The package used a lot of string-formatting, followed by string-splitting.
This looked to originate from attempts to use templating to allow future
extensibility (9a3ab0358e).
Looking at the history of the package, only a single update was made to
these templates, 5 years go, which makes it unlikely that more templating
will be needed.
This patch simplifies the handling of arguments to use `[]string` instead
of a single `string` (and splitting to a `[]string`). This both simplifies
the code somewhat, and prevents user/group-names containing spaces to be
splitted (causing, e.g. `getent` to fail).
Note that user/group-names containing spaces are invalid (or at least
discouraged), there are situations where such names may be used, so we
should avoid breaking on such names.
Before this change, a user/group name with a space in its name would fail;
dockerd --userns-remap="user:domain users"
INFO[2020-08-19T10:26:59.288868661+02:00] Starting up
Error during groupname lookup for "domain users": getent unable to find entry "domain" in group database
With this change:
# Add some possibly problematic usernames for testing
# need to do this manually, as `adduser` / `useradd` won't accept these names
echo 'user name❌1002:1002::/home/one:/bin/false' >> /etc/passwd; \
echo 'user name❌1002:' >> /etc/group; \
echo 'user name:1266401166:65536' >> /etc/subuid; \
echo 'user name:1266401153:65536' >> /etc/subgid; \
echo 'user$HOME❌1003:1003::/home/one:/bin/false' >> /etc/passwd; \
echo 'user$HOME❌1003:' >> /etc/group; \
echo 'user$HOME:1266401166:65536' >> /etc/subuid; \
echo 'user$HOME:1266401153:65536' >> /etc/subgid; \
echo 'user'"'"'name❌1004:1004::/home/one:/bin/false' >> /etc/passwd; \
echo 'user'"'"'name❌1004:' >> /etc/group; \
echo 'user'"'"'name:1266401166:65536' >> /etc/subuid; \
echo 'user'"'"'name:1266401153:65536' >> /etc/subgid; \
echo 'user"name❌1005:1005::/home/one:/bin/false' >> /etc/passwd; \
echo 'user"name❌1005:' >> /etc/group; \
echo 'user"name:1266401166:65536' >> /etc/subuid; \
echo 'user"name:1266401153:65536' >> /etc/subgid;
# Start the daemon using those users
dockerd --userns-remap="user name:user name"
dockerd --userns-remap='user$HOME:user$HOME'
dockerd --userns-remap="user'name":"user'name"
dockerd --userns-remap='user"name':'user"name'
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
When processing the --userns-remap flag, add the
capability to call out to `getent` if the user and
group information is not found via local file
parsing code already in libcontainer/user.
Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
This should not have been in init() as it causes these lookups to happen
in all reexecs of the Docker binary. The only time it needs to be
resolved is when a user is added, which is extremely rare.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com>
Change user/group creation to use flags to adduser/useradd to enforce it
being a system user. Use system user defaults that auto-create a
matching group. These changes allow us to remove all group creation
code, and in doing so we also removed the code that finds available uid,
gid integers and use post-creation query to gather the system-generated
uid and gid.
The only added complexity is that today distros don't auto-create
subordinate ID ranges for a new ID if it is a system ID, so we now need
to handle finding a free range and then calling the `usermod` tool to
add the ranges for that ID. Note that this requires the distro supports
the `-v` and `-w` flags on `usermod` for subordinate ID range additions.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
This fixes errors in ownership on directory creation during build that
can cause inaccessible files depending on the paths in the Dockerfile
and non-existing directories in the starting image.
Add tests for the mkdir variants in pkg/idtools
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
The `pkg/idtools` package supports the creation of user(s) for
retrieving /etc/sub{u,g}id ranges and creation of the UID/GID mappings
provided to clone() to add support for user namespaces in Docker.
Docker-DCO-1.1-Signed-off-by: Phil Estes <estesp@linux.vnet.ibm.com> (github: estesp)
Sebastiaan van Stijn