LXR qemu/qemu-seccomp.c

   1/*
   2 * QEMU seccomp mode 2 support with libseccomp
   3 *
   4 * Copyright IBM, Corp. 2012
   5 *
   6 * Authors:
   7 *  Eduardo Otubo    <eotubo@br.ibm.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2.  See
  10 * the COPYING file in the top-level directory.
  11 *
  12 * Contributions after 2012-01-13 are licensed under the terms of the
  13 * GNU GPL, version 2 or (at your option) any later version.
  14 */
  15#include "qemu/osdep.h"
  16#include <seccomp.h>
  17#include "sysemu/seccomp.h"
  18
  19/* For some architectures (notably ARM) cacheflush is not supported until
  20 * libseccomp 2.2.3, but configure enforces that we are using a more recent
  21 * version on those hosts, so it is OK for this check to be less strict.
  22 */
  23#if SCMP_VER_MAJOR >= 3
  24  #define HAVE_CACHEFLUSH
  25#elif SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR >= 2
  26  #define HAVE_CACHEFLUSH
  27#endif
  28
  29struct QemuSeccompSyscall {
  30    int32_t num;
  31    uint8_t set;
  32};
  33
  34static const struct QemuSeccompSyscall blacklist[] = {
  35    /* default set of syscalls to blacklist */
  36    { SCMP_SYS(reboot),                 QEMU_SECCOMP_SET_DEFAULT },
  37    { SCMP_SYS(swapon),                 QEMU_SECCOMP_SET_DEFAULT },
  38    { SCMP_SYS(swapoff),                QEMU_SECCOMP_SET_DEFAULT },
  39    { SCMP_SYS(syslog),                 QEMU_SECCOMP_SET_DEFAULT },
  40    { SCMP_SYS(mount),                  QEMU_SECCOMP_SET_DEFAULT },
  41    { SCMP_SYS(umount),                 QEMU_SECCOMP_SET_DEFAULT },
  42    { SCMP_SYS(kexec_load),             QEMU_SECCOMP_SET_DEFAULT },
  43    { SCMP_SYS(afs_syscall),            QEMU_SECCOMP_SET_DEFAULT },
  44    { SCMP_SYS(break),                  QEMU_SECCOMP_SET_DEFAULT },
  45    { SCMP_SYS(ftime),                  QEMU_SECCOMP_SET_DEFAULT },
  46    { SCMP_SYS(getpmsg),                QEMU_SECCOMP_SET_DEFAULT },
  47    { SCMP_SYS(gtty),                   QEMU_SECCOMP_SET_DEFAULT },
  48    { SCMP_SYS(lock),                   QEMU_SECCOMP_SET_DEFAULT },
  49    { SCMP_SYS(mpx),                    QEMU_SECCOMP_SET_DEFAULT },
  50    { SCMP_SYS(prof),                   QEMU_SECCOMP_SET_DEFAULT },
  51    { SCMP_SYS(profil),                 QEMU_SECCOMP_SET_DEFAULT },
  52    { SCMP_SYS(putpmsg),                QEMU_SECCOMP_SET_DEFAULT },
  53    { SCMP_SYS(security),               QEMU_SECCOMP_SET_DEFAULT },
  54    { SCMP_SYS(stty),                   QEMU_SECCOMP_SET_DEFAULT },
  55    { SCMP_SYS(tuxcall),                QEMU_SECCOMP_SET_DEFAULT },
  56    { SCMP_SYS(ulimit),                 QEMU_SECCOMP_SET_DEFAULT },
  57    { SCMP_SYS(vserver),                QEMU_SECCOMP_SET_DEFAULT },
  58    /* obsolete */
  59    { SCMP_SYS(readdir),                QEMU_SECCOMP_SET_OBSOLETE },
  60    { SCMP_SYS(_sysctl),                QEMU_SECCOMP_SET_OBSOLETE },
  61    { SCMP_SYS(bdflush),                QEMU_SECCOMP_SET_OBSOLETE },
  62    { SCMP_SYS(create_module),          QEMU_SECCOMP_SET_OBSOLETE },
