This patch changes the default behavior of the seccomp filter from
whitelist to blacklist. By default now all system calls are allowed and
a small black list of definitely forbidden ones was created.
Signed-off-by: Eduardo Otubo <otubo@redhat.com>
---
include/sysemu/seccomp.h | 2 +
qemu-seccomp.c | 264 ++++++-----------------------------------------
vl.c | 1 -
3 files changed, 35 insertions(+), 232 deletions(-)
diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
index cfc06008cb..23b9c3c789 100644
--- a/include/sysemu/seccomp.h
+++ b/include/sysemu/seccomp.h
@@ -15,6 +15,8 @@
#ifndef QEMU_SECCOMP_H
#define QEMU_SECCOMP_H
+#define QEMU_SECCOMP_SET_DEFAULT (1 << 0)
+
#include <seccomp.h>
int seccomp_start(void);
diff --git a/qemu-seccomp.c b/qemu-seccomp.c
index df75d9c471..bc9a1f77ff 100644
--- a/qemu-seccomp.c
+++ b/qemu-seccomp.c
@@ -28,232 +28,34 @@
struct QemuSeccompSyscall {
int32_t num;
- uint8_t priority;
+ int type;
+ uint8_t set;
};
-static const struct QemuSeccompSyscall seccomp_whitelist[] = {
- { SCMP_SYS(timer_settime), 255 },
- { SCMP_SYS(timer_gettime), 254 },
- { SCMP_SYS(futex), 253 },
- { SCMP_SYS(select), 252 },
- { SCMP_SYS(recvfrom), 251 },
- { SCMP_SYS(sendto), 250 },
- { SCMP_SYS(socketcall), 250 },
- { SCMP_SYS(read), 249 },
- { SCMP_SYS(io_submit), 249 },
- { SCMP_SYS(brk), 248 },
- { SCMP_SYS(clone), 247 },
- { SCMP_SYS(mmap), 247 },
- { SCMP_SYS(mprotect), 246 },
- { SCMP_SYS(execve), 245 },
- { SCMP_SYS(open), 245 },
- { SCMP_SYS(ioctl), 245 },
- { SCMP_SYS(socket), 245 },
- { SCMP_SYS(setsockopt), 245 },
- { SCMP_SYS(recvmsg), 245 },
- { SCMP_SYS(sendmsg), 245 },
- { SCMP_SYS(accept), 245 },
- { SCMP_SYS(connect), 245 },
- { SCMP_SYS(socketpair), 245 },
- { SCMP_SYS(bind), 245 },
- { SCMP_SYS(listen), 245 },
- { SCMP_SYS(semget), 245 },
- { SCMP_SYS(ipc), 245 },
- { SCMP_SYS(gettimeofday), 245 },
- { SCMP_SYS(readlink), 245 },
- { SCMP_SYS(access), 245 },
- { SCMP_SYS(prctl), 245 },
- { SCMP_SYS(signalfd), 245 },
- { SCMP_SYS(getrlimit), 245 },
- { SCMP_SYS(getrusage), 245 },
- { SCMP_SYS(set_tid_address), 245 },
- { SCMP_SYS(statfs), 245 },
- { SCMP_SYS(unlink), 245 },
- { SCMP_SYS(wait4), 245 },
- { SCMP_SYS(fcntl64), 245 },
- { SCMP_SYS(fstat64), 245 },
- { SCMP_SYS(stat64), 245 },
- { SCMP_SYS(getgid32), 245 },
- { SCMP_SYS(getegid32), 245 },
- { SCMP_SYS(getuid32), 245 },
- { SCMP_SYS(geteuid32), 245 },
- { SCMP_SYS(sigreturn), 245 },
- { SCMP_SYS(_newselect), 245 },
- { SCMP_SYS(_llseek), 245 },
- { SCMP_SYS(mmap2), 245 },
- { SCMP_SYS(sigprocmask), 245 },
- { SCMP_SYS(sched_getparam), 245 },
- { SCMP_SYS(sched_getscheduler), 245 },
- { SCMP_SYS(fstat), 245 },
- { SCMP_SYS(clock_getres), 245 },
- { SCMP_SYS(sched_get_priority_min), 245 },
- { SCMP_SYS(sched_get_priority_max), 245 },
