[compiler-rt] [compiler-rt][asan] Enable wchar checks: wcscpy/wcsncpy; enable wcscat/wcsncat on Windows (PR #158231)
Yixuan Cao via llvm-commits
llvm-commits at lists.llvm.org
Fri Sep 12 00:54:16 PDT 2025
https://github.com/Cao-Wuhui updated https://github.com/llvm/llvm-project/pull/158231
>From ac85372740245f7cf9563dc5875ffe098282c656 Mon Sep 17 00:00:00 2001
From: Yixuan Cao <caoyixuan2019 at email.szu.edu.cn>
Date: Fri, 12 Sep 2025 14:24:07 +0800
Subject: [PATCH] [compiler-rt][asan] Enable wchar checks: wcscpy/wcsncpy;
enable wcscat/wcsncat on Windows
Summary:
- Add ASan interceptors for wcscpy/wcsncpy and register them.
- Enable wcscat/wcsncat on Windows via platform interceptor macro.
- Add MaybeRealWcsnlen guarded by SANITIZER_INTERCEPT_WCSLEN.
- Update Windows static thunk to forward wchar functions.
- Add tests for wcscpy/wcsncpy/wcscat/wcsncat with standard RUN lines.
Prior work and attribution:
- Based on and extends PR #90909 (author: branh, Microsoft). Thanks for the prior work and review feedback.
https://github.com/llvm/llvm-project/pull/90909
Testing:
- AArch64 Linux: 4 new tests pass; full check-asan passed (0 failures) after enabling profile runtime.
Context:
- Related research background: Tech-ASan (Two-stage check for AddressSanitizer): https://arxiv.org/abs/2506.05022
---
compiler-rt/lib/asan/asan_interceptors.cpp | 44 +++++++++++++++++++
compiler-rt/lib/asan/asan_interceptors.h | 1 +
.../asan/asan_win_static_runtime_thunk.cpp | 4 ++
.../sanitizer_platform_interceptors.h | 2 +-
compiler-rt/test/asan/TestCases/wcscat.cpp | 13 ++++++
compiler-rt/test/asan/TestCases/wcscpy.cpp | 17 +++++++
compiler-rt/test/asan/TestCases/wcsncat.cpp | 13 ++++++
compiler-rt/test/asan/TestCases/wcsncpy.cpp | 13 ++++++
8 files changed, 106 insertions(+), 1 deletion(-)
create mode 100644 compiler-rt/test/asan/TestCases/wcscat.cpp
create mode 100644 compiler-rt/test/asan/TestCases/wcscpy.cpp
create mode 100644 compiler-rt/test/asan/TestCases/wcsncat.cpp
create mode 100644 compiler-rt/test/asan/TestCases/wcsncpy.cpp
diff --git a/compiler-rt/lib/asan/asan_interceptors.cpp b/compiler-rt/lib/asan/asan_interceptors.cpp
index 7c9a08b9083a2..dc56da99a69f0 100644
--- a/compiler-rt/lib/asan/asan_interceptors.cpp
+++ b/compiler-rt/lib/asan/asan_interceptors.cpp
@@ -65,6 +65,15 @@ static inline uptr MaybeRealStrnlen(const char *s, uptr maxlen) {
return internal_strnlen(s, maxlen);
}
+static inline uptr MaybeRealWcsnlen(const wchar_t *s, uptr maxlen) {
+#if SANITIZER_INTERCEPT_STRNLEN
+ if (REAL(wcsnlen)) {
+ return REAL(wcsnlen)(s, maxlen);
+ }
+#endif
+ return internal_wcsnlen(s, maxlen);
+}
+
void SetThreadName(const char *name) {
AsanThread *t = GetCurrentThread();
if (t)
@@ -570,6 +579,26 @@ INTERCEPTOR(char *, strcpy, char *to, const char *from) {
return REAL(strcpy)(to, from);
}
+INTERCEPTOR(wchar_t *, wcscpy, wchar_t *to, const wchar_t *from) {
+ void *ctx;
