[llvm-branch-commits] [compiler-rt] 6925f3c - Reapply "[sanitizer_common] AND signals in BlockSignals instead of deleting (#113443)" for non-Android Linux only (#115790)
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llvm-branch-commits at lists.llvm.org
Tue Nov 19 00:04:52 PST 2024
Author: Thurston Dang
Date: 2024-11-18T18:16:21Z
New Revision: 6925f3c7c7d8b83e2195cb8e473eccdecae42607
URL: https://github.com/llvm/llvm-project/commit/6925f3c7c7d8b83e2195cb8e473eccdecae42607
DIFF: https://github.com/llvm/llvm-project/commit/6925f3c7c7d8b83e2195cb8e473eccdecae42607.diff
LOG: Reapply "[sanitizer_common] AND signals in BlockSignals instead of deleting (#113443)" for non-Android Linux only (#115790)
The original patch (25fd366d6a7d40266ff27c134ed8beb0a90cc33b) was
reverted in 083a5cdbeab09517d8345868970d4f41170d7ed2 because it broke
some buildbots.
This revised patch makes two changes:
- Reverts to *pre-#98200* behavior for Android. This avoids a build
breakage on Android.
- Only define KeepUnblocked if SANITIZER_LINUX: this avoids a build
breakage on solaris, which does not support internal_sigdelset.
N.B. Other buildbot failures were non-sanitizer tests and are therefore
unrelated.
Original commit message:
My earlier patch https://github.com/llvm/llvm-project/pull/98200
caused a regression because it unconditionally unblocked synchronous
signals, even if the user program had deliberately blocked them.
This patch fixes the issue by checking the current signal mask, as
suggested by Vitaly. It also adds tests.
Fixes #113385
(cherry picked from commit 531acf9e2f24977d2556b39229b22f4518a1faa5)
Added:
compiler-rt/lib/sanitizer_common/tests/sanitizer_block_signals.cpp
Modified:
compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
Removed:
################################################################################
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index b9b1f496df7c98..be3b3bd94e2a58 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -160,33 +160,56 @@ void SetSigProcMask(__sanitizer_sigset_t *set, __sanitizer_sigset_t *oldset) {
CHECK_EQ(0, internal_sigprocmask(SIG_SETMASK, set, oldset));
}
+# if SANITIZER_LINUX
+// Deletes the specified signal from newset, if it is not present in oldset
+// Equivalently: newset[signum] = newset[signum] & oldset[signum]
+static void KeepUnblocked(__sanitizer_sigset_t &newset,
+ __sanitizer_sigset_t &oldset, int signum) {
+ // FIXME: https://github.com/google/sanitizers/issues/1816
+ if (SANITIZER_ANDROID || !internal_sigismember(&oldset, signum))
+ internal_sigdelset(&newset, signum);
+}
+# endif
+
// Block asynchronous signals
void BlockSignals(__sanitizer_sigset_t *oldset) {
- __sanitizer_sigset_t set;
- internal_sigfillset(&set);
-# if SANITIZER_LINUX && !SANITIZER_ANDROID
+ __sanitizer_sigset_t newset;
+ internal_sigfillset(&newset);
+
+# if SANITIZER_LINUX
+ __sanitizer_sigset_t currentset;
+
+# if !SANITIZER_ANDROID
+ // FIXME: https://github.com/google/sanitizers/issues/1816
+ SetSigProcMask(NULL, ¤tset);
+
// Glibc uses SIGSETXID signal during setuid call. If this signal is blocked
// on any thread, setuid call hangs.
// See test/sanitizer_common/TestCases/Linux/setuid.c.
- internal_sigdelset(&set, 33);
-# endif
-# if SANITIZER_LINUX
+ KeepUnblocked(newset, currentset, 33);
+# endif // !SANITIZER_ANDROID
+
// Seccomp-BPF-sandboxed processes rely on SIGSYS to handle trapped syscalls.
// If this signal is blocked, such calls cannot be handled and the process may
// hang.
- internal_sigdelset(&set, 31);
+ KeepUnblocked(newset, currentset, 31);
+# if !SANITIZER_ANDROID
// Don't block synchronous signals
- internal_sigdelset(&set, SIGSEGV);
- internal_sigdelset(&set, SIGBUS);
- internal_sigdelset(&set, SIGILL);
- internal_sigdelset(&set, SIGTRAP);
- internal_sigdelset(&set, SIGABRT);
- internal_sigdelset(&set, SIGFPE);
- internal_sigdelset(&set, SIGPIPE);
-# endif
+ // but also don't unblock signals that the user had deliberately blocked.
