Add this syscall to match the profile in containerd
containerd: a6e52c74fa
libseccomp: 53267af3fb
kernel: 9f6c532f59
futex: Add sys_futex_wake()
To complement sys_futex_waitv() add sys_futex_wake(). This syscall
implements what was previously known as FUTEX_WAKE_BITSET except it
uses 'unsigned long' for the bitmask and takes FUTEX2 flags.
The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit d69729e053)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Add this syscall to match the profile in containerd
containerd: a6e52c74fa
libseccomp: 53267af3fb
kernel: cb8c4312af
futex: Add sys_futex_wait()
To complement sys_futex_waitv()/wake(), add sys_futex_wait(). This
syscall implements what was previously known as FUTEX_WAIT_BITSET
except it uses 'unsigned long' for the value and bitmask arguments,
takes timespec and clockid_t arguments for the absolute timeout and
uses FUTEX2 flags.
The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 10d344d176)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Add this syscall to match the profile in containerd
containerd: a6e52c74fa
libseccomp: 53267af3fb
kernel: 0f4b5f9722
futex: Add sys_futex_requeue()
Finish off the 'simple' futex2 syscall group by adding
sys_futex_requeue(). Unlike sys_futex_{wait,wake}() its arguments are
too numerous to fit into a regular syscall. As such, use struct
futex_waitv to pass the 'source' and 'destination' futexes to the
syscall.
This syscall implements what was previously known as FUTEX_CMP_REQUEUE
and uses {val, uaddr, flags} for source and {uaddr, flags} for
destination.
This design explicitly allows requeueing between different types of
futex by having a different flags word per uaddr.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit df57a080b6)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Add this syscall to match the profile in containerd
containerd: a6e52c74fa
libseccomp: 53267af3fb
kernel: c35559f94e
x86/shstk: Introduce map_shadow_stack syscall
When operating with shadow stacks enabled, the kernel will automatically
allocate shadow stacks for new threads, however in some cases userspace
will need additional shadow stacks. The main example of this is the
ucontext family of functions, which require userspace allocating and
pivoting to userspace managed stacks.
Unlike most other user memory permissions, shadow stacks need to be
provisioned with special data in order to be useful. They need to be setup
with a restore token so that userspace can pivot to them via the RSTORSSP
instruction. But, the security design of shadow stacks is that they
should not be written to except in limited circumstances. This presents a
problem for userspace, as to how userspace can provision this special
data, without allowing for the shadow stack to be generally writable.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 8826f402f9)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Add this syscall to match the profile in containerd
containerd: a6e52c74fa
libseccomp: 53267af3fb
kernel: 09da082b07
fs: Add fchmodat2()
On the userspace side fchmodat(3) is implemented as a wrapper
function which implements the POSIX-specified interface. This
interface differs from the underlying kernel system call, which does not
have a flags argument. Most implementations require procfs [1][2].
There doesn't appear to be a good userspace workaround for this issue
but the implementation in the kernel is pretty straight-forward.
The new fchmodat2() syscall allows to pass the AT_SYMLINK_NOFOLLOW flag,
unlike existing fchmodat.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 6f242f1a28)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Add this syscall to match the profile in containerd
containerd: a6e52c74fa
libseccomp: 53267af3fb
kernel: cf264e1329
NAME
cachestat - query the page cache statistics of a file.
SYNOPSIS
#include <sys/mman.h>
struct cachestat_range {
__u64 off;
__u64 len;
};
struct cachestat {
__u64 nr_cache;
__u64 nr_dirty;
__u64 nr_writeback;
__u64 nr_evicted;
__u64 nr_recently_evicted;
};
int cachestat(unsigned int fd, struct cachestat_range *cstat_range,
struct cachestat *cstat, unsigned int flags);
DESCRIPTION
cachestat() queries the number of cached pages, number of dirty
pages, number of pages marked for writeback, number of evicted
pages, number of recently evicted pages, in the bytes range given by
`off` and `len`.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 4d0d5ee10d)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This syscall is gated by CAP_SYS_NICE, matching the profile in containerd.
containerd: a6e52c74fa
libseccomp: d83cb7ac25
kernel: c6018b4b25
mm/mempolicy: add set_mempolicy_home_node syscall
This syscall can be used to set a home node for the MPOL_BIND and
MPOL_PREFERRED_MANY memory policy. Users should use this syscall after
setting up a memory policy for the specified range as shown below.
mbind(p, nr_pages * page_size, MPOL_BIND, new_nodes->maskp,
new_nodes->size + 1, 0);
sys_set_mempolicy_home_node((unsigned long)p, nr_pages * page_size,
home_node, 0);
The syscall allows specifying a home node/preferred node from which
kernel will fulfill memory allocation requests first.
