void SandboxFilterImpl::AllowThreadClone() {
// WARNING: s390 and cris pass the flags in a different arg -- see
// CLONE_BACKWARDS2 in arch/Kconfig in the kernel source -- but we
// don't support seccomp-bpf on those archs yet.
//
// The glibc source hasn't changed the thread creation clone flags
// since 2004, so this *should* be safe to hard-code. Bionic's
// value has changed a few times, and has converged on the same one
// as glibc; allow any of them.
static const int flags_common = CLONE_VM | CLONE_FS | CLONE_FILES |
CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM;
Allow(SYSCALL_WITH_ARG(clone, 0,
#ifdef ANDROID
flags_common | CLONE_DETACHED, // <= JB 4.2
flags_common, // JB 4.3 or KK 4.4
#endif
flags_common | CLONE_SETTLS // Android L or glibc
| CLONE_PARENT_SETTID | CLONE_CHILD_CLEARTID));
}
void
SandboxFilterImplContent::Build() {
/* Most used system calls should be at the top of the whitelist
* for performance reasons. The whitelist BPF filter exits after
* processing any ALLOW_SYSCALL macro.
*
* How are those syscalls found?
* 1) via strace -p <child pid> or/and
* 2) the child will report which system call has been denied by seccomp-bpf,
* just before exiting
* System call number to name mapping is found in:
* bionic/libc/kernel/arch-arm/asm/unistd.h
* or your libc's unistd.h/kernel headers.
*
* Current list order has been optimized through manual guess-work.
* It could be further optimized by analyzing the output of:
* 'strace -c -p <child pid>' for most used web apps.
*/
Allow(SYSCALL(futex));
Allow(SOCKETCALL(recvmsg, RECVMSG));
Allow(SOCKETCALL(sendmsg, SENDMSG));
// mmap2 is a little different from most off_t users, because it's
// passed in a register (so it's a problem for even a "new" 32-bit
// arch) -- and the workaround, mmap2, passes a page offset instead.
#if SYSCALL_EXISTS(mmap2)
Allow(SYSCALL(mmap2));
#else
Allow(SYSCALL(mmap));
#endif
Allow(SYSCALL(clock_gettime));
Allow(SYSCALL(epoll_wait));
Allow(SYSCALL(gettimeofday));
Allow(SYSCALL(read));
Allow(SYSCALL(write));
// 32-bit lseek is used, at least on Android, to implement ANSI fseek.
#if SYSCALL_EXISTS(_llseek)
Allow(SYSCALL(_llseek));
#endif
Allow(SYSCALL(lseek));
// Android also uses 32-bit ftruncate.
Allow(SYSCALL(ftruncate));
#if SYSCALL_EXISTS(ftruncate64)
Allow(SYSCALL(ftruncate64));
#endif
/* ioctl() is for GL. Remove when GL proxy is implemented.
* Additionally ioctl() might be a place where we want to have
* argument filtering */
Allow(SYSCALL(ioctl));
Allow(SYSCALL(close));
Allow(SYSCALL(munmap));
Allow(SYSCALL(mprotect));
Allow(SYSCALL(writev));
Allow(SYSCALL(clone));
Allow(SYSCALL(brk));
#if SYSCALL_EXISTS(set_thread_area)
Allow(SYSCALL(set_thread_area));
#endif
Allow(SYSCALL(getpid));
Allow(SYSCALL(gettid));
Allow(SYSCALL(getrusage));
Allow(SYSCALL(times));
Allow(SYSCALL(madvise));
Allow(SYSCALL(dup));
Allow(SYSCALL(nanosleep));
Allow(SYSCALL(poll));
// select()'s arguments used to be passed by pointer as a struct.
#if SYSCALL_EXISTS(_newselect)
Allow(SYSCALL(_newselect));
#else
Allow(SYSCALL(select));
#endif
// Some archs used to have 16-bit uid/gid instead of 32-bit.
#if SYSCALL_EXISTS(getuid32)
Allow(SYSCALL(getuid32));
Allow(SYSCALL(geteuid32));
Allow(SYSCALL(getgid32));
Allow(SYSCALL(getegid32));
#else
Allow(SYSCALL(getuid));
Allow(SYSCALL(geteuid));
Allow(SYSCALL(getgid));
Allow(SYSCALL(getegid));
#endif
// Some newer archs (e.g., x64 and x32) have only rt_sigreturn, but
// ARM has and uses both syscalls -- rt_sigreturn for SA_SIGINFO
// handlers and classic sigreturn otherwise.
