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.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 bpf_dsl::ResultExpr RestrictKillTarget(pid_t target_pid, int sysno); 61 62 // Crash if FUTEX_CMP_REQUEUE_PI is used in the second argument of futex(2). 63 bpf_dsl::ResultExpr RestrictFutex(); 64 65 // Crash if |which| is not PRIO_PROCESS. EPERM if |who| is not 0, neither 66 // |target_pid| while calling setpriority(2) / getpriority(2). 67 bpf_dsl::ResultExpr RestrictGetSetpriority(pid_t target_pid); 68 69 // Restrict |clk_id| for clock_getres(), clock_gettime() and clock_settime(). 70 // We allow accessing only CLOCK_MONOTONIC, CLOCK_PROCESS_CPUTIME_ID, 71 // CLOCK_REALTIME, and CLOCK_THREAD_CPUTIME_ID. In particular, this disallows 72 // access to arbitrary per-{process,thread} CPU-time clock IDs (such as those 73 // returned by {clock,pthread}_getcpuclockid), which can leak information 74 // about the state of the host OS. 75 // On Chrome OS, base::TimeTicks::kClockSystemTrace is also allowed. 76 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictClockID(); 77 78 // Restricts |pid| for sched_* syscalls which take a pid as the first argument. 79 // We only allow calling these syscalls if the pid argument is equal to the pid 80 // of the sandboxed process or 0 (indicating the current thread). The following 81 // syscalls are supported: 82 // 83 // sched_getaffinity(), sched_getattr(), sched_getparam(), sched_getscheduler(), 84 // sched_rr_get_interval(), sched_setaffinity(), sched_setattr(), 85 // sched_setparam(), sched_setscheduler() 86 SANDBOX_EXPORT bpf_dsl::ResultExpr RestrictSchedTarget(pid_t target_pid, 87 int sysno); 88 89 } // namespace sandbox. 90 91 #endif // SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SYSCALL_PARAMETERS_RESTRICTIONS_H_ 92
