mirror of
https://github.com/cloud-hypervisor/cloud-hypervisor.git
synced 2024-12-22 05:35:20 +00:00
106 lines
3.0 KiB
Markdown
106 lines
3.0 KiB
Markdown
# Sandboxing using Landlock
|
|
|
|
Landlock is a lightweight mechanism to allow unprivileged applications to
|
|
sandbox themselves.
|
|
|
|
During initial stages of running, applications can define the set of resources
|
|
(mostly files) they need to access during their lifetime. All such rules are
|
|
used to create a ruleset. Once the ruleset is applied, the process cannot access
|
|
any resources outside of the ruleset during its lifetime, even if it were
|
|
compromised.
|
|
|
|
Under the scope of `read` and `write` access, Landlock currently allows some
|
|
additional accesses (eg: for now, access to extended file attributes is always
|
|
allowed). Eventually, Landlock will only allow accesses similar to Unix
|
|
permissions.
|
|
|
|
## Host Setup
|
|
|
|
Landlock should be enabled in Host kernel to use it with cloud-hypervisor.
|
|
Please following [Kernel-Support](https://docs.kernel.org/userspace-api/landlock.html#kernel-support) link to enable Landlock on Host kernel.
|
|
|
|
|
|
Landlock support can be checked with following command:
|
|
```
|
|
$ sudo dmesg | grep -w landlock
|
|
[ 0.000000] landlock: Up and running.
|
|
```
|
|
Linux kernel confirms Landlock support with above message in dmesg.
|
|
|
|
## Enable Landlock
|
|
|
|
At the time of enabling Landlock, Cloud-Hypervisor process needs the complete
|
|
list of files it accesses over its lifetime. So, Landlock is enabled `vm_create`
|
|
stage of guest boot.
|
|
|
|
### Command Line
|
|
Append `--landlock` to Cloud-Hypervisor's command line to enable Landlock
|
|
support.
|
|
|
|
If you expect guest to access additional paths after it boots
|
|
(ex: during hotplug), those paths can be passed using `--landlock-rules` command
|
|
line parameter.
|
|
|
|
### API
|
|
Landlock can also be enabled during `vm.create` request by passing a config like below:
|
|
|
|
```
|
|
{
|
|
...
|
|
"landlock_enable": true,
|
|
"landlock_rules": [
|
|
{
|
|
"path": "/tmp/disk1",
|
|
"access": "rw"
|
|
},
|
|
{
|
|
"path": "/tmp/disk2",
|
|
"access": "rw"
|
|
}
|
|
]
|
|
...
|
|
}
|
|
```
|
|
|
|
|
|
## Usage Examples
|
|
|
|
To enable Landlock:
|
|
|
|
```
|
|
./cloud-hypervisor \
|
|
--kernel ./linux-cloud-hypervisor/arch/x86/boot/compressed/vmlinux.bin \
|
|
--disk path=focal-server-cloudimg-amd64.raw path=/tmp/ubuntu-cloudinit.img \
|
|
--cmdline "console=hvc0 root=/dev/vda1 rw" \
|
|
--cpus boot=4 \
|
|
--memory size=1024M \
|
|
--net "tap=,mac=,ip=,mask=" \
|
|
--landlock
|
|
```
|
|
Hotplugging any new file-backed resources to above guest will result in
|
|
**Permission Denied** error.
|
|
|
|
To enable Landlock with hotplug support:
|
|
|
|
```
|
|
./cloud-hypervisor \
|
|
--api-socket /tmpXXXX/ch.socket \
|
|
--kernel ./linux-cloud-hypervisor/arch/x86/boot/compressed/vmlinux.bin \
|
|
--disk path=focal-server-cloudimg-amd64.raw path=/tmp/ubuntu-cloudinit.img \
|
|
--cmdline "console=hvc0 root=/dev/vda1 rw" \
|
|
--cpus boot=4 \
|
|
--memory size=1024M \
|
|
--net "tap=,mac=,ip=,mask=" \
|
|
--landlock \
|
|
--landlock-rules path="/path/to/hotplug1",access="rw" path="/path/to/hotplug2",access="rw"
|
|
|
|
./ch-remote --api-socket /tmpXXXX/ch.socket \
|
|
add-disk "path=/path/to/hotplug/blk.raw"
|
|
```
|
|
|
|
`--landlock-rules` accepts file or directory paths among its options.
|
|
|
|
# References
|
|
|
|
* https://landlock.io/
|