asan_linux.cc revision 6a211c5814e25d6745a5058cc0e499e5235d3821
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> 44extern "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 57typedef 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? 64extern "C" { 65SANITIZER_INTERFACE_ATTRIBUTE 66asan_rt_version_t __asan_rt_version; 67} 68 69namespace __asan { 70 71void MaybeReexec() { 72 // No need to re-exec on Linux. 73} 74 75void *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? 82void AsanCheckDynamicRTPrereqs() {} 83void AsanCheckIncompatibleRT() {} 84#else 85static 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 99static bool IsDynamicRTName(const char *libname) { 100 return internal_strstr(libname, "libclang_rt.asan") || 101 internal_strstr(libname, "libasan.so"); 102} 103 104static void ReportIncompatibleRT() { 105 Report("Your application is linked against incompatible ASan runtimes.\n"); 106 Die(); 107} 108 109void 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 121void 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 151void 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 223bool AsanInterceptsSignal(int signum) { 224 return signum == SIGSEGV && common_flags()->handle_segv; 225} 226 227void AsanPlatformThreadInit() { 228 // Nothing here for now. 229} 230 231#if !SANITIZER_ANDROID 232void 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 238void ReadContextStack(void *context, uptr *stack, uptr *ssize) { 239 UNIMPLEMENTED(); 240} 241#endif 242 243void *AsanDlSymNext(const char *sym) { 244 return dlsym(RTLD_NEXT, sym); 245} 246 247} // namespace __asan 248 249#endif // SANITIZER_FREEBSD || SANITIZER_LINUX 250