- { SCMP_SYS(stat), 245 },
- { SCMP_SYS(uname), 245 },
- { SCMP_SYS(eventfd2), 245 },
- { SCMP_SYS(io_getevents), 245 },
- { SCMP_SYS(dup), 245 },
- { SCMP_SYS(dup2), 245 },
- { SCMP_SYS(dup3), 245 },
- { SCMP_SYS(gettid), 245 },
- { SCMP_SYS(getgid), 245 },
- { SCMP_SYS(getegid), 245 },
- { SCMP_SYS(getuid), 245 },
- { SCMP_SYS(geteuid), 245 },
- { SCMP_SYS(timer_create), 245 },
- { SCMP_SYS(times), 245 },
- { SCMP_SYS(exit), 245 },
- { SCMP_SYS(clock_gettime), 245 },
- { SCMP_SYS(time), 245 },
- { SCMP_SYS(restart_syscall), 245 },
- { SCMP_SYS(pwrite64), 245 },
- { SCMP_SYS(nanosleep), 245 },
- { SCMP_SYS(chown), 245 },
- { SCMP_SYS(openat), 245 },
- { SCMP_SYS(getdents), 245 },
- { SCMP_SYS(timer_delete), 245 },
- { SCMP_SYS(exit_group), 245 },
- { SCMP_SYS(rt_sigreturn), 245 },
- { SCMP_SYS(sync), 245 },
- { SCMP_SYS(pread64), 245 },
- { SCMP_SYS(madvise), 245 },
- { SCMP_SYS(set_robust_list), 245 },
- { SCMP_SYS(lseek), 245 },
- { SCMP_SYS(pselect6), 245 },
- { SCMP_SYS(fork), 245 },
- { SCMP_SYS(rt_sigprocmask), 245 },
- { SCMP_SYS(write), 244 },
- { SCMP_SYS(fcntl), 243 },
- { SCMP_SYS(tgkill), 242 },
- { SCMP_SYS(kill), 242 },
- { SCMP_SYS(rt_sigaction), 242 },
- { SCMP_SYS(pipe2), 242 },
- { SCMP_SYS(munmap), 242 },
- { SCMP_SYS(mremap), 242 },
- { SCMP_SYS(fdatasync), 242 },
- { SCMP_SYS(close), 242 },
- { SCMP_SYS(rt_sigpending), 242 },
- { SCMP_SYS(rt_sigtimedwait), 242 },
- { SCMP_SYS(readv), 242 },
- { SCMP_SYS(writev), 242 },
- { SCMP_SYS(preadv), 242 },
- { SCMP_SYS(pwritev), 242 },
- { SCMP_SYS(setrlimit), 242 },
- { SCMP_SYS(ftruncate), 242 },
- { SCMP_SYS(lstat), 242 },
- { SCMP_SYS(pipe), 242 },
- { SCMP_SYS(umask), 242 },
- { SCMP_SYS(chdir), 242 },
- { SCMP_SYS(setitimer), 242 },
- { SCMP_SYS(setsid), 242 },
- { SCMP_SYS(poll), 242 },
- { SCMP_SYS(epoll_create), 242 },
- { SCMP_SYS(epoll_ctl), 242 },
- { SCMP_SYS(epoll_wait), 242 },
- { SCMP_SYS(waitpid), 242 },
- { SCMP_SYS(getsockname), 242 },
- { SCMP_SYS(getpeername), 242 },
- { SCMP_SYS(accept4), 242 },
- { SCMP_SYS(timerfd_settime), 242 },
- { SCMP_SYS(newfstatat), 241 },
- { SCMP_SYS(shutdown), 241 },
- { SCMP_SYS(getsockopt), 241 },
- { SCMP_SYS(semop), 241 },
- { SCMP_SYS(semtimedop), 241 },
- { SCMP_SYS(epoll_ctl_old), 241 },
- { SCMP_SYS(epoll_wait_old), 241 },
- { SCMP_SYS(epoll_pwait), 241 },
- { SCMP_SYS(epoll_create1), 241 },
- { SCMP_SYS(ppoll), 241 },
- { SCMP_SYS(creat), 241 },
- { SCMP_SYS(link), 241 },
- { SCMP_SYS(getpid), 241 },
- { SCMP_SYS(getppid), 241 },
- { SCMP_SYS(getpgrp), 241 },
- { SCMP_SYS(getpgid), 241 },
- { SCMP_SYS(getsid), 241 },
- { SCMP_SYS(getdents64), 241 },
- { SCMP_SYS(getresuid), 241 },
- { SCMP_SYS(getresgid), 241 },
- { SCMP_SYS(getgroups), 241 },
- { SCMP_SYS(getresuid32), 241 },
