blob: eed02ce4f6aa668a43ecffa592189a8874700674 [file] [log] [blame]
//===-- sanitizer_posix_libcdep.cpp ---------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is shared between AddressSanitizer and ThreadSanitizer
// run-time libraries and implements libc-dependent POSIX-specific functions
// from sanitizer_libc.h.
//===----------------------------------------------------------------------===//
#include "sanitizer_platform.h"
#if SANITIZER_POSIX
#include "sanitizer_common.h"
#include "sanitizer_flags.h"
#include "sanitizer_platform_limits_netbsd.h"
#include "sanitizer_platform_limits_posix.h"
#include "sanitizer_platform_limits_solaris.h"
#include "sanitizer_posix.h"
#include "sanitizer_procmaps.h"
#include <errno.h>
#include <fcntl.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#if SANITIZER_FREEBSD
// The MAP_NORESERVE define has been removed in FreeBSD 11.x, and even before
// that, it was never implemented. So just define it to zero.
#undef MAP_NORESERVE
#define MAP_NORESERVE 0
#endif
typedef void (*sa_sigaction_t)(int, siginfo_t *, void *);
namespace __sanitizer {
u32 GetUid() {
return getuid();
}
uptr GetThreadSelf() {
return (uptr)pthread_self();
}
void ReleaseMemoryPagesToOS(uptr beg, uptr end) {
uptr page_size = GetPageSizeCached();
uptr beg_aligned = RoundUpTo(beg, page_size);
uptr end_aligned = RoundDownTo(end, page_size);
if (beg_aligned < end_aligned)
internal_madvise(beg_aligned, end_aligned - beg_aligned,
SANITIZER_MADVISE_DONTNEED);
}
void SetShadowRegionHugePageMode(uptr addr, uptr size) {
#ifdef MADV_NOHUGEPAGE // May not be defined on old systems.
if (common_flags()->no_huge_pages_for_shadow)
internal_madvise(addr, size, MADV_NOHUGEPAGE);
else
internal_madvise(addr, size, MADV_HUGEPAGE);
#endif // MADV_NOHUGEPAGE
}
bool DontDumpShadowMemory(uptr addr, uptr length) {
#if defined(MADV_DONTDUMP)
return internal_madvise(addr, length, MADV_DONTDUMP) == 0;
#elif defined(MADV_NOCORE)
return internal_madvise(addr, length, MADV_NOCORE) == 0;
#else
return true;
#endif // MADV_DONTDUMP
}
static rlim_t getlim(int res) {
rlimit rlim;
CHECK_EQ(0, getrlimit(res, &rlim));
return rlim.rlim_cur;
}
static void setlim(int res, rlim_t lim) {
struct rlimit rlim;
if (getrlimit(res, const_cast<struct rlimit *>(&rlim))) {
Report("ERROR: %s getrlimit() failed %d\n", SanitizerToolName, errno);
Die();
}
rlim.rlim_cur = lim;
if (setrlimit(res, const_cast<struct rlimit *>(&rlim))) {
Report("ERROR: %s setrlimit() failed %d\n", SanitizerToolName, errno);
Die();
}
}
void DisableCoreDumperIfNecessary() {
if (common_flags()->disable_coredump) {
setlim(RLIMIT_CORE, 0);
}
}
bool StackSizeIsUnlimited() {
rlim_t stack_size = getlim(RLIMIT_STACK);
return (stack_size == RLIM_INFINITY);
}
void SetStackSizeLimitInBytes(uptr limit) {
setlim(RLIMIT_STACK, (rlim_t)limit);
CHECK(!StackSizeIsUnlimited());
}
bool AddressSpaceIsUnlimited() {
rlim_t as_size = getlim(RLIMIT_AS);
return (as_size == RLIM_INFINITY);
}
void SetAddressSpaceUnlimited() {
setlim(RLIMIT_AS, RLIM_INFINITY);
CHECK(AddressSpaceIsUnlimited());
}
void Abort() {
#if !SANITIZER_GO
// If we are handling SIGABRT, unhandle it first.
