diff options
Diffstat (limited to 'tools/virtiofsd/passthrough_seccomp.c')
| -rw-r--r-- | tools/virtiofsd/passthrough_seccomp.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/tools/virtiofsd/passthrough_seccomp.c b/tools/virtiofsd/passthrough_seccomp.c new file mode 100644 index 000000000..a3ce9f898 --- /dev/null +++ b/tools/virtiofsd/passthrough_seccomp.c @@ -0,0 +1,177 @@ +/* + * Seccomp sandboxing for virtiofsd + * + * Copyright (C) 2019 Red Hat, Inc. + * + * SPDX-License-Identifier: GPL-2.0-or-later + */ + +#include "qemu/osdep.h" +#include "passthrough_seccomp.h" +#include "fuse_i.h" +#include "fuse_log.h" +#include <seccomp.h> + +/* Bodge for libseccomp 2.4.2 which broke ppoll */ +#if !defined(__SNR_ppoll) && defined(__SNR_brk) +#ifdef __NR_ppoll +#define __SNR_ppoll __NR_ppoll +#else +#define __SNR_ppoll __PNR_ppoll +#endif +#endif + +static const int syscall_allowlist[] = { + /* TODO ireg sem*() syscalls */ + SCMP_SYS(brk), + SCMP_SYS(capget), /* For CAP_FSETID */ + SCMP_SYS(capset), + SCMP_SYS(clock_gettime), + SCMP_SYS(clone), +#ifdef __NR_clone3 + SCMP_SYS(clone3), +#endif + SCMP_SYS(close), + SCMP_SYS(copy_file_range), + SCMP_SYS(dup), + SCMP_SYS(eventfd2), + SCMP_SYS(exit), + SCMP_SYS(exit_group), + SCMP_SYS(fallocate), + SCMP_SYS(fchdir), + SCMP_SYS(fchmod), + SCMP_SYS(fchmodat), + SCMP_SYS(fchownat), + SCMP_SYS(fcntl), + SCMP_SYS(fdatasync), + SCMP_SYS(fgetxattr), + SCMP_SYS(flistxattr), + SCMP_SYS(flock), + SCMP_SYS(fremovexattr), + SCMP_SYS(fsetxattr), + SCMP_SYS(fstat), + SCMP_SYS(fstatfs), + SCMP_SYS(fstatfs64), + SCMP_SYS(fsync), + SCMP_SYS(ftruncate), + SCMP_SYS(futex), + SCMP_SYS(getdents), + SCMP_SYS(getdents64), + SCMP_SYS(getegid), + SCMP_SYS(geteuid), + SCMP_SYS(getpid), + SCMP_SYS(gettid), + SCMP_SYS(gettimeofday), + SCMP_SYS(getxattr), + SCMP_SYS(linkat), + SCMP_SYS(listxattr), + SCMP_SYS(lseek), + SCMP_SYS(_llseek), /* For POWER */ + SCMP_SYS(madvise), + SCMP_SYS(mkdirat), + SCMP_SYS(mknodat), + SCMP_SYS(mmap), + SCMP_SYS(mprotect), + SCMP_SYS(mremap), + SCMP_SYS(munmap), + SCMP_SYS(newfstatat), + SCMP_SYS(statx), + SCMP_SYS(open), + SCMP_SYS(openat), + SCMP_SYS(ppoll), + SCMP_SYS(prctl), /* TODO restrict to just PR_SET_NAME? */ + SCMP_SYS(preadv), + SCMP_SYS(pread64), + SCMP_SYS(pwritev), + SCMP_SYS(pwrite64), + SCMP_SYS(read), + SCMP_SYS(readlinkat), + SCMP_SYS(recvmsg), + SCMP_SYS(renameat), + SCMP_SYS(renameat2), + SCMP_SYS(removexattr), + SCMP_SYS(restart_syscall), + SCMP_SYS(rt_sigaction), + SCMP_SYS(rt_sigprocmask), + SCMP_SYS(rt_sigreturn), + SCMP_SYS(sched_getattr), + SCMP_SYS(sched_setattr), + SCMP_SYS(sendmsg), + SCMP_SYS(setresgid), + SCMP_SYS(setresuid), +#ifdef __NR_setresgid32 + SCMP_SYS(setresgid32), +#endif +#ifdef __NR_setresuid32 + SCMP_SYS(setresuid32), +#endif + SCMP_SYS(set_robust_list), + SCMP_SYS(setxattr), + SCMP_SYS(symlinkat), + SCMP_SYS(time), /* Rarely needed, except on static builds */ + SCMP_SYS(tgkill), + SCMP_SYS(unlinkat), + SCMP_SYS(unshare), + SCMP_SYS(utimensat), + SCMP_SYS(write), + SCMP_SYS(writev), + SCMP_SYS(umask), +}; + +/* Syscalls used when --syslog is enabled */ +static const int syscall_allowlist_syslog[] = { + SCMP_SYS(send), + SCMP_SYS(sendto), +}; + +static void add_allowlist(scmp_filter_ctx ctx, const int syscalls[], size_t len) +{ + size_t i; + + for (i = 0; i < len; i++) { + if (seccomp_rule_add(ctx, SCMP_ACT_ALLOW, syscalls[i], 0) != 0) { + fuse_log(FUSE_LOG_ERR, "seccomp_rule_add syscall %d failed\n", + syscalls[i]); + exit(1); + } + } +} + +void setup_seccomp(bool enable_syslog) +{ + scmp_filter_ctx ctx; + +#ifdef SCMP_ACT_KILL_PROCESS + ctx = seccomp_init(SCMP_ACT_KILL_PROCESS); + /* Handle a newer libseccomp but an older kernel */ + if (!ctx && errno == EOPNOTSUPP) { + ctx = seccomp_init(SCMP_ACT_TRAP); + } +#else + ctx = seccomp_init(SCMP_ACT_TRAP); +#endif + if (!ctx) { + fuse_log(FUSE_LOG_ERR, "seccomp_init() failed\n"); + exit(1); + } + + add_allowlist(ctx, syscall_allowlist, G_N_ELEMENTS(syscall_allowlist)); + if (enable_syslog) { + add_allowlist(ctx, syscall_allowlist_syslog, + G_N_ELEMENTS(syscall_allowlist_syslog)); + } + + /* libvhost-user calls this for post-copy migration, we don't need it */ + if (seccomp_rule_add(ctx, SCMP_ACT_ERRNO(ENOSYS), + SCMP_SYS(userfaultfd), 0) != 0) { + fuse_log(FUSE_LOG_ERR, "seccomp_rule_add userfaultfd failed\n"); + exit(1); + } + + if (seccomp_load(ctx) < 0) { + fuse_log(FUSE_LOG_ERR, "seccomp_load() failed\n"); + exit(1); + } + + seccomp_release(ctx); +} |