sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.h

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SYSCALL_PARAMETERS_RESTRICTIONS_H_
   6 #define SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SYSCALL_PARAMETERS_RESTRICTIONS_H_
   7
   8 #include <unistd.h>
   9
  10 #include "build/build_config.h"
  11 #include "sandbox/linux/bpf_dsl/bpf_dsl_forward.h"
  12 #include "sandbox/sandbox_export.h"
  13
  14 // These are helpers to build seccomp-bpf policies, i.e. policies for a
  15 // sandbox that reduces the Linux kernel's attack surface. They return a
  16 // bpf_dsl::ResultExpr suitable to restrict certain system call parameters.
  17
  18 namespace sandbox {
  19
  20 // Allow clone(2) for threads.
  21 // Reject fork(2) attempts with EPERM.
  22 // Don't restrict on ASAN.
  23 // Crash if anything else is attempted.
  24 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictCloneToThreadsAndEPERMFork();
  25
  26 // Allow PR_SET_NAME, PR_SET_DUMPABLE, PR_GET_DUMPABLE.
  27 // Crash if anything else is attempted.
  28 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictPrctl();
  29
  30 // Allow TCGETS and FIONREAD.
  31 // Crash if anything else is attempted.
  32 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictIoctl();
  33
  34 // Restrict the flags argument in mmap(2).
  35 // Only allow: MAP_SHARED | MAP_PRIVATE | MAP_ANONYMOUS |
  36 // MAP_STACK | MAP_NORESERVE | MAP_FIXED | MAP_DENYWRITE.
  37 // Crash if any other flag is used.
  38 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictMmapFlags();
  39
  40 // Restrict the prot argument in mprotect(2).
  41 // Only allow: PROT_READ | PROT_WRITE | PROT_EXEC.
  42 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictMprotectFlags();
  43
  44 // Restrict fcntl(2) cmd argument to:
  45 // We allow F_GETFL, F_SETFL, F_GETFD, F_SETFD, F_DUPFD, F_DUPFD_CLOEXEC,
  46 // F_SETLK, F_SETLKW and F_GETLK.
  47 // Also, in F_SETFL, restrict the allowed flags to: O_ACCMODE | O_APPEND |
  48 // O_NONBLOCK | O_SYNC | O_LARGEFILE | O_CLOEXEC | O_NOATIME.
  49 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictFcntlCommands();
  50
  51 #if defined(__i386__) || defined(__mips__)
  52 // Restrict socketcall(2) to only allow socketpair(2), send(2), recv(2),
  53 // sendto(2), recvfrom(2), shutdown(2), sendmsg(2) and recvmsg(2).
  54 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictSocketcallCommand();
  55 #endif
  56
  57 // Restrict |sysno| (which must be kill, tkill or tgkill) by allowing tgkill or
  58 // kill iff the first parameter is |target_pid|, crashing otherwise or if
  59 // |sysno| is tkill.
  60 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictKillTarget(pid_t target_pid,
  61                                                       int sysno);
  62
  63 // Crash if FUTEX_CMP_REQUEUE_PI is used in the second argument of futex(2).
  64 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictFutex();
  65
  66 // Crash if |which| is not PRIO_PROCESS. EPERM if |who| is not 0, neither
  67 // |target_pid| while calling setpriority(2) / getpriority(2).
  68 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictGetSetpriority(pid_t target_pid);
  69
  70 // Restrict |clk_id| for clock_getres(), clock_gettime() and clock_settime().
  71 // We allow accessing only CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID,
  72 // CLOCK_REALTIME, and CLOCK_THREAD_CPUTIME_ID.  In particular, this disallows
  73 // access to arbitrary per-{process,thread} CPU-time clock IDs (such as those
  74 // returned by {clock,pthread}_getcpuclockid), which can leak information
  75 // about the state of the host OS.
  76 // On Chrome OS, base::TimeTicks::kClockSystemTrace is also allowed.
  77 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictClockID();
  78
  79 // Restricts |pid| for sched_* syscalls which take a pid as the first argument.
  80 // We only allow calling these syscalls if the pid argument is equal to the pid
  81 // of the sandboxed process or 0 (indicating the current thread).  The following
  82 // syscalls are supported:
  83 //
  84 // sched_getaffinity(), sched_getattr(), sched_getparam(), sched_getscheduler(),
  85 // sched_rr_get_interval(), sched_setaffinity(), sched_setattr(),
  86 // sched_setparam(), sched_setscheduler()
  87 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictSchedTarget(pid_t target_pid,
  88                                                        int sysno);
  89
  90 // Restricts the |pid| argument of prlimit64 to 0 (meaning the calling process)
  91 // or target_pid.
  92 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictPrlimit64(pid_t target_pid);
  93
  94 // Restricts the |who| argument of getrusage to RUSAGE_SELF (meaning the calling
  95 // process).
  96 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictGetrusage();
  97
  98 }  // namespace sandbox.
  99
 100 #endif  // SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SYSCALL_PARAMETERS_RESTRICTIONS_H_