// TODO(vitalybuka): Check if handler belongs to sanitizer.
if (GetHandleSignalMode(SIGABRT) != kHandleSignalNo) {
struct sigaction sigact;
internal_memset(&sigact, 0, sizeof(sigact));
sigact.sa_handler = SIG_DFL;
internal_sigaction(SIGABRT, &sigact, nullptr);
}
#endif
abort();
}
int Atexit(void (*function)(void)) {
#if !SANITIZER_GO
return atexit(function);
#else
return 0;
#endif
}
bool CreateDir(const char *pathname) { return mkdir(pathname, 0755) == 0; }
bool SupportsColoredOutput(fd_t fd) {
return isatty(fd) != 0;
}
#if !SANITIZER_GO
// TODO(glider): different tools may require different altstack size.
static uptr GetAltStackSize() {
// Note: since GLIBC_2.31, SIGSTKSZ may be a function call, so this may be
// more costly that you think. However GetAltStackSize is only call 2-3 times
// per thread so don't cache the evaluation.
return SIGSTKSZ * 4;
}
void SetAlternateSignalStack() {
stack_t altstack, oldstack;
CHECK_EQ(0, sigaltstack(nullptr, &oldstack));
// If the alternate stack is already in place, do nothing.
// Android always sets an alternate stack, but it's too small for us.
if (!SANITIZER_ANDROID && !(oldstack.ss_flags & SS_DISABLE)) return;
// TODO(glider): the mapped stack should have the MAP_STACK flag in the
// future. It is not required by man 2 sigaltstack now (they're using
// malloc()).
altstack.ss_size = GetAltStackSize();
altstack.ss_sp = (char *)MmapOrDie(altstack.ss_size, __func__);
altstack.ss_flags = 0;
CHECK_EQ(0, sigaltstack(&altstack, nullptr));
}
void UnsetAlternateSignalStack() {
stack_t altstack, oldstack;
altstack.ss_sp = nullptr;
altstack.ss_flags = SS_DISABLE;
altstack.ss_size = GetAltStackSize(); // Some sane value required on Darwin.
CHECK_EQ(0, sigaltstack(&altstack, &oldstack));
UnmapOrDie(oldstack.ss_sp, oldstack.ss_size);
}
static void MaybeInstallSigaction(int signum,
SignalHandlerType handler) {
if (GetHandleSignalMode(signum) == kHandleSignalNo) return;
struct sigaction sigact;
internal_memset(&sigact, 0, sizeof(sigact));
sigact.sa_sigaction = (sa_sigaction_t)handler;
// Do not block the signal from being received in that signal's handler.
// Clients are responsible for handling this correctly.
sigact.sa_flags = SA_SIGINFO | SA_NODEFER;
if (common_flags()->use_sigaltstack) sigact.sa_flags |= SA_ONSTACK;
CHECK_EQ(0, internal_sigaction(signum, &sigact, nullptr));
VReport(1, "Installed the sigaction for signal %d\n", signum);
}
void InstallDeadlySignalHandlers(SignalHandlerType handler) {
// Set the alternate signal stack for the main thread.
// This will cause SetAlternateSignalStack to be called twice, but the stack
// will be actually set only once.
if (common_flags()->use_sigaltstack) SetAlternateSignalStack();
MaybeInstallSigaction(SIGSEGV, handler);
MaybeInstallSigaction(SIGBUS, handler);
MaybeInstallSigaction(SIGABRT, handler);
MaybeInstallSigaction(SIGFPE, handler);
MaybeInstallSigaction(SIGILL, handler);
MaybeInstallSigaction(SIGTRAP, handler);
}
bool SignalContext::IsStackOverflow() const {
// Access at a reasonable offset above SP, or slightly below it (to account
// for x86_64 or PowerPC redzone, ARM push of multiple registers, etc) is
// probably a stack overflow.
#ifdef __s390__
// On s390, the fault address in siginfo points to start of the page, not
// to the precise word that was accessed. Mask off the low bits of sp to
// take it into account.
bool IsStackAccess = addr >= (sp & ~0xFFF) && addr < sp + 0xFFFF;
#else
// Let's accept up to a page size away from top of stack. Things like stack
// probing can trigger accesses with such large offsets.
bool IsStackAccess = addr + GetPageSizeCached() > sp && addr < sp + 0xFFFF;
#endif
#if __powerpc__
// Large stack frames can be allocated with e.g.
// lis r0,-10000
// stdux r1,r1,r0 # store sp to [sp-10000] and update sp by -10000
// If the store faults then sp will not have been updated, so test above
// will not work, because the fault address will be more than just "slightly"
// below sp.
if (!IsStackAccess && IsAccessibleMemoryRange(pc, 4)) {
u32 inst = *(unsigned *)pc;
u32 ra = (inst >> 16) & 0x1F;
u32 opcd = inst >> 26;
u32 xo = (inst >> 1) & 0x3FF;
// Check for store-with-update to sp. The instructions we accept are:
// stbu rs,d(ra) stbux rs,ra,rb
// sthu rs,d(ra) sthux rs,ra,rb
// stwu rs,d(ra) stwux rs,ra,rb
// stdu rs,ds(ra) stdux rs,ra,rb
// where ra is r1 (the stack pointer).
