Commit graph

23 commits

Author SHA1 Message Date
Sebastiaan van Stijn
df965f51bf
pkg/idtools: remove deprecated NewIdentityMapping, UIDS() and GIDS()
These were deprecated in 098a44c07f, which is
in the 22.06 branch, and no longer in use since e05f614267
so we can remove them from the master branch.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2022-08-09 18:03:29 +02:00
Cory Snider
098a44c07f Finish refactor of UID/GID usage to a new struct
Finish the refactor which was partially completed with commit
34536c498d, passing around IdentityMapping structs instead of pairs of
[]IDMap slices.

Existing code which uses []IDMap relies on zero-valued fields to be
valid, empty mappings. So in order to successfully finish the
refactoring without introducing bugs, their replacement therefore also
needs to have a useful zero value which represents an empty mapping.
Change IdentityMapping to be a pass-by-value type so that there are no
nil pointers to worry about.

The functionality provided by the deprecated NewIDMappingsFromMaps
function is required by unit tests to to construct arbitrary
IdentityMapping values. And the daemon will always need to access the
mappings to pass them to the Linux kernel. Accommodate these use cases
by exporting the struct fields instead. BuildKit currently depends on
the UIDs and GIDs methods so we cannot get rid of them yet.

Signed-off-by: Cory Snider <csnider@mirantis.com>
2022-03-14 16:28:57 -04:00
Brian Goff
66dffbec86
Ensure MkdirAllAndChown also sets perms
Generally if we ever need to change perms of a dir, between versions,
this ensures the permissions actually change when we think it should
change without having to handle special cases if it already existed.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit edb62a3ace)
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2021-02-02 13:01:20 +01:00
Akhil Mohan
7ad0da7051
remove group name from identity mapping
NewIdentityMapping took group name as an argument, and used
the group name also to parse the /etc/sub{uid,gui}. But as per
linux man pages, the sub{uid,gid} file maps username or uid,
not a group name.

Therefore, all occurrences where mapping is used need to
consider only username and uid. Code trying to map using gid
and group name in the daemon is also removed.

Signed-off-by: Akhil Mohan <akhil.mohan@mayadata.io>
2020-06-03 20:04:42 +05:30
Kir Kolyshkin
745ed9686b pkg/idtools: fix use of bufio.Scanner.Err
The Err() method should be called after the Scan() loop,
not inside it.

Fixes: 9a3ab0358e
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2020-03-31 14:32:49 -07:00
Jonas Dohse
c4628d79d2 Stop sorting uid and gid ranges in id maps
Moby currently sorts uid and gid ranges in id maps. This causes subuid
and subgid files to be interpreted wrongly.

The subuid file

```
> cat /etc/subuid
jonas:100000:1000
jonas:1000:1
```

configures that the container uids 0-999 are mapped to the host uids
100000-100999 and uid 1000 in the container is mapped to uid 1000 on the
host. The expected uid_map is:

```
> docker run ubuntu cat /proc/self/uid_map
         0     100000       1000
      1000       1000          1
```

Moby currently sorts the ranges by the first id in the range. Therefore
with the subuid file above the uid 0 in the container is mapped to uid
100000 on host and the uids 1-1000 in container are mapped to the uids
1-1000 on the host. The resulting uid_map is:

```
> docker run ubuntu cat /proc/self/uid_map
         0       1000          1
         1     100000       1000
```

The ordering was implemented to work around a limitation in Linux 3.8.
This is fixed since Linux 3.9 as stated on the user namespaces manpage
[1]:

> In the initial implementation (Linux 3.8), this requirement was
> satisfied by a simplistic implementation that imposed the further
> requirement that the values in both field 1 and field 2 of successive
> lines must be in ascending numerical order, which prevented some
> otherwise valid maps from being created.  Linux 3.9 and later fix this
> limitation, allowing any valid set of nonoverlapping maps.

This fix changes the interpretation of subuid and subgid files which do
not have the ids of in the numerical order for each individual user.
This breaks users that rely on the current behaviour.

The desired mapping above - map low user ids in the container to high
user ids on the host and some higher user ids in the container to lower
user on host - can unfortunately not archived with the current
behaviour.

[1] http://man7.org/linux/man-pages/man7/user_namespaces.7.html

Signed-off-by: Jonas Dohse <jonas@dohse.ch>
2019-06-03 15:50:26 +02:00
Salahuddin Khan
763d839261 Add ADD/COPY --chown flag support to Windows
This implements chown support on Windows. Built-in accounts as well
as accounts included in the SAM database of the container are supported.

NOTE: IDPair is now named Identity and IDMappings is now named
IdentityMapping.

The following are valid examples:
ADD --chown=Guest . <some directory>
COPY --chown=Administrator . <some directory>
COPY --chown=Guests . <some directory>
COPY --chown=ContainerUser . <some directory>

On Windows an owner is only granted the permission to read the security
descriptor and read/write the discretionary access control list. This
fix also grants read/write and execute permissions to the owner.