+ ASAN_INTERCEPTOR_ENTER(ctx, wcscpy);
+ if constexpr (SANITIZER_APPLE) {
+ if (UNLIKELY(!AsanInited()))
+ return REAL(wcscpy)(to, from);
+ } else {
+ if (!TryAsanInitFromRtl())
+ return REAL(wcscpy)(to, from);
+ }
+
+ if (flags()->replace_str) {
+ uptr from_size = (internal_wcslen(from) + 1) * sizeof(wchar_t);
+ CHECK_RANGES_OVERLAP("wcscpy", to, from_size, from, from_size);
+ ASAN_READ_RANGE(ctx, from, from_size);
+ ASAN_WRITE_RANGE(ctx, to, from_size);
+ }
+ return REAL(wcscpy)(to, from);
+}
+
// Windows doesn't always define the strdup identifier,
// and when it does it's a macro defined to either _strdup
// or _strdup_dbg, _strdup_dbg ends up calling _strdup, so
@@ -633,6 +662,19 @@ INTERCEPTOR(char*, strncpy, char *to, const char *from, usize size) {
return REAL(strncpy)(to, from, size);
}
+INTERCEPTOR(wchar_t *, wcsncpy, wchar_t *to, const wchar_t *from, usize size) {
+ void *ctx;
+ ASAN_INTERCEPTOR_ENTER(ctx, wcsncpy);
+ AsanInitFromRtl();
+ if (flags()->replace_str) {
+ uptr from_size = Min<uptr>(size, MaybeRealWcsnlen(from, size) + 1) * sizeof(wchar_t);
+ CHECK_RANGES_OVERLAP("wcsncpy", to, from_size, from, from_size);
+ ASAN_READ_RANGE(ctx, from, from_size);
+ ASAN_WRITE_RANGE(ctx, to, size * sizeof(wchar_t));
+ }
+ return REAL(wcsncpy)(to, from, size);
+}
+
template <typename Fn>
static ALWAYS_INLINE auto StrtolImpl(void *ctx, Fn real, const char *nptr,
char **endptr, int base)
@@ -808,6 +850,8 @@ void InitializeAsanInterceptors() {
ASAN_INTERCEPT_FUNC(strcpy);
ASAN_INTERCEPT_FUNC(strncat);
ASAN_INTERCEPT_FUNC(strncpy);
+ ASAN_INTERCEPT_FUNC(wcscpy);
+ ASAN_INTERCEPT_FUNC(wcsncpy);
ASAN_INTERCEPT_FUNC(strdup);
# if ASAN_INTERCEPT___STRDUP
ASAN_INTERCEPT_FUNC(__strdup);
diff --git a/compiler-rt/lib/asan/asan_interceptors.h b/compiler-rt/lib/asan/asan_interceptors.h
index 3e2386eaf8092..33d4210b5815c 100644
--- a/compiler-rt/lib/asan/asan_interceptors.h
+++ b/compiler-rt/lib/asan/asan_interceptors.h
@@ -129,6 +129,7 @@ DECLARE_REAL(char*, strchr, const char *str, int c)
DECLARE_REAL(SIZE_T, strlen, const char *s)
DECLARE_REAL(char*, strncpy, char *to, const char *from, SIZE_T size)
DECLARE_REAL(SIZE_T, strnlen, const char *s, SIZE_T maxlen)
+DECLARE_REAL(SIZE_T, wcsnlen, const wchar_t *s, SIZE_T maxlen)
DECLARE_REAL(char*, strstr, const char *s1, const char *s2)
# if !SANITIZER_APPLE
diff --git a/compiler-rt/lib/asan/asan_win_static_runtime_thunk.cpp b/compiler-rt/lib/asan/asan_win_static_runtime_thunk.cpp
index 4a69b66574039..8e88f77a2536d 100644
--- a/compiler-rt/lib/asan/asan_win_static_runtime_thunk.cpp
+++ b/compiler-rt/lib/asan/asan_win_static_runtime_thunk.cpp
@@ -65,6 +65,10 @@ INTERCEPT_LIBRARY_FUNCTION_ASAN(strstr);
INTERCEPT_LIBRARY_FUNCTION_ASAN(strtok);
INTERCEPT_LIBRARY_FUNCTION_ASAN(wcslen);
INTERCEPT_LIBRARY_FUNCTION_ASAN(wcsnlen);
+INTERCEPT_LIBRARY_FUNCTION_ASAN(wcscat);
+INTERCEPT_LIBRARY_FUNCTION_ASAN(wcsncat);
+INTERCEPT_LIBRARY_FUNCTION_ASAN(wcscpy);