...
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
(cherry picked from commit 1251982cf7)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This syncs the seccomp profile with changes made to containerd's default
profile in [1].
The original containerd issue and PR mention:
> Security experts generally believe io_uring to be unsafe. In fact
> Google ChromeOS and Android have turned it off, plus all Google
> production servers turn it off. Based on the blog published by Google
> below it seems like a bunch of vulnerabilities related to io_uring can
> be exploited to breakout of the container.
>
> [2]
>
> Other security reaserchers also hold this opinion: see [3] for a
> blackhat presentation on io_uring exploits.
For the record, these syscalls were added to the allowlist in [4].
[1]: a48ddf4a20
[2]: https://security.googleblog.com/2023/06/learnings-from-kctf-vrps-42-linux.html
[3]: https://i.blackhat.com/BH-US-23/Presentations/US-23-Lin-bad_io_uring.pdf
[4]: https://github.com/moby/moby/pull/39415
Signed-off-by: Albin Kerouanton <albinker@gmail.com>
This syncs the seccomp-profile with the latest changes in containerd's
profile, applying the same changes as 17a9324035
Some background from the associated ticket:
> We want to use vsock for guest-host communication on KubeVirt
> (https://github.com/kubevirt/kubevirt). In KubeVirt we run VMs in pods.
>
> However since anyone can just connect from any pod to any VM with the
> default seccomp settings, we cannot limit connection attempts to our
> privileged node-agent.
>
> ### Describe the solution you'd like
> We want to deny the `socket` syscall for the `AF_VSOCK` family by default.
>
> I see in [1] and [2] that AF_VSOCK was actually already blocked for some
> time, but that got reverted since some architectures support the `socketcall`
> syscall which can't be restricted properly. However we are mostly interested
> in `arm64` and `amd64` where limiting `socket` would probably be enough.
>
> ### Additional context
> I know that in theory we could use our own seccomp profiles, but we would want
> to provide security for as many users as possible which use KubeVirt, and there
> it would be very helpful if this protection could be added by being part of the
> DefaultRuntime profile to easily ensure that it is active for all pods [3].
>
> Impact on existing workloads: It is unlikely that this will disturb any existing
> workload, becuase VSOCK is almost exclusively used for host-guest commmunication.
> However if someone would still use it: Privileged pods would still be able to
> use `socket` for `AF_VSOCK`, custom seccomp policies could be applied too.
> Further it was already blocked for quite some time and the blockade got lifted
> due to reasons not related to AF_VSOCK.
>
> The PR in KubeVirt which adds VSOCK support for additional context: [4]
>
> [1]: https://github.com/moby/moby/pull/29076#commitcomment-21831387
> [2]: dcf2632945
> [3]: https://kubernetes.io/docs/tutorials/security/seccomp/#enable-the-use-of-runtimedefault-as-the-default-seccomp-profile-for-all-workloads
> [4]: https://github.com/kubevirt/kubevirt/pull/8546
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Update the profile to make use of CAP_BPF and CAP_PERFMON capabilities. Prior to
kernel 5.8, bpf and perf_event_open required CAP_SYS_ADMIN. This change enables
finer control of the privilege setting, thus allowing us to run certain system
tracing tools with minimal privileges.
Based on the original patch from Henry Wang in the containerd repository.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Add pkey_alloc(2), pkey_free(2) and pkey_mprotect(2) in seccomp default profile.
pkey_alloc(2), pkey_free(2) and pkey_mprotect(2) can only configure
the calling process's own memory, so they are existing "safe for everyone" syscalls.
close issue: #43481
Signed-off-by: zhubojun <bojun.zhu@foxmail.com>
This commit allows the Landlock[0] system calls in the default seccomp
policy.