- { SCMP_SYS(getresgid32), 241 },
- { SCMP_SYS(getgroups32), 241 },
- { SCMP_SYS(signal), 241 },
- { SCMP_SYS(sigaction), 241 },
- { SCMP_SYS(sigsuspend), 241 },
- { SCMP_SYS(sigpending), 241 },
- { SCMP_SYS(truncate64), 241 },
- { SCMP_SYS(ftruncate64), 241 },
- { SCMP_SYS(fchown32), 241 },
- { SCMP_SYS(chown32), 241 },
- { SCMP_SYS(lchown32), 241 },
- { SCMP_SYS(statfs64), 241 },
- { SCMP_SYS(fstatfs64), 241 },
- { SCMP_SYS(fstatat64), 241 },
- { SCMP_SYS(lstat64), 241 },
- { SCMP_SYS(sendfile64), 241 },
- { SCMP_SYS(ugetrlimit), 241 },
- { SCMP_SYS(alarm), 241 },
- { SCMP_SYS(rt_sigsuspend), 241 },
- { SCMP_SYS(rt_sigqueueinfo), 241 },
- { SCMP_SYS(rt_tgsigqueueinfo), 241 },
- { SCMP_SYS(sigaltstack), 241 },
- { SCMP_SYS(signalfd4), 241 },
- { SCMP_SYS(truncate), 241 },
- { SCMP_SYS(fchown), 241 },
- { SCMP_SYS(lchown), 241 },
- { SCMP_SYS(fchownat), 241 },
- { SCMP_SYS(fstatfs), 241 },
- { SCMP_SYS(getitimer), 241 },
- { SCMP_SYS(syncfs), 241 },
- { SCMP_SYS(fsync), 241 },
- { SCMP_SYS(fchdir), 241 },
- { SCMP_SYS(msync), 241 },
- { SCMP_SYS(sched_setparam), 241 },
- { SCMP_SYS(sched_setscheduler), 241 },
- { SCMP_SYS(sched_yield), 241 },
- { SCMP_SYS(sched_rr_get_interval), 241 },
- { SCMP_SYS(sched_setaffinity), 241 },
- { SCMP_SYS(sched_getaffinity), 241 },
- { SCMP_SYS(readahead), 241 },
- { SCMP_SYS(timer_getoverrun), 241 },
- { SCMP_SYS(unlinkat), 241 },
- { SCMP_SYS(readlinkat), 241 },
- { SCMP_SYS(faccessat), 241 },
- { SCMP_SYS(get_robust_list), 241 },
- { SCMP_SYS(splice), 241 },
- { SCMP_SYS(vmsplice), 241 },
- { SCMP_SYS(getcpu), 241 },
- { SCMP_SYS(sendmmsg), 241 },
- { SCMP_SYS(recvmmsg), 241 },
- { SCMP_SYS(prlimit64), 241 },
- { SCMP_SYS(waitid), 241 },
- { SCMP_SYS(io_cancel), 241 },
- { SCMP_SYS(io_setup), 241 },
- { SCMP_SYS(io_destroy), 241 },
- { SCMP_SYS(arch_prctl), 240 },
- { SCMP_SYS(mkdir), 240 },
- { SCMP_SYS(fchmod), 240 },
- { SCMP_SYS(shmget), 240 },
- { SCMP_SYS(shmat), 240 },
- { SCMP_SYS(shmdt), 240 },
- { SCMP_SYS(timerfd_create), 240 },
- { SCMP_SYS(shmctl), 240 },
- { SCMP_SYS(mlockall), 240 },
- { SCMP_SYS(mlock), 240 },
- { SCMP_SYS(munlock), 240 },
- { SCMP_SYS(semctl), 240 },
- { SCMP_SYS(fallocate), 240 },
- { SCMP_SYS(fadvise64), 240 },
- { SCMP_SYS(inotify_init1), 240 },
- { SCMP_SYS(inotify_add_watch), 240 },
- { SCMP_SYS(mbind), 240 },
- { SCMP_SYS(memfd_create), 240 },
-#ifdef HAVE_CACHEFLUSH
- { SCMP_SYS(cacheflush), 240 },
-#endif
- { SCMP_SYS(sysinfo), 240 },
+static const struct QemuSeccompSyscall blacklist[] = {
+ /* default set of syscalls to blacklist */
+ { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT },
+ { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT },
};
int seccomp_start(void)
@@ -262,19 +64,19 @@ int seccomp_start(void)
unsigned int i = 0;
