rootless podman run --network=none from inside a container due to default_sysctls ping_group_range

[bburky]

Description

Inside a container /proc/sys/net/ipv4/ping_group_range may not exist. The default_sysctls include net.ipv4.ping_group_range=0 0. If rootless podman is run inside a container, accessing this file may fail.

I discovered this when trying to run a rootless podman run --network=none ... inside a Kubernetes container.

Steps to reproduce the issue:

To reproduce the issue, run the following command which fails with Error: OCI runtime error: open /proc/sys/net/ipv4/ping_group_range: Read-only file system:

podman run --rm -it \
    --security-opt=label=disable \
    --security-opt=seccomp=unconfined \
    --env STORAGE_DRIVER=vfs \
    --user=podman \
    quay.io/podman/stable:v3.4.4 \
        podman run --rm -it --network=none alpine

A workaround is editing ~/.config/containers/containers.conf inside the container to not include net.ipv4.ping_group_range:

[containers]
volumes = [
	"/proc:/proc",
]
default_sysctls = []

Describe the results you received:

Error: OCI runtime error: open /proc/sys/net/ipv4/ping_group_range: Read-only file system

Additional information you deem important (e.g. issue happens only occasionally):

Output of podman version:

Version:      3.4.4
API Version:  3.4.4
Go Version:   go1.16.8
Built:        Wed Dec  8 21:45:07 2021
OS/Arch:      linux/amd64

Output of podman info --debug:

podman info --debug

host:
  arch: amd64
  buildahVersion: 1.23.1
  cgroupControllers:
  - memory
  - pids
  cgroupManager: cgroupfs
  cgroupVersion: v2
  conmon:
    package: conmon-2.1.0-2.fc35.x86_64
    path: /usr/bin/conmon
    version: 'conmon version 2.1.0, commit: '
  cpus: 1
  distribution:
    distribution: fedora
    variant: container
    version: "35"
  eventLogger: file
  hostname: 0258298c13b6
  idMappings:
    gidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 10000
      size: 5000
    uidmap:
    - container_id: 0
      host_id: 1000
      size: 1
    - container_id: 1
      host_id: 10000
      size: 5000
  kernel: 5.15.17-200.fc35.x86_64
  linkmode: dynamic
  logDriver: k8s-file
  memFree: 543858688
  memTotal: 2061381632
  ociRuntime:
    name: crun
    package: crun-1.4.2-1.fc35.x86_64
    path: /usr/bin/crun
    version: |-
      crun version 1.4.2
      commit: f6fbc8f840df1a414f31a60953ae514fa497c748
      spec: 1.0.0
      +SYSTEMD +SELINUX +APPARMOR +CAP +SECCOMP +EBPF +CRIU +YAJL
  os: linux
  remoteSocket:
    path: /tmp/podman-run-1000/podman/podman.sock
  security:
    apparmorEnabled: false
    capabilities: CAP_CHOWN,CAP_DAC_OVERRIDE,CAP_FOWNER,CAP_FSETID,CAP_KILL,CAP_NET_BIND_SERVICE,CAP_SETFCAP,CAP_SETGID,CAP_SETPCAP,CAP_SETUID,CAP_SYS_CHROOT
    rootless: true
    seccompEnabled: true
    seccompProfilePath: /usr/share/containers/seccomp.json
    selinuxEnabled: false
  serviceIsRemote: false
  slirp4netns:
    executable: /usr/bin/slirp4netns
    package: slirp4netns-1.1.12-2.fc35.x86_64
    version: |-
      slirp4netns version 1.1.12
      commit: 7a104a101aa3278a2152351a082a6df71f57c9a3
      libslirp: 4.6.1
      SLIRP_CONFIG_VERSION_MAX: 3
      libseccomp: 2.5.3
  swapFree: 0
  swapTotal: 0
  uptime: 25m 43.5s
plugins:
  log:
  - k8s-file
  - none
  - journald
  network:
  - bridge
  - macvlan
  volume:
  - local
registries:
  search:
  - registry.fedoraproject.org
  - registry.access.redhat.com
  - docker.io
  - quay.io
store:
  configFile: /home/podman/.config/containers/storage.conf
  containerStore:
    number: 0
    paused: 0
    running: 0
    stopped: 0
  graphDriverName: vfs
  graphOptions: {}
  graphRoot: /home/podman/.local/share/containers/storage
  graphStatus: {}
  imageStore:
    number: 1
  runRoot: /tmp/podman-run-1000/containers
  volumePath: /home/podman/.local/share/containers/storage/volumes
version:
  APIVersion: 3.4.4
  Built: 1638999907
  BuiltTime: Wed Dec  8 21:45:07 2021
  GitCommit: ""
  GoVersion: go1.16.8
  OsArch: linux/amd64
  Version: 3.4.4

Package info (e.g. output of rpm -q podman or apt list podman):

podman-3.4.4-1.fc35.x86_64

Have you tested with the latest version of Podman and have you checked the Podman Troubleshooting Guide?

Yes

Additional environment details (AWS, VirtualBox, physical, etc.):

Rootless podman running inside a containerized environment without /proc/sys/net/ipv4/ping_group_range

This is mostly a duplicate of #8482, but for --network=none this time. 0d70df1 fixed this only for --network=host. Adding a check for network=none in specgen/generate/security.go may fix this?

/kind bug

[rhatdan]

I am not sure what you want Podman to fix here. Are you looking at quay.io/podman/stable?

[bburky]

Basically the same as #8482, which updated podman to not set sysctls when rootless --network=host is set. Similarly, don't set sysctls when rootless --network=none.

[giuseppe]

I think it makes sense. Opened a PR: #13250

[giuseppe]

since the fix was not accepted, should we close this issue?