  63    { SCMP_SYS(get_kernel_syms),        QEMU_SECCOMP_SET_OBSOLETE },
  64    { SCMP_SYS(query_module),           QEMU_SECCOMP_SET_OBSOLETE },
  65    { SCMP_SYS(sgetmask),               QEMU_SECCOMP_SET_OBSOLETE },
  66    { SCMP_SYS(ssetmask),               QEMU_SECCOMP_SET_OBSOLETE },
  67    { SCMP_SYS(sysfs),                  QEMU_SECCOMP_SET_OBSOLETE },
  68    { SCMP_SYS(uselib),                 QEMU_SECCOMP_SET_OBSOLETE },
  69    { SCMP_SYS(ustat),                  QEMU_SECCOMP_SET_OBSOLETE },
  70    /* privileged */
  71    { SCMP_SYS(setuid),                 QEMU_SECCOMP_SET_PRIVILEGED },
  72    { SCMP_SYS(setgid),                 QEMU_SECCOMP_SET_PRIVILEGED },
  73    { SCMP_SYS(setpgid),                QEMU_SECCOMP_SET_PRIVILEGED },
  74    { SCMP_SYS(setsid),                 QEMU_SECCOMP_SET_PRIVILEGED },
  75    { SCMP_SYS(setreuid),               QEMU_SECCOMP_SET_PRIVILEGED },
  76    { SCMP_SYS(setregid),               QEMU_SECCOMP_SET_PRIVILEGED },
  77    { SCMP_SYS(setresuid),              QEMU_SECCOMP_SET_PRIVILEGED },
  78    { SCMP_SYS(setresgid),              QEMU_SECCOMP_SET_PRIVILEGED },
  79    { SCMP_SYS(setfsuid),               QEMU_SECCOMP_SET_PRIVILEGED },
  80    { SCMP_SYS(setfsgid),               QEMU_SECCOMP_SET_PRIVILEGED },
  81    /* spawn */
  82    { SCMP_SYS(fork),                   QEMU_SECCOMP_SET_SPAWN },
  83    { SCMP_SYS(vfork),                  QEMU_SECCOMP_SET_SPAWN },
  84    { SCMP_SYS(execve),                 QEMU_SECCOMP_SET_SPAWN },
  85    /* resource control */
  86    { SCMP_SYS(getpriority),            QEMU_SECCOMP_SET_RESOURCECTL },
  87    { SCMP_SYS(setpriority),            QEMU_SECCOMP_SET_RESOURCECTL },
  88    { SCMP_SYS(sched_setparam),         QEMU_SECCOMP_SET_RESOURCECTL },
  89    { SCMP_SYS(sched_getparam),         QEMU_SECCOMP_SET_RESOURCECTL },
  90    { SCMP_SYS(sched_setscheduler),     QEMU_SECCOMP_SET_RESOURCECTL },
  91    { SCMP_SYS(sched_getscheduler),     QEMU_SECCOMP_SET_RESOURCECTL },
  92    { SCMP_SYS(sched_setaffinity),      QEMU_SECCOMP_SET_RESOURCECTL },
  93    { SCMP_SYS(sched_getaffinity),      QEMU_SECCOMP_SET_RESOURCECTL },
  94    { SCMP_SYS(sched_get_priority_max), QEMU_SECCOMP_SET_RESOURCECTL },
  95    { SCMP_SYS(sched_get_priority_min), QEMU_SECCOMP_SET_RESOURCECTL },
  96};
  97
  98
  99int seccomp_start(uint32_t seccomp_opts)
 100{
 101    int rc = 0;
 102    unsigned int i = 0;
 103    scmp_filter_ctx ctx;
 104
 105    ctx = seccomp_init(SCMP_ACT_ALLOW);
 106    if (ctx == NULL) {
 107        rc = -1;
 108        goto seccomp_return;
 109    }
 110
 111    for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
 112        if (!(seccomp_opts & blacklist[i].set)) {
 113            continue;
 114        }
 115
 116        rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
 117        if (rc < 0) {
 118            goto seccomp_return;
 119        }
 120    }
 121
 122    rc = seccomp_load(ctx);
 123
 124  seccomp_return:
 125    seccomp_release(ctx);
 126    return rc;
 127}
 128