if (ra == 1 &&
(opcd == 39 || opcd == 45 || opcd == 37 || opcd == 62 ||
(opcd == 31 && (xo == 247 || xo == 439 || xo == 183 || xo == 181))))
IsStackAccess = true;
}
#endif // __powerpc__
// We also check si_code to filter out SEGV caused by something else other
// then hitting the guard page or unmapped memory, like, for example,
// unaligned memory access.
auto si = static_cast<const siginfo_t *>(siginfo);
return IsStackAccess &&
(si->si_code == si_SEGV_MAPERR || si->si_code == si_SEGV_ACCERR);
}
#endif // SANITIZER_GO
bool IsAccessibleMemoryRange(uptr beg, uptr size) {
uptr page_size = GetPageSizeCached();
// Checking too large memory ranges is slow.
CHECK_LT(size, page_size * 10);
int sock_pair[2];
if (pipe(sock_pair))
return false;
uptr bytes_written =
internal_write(sock_pair[1], reinterpret_cast<void *>(beg), size);
int write_errno;
bool result;
if (internal_iserror(bytes_written, &write_errno)) {
CHECK_EQ(EFAULT, write_errno);
result = false;
} else {
result = (bytes_written == size);
}
internal_close(sock_pair[0]);
internal_close(sock_pair[1]);
return result;
}
void PlatformPrepareForSandboxing(__sanitizer_sandbox_arguments *args) {
// Some kinds of sandboxes may forbid filesystem access, so we won't be able
// to read the file mappings from /proc/self/maps. Luckily, neither the
// process will be able to load additional libraries, so it's fine to use the
// cached mappings.
MemoryMappingLayout::CacheMemoryMappings();
}
static bool MmapFixed(uptr fixed_addr, uptr size, int additional_flags,
const char *name) {
size = RoundUpTo(size, GetPageSizeCached());
fixed_addr = RoundDownTo(fixed_addr, GetPageSizeCached());
uptr p =
MmapNamed((void *)fixed_addr, size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_FIXED | additional_flags | MAP_ANON, name);
int reserrno;
if (internal_iserror(p, &reserrno)) {
Report("ERROR: %s failed to "
"allocate 0x%zx (%zd) bytes at address %zx (errno: %d)\n",
SanitizerToolName, size, size, fixed_addr, reserrno);
return false;
}
IncreaseTotalMmap(size);
return true;
}
bool MmapFixedNoReserve(uptr fixed_addr, uptr size, const char *name) {
return MmapFixed(fixed_addr, size, MAP_NORESERVE, name);
}
bool MmapFixedSuperNoReserve(uptr fixed_addr, uptr size, const char *name) {
#if SANITIZER_FREEBSD
if (common_flags()->no_huge_pages_for_shadow)
return MmapFixedNoReserve(fixed_addr, size, name);
// MAP_NORESERVE is implicit with FreeBSD
return MmapFixed(fixed_addr, size, MAP_ALIGNED_SUPER, name);
#else
bool r = MmapFixedNoReserve(fixed_addr, size, name);
if (r)
SetShadowRegionHugePageMode(fixed_addr, size);
return r;
#endif
}
uptr ReservedAddressRange::Init(uptr size, const char *name, uptr fixed_addr) {
base_ = fixed_addr ? MmapFixedNoAccess(fixed_addr, size, name)
: MmapNoAccess(size);
size_ = size;
name_ = name;
(void)os_handle_; // unsupported
return reinterpret_cast<uptr>(base_);
}
// Uses fixed_addr for now.
// Will use offset instead once we've implemented this function for real.
uptr ReservedAddressRange::Map(uptr fixed_addr, uptr size, const char *name) {
return reinterpret_cast<uptr>(
MmapFixedOrDieOnFatalError(fixed_addr, size, name));
}
uptr ReservedAddressRange::MapOrDie(uptr fixed_addr, uptr size,
const char *name) {
return reinterpret_cast<uptr>(MmapFixedOrDie(fixed_addr, size, name));
}
void ReservedAddressRange::Unmap(uptr addr, uptr size) {
CHECK_LE(size, size_);
if (addr == reinterpret_cast<uptr>(base_))
// If we unmap the whole range, just null out the base.
