Adding upstream version 9.0.0.

Signed-off-by: Daniel Baumann <daniel@debian.org>

10 files changed, 1271 insertions, 0 deletions

diff --git a/modules/validation/binding.go b/modules/validation/binding.go
new file mode 100644
index 0000000..cb0a506
--- /dev/null
+++ b/modules/validation/binding.go
@@ -0,0 +1,209 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+
+	"code.gitea.io/gitea/modules/auth"
+	"code.gitea.io/gitea/modules/git"
+
+	"gitea.com/go-chi/binding"
+	"github.com/gobwas/glob"
+)
+
+const (
+	// ErrGitRefName is git reference name error
+	ErrGitRefName = "GitRefNameError"
+	// ErrGlobPattern is returned when glob pattern is invalid
+	ErrGlobPattern = "GlobPattern"
+	// ErrRegexPattern is returned when a regex pattern is invalid
+	ErrRegexPattern = "RegexPattern"
+	// ErrUsername is username error
+	ErrUsername = "UsernameError"
+	// ErrInvalidGroupTeamMap is returned when a group team mapping is invalid
+	ErrInvalidGroupTeamMap = "InvalidGroupTeamMap"
+)
+
+// AddBindingRules adds additional binding rules
+func AddBindingRules() {
+	addGitRefNameBindingRule()
+	addValidURLBindingRule()
+	addValidSiteURLBindingRule()
+	addGlobPatternRule()
+	addRegexPatternRule()
+	addGlobOrRegexPatternRule()
+	addUsernamePatternRule()
+	addValidGroupTeamMapRule()
+}
+
+func addGitRefNameBindingRule() {
+	// Git refname validation rule
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return strings.HasPrefix(rule, "GitRefName")
+		},
+		IsValid: func(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+			str := fmt.Sprintf("%v", val)
+
+			if !git.IsValidRefPattern(str) {
+				errs.Add([]string{name}, ErrGitRefName, "GitRefName")
+				return false, errs
+			}
+			return true, errs
+		},
+	})
+}
+
+func addValidURLBindingRule() {
+	// URL validation rule
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return strings.HasPrefix(rule, "ValidUrl")
+		},
+		IsValid: func(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+			str := fmt.Sprintf("%v", val)
+			if len(str) != 0 && !IsValidURL(str) {
+				errs.Add([]string{name}, binding.ERR_URL, "Url")
+				return false, errs
+			}
+
+			return true, errs
+		},
+	})
+}
+
+func addValidSiteURLBindingRule() {
+	// URL validation rule
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return strings.HasPrefix(rule, "ValidSiteUrl")
+		},
+		IsValid: func(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+			str := fmt.Sprintf("%v", val)
+			if len(str) != 0 && !IsValidSiteURL(str) {
+				errs.Add([]string{name}, binding.ERR_URL, "Url")
+				return false, errs
+			}
+
+			return true, errs
+		},
+	})
+}
+
+func addGlobPatternRule() {
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return rule == "GlobPattern"
+		},
+		IsValid: globPatternValidator,
+	})
+}
+
+func globPatternValidator(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+	str := fmt.Sprintf("%v", val)
+
+	if len(str) != 0 {
+		if _, err := glob.Compile(str); err != nil {
+			errs.Add([]string{name}, ErrGlobPattern, err.Error())
+			return false, errs
+		}
+	}
+
+	return true, errs
+}
+
+func addRegexPatternRule() {
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return rule == "RegexPattern"
+		},
+		IsValid: regexPatternValidator,
+	})
+}
+
+func regexPatternValidator(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+	str := fmt.Sprintf("%v", val)
+
+	if _, err := regexp.Compile(str); err != nil {
+		errs.Add([]string{name}, ErrRegexPattern, err.Error())
+		return false, errs
+	}
+
+	return true, errs
+}
+
+func addGlobOrRegexPatternRule() {
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return rule == "GlobOrRegexPattern"
+		},
+		IsValid: func(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+			str := strings.TrimSpace(fmt.Sprintf("%v", val))
+
+			if len(str) >= 2 && strings.HasPrefix(str, "/") && strings.HasSuffix(str, "/") {
+				return regexPatternValidator(errs, name, str[1:len(str)-1])
+			}
+			return globPatternValidator(errs, name, val)
+		},
+	})
+}
+
+func addUsernamePatternRule() {
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return rule == "Username"
+		},
+		IsValid: func(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+			str := fmt.Sprintf("%v", val)
+			if !IsValidUsername(str) {
+				errs.Add([]string{name}, ErrUsername, "invalid username")
+				return false, errs
+			}
+			return true, errs
