From b2662e43f2259b1b7dcada1f9c1a85997187fec6 Mon Sep 17 00:00:00 2001
From: Sebastiaan van Stijn <github@gone.nl>
Date: Wed, 13 Feb 2019 16:48:59 +0100
Subject: [PATCH] Add back validation for invalid label values on containers

This adds validation to `docker container run` / `docker container create`;

Validation of labels provided through flags was removed in 31dc5c0a9a8bdc11c7ad335aebb753ed527caa5a,
after the validation was changed to fix labels without values, and to prevent
labels from being expanded with environment variables in 2b17f4c8a8caad552025edb05a73db683fb8a5c6

However, now empty label names from _files_ (`--label-file`) followed different
validation rules than labels passed through `--label`.

This patch adds back minimal validation for labels passed through the command-line

Before this patch:

```bash
docker container create \
  --name label \
  --label==with-leading-equal-sign \
  --label=without-value \
  --label=somelabel=somevalue \
  --label "  =  " \
  --label=with-quotes-in-value='{"foo"}' \
  --label='with"quotes"in-key=test' \
  busybox

docker container inspect --format '{{json .Config.Labels}}' label
```

```json
{
  "": "with-leading-equal-sign",
  "  ": "  ",
  "somelabel": "somevalue",
  "with\"quotes\"in-key": "test",
  "with-quotes-in-value": "{\"foo\"}",
  "without-value": ""
}
```

After this patch:

```bash
docker container create \
  --name label \
  --label==with-leading-equal-sign \
  --label=without-value \
  --label=somelabel=somevalue \
  --label "  =  " \
  --label=with-quotes-in-value='{"foo"}' \
  --label='with"quotes"in-key=test' \
  busybox

invalid argument "=with-leading-equal-sign" for "-l, --label" flag: invalid label format: "=with-leading-equal-sign"
```

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 cli/command/container/opts.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cli/command/container/opts.go b/cli/command/container/opts.go
index 4546839629d0..8074194b1df9 100644
--- a/cli/command/container/opts.go
+++ b/cli/command/container/opts.go
@@ -147,7 +147,7 @@ func addFlags(flags *pflag.FlagSet) *containerOptions {
 		expose:            opts.NewListOpts(nil),
 		extraHosts:        opts.NewListOpts(opts.ValidateExtraHost),
 		groupAdd:          opts.NewListOpts(nil),
-		labels:            opts.NewListOpts(nil),
+		labels:            opts.NewListOpts(opts.ValidateLabel),
 		labelsFile:        opts.NewListOpts(nil),
 		linkLocalIPs:      opts.NewListOpts(nil),
 		links:             opts.NewListOpts(opts.ValidateLink),