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/*
* QEMU seccomp mode 2 support with libseccomp
*
* Copyright IBM, Corp. 2012
*
* Authors:
* Eduardo Otubo <eotubo@br.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu/osdep.h"
#include <seccomp.h>
#include "sysemu/seccomp.h"
/* For some architectures (notably ARM) cacheflush is not supported until
* libseccomp 2.2.3, but configure enforces that we are using a more recent
* version on those hosts, so it is OK for this check to be less strict.
*/
#if SCMP_VER_MAJOR >= 3
#define HAVE_CACHEFLUSH
#elif SCMP_VER_MAJOR == 2 && SCMP_VER_MINOR >= 2
#define HAVE_CACHEFLUSH
#endif
struct QemuSeccompSyscall {
int32_t num;
uint8_t set;
};
static const struct QemuSeccompSyscall blacklist[] = {
/* default set of syscalls to blacklist */
{ SCMP_SYS(reboot), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(swapon), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(swapoff), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(syslog), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(mount), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(umount), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(kexec_load), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(afs_syscall), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(break), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(ftime), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(getpmsg), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(gtty), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(lock), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(mpx), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(prof), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(profil), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(putpmsg), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(security), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(stty), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(tuxcall), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(ulimit), QEMU_SECCOMP_SET_DEFAULT },
{ SCMP_SYS(vserver), QEMU_SECCOMP_SET_DEFAULT },
/* obsolete */
{ SCMP_SYS(readdir), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(_sysctl), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(bdflush), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(create_module), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(get_kernel_syms), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(query_module), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(sgetmask), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(ssetmask), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(sysfs), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(uselib), QEMU_SECCOMP_SET_OBSOLETE },
{ SCMP_SYS(ustat), QEMU_SECCOMP_SET_OBSOLETE },
/* privileged */
{ SCMP_SYS(setuid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setgid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setpgid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setsid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setreuid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setregid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setresuid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setresgid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setfsuid), QEMU_SECCOMP_SET_PRIVILEGED },
{ SCMP_SYS(setfsgid), QEMU_SECCOMP_SET_PRIVILEGED },
/* spawn */
{ SCMP_SYS(fork), QEMU_SECCOMP_SET_SPAWN },
{ SCMP_SYS(vfork), QEMU_SECCOMP_SET_SPAWN },
{ SCMP_SYS(execve), QEMU_SECCOMP_SET_SPAWN },
};
int seccomp_start(uint32_t seccomp_opts)
{
int rc = 0;
unsigned int i = 0;
scmp_filter_ctx ctx;
ctx = seccomp_init(SCMP_ACT_ALLOW);
if (ctx == NULL) {
rc = -1;
goto seccomp_return;
}
for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
if (!(seccomp_opts & blacklist[i].set)) {
continue;
}
rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
if (rc < 0) {
goto seccomp_return;
}
}
rc = seccomp_load(ctx);
seccomp_return:
seccomp_release(ctx);
return rc;
}
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