Landlock was introduced in kernel 5.13, to fill the gap that inspecting
filepaths passed as arguments to filesystem system calls is not really
possible with pure `seccomp` (unless involving `ptrace`).
Allowing Landlock by default fits in with allowing `seccomp` for
containerized applications to voluntarily restrict their access rights
to files within the container.
[0]: https://www.kernel.org/doc/html/latest/userspace-api/landlock.html
Signed-off-by: Tudor Brindus <me@tbrindus.ca>
This system call is only available on the 32- and 64-bit PowerPC, it is
used by modern programming language implementations (such as gcc-go) to
implement coroutine features through userspace context switches.
Other container environment, such as Systemd nspawn already whitelist
this system call in their seccomp profile [1] [2]. As such, it would be
nice to also whitelist it in moby.
This issue was encountered on Alpine Linux GitLab CI system, which uses
moby, when attempting to execute gcc-go compiled software on ppc64le.
[1]: https://github.com/systemd/systemd/pull/9487
[2]: https://github.com/systemd/systemd/issues/9485
Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Since commit "seccomp: Sync fields with runtime-spec fields"
(5d244675bd) we support to specify the
DefaultErrnoRet to be used.
Before that commit it was not specified and EPERM was used by default.
This commit keeps the same behaviour but just makes it explicit that the
default is EPERM.
Signed-off-by: Rodrigo Campos <rodrigo@kinvolk.io>
If no seccomp policy is requested, then the built-in default policy in
dockerd applies. This has no rule for "clone3" defined, nor any default
errno defined. So when runc receives the config it attempts to determine
a default errno, using logic defined in its commit:
7a8d7162f9
As explained in the above commit message, runc uses a heuristic to
decide which errno to return by default:
[quote]
The solution applied here is to prepend a "stub" filter which returns
-ENOSYS if the requested syscall has a larger syscall number than any
syscall mentioned in the filter. The reason for this specific rule is
that syscall numbers are (roughly) allocated sequentially and thus newer
syscalls will (usually) have a larger syscall number -- thus causing our
filters to produce -ENOSYS if the filter was written before the syscall
existed.
[/quote]
Unfortunately clone3 appears to one of the edge cases that does not
result in use of ENOSYS, instead ending up with the historical EPERM
errno.
Latest glibc (2.33.9000, in Fedora 35 rawhide) will attempt to use
clone3 by default. If it sees ENOSYS then it will automatically
fallback to using clone. Any other errno is treated as a fatal
error. Thus when docker seccomp policy triggers EPERM from clone3,
no fallback occurs and programs are thus unable to spawn threads.
The clone3 syscall is much more complicated than clone, most notably its
flags are not exposed as a directly argument any more. Instead they are
hidden inside a struct. This means that seccomp filters are unable to
apply policy based on values seen in flags. Thus we can't directly
replicate the current "clone" filtering for "clone3". We can at least
ensure "clone3" returns ENOSYS errno, to trigger fallback to "clone"
at which point we can filter on flags.
Fixes: https://github.com/moby/moby/issues/42680
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
This makes the type better reflect the difference with the "runtime" profile;
our local type is used to generate a runtime-spec seccomp profile and extends
the runtime-spec type with additional fields; adding a "Name" field for backward
compatibility with older JSON representations, additional "Comment" metadata,
and conditional rules ("Includes", "Excludes") used during generation to adjust
the profile based on the container (capabilities) and host's (architecture, kernel)
configuration.
This change introduces one change in the type; the "runtime-spec" type uses a
`[]LinuxSeccompArg` for the `Args` field, whereas the local type used pointers;
`[]*LinuxSeccompArg`.
In addition, the runtime-spec Syscall type brings a new `ErrnoRet` field, allowing
the profile to specify the errno code returned for the syscall, which allows
changing the default EPERM for specific syscalls.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
These syscalls were disabled in #18971
due to them requiring CAP_PTRACE. CAP_PTRACE was blocked by default due
to a ptrace related exploit. This has been patched in the Linux kernel
(version 4.8) and thus `ptrace` has been re-enabled. However, these
associated syscalls seem to have been left behind. This commit brings
them in line with `ptrace`, and re-enables it for kernel > 4.8.
