https://github.com/ziqingluo-90 created
https://github.com/llvm/llvm-project/pull/129169
`MeasureTokenLength` may return an unsigned 0 representing failure in obtaining
length of a token. The analysis now gives up on such cases. Otherwise, there
might be issues caused by unsigned integer "overflow".
>From f37be15d5df3e8fac5c279862972beb2076c63a8 Mon Sep 17 00:00:00 2001
From: Ziqing Luo <ziqing_...@apple.com>
Date: Thu, 27 Feb 2025 17:23:53 -0800
Subject: [PATCH] [-Wunsafe-buffer-usage] Fix a potential overflow bug reported
by #126334
`MeasureTokenLength` may return an unsigned 0 representing
failure in obtaining length of a token. The analysis now gives
up on such cases. Otherwise, there might be issues caused by
unsigned integer "overflow".
---
clang/lib/Analysis/UnsafeBufferUsage.cpp | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/clang/lib/Analysis/UnsafeBufferUsage.cpp
b/clang/lib/Analysis/UnsafeBufferUsage.cpp
index ff4f940a596e3..12e99143cb148 100644
--- a/clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ b/clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -2364,12 +2364,13 @@ template <typename NodeTy>
static std::optional<SourceLocation>
getEndCharLoc(const NodeTy *Node, const SourceManager &SM,
const LangOptions &LangOpts) {
- unsigned TkLen = Lexer::MeasureTokenLength(Node->getEndLoc(), SM, LangOpts);
- SourceLocation Loc = Node->getEndLoc().getLocWithOffset(TkLen - 1);
-
- if (Loc.isValid())
- return Loc;
+ if (unsigned TkLen =
+ Lexer::MeasureTokenLength(Node->getEndLoc(), SM, LangOpts)) {
+ SourceLocation Loc = Node->getEndLoc().getLocWithOffset(TkLen - 1);
+ if (Loc.isValid())
+ return Loc;
+ }
return std::nullopt;
}
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