| 1 | //=-- ubsan_signals_standalone.cpp ----------------------------------------===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | // |
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| 9 | // Installs signal handlers and related interceptors for UBSan standalone. |
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| 10 | // |
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| 11 | //===----------------------------------------------------------------------===// |
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| 12 | |
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| 13 | #include "ubsan_platform.h" |
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| 14 | #include "sanitizer_common/sanitizer_platform.h" |
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| 15 | #if CAN_SANITIZE_UB |
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| 16 | #include "interception/interception.h" |
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| 17 | #include "sanitizer_common/sanitizer_stacktrace.h" |
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| 18 | #include "ubsan_diag.h" |
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| 19 | #include "ubsan_init.h" |
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| 20 | |
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| 21 | // Interception of signals breaks too many things on Android. |
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| 22 | // * It requires that ubsan is the first dependency of the main executable for |
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| 23 | // the interceptors to work correctly. This complicates deployment, as it |
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| 24 | // prevents us from enabling ubsan on random platform modules independently. |
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| 25 | // * For this to work with ART VM, ubsan signal handler has to be set after the |
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| 26 | // debuggerd handler, but before the ART handler. |
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| 27 | // * Interceptors don't work at all when ubsan runtime is loaded late, ex. when |
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| 28 | // it is part of an APK that does not use wrap.sh method. |
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| 29 | #if SANITIZER_FUCHSIA || SANITIZER_ANDROID |
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| 30 | |
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| 31 | namespace __ubsan { |
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| 32 | void InitializeDeadlySignals() {} |
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| 33 | } |
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| 34 | |
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| 35 | #else |
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| 36 | |
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| 37 | namespace __ubsan { |
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| 38 | void InitializeDeadlySignals(); |
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| 39 | } // namespace __ubsan |
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| 40 | |
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| 41 | #define COMMON_INTERCEPT_FUNCTION(name) INTERCEPT_FUNCTION(name) |
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| 42 | #define SIGNAL_INTERCEPTOR_ENTER() __ubsan::InitializeDeadlySignals() |
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| 43 | #include "sanitizer_common/sanitizer_signal_interceptors.inc" |
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| 44 | |
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| 45 | // TODO(yln): Temporary workaround. Will be removed. |
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| 46 | void ubsan_GetStackTrace(BufferedStackTrace *stack, uptr max_depth, |
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| 47 | uptr pc, uptr bp, void *context, bool fast); |
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| 48 | |
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| 49 | namespace __ubsan { |
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| 50 | |
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| 51 | static void OnStackUnwind(const SignalContext &sig, const void *, |
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| 52 | BufferedStackTrace *stack) { |
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| 53 | ubsan_GetStackTrace(stack, max_depth: kStackTraceMax, |
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| 54 | pc: StackTrace::GetNextInstructionPc(pc: sig.pc), bp: sig.bp, |
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| 55 | context: sig.context, fast: common_flags()->fast_unwind_on_fatal); |
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| 56 | } |
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| 57 | |
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| 58 | static void UBsanOnDeadlySignal(int signo, void *siginfo, void *context) { |
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| 59 | HandleDeadlySignal(siginfo, context, tid: GetTid(), unwind: &OnStackUnwind, unwind_context: nullptr); |
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| 60 | } |
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| 61 | |
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| 62 | static bool is_initialized = false; |
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| 63 | |
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| 64 | void InitializeDeadlySignals() { |
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| 65 | if (is_initialized) |
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| 66 | return; |
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| 67 | is_initialized = true; |
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| 68 | InitializeSignalInterceptors(); |
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| 69 | #if SANITIZER_INTERCEPT_SIGNAL_AND_SIGACTION |
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| 70 | // REAL(sigaction_symname) is nullptr in a static link. Bail out. |
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| 71 | if (!REAL(sigaction_symname)) |
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| 72 | return; |
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| 73 | #endif |
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| 74 | InstallDeadlySignalHandlers(handler: &UBsanOnDeadlySignal); |
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| 75 | } |
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| 76 | |
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| 77 | } // namespace __ubsan |
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| 78 | |
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| 79 | #endif |
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| 80 | |
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| 81 | #endif // CAN_SANITIZE_UB |
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| 82 | |
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