#if SYSCALL_EXISTS(sigreturn)
Allow(SYSCALL(sigreturn));
#endif
Allow(SYSCALL(rt_sigreturn));
Allow(SYSCALL_LARGEFILE(fcntl, fcntl64));
/* Must remove all of the following in the future, when no longer used */
/* open() is for some legacy APIs such as font loading. */
/* See bug 906996 for removing unlink(). */
Allow(SYSCALL_LARGEFILE(fstat, fstat64));
Allow(SYSCALL_LARGEFILE(stat, stat64));
Allow(SYSCALL_LARGEFILE(lstat, lstat64));
Allow(SOCKETCALL(socketpair, SOCKETPAIR));
Deny(EACCES, SOCKETCALL(socket, SOCKET));
Allow(SYSCALL(open));
Allow(SYSCALL(readlink)); /* Workaround for bug 964455 */
Allow(SYSCALL(prctl));
Allow(SYSCALL(access));
Allow(SYSCALL(unlink));
Allow(SYSCALL(fsync));
Allow(SYSCALL(msync));
#if defined(ANDROID) && !defined(MOZ_MEMORY)
// Android's libc's realloc uses mremap.
Allow(SYSCALL(mremap));
#endif
/* Should remove all of the following in the future, if possible */
Allow(SYSCALL(getpriority));
Allow(SYSCALL(sched_get_priority_min));
Allow(SYSCALL(sched_get_priority_max));
Allow(SYSCALL(setpriority));
// rt_sigprocmask is passed the sigset_t size. On older archs,
// sigprocmask is a compatibility shim that assumes the pre-RT size.
#if SYSCALL_EXISTS(sigprocmask)
Allow(SYSCALL(sigprocmask));
#endif
Allow(SYSCALL(rt_sigprocmask));
// Used by profiler. Also used for raise(), which causes problems
// with Android KitKat abort(); see bug 1004832.
Allow(SYSCALL_WITH_ARG(tgkill, 0, uint32_t(getpid())));
Allow(SOCKETCALL(sendto, SENDTO));
Allow(SOCKETCALL(recvfrom, RECVFROM));
Allow(SYSCALL_LARGEFILE(getdents, getdents64));
Allow(SYSCALL(epoll_ctl));
Allow(SYSCALL(sched_yield));
Allow(SYSCALL(sched_getscheduler));
Allow(SYSCALL(sched_setscheduler));
Allow(SYSCALL(sched_getparam));
Allow(SYSCALL(sched_setparam));
Allow(SYSCALL(sigaltstack));
/* Always last and always OK calls */
/* Architecture-specific very infrequently used syscalls */
#if SYSCALL_EXISTS(sigaction)
Allow(SYSCALL(sigaction));
#endif
Allow(SYSCALL(rt_sigaction));
#ifdef ARM_SYSCALL
Allow(ARM_SYSCALL(breakpoint));
Allow(ARM_SYSCALL(cacheflush));
Allow(ARM_SYSCALL(usr26));
Allow(ARM_SYSCALL(usr32));
Allow(ARM_SYSCALL(set_tls));
#endif
/* restart_syscall is called internally, generally when debugging */
Allow(SYSCALL(restart_syscall));
/* linux desktop is not as performance critical as mobile */
/* we can place desktop syscalls at the end */
#ifndef ANDROID
Allow(SYSCALL(stat));
Allow(SYSCALL(getdents));
Allow(SYSCALL(lstat));
#if SYSCALL_EXISTS(mmap2)
Allow(SYSCALL(mmap2));
#else
Allow(SYSCALL(mmap));
#endif
Allow(SYSCALL(openat));
Allow(SYSCALL(fcntl));
Allow(SYSCALL(fstat));
Allow(SYSCALL(readlink));
Allow(SOCKETCALL(getsockname, GETSOCKNAME));
Allow(SYSCALL(getuid));
Allow(SYSCALL(geteuid));
Allow(SYSCALL(mkdir));
Allow(SYSCALL(getcwd));
Allow(SYSCALL(readahead));
Allow(SYSCALL(pread64));
Allow(SYSCALL(statfs));
Allow(SYSCALL(pipe));
#if SYSCALL_EXISTS(ugetrlimit)
Allow(SYSCALL(ugetrlimit));
#else
Allow(SYSCALL(getrlimit));
#endif
Allow(SOCKETCALL(shutdown, SHUTDOWN));
Allow(SOCKETCALL(getpeername, GETPEERNAME));
Allow(SYSCALL(eventfd2));
Allow(SYSCALL(clock_getres));
Allow(SYSCALL(sysinfo));
Allow(SYSCALL(getresuid));
Allow(SYSCALL(umask));
Allow(SYSCALL(getresgid));
Allow(SYSCALL(poll));
Allow(SYSCALL(inotify_init1));
Allow(SYSCALL(wait4));
Allow(SYSVIPCCALL(shmctl, SHMCTL));
Allow(SYSCALL(set_robust_list));
Allow(SYSCALL(rmdir));
Allow(SOCKETCALL(recvfrom, RECVFROM));
Allow(SYSVIPCCALL(shmdt, SHMDT));
Allow(SYSCALL(pipe2));
Allow(SOCKETCALL(setsockopt, SETSOCKOPT));
Allow(SYSVIPCCALL(shmat, SHMAT));
Allow(SYSCALL(set_tid_address));
Allow(SYSCALL(inotify_add_watch));
Allow(SYSCALL(rt_sigprocmask));
Allow(SYSVIPCCALL(shmget, SHMGET));
#if SYSCALL_EXISTS(utimes)
Allow(SYSCALL(utimes));
#else
Allow(SYSCALL(utime));
#endif
#if SYSCALL_EXISTS(arch_prctl)
Allow(SYSCALL(arch_prctl));
#endif
Allow(SYSCALL(sched_getaffinity));
/* We should remove all of the following in the future (possibly even more) */
Allow(SOCKETCALL(socket, SOCKET));
Allow(SYSCALL(chmod));
Allow(SYSCALL(execve));
Allow(SYSCALL(rename));
Allow(SYSCALL(symlink));
Allow(SOCKETCALL(connect, CONNECT));
Allow(SYSCALL(quotactl));
Allow(SYSCALL(kill));
Allow(SOCKETCALL(sendto, SENDTO));
#endif
/* nsSystemInfo uses uname (and we cache an instance, so */
/* the info remains present even if we block the syscall) */
Allow(SYSCALL(uname));
Allow(SYSCALL(exit_group));
Allow(SYSCALL(exit));
}
void SandboxFilterImplGMP::Build() {
// As for content processes, check the most common syscalls first.
