When starting a new container, and the very last step of executing of a
user process fails (last lines of (*linuxStandardInit).Init), it is too
late to print a proper error since both the log pipe and the init pipe
are closed.
This is partially mitigated by using exec.LookPath() which is supposed
to say whether we will be able to execute or not. Alas, it fails to do
so when the binary to be executed resides on a filesystem mounted with
noexec flag.
A workaround would be to use access(2) with X_OK flag. Alas, it is not
working when runc itself is a setuid (or setgid) binary. In this case,
faccessat2(2) with AT_EACCESS can be used, but it is only available
since Linux v5.8.
So, use faccessat2(2) with AT_EACCESS if available. If not, fall back to
access(2) for non-setuid runc, and do nothing for setuid runc (as there
is nothing we can do). Note that this check if in addition to whatever
exec.LookPath does.
Fixes https://github.com/opencontainers/runc/issues/3520
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
If the container binary to be run is removed in between runc create
and runc start, the latter spits the following error:
> can't exec user process: no such file or directory
This is a bit confusing since we don't see what file is missing.
Wrap the unix.Exec error into os.PathError, like in many other cases,
to provide some context. Remove the error wrapping from
(*linuxStandardInit).Init as it is now redundant.
With this patch, the error is now:
> exec /bin/false: no such file or directory
Reported-by: Daniel J Walsh <dwalsh@redhat.com>
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Go 1.17 introduce this new (and better) way to specify build tags.
For more info, see https://golang.org/design/draft-gobuild.
As a way to seamlessly switch from old to new build tags, gofmt (and
gopls) from go 1.17 adds the new tags along with the old ones.
Later, when go < 1.17 is no longer supported, the old build tags
can be removed.
Now, as I started to use latest gopls (v0.7.1), it adds these tags
while I edit. Rather than to randomly add new build tags, I guess
it is better to do it once for all files.
Mind that previous commits removed some tags that were useless,
so this one only touches packages that can at least be built
on non-linux.
Brought to you by
go1.17 fmt ./...
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
When running a script from an azure file share interrupted syscall
occurs quite frequently, to remedy this add retries around execve
syscall, when EINTR is returned.
Signed-off-by: Maksim An <maksiman@microsoft.com>
Moving these utilities to a separate package, so that consumers of this
package don't have to pull in the whole "system" package.
Looking at uses of these utilities (outside of runc itself);
`RunningInUserNS()` is used by [various external consumers][1],
so adding a "Deprecated" alias for this.
[1]: https://grep.app/search?current=2&q=.RunningInUserNS
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
In many places (not all of them though) we can use `unix.`
instead of `syscall.` as these are indentical.
In particular, x/sys/unix defines:
```go
type Signal = syscall.Signal
type Errno = syscall.Errno
type SysProcAttr = syscall.SysProcAttr
const ENODEV = syscall.Errno(0x13)
```
and unix.Exec() calls syscall.Exec().
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
This fixes the following compilation error on 32bit ARM:
```
$ GOARCH=arm GOARCH=6 go build ./libcontainer/system/
libcontainer/system/linux.go:119:89: constant 4294967295 overflows int
```
Signed-off-by: Tibor Vass <tibor@docker.com>
When a subreaper is enabled, it might expect to reap a process and
retrieve its exit code. That's the reason why this patch is giving
the possibility to define the usage of a subreaper as a consumer of
libcontainer. Relying on this information, libcontainer will not
wait for signalled processes in case a subreaper has been set.
Fixes#1677
Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
Use IoctlGetInt and IoctlGetTermios/IoctlSetTermios instead of manually
reimplementing them.
Because of unlockpt, the ioctl wrapper is still needed as it needs to
pass a pointer to a value, which is not supported by any ioctl function
in x/sys/unix yet.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Use unix.Prctl() instead of manually reimplementing it using
unix.RawSyscall. Also use unix.SECCOMP_MODE_FILTER instead of locally
defining it.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Since syscall is outdated and broken for some architectures,
use x/sys/unix instead.
There are still some dependencies on the syscall package that will
remain in syscall for the forseeable future:
Errno
Signal
SysProcAttr
Additionally:
- os still uses syscall, so it needs to be kept for anything
returning *os.ProcessState, such as process.Wait.
Signed-off-by: Christy Perez <christy@linux.vnet.ibm.com>
No substantial code change.
Note that some style errors reported by `golint` are not fixed due to possible compatibility issues.
Signed-off-by: Akihiro Suda <suda.kyoto@gmail.com>
Fixes#680
This changes setupRlimit to use the Prlimit syscall (rather than
Setrlimit) and moves the call to the parent process. This is necessary
because Setrlimit would affect the libcontainer consumer if called in
the parent, and would fail if called from the child if the
child process is in a user namespace and the requested rlimit is higher
than that in the parent.
Signed-off-by: Julian Friedman <julz.friedman@uk.ibm.com>
We need to make sure the container is destroyed before closing the stdio
for the container. This becomes a big issues when running in the host's
pid namespace because the other processes could have inherited the stdio
of the initial process. The call to close will just block as they still
have the io open.
Calling destroy before closing io, especially in the host pid namespace
will cause all additional processes to be killed in the container's
cgroup. This will allow the io to be closed successfuly.
This change makes sure the order for destroy and close is correct as
well as ensuring that if any errors encoutered during start or exec will
be handled by terminating the process and destroying the container. We
cannot use defers here because we need to enforce the correct ordering
on destroy.
This also sets the subreaper setting for runc so that when running in
pid host, runc can wait on the addiontal processes launched by the
container, useful on destroy, but also good for reaping the additional
processes that were launched.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
When we launch a container in a new user namespace, we cannot create
devices, so we bind mount the host's devices into place instead.
If we are running in a user namespace (i.e. nested in a container),
then we need to do the same thing. Add a function to detect that
and check for it before doing mknod.
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
---
Changelog - add a comment clarifying what's going on with the
uidmap file.
Kir Kolyshkin