shim/manager: Detect custom AppArmor profile to allow userns creation#144
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akerouanton merged 1 commit intocontainerd:mainfrom Apr 3, 2026
Merged
shim/manager: Detect custom AppArmor profile to allow userns creation#144akerouanton merged 1 commit intocontainerd:mainfrom
akerouanton merged 1 commit intocontainerd:mainfrom
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When kernel.apparmor_restrict_unprivileged_userns=1, check /proc/self/attr/current for a profile name containing the binary name. If found, we are likely running under a custom AppArmor profile that relaxes the userns restriction, so proceed with namespace creation instead of skipping it. Signed-off-by: Paweł Gronowski <pawel.gronowski@docker.com>
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Pull request overview
This PR updates the Linux shim manager’s mount namespace setup logic to better handle Ubuntu-style AppArmor gating of unprivileged user namespace creation, by attempting to detect when the shim is running under a custom AppArmor profile that may allow userns even when the global sysctl is enabled.
Changes:
- Extend
apparmorRestrictsUserns()to treatkernel.apparmor_restrict_unprivileged_userns=1as non-blocking when a “custom” AppArmor profile is detected. - Add
runningUnderCustomProfile()to inspect/proc/self/attr/currentand heuristically match the profile name against the current binary name.
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akerouanton
approved these changes
Apr 3, 2026
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When kernel.apparmor_restrict_unprivileged_userns=1, check /proc/self/attr/current for a profile name containing the binary name.
If found, we are likely running under a custom AppArmor profile that relaxes the userns restriction, so proceed with namespace creation instead of skipping it.