opts: MountOpt: improve validation for whitespace in values

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

Author: thaJeztah

opts/mount.go

@@ -78,15 +78,24 @@ func (m *MountOpt) Set(value string) error {
 	mount.Type = mounttypes.TypeVolume // default to volume mounts
 
 	for _, field := range fields {
-		key, val, ok := strings.Cut(field, "=")
+		key, val, hasValue := strings.Cut(field, "=")
 		if k := strings.TrimSpace(key); k != key {
 			return fmt.Errorf("invalid option '%s' in '%s': option should not have whitespace", k, field)
 		}
+		if hasValue {
+			v := strings.TrimSpace(val)
+			if v == "" {
+				return fmt.Errorf("invalid value for '%s': value is empty", key)
+			}
+			if v != val {
+				return fmt.Errorf("invalid value for '%s' in '%s': value should not have whitespace", key, field)
+			}
+		}
 
 		// TODO(thaJeztah): these options should not be case-insensitive.
 		key = strings.ToLower(key)
 
-		if !ok {
+		if !hasValue {
 			switch key {
 			case "readonly", "ro":
 				mount.ReadOnly = true

opts/mount_test.go

@@ -128,6 +128,21 @@ func TestMountOptErrors(t *testing.T) {
 			value:  "type=volume,src =/foo,target=/foo",
 			expErr: "invalid option 'src' in 'src =/foo': option should not have whitespace",
 		},
+		{
+			doc:    "invalid value is empty",
+			value:  "type=volume,src=,target=/foo",
+			expErr: "invalid value for 'src': value is empty",
+		},
+		{
+			doc:    "invalid value with leading whitespace",
+			value:  "type=volume,src= /foo,target=/foo",
+			expErr: "invalid value for 'src' in 'src= /foo': value should not have whitespace",
+		},
+		{
+			doc:    "invalid value with trailing whitespace",
+			value:  "type=volume,src=/foo ,target=/foo",
+			expErr: "invalid value for 'src' in 'src=/foo ': value should not have whitespace",
+		},
 		{
 			doc:    "missing value",
 			value:  "type=volume,target=/foo,bogus",
@@ -171,8 +186,8 @@ func TestMountOptReadOnly(t *testing.T) {
 	}{
 		{value: "", exp: false},
 		{value: "readonly", exp: true},
-		{value: "readonly=", expErr: `invalid value for readonly: `},
-		{value: "readonly= true", expErr: `invalid value for readonly:  true`},
+		{value: "readonly=", expErr: `invalid value for 'readonly': value is empty`},
+		{value: "readonly= true", expErr: `invalid value for 'readonly' in 'readonly= true': value should not have whitespace`},
 		{value: "readonly=no", expErr: `invalid value for readonly: no`},
 		{value: "readonly=1", exp: true},
 		{value: "readonly=true", exp: true},
@@ -215,8 +230,8 @@ func TestMountOptVolumeNoCopy(t *testing.T) {
 	}{
 		{value: "", exp: false},
 		{value: "volume-nocopy", exp: true},
-		{value: "volume-nocopy=", expErr: `invalid value for volume-nocopy: `},
-		{value: "volume-nocopy= true", expErr: `invalid value for volume-nocopy:  true`},
+		{value: "volume-nocopy=", expErr: `invalid value for 'volume-nocopy': value is empty`},
+		{value: "volume-nocopy= true", expErr: `invalid value for 'volume-nocopy' in 'volume-nocopy= true': value should not have whitespace`},
 		{value: "volume-nocopy=no", expErr: `invalid value for volume-nocopy: no`},
 		{value: "volume-nocopy=1", exp: true},
 		{value: "volume-nocopy=true", exp: true},