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 MaybeReexec() { 72 // No need to re-exec on Linux. 73 } 74 75 void *AsanDoesNotSupportStaticLinkage() { 76 // This will fail to link with -static. 77 return &_DYNAMIC; // defined in link.h 78 } 79 80 #if SANITIZER_ANDROID 81 // FIXME: should we do anything for Android? 82 void AsanCheckDynamicRTPrereqs() {} 83 void AsanCheckIncompatibleRT() {} 84 #else 85 static int FindFirstDSOCallback(struct dl_phdr_info *info, size_t size, 86 void *data) { 87 // Continue until the first dynamic library is found 88 if (!info->dlpi_name || info->dlpi_name[0] == 0) 89 return 0; 90 91 // Ignore vDSO 92 if (internal_strncmp(info->dlpi_name, "linux-", sizeof("linux-") - 1) == 0) 93 return 0; 94 95 *(const char **)data = info->dlpi_name; 96 return 1; 97 } 98 99 static bool IsDynamicRTName(const char *libname) { 100 return internal_strstr(libname, "libclang_rt.asan") || 101 internal_strstr(libname, "libasan.so"); 102 } 103 104 static void ReportIncompatibleRT() { 105 Report("Your application is linked against incompatible ASan runtimes.\n"); 106 Die(); 107 } 108 109 void AsanCheckDynamicRTPrereqs() { 110 // Ensure that dynamic RT is the first DSO in the list 111 const char *first_dso_name = 0; 112 dl_iterate_phdr(FindFirstDSOCallback, &first_dso_name); 113 if (first_dso_name && !IsDynamicRTName(first_dso_name)) { 114 Report("ASan runtime does not come first in initial library list; " 115 "you should either link runtime to your application or " 116 "manually preload it with LD_PRELOAD.\n"); 117 Die(); 118 } 119 } 120 121 void AsanCheckIncompatibleRT() { 122 if (ASAN_DYNAMIC) { 123 if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) { 124 __asan_rt_version = ASAN_RT_VERSION_DYNAMIC; 125 } else if (__asan_rt_version != ASAN_RT_VERSION_DYNAMIC) { 126 ReportIncompatibleRT(); 127 } 128 } else { 129 if (__asan_rt_version == ASAN_RT_VERSION_UNDEFINED) { 130 // Ensure that dynamic runtime is not present. We should detect it 131 // as early as possible, otherwise ASan interceptors could bind to 132 // the functions in dynamic ASan runtime instead of the functions in 133 // system libraries, causing crashes later in ASan initialization. 134 MemoryMappingLayout proc_maps(/*cache_enabled*/true); 135 char filename[128]; 136 while (proc_maps.Next(0, 0, 0, filename, sizeof(filename), 0)) { 137 if (IsDynamicRTName(filename)) { 138 Report("Your application is linked against " 139 "incompatible ASan runtimes.\n"); 140 Die(); 141 } 142 } 143 __asan_rt_version = ASAN_RT_VERSION_STATIC; 144 } else if (__asan_rt_version != ASAN_RT_VERSION_STATIC) { 145 ReportIncompatibleRT(); 146 } 147 } 148 } 149 #endif // SANITIZER_ANDROID 150 151 void GetPcSpBp(void *context, uptr *pc, uptr *sp, uptr *bp) { 152 #if defined(__arm__) 153 ucontext_t *ucontext = (ucontext_t*)context; 154 *pc = ucontext->uc_mcontext.arm_pc; 155 *bp = ucontext->uc_mcontext.arm_fp; 156 *sp = ucontext->uc_mcontext.arm_sp; 157 #elif defined(__aarch64__) 158 ucontext_t *ucontext = (ucontext_t*)context; 159 *pc = ucontext->uc_mcontext.pc; 160 *bp = ucontext->uc_mcontext.regs[29]; 161 *sp = ucontext->uc_mcontext.sp; 162 #elif defined(__hppa__) 163 ucontext_t *ucontext = (ucontext_t*)context; 164 *pc = ucontext->uc_mcontext.sc_iaoq[0]; 165 /* GCC uses %r3 whenever a frame pointer is needed. */ 166 *bp = ucontext->uc_mcontext.sc_gr[3]; 167 *sp = ucontext->uc_mcontext.sc_gr[30]; 168 #elif defined(__x86_64__) 169 # if SANITIZER_FREEBSD 170 ucontext_t *ucontext = (ucontext_t*)context; 171 *pc = ucontext->uc_mcontext.mc_rip; 172 *bp = ucontext->uc_mcontext.mc_rbp; 173 *sp = ucontext->uc_mcontext.mc_rsp; 174 # else 175 ucontext_t *ucontext = (ucontext_t*)context; 176 *pc = ucontext->uc_mcontext.gregs[REG_RIP]; 177 *bp = ucontext->uc_mcontext.gregs[REG_RBP]; 178 *sp = ucontext->uc_mcontext.gregs[REG_RSP]; 179 # endif 180 #elif defined(__i386__) 181 # if SANITIZER_FREEBSD 182 ucontext_t *ucontext = (ucontext_t*)context; 183 *pc = ucontext->uc_mcontext.mc_eip; 184 *bp = ucontext->uc_mcontext.mc_ebp; 185 *sp = ucontext->uc_mcontext.mc_esp; 186 # else 187 ucontext_t *ucontext = (ucontext_t*)context; 188 *pc = ucontext->uc_mcontext.gregs[REG_EIP]; 189 *bp = ucontext->uc_mcontext.gregs[REG_EBP]; 190 *sp = ucontext->uc_mcontext.gregs[REG_ESP]; 191 # endif 192 #elif defined(__powerpc__) || defined(__powerpc64__) 193 ucontext_t *ucontext = (ucontext_t*)context; 194 *pc = ucontext->uc_mcontext.regs->nip; 195 *sp = ucontext->uc_mcontext.regs->gpr[PT_R1]; 196 // The powerpc{,64}-linux ABIs do not specify r31 as the frame 197 // pointer, but GCC always uses r31 when we need a frame pointer. 198 *bp = ucontext->uc_mcontext.regs->gpr[PT_R31]; 199 #elif defined(__sparc__) 200 ucontext_t *ucontext = (ucontext_t*)context; 201 uptr *stk_ptr; 202 # if defined (__arch64__) 203 *pc = ucontext->uc_mcontext.mc_gregs[MC_PC]; 204 *sp = ucontext->uc_mcontext.mc_gregs[MC_O6]; 205 stk_ptr = (uptr *) (*sp + 2047); 206 *bp = stk_ptr[15]; 207 # else 208 *pc = ucontext->uc_mcontext.gregs[REG_PC]; 209 *sp = ucontext->uc_mcontext.gregs[REG_O6]; 210 stk_ptr = (uptr *) *sp; 211 *bp = stk_ptr[15]; 212 # endif 213 #elif defined(__mips__) 214 ucontext_t *ucontext = (ucontext_t*)context; 215 *pc = ucontext->uc_mcontext.gregs[31]; 216 *bp = ucontext->uc_mcontext.gregs[30]; 217 *sp = ucontext->uc_mcontext.gregs[29]; 218 #else 219 # error "Unsupported arch" 220 #endif 221 } 222 223 bool AsanInterceptsSignal(int signum) { 224 return signum == SIGSEGV && common_flags()->handle_segv; 225 } 226 227 void AsanPlatformThreadInit() { 228 // Nothing here for now. 229 } 230 231 #if !SANITIZER_ANDROID 232 void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 233 ucontext_t *ucp = (ucontext_t*)context; 234 *stack = (uptr)ucp->uc_stack.ss_sp; 235 *ssize = ucp->uc_stack.ss_size; 236 } 237 #else 238 void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 239 UNIMPLEMENTED(); 240 } 241 #endif 242 243 void *AsanDlSymNext(const char *sym) { 244 return dlsym(RTLD_NEXT, sym); 245 } 246 247 } // namespace __asan 248 249 #endif // SANITIZER_FREEBSD || SANITIZER_LINUX 250