+ // FIXME: https://github.com/google/sanitizers/issues/1816
+ KeepUnblocked(newset, currentset, SIGSEGV);
+ KeepUnblocked(newset, currentset, SIGBUS);
+ KeepUnblocked(newset, currentset, SIGILL);
+ KeepUnblocked(newset, currentset, SIGTRAP);
+ KeepUnblocked(newset, currentset, SIGABRT);
+ KeepUnblocked(newset, currentset, SIGFPE);
+ KeepUnblocked(newset, currentset, SIGPIPE);
+# endif //! SANITIZER_ANDROID
+
+# endif // SANITIZER_LINUX
- SetSigProcMask(&set, oldset);
+ SetSigProcMask(&newset, oldset);
}
ScopedBlockSignals::ScopedBlockSignals(__sanitizer_sigset_t *copy) {
diff --git a/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt b/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
index 2b4c15125263a9..fef8bb772e0e0d 100644
--- a/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
+++ b/compiler-rt/lib/sanitizer_common/tests/CMakeLists.txt
@@ -15,6 +15,7 @@ set(SANITIZER_UNITTESTS
sanitizer_array_ref_test.cpp
sanitizer_atomic_test.cpp
sanitizer_bitvector_test.cpp
+ sanitizer_block_signals.cpp
sanitizer_bvgraph_test.cpp
sanitizer_chained_origin_depot_test.cpp
sanitizer_common_test.cpp
diff --git a/compiler-rt/lib/sanitizer_common/tests/sanitizer_block_signals.cpp b/compiler-rt/lib/sanitizer_common/tests/sanitizer_block_signals.cpp
new file mode 100644
index 00000000000000..b43648a8aef230
--- /dev/null
+++ b/compiler-rt/lib/sanitizer_common/tests/sanitizer_block_signals.cpp
@@ -0,0 +1,76 @@
+//===-- sanitizer_block_signals.cpp ---------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of sanitizer_common unit tests.
+//
+//===----------------------------------------------------------------------===//
+#include <signal.h>
+#include <stdio.h>
+
+#include "gtest/gtest.h"
+#include "sanitizer_common/sanitizer_linux.h"
+
+namespace __sanitizer {
+
+#if SANITIZER_LINUX && !SANITIZER_ANDROID
+volatile int received_sig = -1;
+
+void signal_handler(int signum) { received_sig = signum; }
+
+TEST(SanitizerCommon, NoBlockSignals) {
+ // No signals blocked
+ signal(SIGUSR1, signal_handler);
+ raise(SIGUSR1);
+ EXPECT_EQ(received_sig, SIGUSR1);
+
+ received_sig = -1;
+ signal(SIGPIPE, signal_handler);
+ raise(SIGPIPE);
+ EXPECT_EQ(received_sig, SIGPIPE);
+}
+
+TEST(SanitizerCommon, BlockSignalsPlain) {
+ // ScopedBlockSignals; SIGUSR1 should be blocked but not SIGPIPE
+ {
+ __sanitizer_sigset_t sigset = {};
+ ScopedBlockSignals block(&sigset);
+
+ received_sig = -1;
+ signal(SIGUSR1, signal_handler);
+ raise(SIGUSR1);
+ EXPECT_EQ(received_sig, -1);
+
+ received_sig = -1;
+ signal(SIGPIPE, signal_handler);
+ raise(SIGPIPE);
+ EXPECT_EQ(received_sig, SIGPIPE);
+ }
+ EXPECT_EQ(received_sig, SIGUSR1);
+}
+
+TEST(SanitizerCommon, BlockSignalsExceptPipe) {
+ // Manually block SIGPIPE; ScopedBlockSignals should not unblock this
+ sigset_t block_sigset;
+ sigemptyset(&block_sigset);
+ sigaddset(&block_sigset, SIGPIPE);
+ sigprocmask(SIG_BLOCK, &block_sigset, NULL);
+ {
+ __sanitizer_sigset_t sigset = {};
+ ScopedBlockSignals block(&sigset);
+
+ received_sig = -1;
+ signal(SIGPIPE, signal_handler);
+ raise(SIGPIPE);
+ EXPECT_EQ(received_sig, -1);
+ }
+ sigprocmask(SIG_UNBLOCK, &block_sigset, NULL);
+ EXPECT_EQ(received_sig, SIGPIPE);
+}
+#endif // SANITIZER_LINUX && !SANITIZER_ANDROID
+
+} // namespace __sanitizer
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