https://github.com/zmodem updated https://github.com/llvm/llvm-project/pull/109258
>From 21f8761abd9909e9f9afe0819da784060cd20829 Mon Sep 17 00:00:00 2001
From: Hans Wennborg <hans at chromium.org>
Date: Wed, 18 Sep 2024 15:54:54 +0200
Subject: [PATCH] [win/asan] Ensure errno gets set correctly for strtol
This fixes two problems with asan's interception of `strtol` on Windows:
1. In the dynamic runtime, the `strtol` interceptor calls out to ntdll's
`strtol` to perform the string conversion. Unfortunately, that
function doesn't set `errno`. This has been a long-standing problem
(#34485), but it was not an issue when using the static runtime.
After the static runtime was removed recently (#107899), the problem
became more urgent.
2. A module linked against the static CRT will have a different instance
of `errno` than the ASan runtime, since that's now always linked
against the dynamic CRT. That means even if the ASan runtime sets
`errno` correctly, the calling module will not see it.
This patch fixes the first problem by making the `strtol` interceptor
call out to `strtoll` instead, and do 32-bit range checks on the result.
I can't think of any reasonable way to fix the second problem, so we
should stop intercepting `strtol` in the static runtime thunk. I checked
the list of functions in the thunk, and `strtol` and `strtoll` are the
only ones that set `errno`. (`strtoll` was already missing, probably by
mistake.)
---
compiler-rt/lib/asan/asan_interceptors.cpp | 27 ++++++++++++++++++-
.../asan/asan_win_static_runtime_thunk.cpp | 5 +++-
compiler-rt/lib/asan/tests/asan_str_test.cpp | 24 +++++++++++++++++
.../lib/sanitizer_common/sanitizer_errno.cpp | 1 +
.../sanitizer_common/sanitizer_errno_codes.h | 1 +
.../test/asan/TestCases/strtol_strict.c | 3 +++
6 files changed, 59 insertions(+), 2 deletions(-)
diff --git a/compiler-rt/lib/asan/asan_interceptors.cpp b/compiler-rt/lib/asan/asan_interceptors.cpp
index 74af2e65e9bfa6..c13bcf2382b0a3 100644
--- a/compiler-rt/lib/asan/asan_interceptors.cpp
+++ b/compiler-rt/lib/asan/asan_interceptors.cpp
@@ -650,9 +650,34 @@ static ALWAYS_INLINE auto StrtolImpl(void *ctx, Fn real, const char *nptr,
return StrtolImpl(ctx, REAL(func), nptr, endptr, base); \
}
-INTERCEPTOR_STRTO_BASE(long, strtol)
INTERCEPTOR_STRTO_BASE(long long, strtoll)
+# if SANITIZER_WINDOWS
+INTERCEPTOR(long, strtol, const char *nptr, char **endptr, int base) {
+ // REAL(strtol) may be ntdll!strtol, which doesn't set errno. Instead,
+ // call REAL(strtoll) and do the range check ourselves.
+ COMPILER_CHECK(sizeof(long) == sizeof(u32));
+
+ void *ctx;
+ ASAN_INTERCEPTOR_ENTER(ctx, strtol);
+ AsanInitFromRtl();
+
+ long long result = StrtolImpl(ctx, REAL(strtoll), nptr, endptr, base);
+
+ if (result > INT32_MAX) {
+ errno = errno_ERANGE;
+ return INT32_MAX;
+ }
+ if (result < INT32_MIN) {
+ errno = errno_ERANGE;
+ return INT32_MIN;
+ }
+ return (long)result;
+}
+# else
+INTERCEPTOR_STRTO_BASE(long, strtol)
+# endif
+
# if SANITIZER_GLIBC
INTERCEPTOR_STRTO_BASE(long, __isoc23_strtol)
INTERCEPTOR_STRTO_BASE(long long, __isoc23_strtoll)
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 9efc693bbf00a2..4a69b66574039c 100644
--- a/compiler-rt/lib/asan/asan_win_static_runtime_thunk.cpp
+++ b/compiler-rt/lib/asan/asan_win_static_runtime_thunk.cpp
@@ -63,10 +63,13 @@ INTERCEPT_LIBRARY_FUNCTION_ASAN(strpbrk);
INTERCEPT_LIBRARY_FUNCTION_ASAN(strspn);
INTERCEPT_LIBRARY_FUNCTION_ASAN(strstr);
INTERCEPT_LIBRARY_FUNCTION_ASAN(strtok);
-INTERCEPT_LIBRARY_FUNCTION_ASAN(strtol);
INTERCEPT_LIBRARY_FUNCTION_ASAN(wcslen);
INTERCEPT_LIBRARY_FUNCTION_ASAN(wcsnlen);
+// 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,
+// its errno is different from the one in the current module.
