1 //===-- asan_linux.cc -----------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file is a part of AddressSanitizer, an address sanity checker. 11 // 12 // Linux-specific details. 13 //===----------------------------------------------------------------------===// 14 15 #include "sanitizer_common/sanitizer_platform.h" 16 #if SANITIZER_FREEBSD || SANITIZER_LINUX 17 18 #include "asan_interceptors.h" 19 #include "asan_internal.h" 20 #include "asan_thread.h" 21 #include "sanitizer_common/sanitizer_flags.h" 22 #include "sanitizer_common/sanitizer_freebsd.h" 23 #include "sanitizer_common/sanitizer_libc.h" 24 #include "sanitizer_common/sanitizer_procmaps.h" 25 26 #include <sys/time.h> 27 #include <sys/resource.h> 28 #include <sys/mman.h> 29 #include <sys/syscall.h> 30 #include <sys/types.h> 31 #include <dlfcn.h> 32 #include <fcntl.h> 33 #include <pthread.h> 34 #include <stdio.h> 35 #include <unistd.h> 36 #include <unwind.h> 37 38 #if SANITIZER_FREEBSD 39 #include <sys/link_elf.h> 40 #endif 41 42 #if SANITIZER_ANDROID || SANITIZER_FREEBSD 43 #include <ucontext.h> 44 extern "C" void* _DYNAMIC; 45 #else 46 #include <sys/ucontext.h> 47 #include <link.h> 48 #endif 49 50 // x86-64 FreeBSD 9.2 and older define 'ucontext_t' incorrectly in 51 // 32-bit mode. 52 #if SANITIZER_FREEBSD && (SANITIZER_WORDSIZE == 32) && \ 53 __FreeBSD_version <= 902001 // v9.2 54 #define ucontext_t xucontext_t 55 #endif 56 57 typedef enum { 58 ASAN_RT_VERSION_UNDEFINED = 0, 59 ASAN_RT_VERSION_DYNAMIC, 60 ASAN_RT_VERSION_STATIC, 61 } asan_rt_version_t; 62 63 // FIXME: perhaps also store abi version here? 64 extern "C" { 65 SANITIZER_INTERFACE_ATTRIBUTE 66 asan_rt_version_t __asan_rt_version; 67 } 68 69 namespace __asan { 70 71 void InitializePlatformInterceptors() {} 72 73 void DisableReexec() { 74 // No need to re-exec on Linux. 75 } 76 77 void MaybeReexec() { 78 // No need to re-exec on Linux. 79 } 80 81 void *AsanDoesNotSupportStaticLinkage() { 82 // This will fail to link with -static. 83 return &_DYNAMIC; // defined in link.h 84 } 85 86 #if SANITIZER_ANDROID 87 // FIXME: should we do anything for Android? 88 void AsanCheckDynamicRTPrereqs() {} 89 void AsanCheckIncompatibleRT() {} 90 #else 91 static int FindFirstDSOCallback(struct dl_phdr_info *info, size_t size, 92 void *data) { 93 // Continue until the first dynamic library is found 94 if (!info->dlpi_name || info->dlpi_name[0] == 0) 95 return 0; 96 97 // Ignore vDSO 98 if (internal_strncmp(info->dlpi_name, "linux-", sizeof("linux-") - 1) == 0) 99 return 0; 100 101 *(const char **)data = info->dlpi_name; 102 return 1; 103 } 104 105 static bool IsDynamicRTName(const char *libname) { 106 return internal_strstr(libname, "libclang_rt.asan") || 107 internal_strstr(libname, "libasan.so"); 108 } 109 110 static void ReportIncompatibleRT() { 111 Report("Your application is linked against incompatible ASan runtimes.\n"); 112 Die(); 113 } 114 115 void AsanCheckDynamicRTPrereqs() { 116 // Ensure that dynamic RT is the first DSO in the list 117 const char *first_dso_name = 0; 118 dl_iterate_phdr(FindFirstDSOCallback, &first_dso_name); 119 if (first_dso_name && !IsDynamicRTName(first_dso_name)) { 120 Report("ASan runtime does not come first in initial library list; " 121 "you should either link runtime to your application or " 122 "manually preload it with LD_PRELOAD.\n"); 123 Die(); 124 } 125 } 126 127 void AsanCheckIncompatibleRT() { 128 if (ASAN_DYNAMIC) { 129 if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) { 130 __asan_rt_version = ASAN_RT_VERSION_DYNAMIC; 131 } else if (__asan_rt_version != ASAN_RT_VERSION_DYNAMIC) { 132 ReportIncompatibleRT(); 133 } 134 } else { 135 if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) { 136 // Ensure that dynamic runtime is not present. We should detect it 137 // as early as possible, otherwise ASan interceptors could bind to 138 // the functions in dynamic ASan runtime instead of the functions in 139 // system libraries, causing crashes later in ASan initialization. 140 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 141 char filename[128]; 142 while (proc_maps.Next(0, 0, 0, filename, sizeof(filename), 0)) { 143 if (IsDynamicRTName(filename)) { 144 Report("Your application is linked against " 145 "incompatible ASan runtimes.\n"); 146 Die(); 147 } 148 } 149 __asan_rt_version = ASAN_RT_VERSION_STATIC; 150 } else if (__asan_rt_version != ASAN_RT_VERSION_STATIC) { 151 ReportIncompatibleRT(); 152 } 153 } 154 } 155 #endif // SANITIZER_ANDROID 156 157 void AsanPlatformThreadInit() { 158 // Nothing here for now. 159 } 160 161 #if !SANITIZER_ANDROID 162 void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 163 ucontext_t *ucp = (ucontext_t*)context; 164 *stack = (uptr)ucp->uc_stack.ss_sp; 165 *ssize = ucp->uc_stack.ss_size; 166 } 167 #else 168 void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 169 UNIMPLEMENTED(); 170 } 171 #endif 172 173 void *AsanDlSymNext(const char *sym) { 174 return dlsym(RTLD_NEXT, sym); 175 } 176 177 } // namespace __asan 178 179 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX 180