scmp_filter_ctx ctx;
- ctx = seccomp_init(SCMP_ACT_KILL);
+ ctx = seccomp_init(SCMP_ACT_ALLOW);
if (ctx == NULL) {
rc = -1;
goto seccomp_return;
}
- for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) {
- rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0);
- if (rc < 0) {
- goto seccomp_return;
+ for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
+ switch (blacklist[i].set) {
+ default:
+ break;
}
- rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num,
- seccomp_whitelist[i].priority);
+
+ rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
if (rc < 0) {
goto seccomp_return;
}
diff --git a/vl.c b/vl.c
index fb1f05b937..76e0b3a946 100644
--- a/vl.c
+++ b/vl.c
@@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt)
static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
{
- /* FIXME: change this to true for 1.3 */
if (qemu_opt_get_bool(opts, "enable", false)) {
#ifdef CONFIG_SECCOMP
if (seccomp_start() < 0) {
--
2.13.5
On Fri, Sep 08, 2017 at 11:10:23AM +0200, Eduardo Otubo wrote: > This patch changes the default behavior of the seccomp filter from > whitelist to blacklist. By default now all system calls are allowed and > a small black list of definitely forbidden ones was created. > > Signed-off-by: Eduardo Otubo <otubo@redhat.com> > --- > include/sysemu/seccomp.h | 2 + > qemu-seccomp.c | 264 ++++++----------------------------------------- > vl.c | 1 - > 3 files changed, 35 insertions(+), 232 deletions(-) Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
On 08.09.2017 11:10, Eduardo Otubo wrote:
> This patch changes the default behavior of the seccomp filter from
> whitelist to blacklist. By default now all system calls are allowed and
> a small black list of definitely forbidden ones was created.
>
> Signed-off-by: Eduardo Otubo <otubo@redhat.com>
> ---
> include/sysemu/seccomp.h | 2 +
> qemu-seccomp.c | 264 ++++++-----------------------------------------
> vl.c | 1 -
> 3 files changed, 35 insertions(+), 232 deletions(-)
>
> diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> index cfc06008cb..23b9c3c789 100644
> --- a/include/sysemu/seccomp.h
> +++ b/include/sysemu/seccomp.h
> @@ -15,6 +15,8 @@
> #ifndef QEMU_SECCOMP_H
> #define QEMU_SECCOMP_H
>
> +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0)
> +
> #include <seccomp.h>
>
> int seccomp_start(void);
> diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> index df75d9c471..bc9a1f77ff 100644
> --- a/qemu-seccomp.c
> +++ b/qemu-seccomp.c
> @@ -28,232 +28,34 @@
>
> struct QemuSeccompSyscall {
> int32_t num;
> - uint8_t priority;
> + int type;
What's this "type" field good for? I failed to spot the place in the
sources where you are using it...? Anyway, some comments here right
after the struct members would be useful.