Signed-off-by: clubby789 <jamie@hill-daniel.co.uk>
These syscalls (some of which have been in Linux for a while but were
missing from the profile) fall into a few buckets:
* close_range(2), epoll_pwait2(2) are just extensions of existing "safe
for everyone" syscalls.
* The mountv2 API syscalls (fs*(2), move_mount(2), open_tree(2)) are
all equivalent to aspects of mount(2) and thus go into the
CAP_SYS_ADMIN category.
* process_madvise(2) is similar to the other process_*(2) syscalls and
thus goes in the CAP_SYS_PTRACE category.
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Restartable Sequences (rseq) are a kernel-based mechanism for fast
update operations on per-core data in user-space. Some libraries, like
the newest version of Google's TCMalloc, depend on it [1].
This also makes dockers default seccomp profile on par with systemd's,
which enabled 'rseq' in early 2019 [2].
1: https://google.github.io/tcmalloc/design.html
2: 6fee3be0b4
Signed-off-by: Florian Schmaus <flo@geekplace.eu>
Add the membarrier syscall to the default seccomp profile.
It is for example used in the implementation of dlopen() in
the musl libc of Alpine images.
Signed-off-by: Julio Guerra <julio@sqreen.com>
Relates to https://patchwork.kernel.org/patch/10756415/
Added to whitelist:
- `clock_getres_time64` (equivalent of `clock_getres`, which was whitelisted)
- `clock_gettime64` (equivalent of `clock_gettime`, which was whitelisted)
- `clock_nanosleep_time64` (equivalent of `clock_nanosleep`, which was whitelisted)
- `futex_time64` (equivalent of `futex`, which was whitelisted)
- `io_pgetevents_time64` (equivalent of `io_pgetevents`, which was whitelisted)
- `mq_timedreceive_time64` (equivalent of `mq_timedreceive`, which was whitelisted)
- `mq_timedsend_time64 ` (equivalent of `mq_timedsend`, which was whitelisted)
- `ppoll_time64` (equivalent of `ppoll`, which was whitelisted)
- `pselect6_time64` (equivalent of `pselect6`, which was whitelisted)
- `recvmmsg_time64` (equivalent of `recvmmsg`, which was whitelisted)
- `rt_sigtimedwait_time64` (equivalent of `rt_sigtimedwait`, which was whitelisted)
- `sched_rr_get_interval_time64` (equivalent of `sched_rr_get_interval`, which was whitelisted)
- `semtimedop_time64` (equivalent of `semtimedop`, which was whitelisted)
- `timer_gettime64` (equivalent of `timer_gettime`, which was whitelisted)
- `timer_settime64` (equivalent of `timer_settime`, which was whitelisted)
- `timerfd_gettime64` (equivalent of `timerfd_gettime`, which was whitelisted)
- `timerfd_settime64` (equivalent of `timerfd_settime`, which was whitelisted)
- `utimensat_time64` (equivalent of `utimensat`, which was whitelisted)
Not added to whitelist:
- `clock_adjtime64` (equivalent of `clock_adjtime`, which was not whitelisted)
- `clock_settime64` (equivalent of `clock_settime`, which was not whitelisted)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
All clone flags for namespace should be denied.
Based-on-patch-by: Kenta Tada <Kenta.Tada@sony.com>
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
io_pgetevents() is a new Linux system call. It is similar to io_getevents()
that is already whitelisted, and adds no special abilities over that system call.
Allow that system call to enable applications that use it.
Fixes#38894.
Signed-off-by: Avi Kivity <avi@scylladb.com>
4.8+ kernels have fixed the ptrace security issues
so we can allow ptrace(2) on the default seccomp
profile if we do the kernel version check.
93e35efb8d
Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>
This call is what is used to implement `dmesg` to get kernel messages
about the host. This can leak substantial information about the host.
It is normally available to unprivileged users on the host, unless
the sysctl `kernel.dmesg_restrict = 1` is set, but this is not set
by standard on the majority of distributions. Blocking this to restrict
leaks about the configuration seems correct.
Fix#37897
See also https://googleprojectzero.blogspot.com/2018/09/a-cache-invalidation-bug-in-linux.html
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
The quotactl syscall is being whitelisted in default seccomp profile,
gated by CAP_SYS_ADMIN.
Signed-off-by: Panagiotis Moustafellos <pmoust@elastic.co>
