1//===-- options.inc ---------------------------------------------*- C++ -*-===// 2// 3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4// See https://llvm.org/LICENSE.txt for license information. 5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6// 7//===----------------------------------------------------------------------===// 8 9#ifndef GWP_ASAN_OPTION 10#error "Define GWP_ASAN_OPTION prior to including this file!" 11#endif 12 13#ifndef GWP_ASAN_DEFAULT_ENABLED 14#define GWP_ASAN_DEFAULT_ENABLED true 15#endif 16 17#ifndef GWP_ASAN_STRINGIFY 18#define GWP_ASAN_STRINGIFY(S) GWP_ASAN_STRINGIFY_(S) 19#define GWP_ASAN_STRINGIFY_(S) #S 20#endif 21 22GWP_ASAN_OPTION(bool, Enabled, GWP_ASAN_DEFAULT_ENABLED, 23 "Is GWP-ASan enabled? Defaults to " GWP_ASAN_STRINGIFY( 24 GWP_ASAN_DEFAULT_ENABLED) ".") 25 26GWP_ASAN_OPTION(int, MaxSimultaneousAllocations, 16, 27 "Number of simultaneously-guarded allocations available in the " 28 "pool. Defaults to 16.") 29 30GWP_ASAN_OPTION(int, SampleRate, 5000, 31 "The probability (1 / SampleRate) that an allocation is " 32 "selected for GWP-ASan sampling. Default is 5000. Sample rates " 33 "up to (2^30 - 1) are supported.") 34 35// Developer note - This option is not actually processed by GWP-ASan itself. It 36// is included here so that a user can specify whether they want signal handlers 37// or not. The supporting allocator should inspect this value to see whether 38// signal handlers need to be installed, and then use 39// crash_handler::installSignalHandlers() in order to install the handlers. Note 40// that in order to support signal handlers, you will need to link against the 41// optional crash_handler component. 42GWP_ASAN_OPTION( 43 bool, InstallSignalHandlers, true, 44 "Install GWP-ASan signal handlers for SIGSEGV during dynamic loading. This " 45 "allows better error reports by providing stack traces for allocation and " 46 "deallocation when reporting a memory error. GWP-ASan's signal handler " 47 "will forward the signal to any previously-installed handler, and user " 48 "programs that install further signal handlers should make sure they do " 49 "the same. Note, if the previously installed SIGSEGV handler is SIG_IGN, " 50 "we terminate the process after dumping the error report.") 51 52GWP_ASAN_OPTION( 53 bool, Recoverable, false, 54 "Install GWP-ASan's signal handler in recoverable mode. This means that " 55 "upon GWP-ASan detecting an error, it'll print the error report, but *not* " 56 "crash. Only one crash per sampled allocation will ever be recorded, and " 57 "if a sampled allocation does actually cause a crash, it'll permanently " 58 "occupy a slot in the pool. The recoverable mode also means that " 59 "previously-installed signal handlers will only be triggered for " 60 "non-GWP-ASan errors, as all GWP-ASan errors won't be forwarded.") 61 62GWP_ASAN_OPTION(bool, InstallForkHandlers, true, 63 "Install GWP-ASan atfork handlers to acquire internal locks " 64 "before fork and release them after.") 65 66GWP_ASAN_OPTION(bool, help, false, "Print a summary of the available options.") 67 68// ============================================================================= 69// ==== WARNING 70// ============================================================================= 71// If you are adding flags to GWP-ASan, please note that GWP-ASan flag strings 72// may be parsed by trusted system components (on Android, GWP-ASan flag strings 73// are parsed by libc during the dynamic loader). This means that GWP-ASan 74// should never feature flags like log paths on disk, because this can lead to 75// arbitrary file write and thus privilege escalation. For an example, see the 76// setuid ASan log_path exploits: https://www.exploit-db.com/exploits/46241. 77// 78// Please place all new flags above this warning, so that the warning always 79// stays at the bottom. 80