+
# if defined(_MSC_VER) && !defined(__clang__)
# pragma warning(pop)
# endif
diff --git a/compiler-rt/lib/asan/tests/asan_str_test.cpp b/compiler-rt/lib/asan/tests/asan_str_test.cpp
index 8b1c1dc459d74f..b28143db860f5e 100644
--- a/compiler-rt/lib/asan/tests/asan_str_test.cpp
+++ b/compiler-rt/lib/asan/tests/asan_str_test.cpp
@@ -638,3 +638,27 @@ TEST(AddressSanitizer, StrtolOOBTest) {
RunStrtolOOBTest(&CallStrtol);
}
#endif
+
+TEST(AddressSanitizer, StrtolOverflow) {
+ if (sizeof(long) == 4) {
+ // Check that errno gets set correctly on 32-bit strtol overflow.
+ long res;
+ errno = 0;
+ res = Ident(strtol("2147483647", NULL, 0));
+ EXPECT_EQ(errno, 0);
+ EXPECT_EQ(res, 2147483647);
+
+ res = Ident(strtol("2147483648", NULL, 0));
+ EXPECT_EQ(errno, ERANGE);
+ EXPECT_EQ(res, 2147483647);
+
+ errno = 0;
+ res = Ident(strtol("-2147483648", NULL, 0));
+ EXPECT_EQ(errno, 0);
+ EXPECT_EQ(res, -2147483648);
+
+ res = Ident(strtol("-2147483649", NULL, 0));
+ EXPECT_EQ(errno, ERANGE);
+ EXPECT_EQ(res, -2147483648);
+ }
+}
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_errno.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_errno.cpp
index cbadf4d924a7e0..a7cdf3256757c7 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_errno.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_errno.cpp
@@ -23,6 +23,7 @@ namespace __sanitizer {
COMPILER_CHECK(errno_ENOMEM == ENOMEM);
COMPILER_CHECK(errno_EBUSY == EBUSY);
COMPILER_CHECK(errno_EINVAL == EINVAL);
+COMPILER_CHECK(errno_ERANGE == ERANGE);
// EOWNERDEAD is not present in some older platforms.
#if defined(EOWNERDEAD)
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h b/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h
index 3917b2817f2e99..9e6e71ec80c15c 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_errno_codes.h
@@ -24,6 +24,7 @@ namespace __sanitizer {
#define errno_ENOMEM 12
#define errno_EBUSY 16
#define errno_EINVAL 22
+#define errno_ERANGE 34
#define errno_ENAMETOOLONG 36
#define errno_ENOSYS 38
diff --git a/compiler-rt/test/asan/TestCases/strtol_strict.c b/compiler-rt/test/asan/TestCases/strtol_strict.c
index bc30c87b18cb30..aa37af07b63dfc 100644
--- a/compiler-rt/test/asan/TestCases/strtol_strict.c
+++ b/compiler-rt/test/asan/TestCases/strtol_strict.c
@@ -23,6 +23,9 @@
// RUN: %env_asan_opts=strict_string_checks=true not %run %t test7 2>&1 | FileCheck %s --check-prefix=CHECK7
// REQUIRES: shadow-scale-3
+// On Windows, strtol cannot be intercepted when statically linked against the CRT.
+// UNSUPPORTED: win32-static-asan
+
#include <assert.h>
#include <stdlib.h>
#include <string.h>