[Bug]: File permissions with custom PostgreSQL image

[konsalex]

Testcontainers version

v0.29.1

Using the latest Testcontainers version?

Yes

Host OS

MacOS

Host arch

Arm

Go version

1.21.8

Docker version

Client:
 Cloud integration: v1.0.35+desktop.11
 Version:           25.0.3
 API version:       1.44
 Go version:        go1.21.6
 Git commit:        4debf41
 Built:             Tue Feb  6 21:13:26 2024
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.28.0 (139021)
 Engine:
  Version:          25.0.3
  API version:      1.44 (minimum version 1.24)
  Go version:       go1.21.6
  Git commit:       f417435
  Built:            Tue Feb  6 21:14:22 2024
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.6.28
  GitCommit:        ae07eda36dd25f8a1b98dfbf587313b99c0190bb
 runc:
  Version:          1.1.12
  GitCommit:        v1.1.12-0-g51d5e94
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

Docker info

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Server:
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  Running: 0
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 Images: 250
 Server Version: 25.0.3
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  Backing Filesystem: extfs
  Supports d_type: true
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  Native Overlay Diff: true
  userxattr: false
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 Cgroup Version: 2
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 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: ae07eda36dd25f8a1b98dfbf587313b99c0190bb
 runc version: v1.1.12-0-g51d5e94
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
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 Operating System: Docker Desktop
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 Live Restore Enabled: false

WARNING: daemon is not using the default seccomp profile

What happened?

There is a miss match between running testcontainer and docker run when I mount files and cannot seem to figure out what is the reason.

Example testcontainer code:

postgresContainer, err := testcontainers.GenericContainer(ctx, testcontainers.GenericContainerRequest{
		ContainerRequest: testcontainers.ContainerRequest{
			Image: "postgresql-mock",
			Name:  "postgresql_mock",
			Env: map[string]string{
				"POSTGRES_USER":     "random",
				"POSTGRES_PASSWORD": "random",
				"POSTGRES_DB":       "random",
				"POSTGRES_HOST":     "postgresql",
			},
			Privileged:   true,  // tested with false also
			ExposedPorts: []string{"5432/tcp", "8080/tcp"},
			WaitingFor: wait.ForExec([]string{"pg_isready && curl --fail localhost:8080/api/tuner/health || exit 1"}),
			Files: []testcontainers.ContainerFile{
				{
					HostFilePath:      "../cert/server.crt",
					ContainerFilePath: "/var/lib/postgresql/server.crt",
					FileMode:          0o640,
				},
				{
					HostFilePath:      "../cert/server.key",
					ContainerFilePath: "/var/lib/postgresql/server.key",
					FileMode:          0o640,
				},
				{
					HostFilePath:      "../cert/root.crt",
					ContainerFilePath: "/var/lib/postgresql/root.crt",
					FileMode:          0o640,
				},
			}
		},
	})

I tested with various file modes also like 0o600, 0o444 0o440 but no luck.

The errors I get are either this:

FATAL:  could not load server certificate file "/var/lib/postgresql/server.crt": SSL error code 2147483661

or that:

File must have permissions u=rw (0600) or less if owned by the database user, or permissions u=rw,g=r (0640) or less if owned by root

The docker run command seems to work fine:

docker run -d -p 5432:5432 -p 8080:8080 --name postgresql-mock --memory="1250m" \
        -e POSTGRES_PASSWORD=random \
        -e POSTGRES_USER=random \
        -e POSTGRES_DB=random \
        -v "$(pwd)/../cert/server.crt:/var/lib/postgresql/server.crt:ro" \
        -v "$(pwd)/../cert/server.key:/var/lib/postgresql/server.key:ro" \
        -v "$(pwd)/../cert/root.crt:/var/lib/postgresql/root.crt:ro" \
        -v /var/run/docker.sock:/var/run/docker.sock \
        postgresql-mock

Relevant log output

FATAL:  could not load server certificate file "/var/lib/postgresql/server.crt": SSL error code 2147483661

Additional information

No response

[bearrito]

Can you try this with 0400 permissions. I believe the error logs from PG are incorrect.

Here is a reference where the 0400 are used - https://access.redhat.com/documentation/fr-fr/red_hat_enterprise_linux/9/html/configuring_and_using_database_servers/proc_configuring-tls-encryption-on-a-postgresql-server_using-postgresql

[konsalex]

I managed to solve this tbh @bearrito , but in a nasty way:

This is running in a custom entry point for postgresql.

chown 999:999 /var/lib/postgresql/server.crt
chown 999:999 /var/lib/postgresql/server.key
chown 999:999 /var/lib/postgresql/root.crt
chmod 600 /var/lib/postgresql/server.crt
chmod 600 /var/lib/postgresql/server.key
chmod 600 /var/lib/postgresql/root.crt

I tried also 0o400 and every possible code available, nothing worked.

[bearrito]

Is the image postgres-mock available?
I imagine what's happening is that root (0) has permission but the postgres user (in your case 999) isn't in the group that can read this.

https://www.postgresql.org/docs/16/ssl-tcp.html

On Unix systems, the permissions on server.key must disallow any access to world or group; achieve this by the command chmod 0600 server.key. Alternatively, the file can be owned by root and have group read access (that is, 0640 permissions). That setup is intended for installations where certificate and key files are managed by the operating system. The user under which the PostgreSQL server runs should then be made a member of the group that has access to those certificate and key file

It seems like what needs to happen is that ContainerFile should expose the uid/gid of the file being copied nominally matching the archive mode https://pkg.go.dev/github.com/docker/[email protected]+incompatible/api/types#CopyToContainerOptions

[konsalex]

I think that is indeed the case. The image is not public, but the idea is the following:

This is the custom docker file

FROM postgres:16.1
....
# Override entrypoint to spin up the mock server as root user
COPY entrypoint.sh /usr/local/bin/entrypoint.sh
RUN chmod +x /usr/local/bin/entrypoint.sh

ENTRYPOINT ["entrypoint.sh"]

And then the entry point:

#!/bin/bash

chown 999:999 /var/lib/postgresql/server.crt
chown 999:999 /var/lib/postgresql/server.key
chown 999:999 /var/lib/postgresql/root.crt
chmod 600 /var/lib/postgresql/server.crt
chmod 600 /var/lib/postgresql/server.key
chmod 600 /var/lib/postgresql/root.crt

# Postgres entrypoint
./usr/local/bin/docker-entrypoint.sh postgres -c ssl=on \
    -c ssl_cert_file=/var/lib/postgresql/server.crt \
    -c ssl_key_file=/var/lib/postgresql/server.key \
    -c ssl_ca_file=/var/lib/postgresql/root.crt &

# Mock server
/docker-entrypoint-initdb.d/server &

tail -f /dev/null

Just to re-iterate, this is not the official pg image workflow of course as we modified the entry point, but this is the scenario we were struggling with @bearrito hope this helps.

[bearrito]

@konsalex This will likely solve your issue after it goes through pr #2473

[konsalex]

Awesome if merged will try out again @bearrito !

[bearrito]

@konsalex I think that PR is now up to the maintainers.

[mdelapenya]

Sorry for the radio silence, nothing related to the PR, just focusing in other tasks, summer PTOs and conferences. I apologise for it if caused troubles.

I'm jumping on that PR now for review, and found this comment pending response. Could anybody take a look? 🙏