We need to update the eBPF library so that we can get the raw syscall
errors from bpf(2) syscalls using errors.Is.
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
(cherry picked from commit fe518a0678)
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
The `errors.Is(err, unix.EINVAL)` check in `haveBpfProgReplace()` was
broken because the `cilium/ebpf` library did not "wrap" errors.
https://github.com/cilium/ebpf/blob/v0.6.0/link/program.go#L72
So the eBPF support of runc was broken for kernel prior to 5.6.
This commit bumps up cilium/ebpf to contain cilium/ebpf PR 320.
Fix opencontainers/runc issue 3008
Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
This package was recently updated to add support for Linux on
32-bit PowerPC (ppc), implemented by gccgo.
Signed-off-by: Ben Hutchings <ben.hutchings@essensium.com>
full diff: https://github.com/cilium/ebpf/compare/v0.4.0...v0.5.0
Breaking changes
------------------------------------------
All LoadPinned*() functions now take LoadPinOptions to control loader behaviour.
Simply pass nil to load with default options.
- LoadPinnedMap()
- LoadPinnedProgram()
- LoadPinnedCgroup()
- LoadPinnedIter()
- LoadPinnedRawLink()
- LoadPinnedNetNs()
Bug fixes
------------------------------------------
- Program.IsPinned() now behaves correctly on maps loaded from bpffs
- Map.Pin() no longer clobbers the destination file if it already exists
Features
------------------------------------------
- Attaching to k(ret)probes and tracepoints can now be done with link.Kprobe(),
link.Kretprobe() and link.Tracepoint()
- Programs of type Kprobe automatically get their KernelVersion fields populated
by detecting the kernel version at runtime
- MapOptions now contains a LoadPinOptions
- ProgSpec now contains a Flags field, adding support for BPF_F_SLEEPABLE
- Made BTF map loader more flexible by looping over Vars in a BTF data section
- Pinned Maps and Programs can now be loaded from bpffs in read-or write-only mode
- Added golangci-lint project configuration, running in CI
Examples
------------------------------------------
kprobe and tracepoint examples updated to use the new link.Kprobe() and link.Tracepoint() API
There is now an example for how to attach eBPF programs to uprobes
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Caught by golangci-lint when enabling golint:
libcontainer/cgroups/ebpf/ebpf.go:35:12: SA1019: prog.Attach is deprecated: use link.RawAttachProgram instead. (staticcheck)
if err := prog.Attach(dirFD, ebpf.AttachCGroupDevice, unix.BPF_F_ALLOW_MULTI); err != nil {
^
libcontainer/cgroups/ebpf/ebpf.go:39:13: SA1019: prog.Detach is deprecated: use link.RawDetachProgram instead. (staticcheck)
if err := prog.Detach(dirFD, ebpf.AttachCGroupDevice, unix.BPF_F_ALLOW_MULTI); err != nil {
^
Worth noting that we currently call prog.Detach() with unix.BPF_F_ALLOW_MULTI;
https://github.com/golang/sys/blob/22da62e12c0cd9c1da93581e1113ca4d82a5be14/unix/zerrors_linux.go#L178
BPF_F_ALLOW_MULTI = 0x2
Looking at the source code for prog.Detach(); https://github.com/cilium/ebpf/blob/v0.4.0/prog.go#L579-L581,
this would _always_ produce an error:
if flags != 0 {
return errors.New("flags must be zero")
}
Note that the flags parameter is not used (except for that validation)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This updates handling of capabilities to match the updated runtime specification,
in https://github.com/opencontainers/runtime-spec/pull/1094.
Prior to that change, the specification required runtimes to produce a (fatal)
error if a container configuration requested capabilities that could not be
granted (either the capability is "unknown" to the runtime, not supported by the
kernel version in use, or not available in the environment that the runtime
operates in).
This caused problems in situations where the runtime was running in a restricted
environment (for example, docker-in-docker), or if there is a mismatch between
the list of capabilities known by higher-level runtimes and the OCI runtime.
Some examples:
- Kernel 5.8 introduced CAP_PERFMON, CAP_BPF, and CAP_CHECKPOINT_RESTORE
capabilities. Docker 20.10.0 ("higher level runtime") shipped with
an updated list of capabilities, and when creating a "privileged" container,
would determine what capabilities are known by the kernel in use, and request
all those capabilities (by including them in the container config).
However, runc did not yet have an updated list of capabilities, and therefore
reject the container specification, producing an error because the new
capabilities were "unknown".
- When running nested containers, for example, when running docker-in-docker,
the "inner" container may be using a more recent version of docker than the
"outer" container. In this situation, the "outer" container may be missing
capabilities that the inner container expects to be supported (based on
kernel version). However, starting the container would fail, because the OCI
runtime could not grant those capabilities (them not being available in the
environment it's running in).
WARN (but otherwise ignore) capabilities that cannot be granted
--------------------------------------------------------------------------------
This patch changes the handling to WARN (but otherwise ignore) capabilities that
are requested in the container config, but cannot be granted, alleviating higher
level runtimes to detect what capabilities are supported (by the kernel, and
in the current environment), as well as avoiding failures in situations where
the higher-level runtime is aware of capabilities that are not (yet) supported
by runc.
Impact on security
--------------------------------------------------------------------------------
Given that `capabilities` is an "allow-list", ignoring unknown capabilities does
not impose a security risk; worst case, a container does not get all requested
capabilities granted and, as a result, some actions may fail.
