Docker socket returns 500 error when used with netcat and piped content

[max-allan]

Description

If I use the docker socket with netcat, from my mac, I get a 500 error. If I do the same command from a container talking to the same socket, I get a 200 response.

Reproduce

1. Run Docker Desktop for OSX.

printf "GET /info HTTP/1.0\n\n" | nc -U /var/run/docker.sock
HTTP/1.0 500 Internal Server Error
Date: Fri, 30 Aug 2024 09:28:29 GMT
Content-Length: 0

Expected behavior

docker run -v /var/run/docker.sock:/var/run/docker.sock -itu0 --entrypoint sh chainguard/netcat:latest
/home/nc # printf "GET /info HTTP/1.0\n\n" | nc -U /var/run/docker.sock
HTTP/1.0 200 OK
Api-Version: 1.46
Content-Type: application/json
Date: Fri, 30 Aug 2024 09:23:59 GMT
Docker-Experimental: false
Ostype: linux
Server: Docker/27.1.1 (linux)

{"ID":"c8eb3d48-7697-4069-ac4d-c2c13c51f6b9","Containers":112, .........}

docker version

docker version
Client: Docker Engine - Community
 Version:           27.0.2
 API version:       1.46
 Go version:        go1.22.4
 Git commit:        912c1ddf8a
 Built:             Wed Jun 26 18:39:48 2024
 OS/Arch:           darwin/arm64
 Context:           desktop-linux

Server: Docker Desktop 4.33.0 (160616)
 Engine:
  Version:          27.1.1
  API version:      1.46 (minimum version 1.24)
  Go version:       go1.21.12
  Git commit:       cc13f95
  Built:            Tue Jul 23 19:57:14 2024
  OS/Arch:          linux/arm64
  Experimental:     false
 containerd:
  Version:          1.7.19
  GitCommit:        2bf793ef6dc9a18e00cb12efb64355c2c9d5eb41
 runc:
  Version:          1.7.19
  GitCommit:        v1.1.13-0-g58aa920
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client: Docker Engine - Community
 Version:    27.0.2
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.16.1-desktop.1
    Path:     /Users/max.allan/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v2.29.1-desktop.1
    Path:     /Users/max.allan/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.34
    Path:     /Users/max.allan/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Alpha) (Docker Inc.)
    Version:  v0.0.14
    Path:     /Users/max.allan/.docker/cli-plugins/docker-desktop
  dev: Docker Dev Environments (Docker Inc.)
    Version:  v0.1.2
    Path:     /Users/max.allan/.docker/cli-plugins/docker-dev
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.25
    Path:     /Users/max.allan/.docker/cli-plugins/docker-extension
  feedback: Provide feedback, right in your terminal! (Docker Inc.)
    Version:  v1.0.5
    Path:     /Users/max.allan/.docker/cli-plugins/docker-feedback
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.3.0
    Path:     /Users/max.allan/.docker/cli-plugins/docker-init
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /Users/max.allan/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.11.0
    Path:     /Users/max.allan/.docker/cli-plugins/docker-scout

Server:
 Containers: 112
  Running: 29
  Paused: 0
  Stopped: 83
 Images: 193
 Server Version: 27.1.1
 Storage Driver: overlay2
  Backing Filesystem: extfs
  Supports d_type: true
  Using metacopy: false
  Native Overlay Diff: true
  userxattr: false
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: 2bf793ef6dc9a18e00cb12efb64355c2c9d5eb41
 runc version: v1.1.13-0-g58aa920
 init version: de40ad0
 Security Options:
  seccomp
   Profile: unconfined
  cgroupns
 Kernel Version: 6.10.0-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: aarch64
 CPUs: 10
 Total Memory: 17.54GiB
 Name: docker-desktop
 ID: c8eb3d48-7697-4069-ac4d-c2c13c51f6b9
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=unix:///Users/max.allan/Library/Containers/com.docker.docker/Data/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  localhost:5000
  localhost:5050
  localhost:8081
  localhost:8082
  127.0.0.0/8
 Live Restore Enabled: false

WARNING: daemon is not using the default seccomp profile

Diagnostics ID

7324A83D-BF87-4D16-A70C-40853C169461/20240830093411

Additional Info

The same happens if I use HTTP/1.1 and add "Host:\n" to the printf.
Or use a heredoc:

 nc -U /var/run/docker.sock << EOF
> GET /info HTTP/1.0
> 
> EOF
HTTP/1.0 500 Internal Server Error

Or socat gives the same 500 error...