opencontainers / opencontainers/runc
Umask behavior doesn't match spec
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Description
In the config section of runtime-spec, it states:
umask: [...] If unspecified, the umask should not be changed from the calling process' umask.
However runc does not seem to follow this:
~/mycontainer $ grep umask config.json
"umask": 5
~/mycontainer $ sudo runc run test
/ # umask
0005
~/mycontainer $ vim config.json
~/mycontainer $ grep umask config.json
~/mycontainer $ umask
0002
~/mycontainer $ sudo runc run test
/ # umask
0022
It looks like the issue originates in rootfs_linux.go:179, where the umask is set to 022 despite umask not being set in config.json.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start in libcontainer/rootfs_linux.go around line 179 and compare the umask handling with the OCI runtime-spec config section. Reproduce the issue using config.json and runc run as shown, checking both an explicit umask and an omitted one. Done means an omitted umask preserves the calling process's umask while an explicit value still applies.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- go
- Domain
- operating-systems
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Clearly specified
- Newbie friendliness
- 48/100