`docker cp` is not setting the right UID & GID to the destination file

[rbelouin]

Expected behavior

According to the documentation, I expect the destination file to have root:root as an owner.

Actual behavior

The destination file is set with 501:dialout as an owner. 501 is the UID of my local user, the one actually invoking docker cp.

Information

Diagnostic ID: 2641786D-4283-438C-A772-0741838174DE

Unfortunately, I'm not sure whether I am allowed to share the Dockerfile publicly.

Steps to reproduce the behavior

[rbelouin dev(authorized-keys-owner)]% echo $UID $GID
501 20
[rbelouin dev(authorized-keys-owner)]% echo plop > plop.txt
[rbelouin dev(authorized-keys-owner*)]% docker cp plop.txt $(docker-compose ps -q website):/root/plop.txt
[rbelouin dev(authorized-keys-owner*)]% docker-compose exec website bash
root@4a53e665800d:~# ls -l
total 8
drwxr-xr-x 2 root root    4096 Apr 27 21:23 keys
-rw-r--r-- 1  501 dialout    5 Jul  3 11:18 plop.txt
root@4a53e665800d:~#

[dsheets]

I can't seem to reproduce this issue using alpine:3.6 -- the copied file is always owned root:root. Could you please try to reduce the test case the exhibits the problem and post a complete reproduction here?

[rbelouin]

Sure!

[dsheets]

It looks like there have been some changes and issues related to this functionality recently: see moby/moby#34099 and related issues/PRs. Maybe you have encountered one of these issues/changes?

[rbelouin]

This could be related indeed, I'm gonna try to reproduce tomorrow. I'll keep you posted.

[rbelouin]

I could reproduce it using ubuntu:trusty by following the steps below:

Docker version:

$ docker --version
Docker version 17.06.0-ce, build 02c1d87

Pull and run the image:

$ docker pull ubuntu:trusty
trusty: Pulling from library/ubuntu
7ee37f181318: Pull complete
df5ffabe5e97: Pull complete
ae2040ed51a1: Pull complete
3ce7010d244b: Pull complete
2538b201d2a6: Pull complete
Digest: sha256:13eecbc0e57928c1cb3ccca3581e2a6f4b0f39c1acf5a279e740e478accd119b
Status: Downloaded newer image for ubuntu:trusty

$ docker images
REPOSITORY                                         TAG                 IMAGE ID            CREATED             SIZE
…
ubuntu                                             trusty              54333f1de4ed        5 days ago          188MB
…

$ docker run -it ubuntu:trusty bash
root@e308875092e5:/#

Get the ID of the created container:

$ docker ps
CONTAINER ID        IMAGE                                             COMMAND                  CREATED             STATUS              PORTS                                        NAMES
e308875092e5        ubuntu:trusty                                     "bash"                   26 seconds ago      Up 25 seconds                                                    lucid_benz

Create a random text file and copy it to the container:

$ echo plop > plop.txt
$ docker cp plop.txt e308875092e5:/root/plop.txt

Confirm the file doesn't have the right UID/GUID:

root@e308875092e5:/# ls -l /root
total 4
-rw-r--r-- 1 501 dialout 5 Jul 26 13:23 plop.txt

[rbelouin]

I also could reproduce it with alpine:3.6 by following the same steps (you just need to use sh instead of bash)

[rbelouin]

Some further info about Docker for mac:

Version 17.06.0-ce-mac19 (18663)
Channel: stable
c98c1c25e0

Docker 17.06.0-ce-mac19 is currently the newest version available.

[mkrawetko]

It still seems to be the problem on macOs High Sierra :(

Docker for mac
Version 17.09.0-ce-mac33 (19543)
Channel: stable
e2f2204fde

[dismantl]

I am able to reproduce the bug on Ubuntu Xenial using @rbelouin's steps above, so it's not just macOS High Sierra. No matter whether I use the "-a" flag or not for docker cp, the copied files always have the UID/GID of the host user.

[docker-robott]

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[ivanlawrence]

/remove-lifecycle stale
I'm getting a similar result:
on Mac Sierra

ivan.lawrence@lap $ sw_vers
ProductName:	Mac OS X
ProductVersion:	10.12.6
BuildVersion:	16G1036

Using latest Docker for Mac (installed today)

ivan.lawrence@lap $ docker version
Client:
 Version:	18.03.0-ce
 API version:	1.37
 Go version:	go1.9.4
 Git commit:	0520e24
 Built:	Wed Mar 21 23:06:22 2018
 OS/Arch:	darwin/amd64
 Experimental:	false
 Orchestrator:	swarm

Server:
 Engine:
  Version:	18.03.0-ce
  API version:	1.37 (minimum version 1.12)
  Go version:	go1.9.4
  Git commit:	0520e24
  Built:	Wed Mar 21 23:14:32 2018
  OS/Arch:	linux/amd64
  Experimental:	true

docker cp a file into container

ivan.lawrence@lap $ docker cp export_bamboo.zip competent_borg:/var/atlassian/bamboo/backups/

results in a UID/GID = 260102358/20

/var/atlassian/bamboo/backups $ stat export_bamboo.zip 
  File: export_bamboo.zip
  Size: 36156801  	Blocks: 70624      IO Block: 4096   regular file
Device: 801h/2049d	Inode: 1707265     Links: 1
Access: (0600/-rw-------)  Uid: (260102358/ UNKNOWN)   Gid: (   20/ dialout)
Access: 2018-03-17 07:50:43.000000000
Modify: 2018-03-17 07:50:43.000000000
Change: 2018-03-29 08:47:46.000000000