+INTERCEPT_LIBRARY_FUNCTION_ASAN(wcsncpy);
// Note: Don't intercept strtol(l). They are supposed to set errno for out-of-
// range values, but since the ASan runtime is linked against the dynamic CRT,
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
index 29987decdff45..88ecd7e16306a 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_platform_interceptors.h
@@ -551,7 +551,7 @@ SANITIZER_WEAK_IMPORT void *aligned_alloc(__sanitizer::usize __alignment,
#define SANITIZER_INTERCEPT_MALLOC_USABLE_SIZE (!SI_MAC && !SI_NETBSD)
#define SANITIZER_INTERCEPT_MCHECK_MPROBE SI_LINUX_NOT_ANDROID
#define SANITIZER_INTERCEPT_WCSLEN 1
-#define SANITIZER_INTERCEPT_WCSCAT SI_POSIX
+#define SANITIZER_INTERCEPT_WCSCAT (SI_POSIX || SI_WINDOWS)
#define SANITIZER_INTERCEPT_WCSDUP SI_POSIX
#define SANITIZER_INTERCEPT_SIGNAL_AND_SIGACTION (!SI_WINDOWS && SI_NOT_FUCHSIA)
#define SANITIZER_INTERCEPT_BSD_SIGNAL SI_ANDROID
diff --git a/compiler-rt/test/asan/TestCases/wcscat.cpp b/compiler-rt/test/asan/TestCases/wcscat.cpp
new file mode 100644
index 0000000000000..6154020788e27
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/wcscat.cpp
@@ -0,0 +1,13 @@
+// REQUIRES: !windows
+// RUN: %clangxx_asan -O0 -fno-builtin %s -o %t && %run %t
+
+#include <wchar.h>
+
+int main() {
+ wchar_t dst[16] = L"ab";
+ const wchar_t *src = L"c";
+ wcscat(dst, src);
+ return 0;
+}
+
+
diff --git a/compiler-rt/test/asan/TestCases/wcscpy.cpp b/compiler-rt/test/asan/TestCases/wcscpy.cpp
new file mode 100644
index 0000000000000..3a58f28555269
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/wcscpy.cpp
@@ -0,0 +1,17 @@
+// REQUIRES: !windows
+// RUN: %clangxx_asan -O0 -fno-builtin %s -o %t && not %run %t 2>&1 | FileCheck %s
+
+#include <wchar.h>
+
+__attribute__((noinline)) void bad_wcs(void) {
+ wchar_t buf[] = L"hello";
+ // CHECK: wcscpy-param-overlap: memory ranges
+ wcscpy(buf, buf + 1);
+}
+
+int main() {
+ bad_wcs();
+ return 0;
+}
+
+
diff --git a/compiler-rt/test/asan/TestCases/wcsncat.cpp b/compiler-rt/test/asan/TestCases/wcsncat.cpp
new file mode 100644
index 0000000000000..d260f9ce2f0f2
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/wcsncat.cpp
@@ -0,0 +1,13 @@
+// REQUIRES: !windows
+// RUN: %clangxx_asan -O0 -fno-builtin %s -o %t && %run %t
+
+#include <wchar.h>
+
+int main() {
+ wchar_t dst[16] = L"ab";
+ const wchar_t *src = L"cd";
+ wcsncat(dst, src, 1);
+ return 0;
+}
+
+
diff --git a/compiler-rt/test/asan/TestCases/wcsncpy.cpp b/compiler-rt/test/asan/TestCases/wcsncpy.cpp
new file mode 100644
index 0000000000000..70023bd1f3379
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/wcsncpy.cpp
@@ -0,0 +1,13 @@
+// REQUIRES: !windows
+// RUN: %clangxx_asan -O0 -fno-builtin %s -o %t && %run %t
+
+#include <wchar.h>
+
+int main() {
+ wchar_t src[] = L"abc";
+ wchar_t dst[4] = {0};
+ wcsncpy(dst, src, 3);
+ return 0;
+}
+
+
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