| // 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 "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" |
| #include "third_party/valgrind/valgrind.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) { |
| 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) { |
| 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(THREAD_SANITIZER) || \ |
| (defined(ARCH_CPU_X86_64) && !defined(__clang__))) && \ |
| !defined(OS_NACL_NONSFI) |
| // If MEMORY_SANITIZER or THREAD_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 or THREAD_SANITIZER is enabled, sigaction |
| // is wrapped, and |act->sa_handler| is injected in order to unpoisonize the |
| // memory passed via callback's arguments for MEMORY_SANITIZER, or handle |
| // signals to check thread consistency for THREAD_SANITIZER. Please see |
| // msan_interceptors.cc and tsan_interceptors.cc for more details. |
| // So, specifically, if MEMORY_SANITIZER is enabled while 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. |
| // As for THREAD_SANITIZER, the intercepted signal handlers are processed more |
| // in other libc functions' interceptors (such as for raise()), so that it |
| // would not work properly. |
| // |
| // 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. |
| // |
| // When this is built with PNaCl toolchain, we should always use sys_sigaction |
| // below, because sigaction() provided by the toolchain is incompatible with |
| // Linux's ABI. So, otherwise, it would just fail. Note that it is not |
| // necessary to think about sigaction() invocation in other places even with |
| // MEMORY_SANITIZER or THREAD_SANITIZER, because it would just fail there. |
| 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 |