Thomas
> + uint8_t set;
> };
>
> -static const struct QemuSeccompSyscall seccomp_whitelist[] = {
> - { SCMP_SYS(timer_settime), 255 },
[...]
> - { SCMP_SYS(memfd_create), 240 },
> -#ifdef HAVE_CACHEFLUSH
> - { SCMP_SYS(cacheflush), 240 },
> -#endif
> - { SCMP_SYS(sysinfo), 240 },
> +static const struct QemuSeccompSyscall blacklist[] = {
> + /* default set of syscalls to blacklist */
> + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT },
> + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT },
> };
>
> int seccomp_start(void)
> @@ -262,19 +64,19 @@ int seccomp_start(void)
> unsigned int i = 0;
> scmp_filter_ctx ctx;
>
> - ctx = seccomp_init(SCMP_ACT_KILL);
> + ctx = seccomp_init(SCMP_ACT_ALLOW);
> if (ctx == NULL) {
> rc = -1;
> goto seccomp_return;
> }
>
> - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) {
> - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0);
> - if (rc < 0) {
> - goto seccomp_return;
> + for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
> + switch (blacklist[i].set) {
> + default:
> + break;
> }
> - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num,
> - seccomp_whitelist[i].priority);
> +
> + rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
> if (rc < 0) {
> goto seccomp_return;
> }
> diff --git a/vl.c b/vl.c
> index fb1f05b937..76e0b3a946 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt)
>
> static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
> {
> - /* FIXME: change this to true for 1.3 */
> if (qemu_opt_get_bool(opts, "enable", false)) {
> #ifdef CONFIG_SECCOMP
> if (seccomp_start() < 0) {
>
On Fri, Sep 08, 2017 at 11:43:27AM +0200, Thomas Huth wrote:
> On 08.09.2017 11:10, Eduardo Otubo wrote:
> > This patch changes the default behavior of the seccomp filter from
> > whitelist to blacklist. By default now all system calls are allowed and
> > a small black list of definitely forbidden ones was created.
> >
> > Signed-off-by: Eduardo Otubo <otubo@redhat.com>
> > ---
> > include/sysemu/seccomp.h | 2 +
> > qemu-seccomp.c | 264 ++++++-----------------------------------------
> > vl.c | 1 -
> > 3 files changed, 35 insertions(+), 232 deletions(-)
> >
> > diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> > index cfc06008cb..23b9c3c789 100644
> > --- a/include/sysemu/seccomp.h
> > +++ b/include/sysemu/seccomp.h
> > @@ -15,6 +15,8 @@
> > #ifndef QEMU_SECCOMP_H
> > #define QEMU_SECCOMP_H
> >
> > +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0)
> > +
> > #include <seccomp.h>
> >
> > int seccomp_start(void);
> > diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> > index df75d9c471..bc9a1f77ff 100644
> > --- a/qemu-seccomp.c
> > +++ b/qemu-seccomp.c
> > @@ -28,232 +28,34 @@
> >
> > struct QemuSeccompSyscall {
> > int32_t num;
> > - uint8_t priority;
> > + int type;
>
> What's this "type" field good for? I failed to spot the place in the
> sources where you are using it...? Anyway, some comments here right
> after the struct members would be useful.
The type is exactly the type of the system call on the blacklist array
below. Being QEMU_SECCOMP_SET_DEFAULT, QEMU_SECCOMP_SET_OBSOLETE, etc.
Do you think comments here worth a full v6?
