3b1deffe936db 100644
--- a/clang/test/Lexer/char-escapes-delimited.c
+++ b/clang/test/Lexer/char-escapes-delimited.c
@@ -58,6 +58,8 @@ void octal(void) {
 #if __WCHAR_MAX__ > 0xFFFF
   unsigned d = L'\o{37777777777}'; // ext-warning {{extension}} cxx2b-warning {{C++2b}}
   unsigned e = L'\o{40000000000}'; // expected-error {{octal escape sequence out of range}}
+  unsigned f = L'\o{100000000000}'; // expected-error {{octal escape sequence out of range}}
+  unsigned g = L'\o{200000000000}'; // expected-error {{octal escape sequence out of range}}
 #else
   unsigned d = L'\o{177777}'; // ext-warning {{extension}} cxx2b-warning {{C++2b}}
   unsigned e = L'\o{200000}'; // expected-error {{octal escape sequence out of range}}