Backward-compatibility
--------------------------------------------------------------------------------
This change should be fully backward compatible. Higher-level runtimes that
already dynamically adjust the list of requested capabilities can continue to do
so. Runtimes that do not adjust will see an improvement (containers can start
even if some of the requested capabilities are not granted). Container processes
MAY fail (as described in "impact on security"), but users can debug this
situation either by looking at the warnings produces by the OCI runtime, or using
tools such as `capsh` / `libcap` to get the list of actual capabilities in the
container.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
Switch from github.com/golang/protobuf (which appears to be obsoleted)
to google.golang.org/protobuf (which appears to be a replacement).
This needs a bump to go-criu v5.
[v2: fix debug print in criuSwrk]
[v3: switch to go-criu v5]
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Having -EPERM is the default was a fairly significant mistake from a
future-proofing standpoint in that it makes any new syscall return a
non-ignorable error (from glibc's point of view). We need to correct
this now because faccessat2(2) is something glibc critically needs to
have support for, but they're blocked on container runtimes because we
return -EPERM unconditionally (leading to confusion in glibc). This is
also a problem we're probably going to keep running into in the future.
Unfortunately there are several issues which stop us from having a clean
solution to this problem:
1. libseccomp has several limitations which require us to emulate
behaviour we want:
a. We cannot do logic based on syscall number, meaning we cannot
specify a "largest known syscall number";
b. libseccomp doesn't know in which kernel version a syscall was
added, and has no API for "minimum kernel version" so we cannot
simply ask libseccomp to generate sane -ENOSYS rules for us.
c. Additional seccomp rules for the same syscall are not treated as
distinct rules -- if rules overlap, seccomp will merge them. This
means we cannot add per-syscall -EPERM fallbacks;
d. There is no inverse operation for SCMP_CMP_MASKED_EQ;
e. libseccomp does not allow you to specify multiple rules for a
single argument, making it impossible to invert OR rules for
arguments.
2. The runtime-spec does not have any way of specifying:
a. The errno for the default action;
b. The minimum kernel version or "newest syscall at time of profile
creation"; nor
c. Which syscalls were intentionally excluded from the allow list
(weird syscalls that are no longer used were excluded entirely,
but Docker et al expect those syscalls to get EPERM not ENOSYS).
3. Certain syscalls should not return -ENOSYS (especially only for
certain argument combinations) because this could also trigger glibc
confusion. This means we have to return -EPERM for certain syscalls
but not as a global default.
4. There is not an obvious (and reasonable) upper limit to syscall
numbers, so we cannot create a set of rules for each syscall above
the largest syscall number in libseccomp. This means we must handle
inverse rules as described below.
5. Any syscall can be specified multiple times, which can make
generation of hotfix rules much harder.
As a result, we have to work around all of these things by coming up
with a heuristic to stop the bleeding. In the future we could hopefully
improve the situation in the runtime-spec and libseccomp.
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.
Sadly this is not a perfect solution because syscalls can be added
out-of-order and the syscall table can contain holes for several
releases. Unfortuntely we do not have a nicer solution at the moment
because there is no library which provides information about which Linux
version a syscall was introduced in. Until that exists, this workaround
will have to be good enough.
The above behaviour only happens if the default action is a blocking
action (in other words it is not SCMP_ACT_LOG or SCMP_ACT_ALLOW). If the
default action is permissive then we don't do any patching.
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
full diff: https://github.com/cilium/ebpf/compare/v0.1.0...v0.2.0
- btf: add go-fuzz targets
- btf: avoid Type copy in FuncProto.walk
- btf: check err in loadSpecFromVmlinux
- btf: handle type name flavours
- CI: test on 5.9 kernel
- cmd/bpf2go: output ELF .o next to the .go file
- link: add AttachSkLookup
- Remove two unused functions
- Support LSM attach
- use buffered I/O to cut down on read syscalls
- Various doc link fixes
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
* cpuset.cpus -> AllowedCPUs
* cpuset.mems -> AllowedMemoryNodes
No test for cgroup v2 resources.unified override, as this requires a
separate test case, and all the unified resources are handled uniformly
so there's little sense to test all parameters.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
full diff: https://github.com/sirupsen/logrus/compare/v1.6.0...v1.7.0
removes dependency on github.com/konsorten/go-windows-terminal-sequences
Features:
* a new buffer pool management API has been added
* a set of `<LogLevel>Fn()` functions have been added
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
full diff: https://github.com/moby/sys/compare/mountinfo/v0.1.3...mountinfo/v0.2.0
Bug fixes:
- Fix path unescaping for paths with double quotes
Improvements:
- Mounted: speed up by adding fast paths using openat2 (Linux-only) and stat
- Mounted: relax path requirements (allow relative, non-cleaned paths, symlinks)
- Unescape fstype and source fields
- Documentation improvements
Testing/CI:
- Unit tests: exclude darwin
- CI: run tests under Fedora 32 to test openat2
- TestGetMounts: fix for Ubuntu build system
- Makefile: fix ignoring test failures
- CI: add cross build
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This updates to the latest version of go-criu (4.0.2) which is based on
CRIU 3.14.
As go-criu provides an existing way to query the CRIU binary for its
version this also removes all the code from runc to handle CRIU version
checking and now relies on go-criu.
An important side effect of this change is that this raises the minimum
CRIU version to 3.0.0 as that is the first CRIU version that supports
CRIU version queries via RPC in contrast to parsing the output of
'criu --version'
CRIU 3.0 has been released in April of 2017.
Signed-off-by: Adrian Reber <areber@redhat.com>
Aleksa Sarai