Update from https://crrev.com/327068

sandbox/linux/services/syscall_wrappers.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sandbox/linux/services/syscall_wrappers.h"
 
 #include <pthread.h>
 #include <sched.h>
 #include <setjmp.h>
 #include <sys/resource.h>
 #include <sys/syscall.h>
 #include <sys/time.h>
 #include <sys/types.h>
 #include <unistd.h>
+#include <cstring>
 
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/third_party/valgrind/valgrind.h"
 #include "build/build_config.h"
+#include "sandbox/linux/system_headers/capability.h"
+#include "sandbox/linux/system_headers/linux_signal.h"
 #include "sandbox/linux/system_headers/linux_syscalls.h"
 
 namespace sandbox {
 
 pid_t sys_getpid(void) {
   return syscall(__NR_getpid);
 }
 
 pid_t sys_gettid(void) {
   return syscall(__NR_gettid);
 }
 
 long sys_clone(unsigned long flags,
                decltype(nullptr) child_stack,
                pid_t* ptid,
                pid_t* ctid,
                decltype(nullptr) tls) {
   const bool clone_tls_used = flags & CLONE_SETTLS;
   const bool invalid_ctid =
       (flags & (CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)) && !ctid;
   const bool invalid_ptid = (flags & CLONE_PARENT_SETTID) && !ptid;
 
   // We do not support CLONE_VM.
   const bool clone_vm_used = flags & CLONE_VM;
   if (clone_tls_used || invalid_ctid || invalid_ptid || clone_vm_used) {
     RAW_LOG(FATAL, "Invalid usage of sys_clone");
   }
 
+  if (ptid) MSAN_UNPOISON(ptid, sizeof(*ptid));
+  if (ctid) MSAN_UNPOISON(ctid, sizeof(*ctid));
   // See kernel/fork.c in Linux. There is different ordering of sys_clone
   // parameters depending on CONFIG_CLONE_BACKWARDS* configuration options.
 #if defined(ARCH_CPU_X86_64)
   return syscall(__NR_clone, flags, child_stack, ptid, ctid, tls);
 #elif defined(ARCH_CPU_X86) || defined(ARCH_CPU_ARM_FAMILY) || \
     defined(ARCH_CPU_MIPS_FAMILY) || defined(ARCH_CPU_MIPS64_FAMILY)
   // CONFIG_CLONE_BACKWARDS defined.
   return syscall(__NR_clone, flags, child_stack, ptid, tls, ctid);
 #endif
 }
 
 long sys_clone(unsigned long flags) {
   return sys_clone(flags, nullptr, nullptr, nullptr, nullptr);
 }
 
 void sys_exit_group(int status) {
   syscall(__NR_exit_group, status);
 }
 
 int sys_seccomp(unsigned int operation,
                 unsigned int flags,
                 const struct sock_fprog* args) {
   return syscall(__NR_seccomp, operation, flags, args);
 }
 
 int sys_prlimit64(pid_t pid,
                   int resource,
                   const struct rlimit64* new_limit,
                   struct rlimit64* old_limit) {
-  return syscall(__NR_prlimit64, pid, resource, new_limit, old_limit);
+  int res = syscall(__NR_prlimit64, pid, resource, new_limit, old_limit);
+  if (res == 0 && old_limit) MSAN_UNPOISON(old_limit, sizeof(*old_limit));
+  return res;
 }
 
 int sys_capget(cap_hdr* hdrp, cap_data* datap) {
-  return syscall(__NR_capget, hdrp, datap);
+  int res = syscall(__NR_capget, hdrp, datap);
+  if (res == 0) {
+    if (hdrp) MSAN_UNPOISON(hdrp, sizeof(*hdrp));
+    if (datap) MSAN_UNPOISON(datap, sizeof(*datap));
+  }
+  return res;
 }
 
 int sys_capset(cap_hdr* hdrp, const cap_data* datap) {
   return syscall(__NR_capset, hdrp, datap);
 }
 