>
> Thomas
>
> > + uint8_t set;
> > };
> >
> > -static const struct QemuSeccompSyscall seccomp_whitelist[] = {
> > - { SCMP_SYS(timer_settime), 255 },
> [...]
> > - { SCMP_SYS(memfd_create), 240 },
> > -#ifdef HAVE_CACHEFLUSH
> > - { SCMP_SYS(cacheflush), 240 },
> > -#endif
> > - { SCMP_SYS(sysinfo), 240 },
> > +static const struct QemuSeccompSyscall blacklist[] = {
> > + /* default set of syscalls to blacklist */
> > + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT },
> > + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT },
> > };
> >
> > int seccomp_start(void)
> > @@ -262,19 +64,19 @@ int seccomp_start(void)
> > unsigned int i = 0;
> > scmp_filter_ctx ctx;
> >
> > - ctx = seccomp_init(SCMP_ACT_KILL);
> > + ctx = seccomp_init(SCMP_ACT_ALLOW);
> > if (ctx == NULL) {
> > rc = -1;
> > goto seccomp_return;
> > }
> >
> > - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) {
> > - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0);
> > - if (rc < 0) {
> > - goto seccomp_return;
> > + for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
> > + switch (blacklist[i].set) {
> > + default:
> > + break;
> > }
> > - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num,
> > - seccomp_whitelist[i].priority);
> > +
> > + rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
> > if (rc < 0) {
> > goto seccomp_return;
> > }
> > diff --git a/vl.c b/vl.c
> > index fb1f05b937..76e0b3a946 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt)
> >
> > static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
> > {
> > - /* FIXME: change this to true for 1.3 */
> > if (qemu_opt_get_bool(opts, "enable", false)) {
> > #ifdef CONFIG_SECCOMP
> > if (seccomp_start() < 0) {
> >
>
>
--
Eduardo Otubo
Senior Software Engineer @ RedHat
On 08.09.2017 11:50, Eduardo Otubo wrote:
> On Fri, Sep 08, 2017 at 11:43:27AM +0200, Thomas Huth wrote:
>> On 08.09.2017 11:10, Eduardo Otubo wrote:
>>> This patch changes the default behavior of the seccomp filter from
>>> whitelist to blacklist. By default now all system calls are allowed and
>>> a small black list of definitely forbidden ones was created.
>>>
>>> Signed-off-by: Eduardo Otubo <otubo@redhat.com>
>>> ---
>>> include/sysemu/seccomp.h | 2 +
>>> qemu-seccomp.c | 264 ++++++-----------------------------------------
>>> vl.c | 1 -
>>> 3 files changed, 35 insertions(+), 232 deletions(-)
>>>
>>> diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
>>> index cfc06008cb..23b9c3c789 100644
>>> --- a/include/sysemu/seccomp.h
>>> +++ b/include/sysemu/seccomp.h
>>> @@ -15,6 +15,8 @@
>>> #ifndef QEMU_SECCOMP_H
>>> #define QEMU_SECCOMP_H
>>>
>>> +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0)
>>> +
>>> #include <seccomp.h>
>>>
>>> int seccomp_start(void);
>>> diff --git a/qemu-seccomp.c b/qemu-seccomp.c
>>> index df75d9c471..bc9a1f77ff 100644
>>> --- a/qemu-seccomp.c
>>> +++ b/qemu-seccomp.c
>>> @@ -28,232 +28,34 @@
>>>
>>> struct QemuSeccompSyscall {
>>> int32_t num;
>>> - uint8_t priority;
>>> + int type;
>>
>> What's this "type" field good for? I failed to spot the place in the
>> sources where you are using it...? Anyway, some comments here right
>> after the struct members would be useful.
>
> The type is exactly the type of the system call on the blacklist array
> below. Being QEMU_SECCOMP_SET_DEFAULT, QEMU_SECCOMP_SET_OBSOLETE, etc.
Sorry, I still do not understand. If that's the case, what's the
difference between the "type" field and the "set" field? Where do you
use the "type" field?
