If a relative pathed exe is used for InitArgs init will fail to run if Cwd is not set the original path.
Prevent failure of init to run by ensuring that exe in InitArgs is an absolute path.
Signed-off-by: Steven Hartland <steven.hartland@multiplay.co.uk>
If we pass a file descriptor to the host filesystem while joining a
container, there is a race condition where a process inside the
container can ptrace(2) the joining process and stop it from closing its
file descriptor to the stateDirFd. Then the process can access the
*host* filesystem from that file descriptor. This was fixed in part by
5d93fed3d2 ("Set init processes as non-dumpable"), but that fix is
more of a hail-mary than an actual fix for the underlying issue.
To fix this, don't open or pass the stateDirFd to the init process
unless we're creating a new container. A proper fix for this would be to
remove the need for even passing around directory file descriptors
(which are quite dangerous in the context of mount namespaces).
There is still an issue with containers that have CAP_SYS_PTRACE and are
using the setns(2)-style of joining a container namespace. Currently I'm
not really sure how to fix it without rampant layer violation.
Fixes: CVE-2016-9962
Fixes: 5d93fed3d2 ("Set init processes as non-dumpable")
Signed-off-by: Aleksa Sarai <asarai@suse.de>
When signaling children and the signal is SIGKILL wait for children
otherwise conditionally wait for children which are ready to report.
This reaps all children which exited due to the signal sent without
blocking indefinitely.
Also:
* Ignore ignore ECHILD, which means the child has already gone.
Signed-off-by: Steven Hartland <steven.hartland@multiplay.co.uk>
We could fail and return in tty.recvtty() and miss
tty.Close(), which might cause broken console output.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Ensure that the pipe is always closed during the error processing of StartInitialization.
Also:
* Fix a comment typo.
* Use newContainerInit directly as there's no need for i to be an initer.
* Move the comment about the behaviour of Init() directly above it, clarifying what happens for all defers.
Signed-off-by: Steven Hartland <steven.hartland@multiplay.co.uk>
Add the import of nsenter to the example in libcontainer's README.md, as without it none of the example code works.
Signed-off-by: Steven Hartland <steven.hartland@multiplay.co.uk>
POSIX mandates that `cmsg_len` in `struct cmsghdr` is a `socklen_t`,
which is an `unsigned int`. Musl libc as used in Alpine implements
this; Glibc ignores the spec and makes it a `size_t` ie `unsigned long`.
To avoid the `-Wformat=` warning from the `%lu` on Alpine, cast this
to an `unsigned long` always.
Signed-off-by: Justin Cormack <justin.cormack@docker.com>
Add godoc links to README.md files for runc and libcontainer so its easy to access the golang documentation.
Signed-off-by: Steven Hartland <steven.hartland@multiplay.co.uk>
signalAllProcesses was making the assumption that the requested signal was SIGKILL, possibly due to the signal parameter being added at a later date, and hence it was safe to wait for all processes which is not the case.
BaseContainer.Signal(s os.Signal, all bool) exposes this functionality to consumers, so an arbitrary signal could be used which is not guaranteed to make the processes exit.
Correct the documentation for signalAllProcesses around the signal delivered and update it so that the wait is only performed on SIGKILL hence making it safe to process other signals without risk of blocking forever, while still maintaining compatibility to SIGKILL callers.
Signed-off-by: Steven Hartland <steven.hartland@multiplay.co.uk>
commit b517076907 added a check that kill accepts two arguments.
Since the second argument is optional, change it back to accept the
shorter form "kill CONTAINER".
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
The parameters passed to `GetExecUser` is not correct.
Consider the following code:
```
package main
import (
"fmt"
"io"
"os"
)
func main() {
passwd, err := os.Open("/etc/passwd1")
if err != nil {
passwd = nil
} else {
defer passwd.Close()
}
err = GetUserPasswd(passwd)
if err != nil {
fmt.Printf("%#v\n", err)
}
}
func GetUserPasswd(r io.Reader) error {
if r == nil {
return fmt.Errorf("nil source for passwd-formatted
data")
} else {
fmt.Printf("r = %#v\n", r)
}
return nil
}
```
If the file `/etc/passwd1` is not exist, we expect to return
`nil source for passwd-formatted data` error, and in fact, the func
`GetUserPasswd` return nil.
The same logic exists in runc code. this patch fix it.
Signed-off-by: Wang Long <long.wanglong@huawei.com>
The `bufio.Scanner.Scan` method returns false either by reaching the
end of the input or an error. After Scan returns false, the Err method
will return any error that occurred during scanning, except that if it
was io.EOF, Err will return nil.
We should check the error when Scan return false(out of the for loop).
Signed-off-by: Wang Long <long.wanglong@huawei.com>
This sets the init processes that join and setup the container's
namespaces as non-dumpable before they setns to the container's pid (or
any other ) namespace.
This settings is automatically reset to the default after the Exec in
the container so that it does not change functionality for the
applications that are running inside, just our init processes.
This prevents parent processes, the pid 1 of the container, to ptrace
the init process before it drops caps and other sets LSMs.
This patch also ensures that the stateDirFD being used is still closed
prior to exec, even though it is set as O_CLOEXEC, because of the order
in the kernel.
https://github.com/torvalds/linux/blob/v4.9/fs/exec.c#L1290-L1318
The order during the exec syscall is that the process is set back to
dumpable before O_CLOEXEC are processed.
Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
On some systems, when we mount some cgroup subsystems into
a same mountpoint, the name sequence of mount options and
cgroup directory name can not be the same.
For example, the mount option is cpuacct,cpu, but
mountpoint name is /sys/fs/cgroup/cpu,cpuacct. In current
runc, we set mount destination name from combining
subsystems, which comes from mount option from
/proc/self/mountinfo, so in my case the name would be
/sys/fs/cgroup/cpuacct,cpu, which is differernt from
host, and will break some applications.
Fix it by using directory name from host mountpoint.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Set minimal required args to 1 for `exec` command to roll back to
previous behavior, also modify help message a little bit.
Signed-off-by: Zhang Wei <zhangwei555@huawei.com>
Qiang Huang
Mrunal Patel
Michael Crosby
Giuseppe Scrivano
Steven Hartland
Aleksa Sarai
Antonio Murdaca
Daniel, Dao Quang Minh
Justin Cormack
rainrambler
Wang Long
Mrunal Patel
Zhang Wei