+int sys_getresuid(uid_t* ruid, uid_t* euid, uid_t* suid) {
+  int res;
+#if defined(ARCH_CPU_X86) || defined(ARCH_CPU_ARMEL)
+  // On 32-bit x86 or 32-bit arm, getresuid supports 16bit values only.
+  // Use getresuid32 instead.
+  res = syscall(__NR_getresuid32, ruid, euid, suid);
+#else
+  res = syscall(__NR_getresuid, ruid, euid, suid);
+#endif
+  if (res == 0) {
+    if (ruid) MSAN_UNPOISON(ruid, sizeof(*ruid));
+    if (euid) MSAN_UNPOISON(euid, sizeof(*euid));
+    if (suid) MSAN_UNPOISON(suid, sizeof(*suid));
+  }
+  return res;
+}
+
+int sys_getresgid(gid_t* rgid, gid_t* egid, gid_t* sgid) {
+  int res;
+#if defined(ARCH_CPU_X86) || defined(ARCH_CPU_ARMEL)
+  // On 32-bit x86 or 32-bit arm, getresgid supports 16bit values only.
+  // Use getresgid32 instead.
+  res = syscall(__NR_getresgid32, rgid, egid, sgid);
+#else
+  res = syscall(__NR_getresgid, rgid, egid, sgid);
+#endif
+  if (res == 0) {
+    if (rgid) MSAN_UNPOISON(rgid, sizeof(*rgid));
+    if (egid) MSAN_UNPOISON(egid, sizeof(*egid));
+    if (sgid) MSAN_UNPOISON(sgid, sizeof(*sgid));
+  }
+  return res;
+}
+
+int sys_chroot(const char* path) {
+  return syscall(__NR_chroot, path);
+}
+
+int sys_unshare(int flags) {
+  return syscall(__NR_unshare, flags);
+}
+
+int sys_sigprocmask(int how, const sigset_t* set, decltype(nullptr) oldset) {
+  // In some toolchain (in particular Android and PNaCl toolchain),
+  // sigset_t is 32 bits, but Linux ABI requires 64 bits.
+  uint64_t linux_value = 0;
+  std::memcpy(&linux_value, set, std::min(sizeof(sigset_t), sizeof(uint64_t)));
+  return syscall(__NR_rt_sigprocmask, how, &linux_value, nullptr,
+                 sizeof(linux_value));
+}
+
+#if defined(MEMORY_SANITIZER) || \
+    (defined(ARCH_CPU_X86_64) && defined(__GNUC__) && !defined(__clang__))
+// If MEMORY_SANITIZER is enabled, it is necessary to call sigaction() here,
+// rather than the direct syscall (sys_sigaction() defined by ourselves).
+// It is because, if MEMORY_SANITIZER is enabled, sigaction is wrapped, and
+// |act->sa_handler| is injected in order to unpoisonize the memory passed via
+// callback's arguments. Please see msan_interceptors.cc for more details.
+// So, if the direct syscall is used, as MEMORY_SANITIZER does not know about
+// it, sigaction() invocation in other places would be broken (in more precise,
+// returned |oldact| would have a broken |sa_handler| callback).
+// Practically, it would break NaCl's signal handler installation.
+// cf) native_client/src/trusted/service_runtime/linux/nacl_signal.c.
+//
+// Also on x86_64 architecture, we need naked function for rt_sigreturn.
+// However, there is no simple way to define it with GCC. Note that the body
+// of function is actually very small (only two instructions), but we need to
+// define much debug information in addition, otherwise backtrace() used by
+// base::StackTrace would not work so that some tests would fail.
+int sys_sigaction(int signum,
+                  const struct sigaction* act,
+                  struct sigaction* oldact) {
+  return sigaction(signum, act, oldact);
+}
+#else
+// struct sigaction is different ABI from the Linux's.
+struct KernelSigAction {
+  void (*kernel_handler)(int);
+  uint32_t sa_flags;
+  void (*sa_restorer)(void);
+  uint64_t sa_mask;
+};
+
+// On X86_64 arch, it is necessary to set sa_restorer always.
+#if defined(ARCH_CPU_X86_64)
+#if !defined(SA_RESTORER)
+#define SA_RESTORER 0x04000000
+#endif
+
+// rt_sigreturn is a special system call that interacts with the user land
+// stack. Thus, here prologue must not be created, which implies syscall()
+// does not work properly, too. Note that rt_sigreturn will never return.
+static __attribute__((naked)) void sys_rt_sigreturn() {
+  // Just invoke rt_sigreturn system call.
+  asm volatile ("syscall\n"
+                :: "a"(__NR_rt_sigreturn));
+}
+#endif
+
+int sys_sigaction(int signum,
+                  const struct sigaction* act,
+                  struct sigaction* oldact) {
+  KernelSigAction kernel_act = {};
+  if (act) {
+    kernel_act.kernel_handler = act->sa_handler;
+    std::memcpy(&kernel_act.sa_mask, &act->sa_mask,
+                std::min(sizeof(kernel_act.sa_mask), sizeof(act->sa_mask)));
+    kernel_act.sa_flags = act->sa_flags;
+
+#if defined(ARCH_CPU_X86_64)
+    if (!(kernel_act.sa_flags & SA_RESTORER)) {
+      kernel_act.sa_flags |= SA_RESTORER;
+      kernel_act.sa_restorer = sys_rt_sigreturn;
+    }
+#endif
+  }
+
+  KernelSigAction kernel_oldact = {};
+  int result = syscall(__NR_rt_sigaction, signum, act ? &kernel_act : nullptr,
+                       oldact ? &kernel_oldact : nullptr, sizeof(uint64_t));
+  if (result == 0 && oldact) {
+    oldact->sa_handler = kernel_oldact.kernel_handler;
+    sigemptyset(&oldact->sa_mask);
+    std::memcpy(&oldact->sa_mask, &kernel_oldact.sa_mask,
+                std::min(sizeof(kernel_act.sa_mask), sizeof(act->sa_mask)));
+    oldact->sa_flags = kernel_oldact.sa_flags;
+  }
+  return result;
+}
+
+#endif  // defined(MEMORY_SANITIZER)
+
 }  // namespace sandbox