diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp index 8b1850f85010cf..04b095dca904ab 100644 --- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp +++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp @@ -164,33 +164,56 @@ 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 +#include + +#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