base_ = (size == size_) ? nullptr : reinterpret_cast<void*>(addr + size);
else
CHECK_EQ(addr + size, reinterpret_cast<uptr>(base_) + size_);
size_ -= size;
UnmapOrDie(reinterpret_cast<void*>(addr), size);
}
void *MmapFixedNoAccess(uptr fixed_addr, uptr size, const char *name) {
return (void *)MmapNamed((void *)fixed_addr, size, PROT_NONE,
MAP_PRIVATE | MAP_FIXED | MAP_NORESERVE | MAP_ANON,
name);
}
void *MmapNoAccess(uptr size) {
unsigned flags = MAP_PRIVATE | MAP_ANON | MAP_NORESERVE;
return (void *)internal_mmap(nullptr, size, PROT_NONE, flags, -1, 0);
}
// This function is defined elsewhere if we intercepted pthread_attr_getstack.
extern "C" {
SANITIZER_WEAK_ATTRIBUTE int
real_pthread_attr_getstack(void *attr, void **addr, size_t *size);
} // extern "C"
int my_pthread_attr_getstack(void *attr, void **addr, uptr *size) {
#if !SANITIZER_GO && !SANITIZER_MAC
if (&real_pthread_attr_getstack)
return real_pthread_attr_getstack((pthread_attr_t *)attr, addr,
(size_t *)size);
#endif
return pthread_attr_getstack((pthread_attr_t *)attr, addr, (size_t *)size);
}
#if !SANITIZER_GO
void AdjustStackSize(void *attr_) {
pthread_attr_t *attr = (pthread_attr_t *)attr_;
uptr stackaddr = 0;
uptr stacksize = 0;
my_pthread_attr_getstack(attr, (void**)&stackaddr, &stacksize);
// GLibC will return (0 - stacksize) as the stack address in the case when
// stacksize is set, but stackaddr is not.
bool stack_set = (stackaddr != 0) && (stackaddr + stacksize != 0);
// We place a lot of tool data into TLS, account for that.
const uptr minstacksize = GetTlsSize() + 128*1024;
if (stacksize < minstacksize) {
if (!stack_set) {
if (stacksize != 0) {
VPrintf(1, "Sanitizer: increasing stacksize %zu->%zu\n", stacksize,
minstacksize);
pthread_attr_setstacksize(attr, minstacksize);
}
} else {
Printf("Sanitizer: pre-allocated stack size is insufficient: "
"%zu < %zu\n", stacksize, minstacksize);
Printf("Sanitizer: pthread_create is likely to fail.\n");
}
}
}
#endif // !SANITIZER_GO
pid_t StartSubprocess(const char *program, const char *const argv[],
const char *const envp[], fd_t stdin_fd, fd_t stdout_fd,
fd_t stderr_fd) {
auto file_closer = at_scope_exit([&] {
if (stdin_fd != kInvalidFd) {
internal_close(stdin_fd);
}
if (stdout_fd != kInvalidFd) {
internal_close(stdout_fd);
}
if (stderr_fd != kInvalidFd) {
internal_close(stderr_fd);
}
});
int pid = internal_fork();
if (pid < 0) {
int rverrno;
if (internal_iserror(pid, &rverrno)) {
Report("WARNING: failed to fork (errno %d)\n", rverrno);
}
return pid;
}
if (pid == 0) {
// Child subprocess
if (stdin_fd != kInvalidFd) {
internal_close(STDIN_FILENO);
internal_dup2(stdin_fd, STDIN_FILENO);
internal_close(stdin_fd);
}
if (stdout_fd != kInvalidFd) {
internal_close(STDOUT_FILENO);
internal_dup2(stdout_fd, STDOUT_FILENO);
internal_close(stdout_fd);
}
if (stderr_fd != kInvalidFd) {
internal_close(STDERR_FILENO);
internal_dup2(stderr_fd, STDERR_FILENO);
internal_close(stderr_fd);
}
for (int fd = sysconf(_SC_OPEN_MAX); fd > 2; fd--) internal_close(fd);
internal_execve(program, const_cast<char **>(&argv[0]),
const_cast<char *const *>(envp));
internal__exit(1);
}
return pid;
}
bool IsProcessRunning(pid_t pid) {
int process_status;
uptr waitpid_status = internal_waitpid(pid, &process_status, WNOHANG);
int local_errno;
if (internal_iserror(waitpid_status, &local_errno)) {
VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
return false;
}
return waitpid_status == 0;
}
int WaitForProcess(pid_t pid) {
int process_status;
uptr waitpid_status = internal_waitpid(pid, &process_status, 0);
int local_errno;
if (internal_iserror(waitpid_status, &local_errno)) {
VReport(1, "Waiting on the process failed (errno %d).\n", local_errno);
return -1;
}
return process_status;
}
bool IsStateDetached(int state) {
return state == PTHREAD_CREATE_DETACHED;
}
} // namespace __sanitizer
#endif // SANITIZER_POSIX