From 610b52d8005f10ae1b193f9c08ebf40de49623dd Mon Sep 17 00:00:00 2001
From: Sebastiaan van Stijn <github@gone.nl>
Date: Mon, 28 Aug 2023 11:46:49 +0200
Subject: [PATCH] ParseRestartPolicy: validate for missing policy-names

Also make it slightly more clearer we're returning a default (empty)
policy if the input is empty.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
---
 cli/command/container/opts_test.go |  4 ++++
 opts/parse.go                      | 13 +++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/cli/command/container/opts_test.go b/cli/command/container/opts_test.go
index 460c74fad06f..82ce73bd67cd 100644
--- a/cli/command/container/opts_test.go
+++ b/cli/command/container/opts_test.go
@@ -714,6 +714,10 @@ func TestParseRestartPolicy(t *testing.T) {
 				Name: "no",
 			},
 		},
+		{
+			input:       ":1",
+			expectedErr: "invalid restart policy format: no policy provided before colon",
+		},
 		{
 			input: "always",
 			expected: container.RestartPolicy{
diff --git a/opts/parse.go b/opts/parse.go
index 017577e4bf09..f74cff74475f 100644
--- a/opts/parse.go
+++ b/opts/parse.go
@@ -71,13 +71,18 @@ func ConvertKVStringsToMapWithNil(values []string) map[string]*string {
 
 // ParseRestartPolicy returns the parsed policy or an error indicating what is incorrect
 func ParseRestartPolicy(policy string) (container.RestartPolicy, error) {
-	p := container.RestartPolicy{}
-
 	if policy == "" {
-		return p, nil
+		// for backward-compatibility, we don't set the default ("no")
+		// policy here, because older versions of the engine may not
+		// support it.
+		return container.RestartPolicy{}, nil
 	}
 
-	k, v, _ := strings.Cut(policy, ":")
+	p := container.RestartPolicy{}
+	k, v, ok := strings.Cut(policy, ":")
+	if ok && k == "" {
+		return container.RestartPolicy{}, fmt.Errorf("invalid restart policy format: no policy provided before colon")
+	}
 	if v != "" {
 		count, err := strconv.Atoi(v)
 		if err != nil {