Thomas
>>> + uint8_t set;
>>> };
>>>
>>> -static const struct QemuSeccompSyscall seccomp_whitelist[] = {
>>> - { SCMP_SYS(timer_settime), 255 },
>> [...]
>>> - { SCMP_SYS(memfd_create), 240 },
>>> -#ifdef HAVE_CACHEFLUSH
>>> - { SCMP_SYS(cacheflush), 240 },
>>> -#endif
>>> - { SCMP_SYS(sysinfo), 240 },
>>> +static const struct QemuSeccompSyscall blacklist[] = {
>>> + /* default set of syscalls to blacklist */
>>> + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT },
>>> };
>>>
>>> int seccomp_start(void)
>>> @@ -262,19 +64,19 @@ int seccomp_start(void)
>>> unsigned int i = 0;
>>> scmp_filter_ctx ctx;
>>>
>>> - ctx = seccomp_init(SCMP_ACT_KILL);
>>> + ctx = seccomp_init(SCMP_ACT_ALLOW);
>>> if (ctx == NULL) {
>>> rc = -1;
>>> goto seccomp_return;
>>> }
>>>
>>> - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) {
>>> - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0);
>>> - if (rc < 0) {
>>> - goto seccomp_return;
>>> + for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
>>> + switch (blacklist[i].set) {
>>> + default:
>>> + break;
>>> }
>>> - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num,
>>> - seccomp_whitelist[i].priority);
>>> +
>>> + rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
>>> if (rc < 0) {
>>> goto seccomp_return;
>>> }
>>> diff --git a/vl.c b/vl.c
>>> index fb1f05b937..76e0b3a946 100644
>>> --- a/vl.c
>>> +++ b/vl.c
>>> @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt)
>>>
>>> static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
>>> {
>>> - /* FIXME: change this to true for 1.3 */
>>> if (qemu_opt_get_bool(opts, "enable", false)) {
>>> #ifdef CONFIG_SECCOMP
>>> if (seccomp_start() < 0) {
>>>
>>
>>
>
On Fri, Sep 08, 2017 at 11:52:42AM +0200, Thomas Huth wrote:
> On 08.09.2017 11:50, Eduardo Otubo wrote:
> > On Fri, Sep 08, 2017 at 11:43:27AM +0200, Thomas Huth wrote:
> >> On 08.09.2017 11:10, Eduardo Otubo wrote:
> >>> This patch changes the default behavior of the seccomp filter from
> >>> whitelist to blacklist. By default now all system calls are allowed and
> >>> a small black list of definitely forbidden ones was created.
> >>>
> >>> Signed-off-by: Eduardo Otubo <otubo@redhat.com>
> >>> ---
> >>> include/sysemu/seccomp.h | 2 +
> >>> qemu-seccomp.c | 264 ++++++-----------------------------------------
> >>> vl.c | 1 -
> >>> 3 files changed, 35 insertions(+), 232 deletions(-)
> >>>
> >>> diff --git a/include/sysemu/seccomp.h b/include/sysemu/seccomp.h
> >>> index cfc06008cb..23b9c3c789 100644
> >>> --- a/include/sysemu/seccomp.h
> >>> +++ b/include/sysemu/seccomp.h
> >>> @@ -15,6 +15,8 @@
> >>> #ifndef QEMU_SECCOMP_H
> >>> #define QEMU_SECCOMP_H
> >>>
> >>> +#define QEMU_SECCOMP_SET_DEFAULT (1 << 0)
> >>> +
> >>> #include <seccomp.h>
> >>>
> >>> int seccomp_start(void);
> >>> diff --git a/qemu-seccomp.c b/qemu-seccomp.c
> >>> index df75d9c471..bc9a1f77ff 100644
> >>> --- a/qemu-seccomp.c
> >>> +++ b/qemu-seccomp.c
> >>> @@ -28,232 +28,34 @@
> >>>
> >>> struct QemuSeccompSyscall {
> >>> int32_t num;
> >>> - uint8_t priority;
> >>> + int type;
> >>
> >> What's this "type" field good for? I failed to spot the place in the
> >> sources where you are using it...? Anyway, some comments here right
> >> after the struct members would be useful.