Allow(SYSCALL_WITH_ARG(clock_gettime, 0, CLOCK_MONOTONIC, CLOCK_REALTIME));
Allow(SYSCALL(futex));
Allow(SYSCALL(gettimeofday));
Allow(SYSCALL(poll));
Allow(SYSCALL(write));
Allow(SYSCALL(read));
Allow(SYSCALL(epoll_wait));
Allow(SYSCALL(epoll_pwait));
Allow(SOCKETCALL(recvmsg, RECVMSG));
Allow(SOCKETCALL(sendmsg, SENDMSG));
Allow(SYSCALL(time));
Allow(SYSCALL(sched_yield));
// Nothing after this line is performance-critical.
#if SYSCALL_EXISTS(mmap2)
Allow(SYSCALL(mmap2));
#else
Allow(SYSCALL(mmap));
#endif
Allow(SYSCALL_LARGEFILE(fstat, fstat64));
Allow(SYSCALL(munmap));
Allow(SYSCALL(getpid));
Allow(SYSCALL(gettid));
AllowThreadClone();
Allow(SYSCALL_WITH_ARG(prctl, 0, PR_GET_SECCOMP, PR_SET_NAME));
#if SYSCALL_EXISTS(set_robust_list)
Allow(SYSCALL(set_robust_list));
#endif
// NSPR can call this when creating a thread, but it will accept a
// polite "no".
Deny(EACCES, SYSCALL(getpriority));
// But if thread creation races with sandbox startup, that call
// could succeed, and then we get one of these:
Deny(EACCES, SYSCALL(setpriority));
// Stack bounds are obtained via pthread_getattr_np, which calls
// this but doesn't actually need it:
Deny(ENOSYS, SYSCALL(sched_getaffinity));
#ifdef MOZ_ASAN
Allow(SYSCALL(sigaltstack));
// ASAN's error reporter wants to know if stderr is a tty.
Deny(ENOTTY, SYSCALL_WITH_ARG(ioctl, 0, STDERR_FILENO));
// ...and before compiler-rt r209773, it will call readlink and use
// the cached value only if that fails:
Deny(ENOENT, SYSCALL(readlink));
// ...and if it found an external symbolizer, it will try to run it:
// (See also bug 1081242 comment #7.)
Deny(ENOENT, SYSCALL_LARGEFILE(stat, stat64));
#endif
Allow(SYSCALL(mprotect));
Allow(SYSCALL_WITH_ARG(madvise, 2, MADV_DONTNEED));
#if SYSCALL_EXISTS(sigreturn)
Allow(SYSCALL(sigreturn));
#endif
Allow(SYSCALL(rt_sigreturn));
Allow(SYSCALL(restart_syscall));
Allow(SYSCALL(close));
// "Sleeping for 300 seconds" in debug crashes; possibly other uses.
Allow(SYSCALL(nanosleep));
// For the crash reporter:
#if SYSCALL_EXISTS(sigprocmask)
Allow(SYSCALL(sigprocmask));
#endif
Allow(SYSCALL(rt_sigprocmask));
#if SYSCALL_EXISTS(sigaction)
Allow(SYSCALL(sigaction));
#endif
Allow(SYSCALL(rt_sigaction));
Allow(SYSCALL(pipe));
Allow(SYSCALL_WITH_ARG(tgkill, 0, uint32_t(getpid())));
Allow(SYSCALL_WITH_ARG(prctl, 0, PR_SET_DUMPABLE));
// Note for when GMP is supported on an ARM platform: Add whichever
// of the ARM-specific syscalls are needed for this type of process.
Allow(SYSCALL(epoll_ctl));
Allow(SYSCALL(exit));
Allow(SYSCALL(exit_group));
}
