2 files changed, 114 insertions, 0 deletions

diff --git a/model/config.go b/model/config.go
index d5a8ad38e..074632a67 100644
--- a/model/config.go
+++ b/model/config.go
@@ -8,6 +8,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"regexp"
 	"strings"
 	"time"
 )
@@ -1772,10 +1773,16 @@ func (s *MessageExportSettings) SetDefaults() {
 }
 
 type DisplaySettings struct {
+	CustomUrlSchemes     *[]string
 	ExperimentalTimezone *bool
 }
 
 func (s *DisplaySettings) SetDefaults() {
+	if s.CustomUrlSchemes == nil {
+		customUrlSchemes := []string{}
+		s.CustomUrlSchemes = &customUrlSchemes
+	}
+
 	if s.ExperimentalTimezone == nil {
 		s.ExperimentalTimezone = NewBool(false)
 	}
@@ -1968,6 +1975,10 @@ func (o *Config) IsValid() *AppError {
 		return err
 	}
 
+	if err := o.DisplaySettings.isValid(); err != nil {
+		return err
+	}
+
 	return nil
 }
 
@@ -2348,6 +2359,26 @@ func (mes *MessageExportSettings) isValid(fs FileSettings) *AppError {
 	return nil
 }
 
+func (ds *DisplaySettings) isValid() *AppError {
+	if len(*ds.CustomUrlSchemes) != 0 {
+		validProtocolPattern := regexp.MustCompile(`(?i)^\s*[a-z][a-z0-9+.-]*\s*$`)
+
+		for _, scheme := range *ds.CustomUrlSchemes {
+			if !validProtocolPattern.MatchString(scheme) {
+				return NewAppError(
+					"Config.IsValid",
+					"model.config.is_valid.display.custom_url_schemes.app_error",
+					map[string]interface{}{"Protocol": scheme},
+					"",
+					http.StatusBadRequest,
+				)
+			}
+		}
+	}
+
+	return nil
+}
+
 func (o *Config) GetSanitizeOptions() map[string]bool {
 	options := map[string]bool{}
 	options["fullname"] = o.PrivacySettings.ShowFullName
diff --git a/model/config_test.go b/model/config_test.go
index b7533145b..5406d680d 100644
--- a/model/config_test.go
+++ b/model/config_test.go
@@ -436,3 +436,86 @@ func TestMessageExportSetDefaultsExportDisabledExportFromTimestampNonZero(t *tes
 	require.Equal(t, int64(0), *mes.ExportFromTimestamp)
 	require.Equal(t, 10000, *mes.BatchSize)
 }
+
+func TestDisplaySettingsIsValidCustomUrlSchemes(t *testing.T) {
+	tests := []struct {
+		name  string
+		value []string
+		valid bool
+	}{
+		{
+			name:  "empty",
+			value: []string{},
+			valid: true,
+		},
+		{
+			name:  "custom protocol",
+			value: []string{"steam"},
+			valid: true,
+		},
+		{
+			name:  "multiple custom protocols",
+			value: []string{"bitcoin", "rss", "redis"},
+			valid: true,
+		},
+		{
+			name:  "containing numbers",
+			value: []string{"ut2004", "ts3server", "h323"},
+			valid: true,
+		},
+		{
+			name:  "containing period",
+			value: []string{"iris.beep"},
+			valid: true,
+		},
+		{
+			name:  "containing hyphen",
+			value: []string{"ms-excel"},
+			valid: true,
+		},
+		{
+			name:  "containing plus",
+			value: []string{"coap+tcp", "coap+ws"},
+			valid: true,
+		},
+		{
+			name:  "starting with number",
+			value: []string{"4four"},
+			valid: false,
+		},
+		{
+			name:  "starting with period",
+			value: []string{"data", ".dot"},
+			valid: false,
+		},
+		{
+			name:  "starting with hyphen",
+			value: []string{"-hyphen", "dns"},
+			valid: false,
+		},
+		{
+			name:  "invalid symbols",
+			value: []string{"!!fun!!"},
+			valid: false,
+		},
+		{
+			name:  "invalid letters",
+			value: []string{"école"},
+			valid: false,
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			ds := &DisplaySettings{}
+			ds.SetDefaults()
+
+			ds.CustomUrlSchemes = &test.value
+
+			if err := ds.isValid(); err != nil && test.valid {
+				t.Error("Expected CustomUrlSchemes to be valid but got error:", err)
+			} else if err == nil && !test.valid {
+				t.Error("Expected CustomUrlSchemes to be invalid but got no error")
+			}
+		})
+	}
+}