Signed-off-by: Salahuddin Khan <salah@docker.com>
2018-08-13 21:59:11 -07:00
Sebastiaan van Stijn
f23c00d870
Various code-cleanup
remove unnescessary import aliases, brackets, and so on.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2018-05-23 17:50:54 +02:00
Daniel Nephin
4f0d95fa6e Add canonical import comment
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2018-02-05 16:51:57 -05:00
Kir Kolyshkin
516010e92d Simplify/fix MkdirAll usage
This subtle bug keeps lurking in because error checking for `Mkdir()`
and `MkdirAll()` is slightly different wrt to `EEXIST`/`IsExist`:

 - for `Mkdir()`, `IsExist` error should (usually) be ignored
   (unless you want to make sure directory was not there before)
   as it means "the destination directory was already there"

 - for `MkdirAll()`, `IsExist` error should NEVER be ignored.

Mostly, this commit just removes ignoring the IsExist error, as it
should not be ignored.

Also, there are a couple of cases then IsExist is handled as
"directory already exist" which is wrong. As a result, some code
that never worked as intended is now removed.

NOTE that `idtools.MkdirAndChown()` behaves like `os.MkdirAll()`
rather than `os.Mkdir()` -- so its description is amended accordingly,
and its usage is handled as such (i.e. IsExist error is not ignored).

For more details, a quote from my runc commit 6f82d4b (July 2015):

    TL;DR: check for IsExist(err) after a failed MkdirAll() is both
    redundant and wrong -- so two reasons to remove it.

    Quoting MkdirAll documentation:

    > MkdirAll creates a directory named path, along with any necessary
    > parents, and returns nil, or else returns an error. If path
    > is already a directory, MkdirAll does nothing and returns nil.

    This means two things:

    1. If a directory to be created already exists, no error is
    returned.

    2. If the error returned is IsExist (EEXIST), it means there exists
    a non-directory with the same name as MkdirAll need to use for
    directory. Example: we want to MkdirAll("a/b"), but file "a"
    (or "a/b") already exists, so MkdirAll fails.

    The above is a theory, based on quoted documentation and my UNIX
    knowledge.

    3. In practice, though, current MkdirAll implementation [1] returns
    ENOTDIR in most of cases described in #2, with the exception when
    there is a race between MkdirAll and someone else creating the
    last component of MkdirAll argument as a file. In this very case
    MkdirAll() will indeed return EEXIST.

    Because of #1, IsExist check after MkdirAll is not needed.

    Because of #2 and #3, ignoring IsExist error is just plain wrong,
    as directory we require is not created. It's cleaner to report
    the error now.

    Note this error is all over the tree, I guess due to copy-paste,
    or trying to follow the same usage pattern as for Mkdir(),
    or some not quite correct examples on the Internet.

    [1] https://github.com/golang/go/blob/f9ed2f75/src/os/path.go

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
2017-11-27 17:32:12 -08:00
Sebastiaan van Stijn
38b3af567f
Remove deprecated MkdirAllAs(), MkdirAs()
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2017-11-21 13:53:54 +01:00
Sebastiaan van Stijn
ce66470f54
Minor refactor in idtools
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
2017-11-21 13:49:58 +01:00
Daniel Nephin
93fbdb69ac Remove error return from RootPair
There is no case which would resolve in this error. The root user always exists, and if the id maps are empty, the default value of 0 is correct.

Signed-off-by: Daniel Nephin <dnephin@docker.com>
2017-06-07 11:45:33 -04:00
Daniel Nephin
6150ebf7b4 Remove MkdirAllNewAs and update tests.
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2017-06-07 11:44:34 -04:00
Daniel Nephin
df248d31d9 Remove ToHost and replace it with IDMappings.ToHost
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2017-06-07 11:44:34 -04:00
Daniel Nephin
5672eeb5e0 Convert tarAppender to the newIDMappings.
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2017-06-07 11:44:34 -04:00
Daniel Nephin
967ef7e6d2 Remove unused functions from archive.
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2017-06-07 11:44:33 -04:00
Daniel Nephin
09cd96c5ad Partial refactor of UID/GID usage to use a unified struct.
Signed-off-by: Daniel Nephin <dnephin@docker.com>
2017-06-07 11:44:33 -04:00
Phil Estes
c18e7f3a04 Change subordinate range-owning user to be a system user
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)
2016-03-16 18:44:10 -04:00
Antonio Murdaca
bf04d68db2 pkg: idtools: fix subid files parsing
Since Docker is already skipping newlines in /etc/sub{uid,gid},
this patch skips commented out lines - otherwise Docker fails to start.
Add unit test also.

Signed-off-by: Antonio Murdaca <runcom@redhat.com>
2016-02-26 15:42:05 +01:00
Phil Estes
ae8c004dc1 Correct build-time directory creation with user namespaced daemon
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)
2015-10-20 08:59:48 -04:00
John Howard
bfe252b781 Windows: Daemon broken on master
Signed-off-by: John Howard <jhoward@microsoft.com>
2015-10-12 09:11:19 -07:00
Phil Estes
9a3ab0358e Add utility/support package for user namespace support
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)
2015-10-09 17:44:47 -04:00