> >
> > The type is exactly the type of the system call on the blacklist array
> > below. Being QEMU_SECCOMP_SET_DEFAULT, QEMU_SECCOMP_SET_OBSOLETE, etc.
>
> Sorry, I still do not understand. If that's the case, what's the
> difference between the "type" field and the "set" field? Where do you
> use the "type" field?
HARGH, sorry. Perhaps I was debugging tis for too long and didn't
notice it. This was for debug purposes only. I'll remove and resend.
Thanks for spotting this.
> >>> + uint8_t set;
> >>> };
> >>>
> >>> -static const struct QemuSeccompSyscall seccomp_whitelist[] = {
> >>> - { SCMP_SYS(timer_settime), 255 },
> >> [...]
> >>> - { SCMP_SYS(memfd_create), 240 },
> >>> -#ifdef HAVE_CACHEFLUSH
> >>> - { SCMP_SYS(cacheflush), 240 },
> >>> -#endif
> >>> - { SCMP_SYS(sysinfo), 240 },
> >>> +static const struct QemuSeccompSyscall blacklist[] = {
> >>> + /* default set of syscalls to blacklist */
> >>> + { SCMP_SYS(reboot), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(swapon), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(swapoff), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(syslog), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(mount), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(umount), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(kexec_load), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(afs_syscall), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(break), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(ftime), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(getpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(gtty), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(lock), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(mpx), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(prof), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(profil), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(putpmsg), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(security), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(stty), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(tuxcall), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(ulimit), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> + { SCMP_SYS(vserver), 1, QEMU_SECCOMP_SET_DEFAULT },
> >>> };
> >>>
> >>> int seccomp_start(void)
> >>> @@ -262,19 +64,19 @@ int seccomp_start(void)
> >>> unsigned int i = 0;
> >>> scmp_filter_ctx ctx;
> >>>
> >>> - ctx = seccomp_init(SCMP_ACT_KILL);
> >>> + ctx = seccomp_init(SCMP_ACT_ALLOW);
> >>> if (ctx == NULL) {
> >>> rc = -1;
> >>> goto seccomp_return;
> >>> }
> >>>
> >>> - for (i = 0; i < ARRAY_SIZE(seccomp_whitelist); i++) {
> >>> - rc = seccomp_rule_add(ctx, SCMP_ACT_ALLOW, seccomp_whitelist[i].num, 0);
> >>> - if (rc < 0) {
> >>> - goto seccomp_return;
> >>> + for (i = 0; i < ARRAY_SIZE(blacklist); i++) {
> >>> + switch (blacklist[i].set) {
> >>> + default:
> >>> + break;
> >>> }
> >>> - rc = seccomp_syscall_priority(ctx, seccomp_whitelist[i].num,
> >>> - seccomp_whitelist[i].priority);
> >>> +
> >>> + rc = seccomp_rule_add(ctx, SCMP_ACT_KILL, blacklist[i].num, 0);
> >>> if (rc < 0) {
> >>> goto seccomp_return;
> >>> }
> >>> diff --git a/vl.c b/vl.c
> >>> index fb1f05b937..76e0b3a946 100644
> >>> --- a/vl.c
> >>> +++ b/vl.c
> >>> @@ -1032,7 +1032,6 @@ static int bt_parse(const char *opt)
> >>>
> >>> static int parse_sandbox(void *opaque, QemuOpts *opts, Error **errp)
> >>> {
> >>> - /* FIXME: change this to true for 1.3 */
> >>> if (qemu_opt_get_bool(opts, "enable", false)) {
> >>> #ifdef CONFIG_SECCOMP
> >>> if (seccomp_start() < 0) {
> >>>
> >>
> >>
> >
>
--
Eduardo Otubo
Senior Software Engineer @ RedHat
© 2016 - 2026 Red Hat, Inc.