+		},
+	})
+}
+
+func addValidGroupTeamMapRule() {
+	binding.AddRule(&binding.Rule{
+		IsMatch: func(rule string) bool {
+			return strings.HasPrefix(rule, "ValidGroupTeamMap")
+		},
+		IsValid: func(errs binding.Errors, name string, val any) (bool, binding.Errors) {
+			_, err := auth.UnmarshalGroupTeamMapping(fmt.Sprintf("%v", val))
+			if err != nil {
+				errs.Add([]string{name}, ErrInvalidGroupTeamMap, err.Error())
+				return false, errs
+			}
+
+			return true, errs
+		},
+	})
+}
+
+func portOnly(hostport string) string {
+	colon := strings.IndexByte(hostport, ':')
+	if colon == -1 {
+		return ""
+	}
+	if i := strings.Index(hostport, "]:"); i != -1 {
+		return hostport[i+len("]:"):]
+	}
+	if strings.Contains(hostport, "]") {
+		return ""
+	}
+	return hostport[colon+len(":"):]
+}
+
+func validPort(p string) bool {
+	for _, r := range []byte(p) {
+		if r < '0' || r > '9' {
+			return false
+		}
+	}
+	return true
+}
diff --git a/modules/validation/binding_test.go b/modules/validation/binding_test.go
new file mode 100644
index 0000000..01ff4e3
--- /dev/null
+++ b/modules/validation/binding_test.go
@@ -0,0 +1,62 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"gitea.com/go-chi/binding"
+	chi "github.com/go-chi/chi/v5"
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	testRoute = "/test"
+)
+
+type (
+	validationTestCase struct {
+		description    string
+		data           any
+		expectedErrors binding.Errors
+	}
+
+	TestForm struct {
+		BranchName   string `form:"BranchName" binding:"GitRefName"`
+		URL          string `form:"ValidUrl" binding:"ValidUrl"`
+		GlobPattern  string `form:"GlobPattern" binding:"GlobPattern"`
+		RegexPattern string `form:"RegexPattern" binding:"RegexPattern"`
+	}
+)
+
+func performValidationTest(t *testing.T, testCase validationTestCase) {
+	httpRecorder := httptest.NewRecorder()
+	m := chi.NewRouter()
+
+	m.Post(testRoute, func(resp http.ResponseWriter, req *http.Request) {
+		actual := binding.Validate(req, testCase.data)
+		// see https://github.com/stretchr/testify/issues/435
+		if actual == nil {
+			actual = binding.Errors{}
+		}
+
+		assert.Equal(t, testCase.expectedErrors, actual)
+	})
+
+	req, err := http.NewRequest("POST", testRoute, nil)
+	if err != nil {
+		panic(err)
+	}
+	req.Header.Add("Content-Type", "x-www-form-urlencoded")
+	m.ServeHTTP(httpRecorder, req)
+
+	switch httpRecorder.Code {
+	case http.StatusNotFound:
+		panic("Routing is messed up in test fixture (got 404): check methods and paths")
+	case http.StatusInternalServerError:
+		panic("Something bad happened on '" + testCase.description + "'")
+	}
+}
diff --git a/modules/validation/glob_pattern_test.go b/modules/validation/glob_pattern_test.go
new file mode 100644
index 0000000..1bf622e
--- /dev/null
+++ b/modules/validation/glob_pattern_test.go
@@ -0,0 +1,61 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"testing"
+
+	"gitea.com/go-chi/binding"
+	"github.com/gobwas/glob"
+)
+
+func getGlobPatternErrorString(pattern string) string {
+	// It would be unwise to rely on that glob
+	// compilation errors don't ever change.
+	if _, err := glob.Compile(pattern); err != nil {
+		return err.Error()
+	}
+	return ""
+}
+
+var globValidationTestCases = []validationTestCase{
+	{
+		description: "Empty glob pattern",
+		data: TestForm{
+			GlobPattern: "",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "Valid glob",
+		data: TestForm{
+			GlobPattern: "{master,release*}",
+		},
+		expectedErrors: binding.Errors{},
+	},
+
+	{
+		description: "Invalid glob",
+		data: TestForm{
+			GlobPattern: "[a-",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"GlobPattern"},
+				Classification: ErrGlobPattern,
+				Message:        getGlobPatternErrorString("[a-"),
+			},
+		},
+	},
+}
+
+func Test_GlobPatternValidation(t *testing.T) {
+	AddBindingRules()
+
+	for _, testCase := range globValidationTestCases {
+		t.Run(testCase.description, func(t *testing.T) {
+			performValidationTest(t, testCase)
+		})
+	}
+}
diff --git a/modules/validation/helpers.go b/modules/validation/helpers.go
new file mode 100644
index 0000000..567ad86
--- /dev/null
+++ b/modules/validation/helpers.go
@@ -0,0 +1,136 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"net"
+	"net/url"
+	"regexp"
+	"strings"
+
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/gobwas/glob"
+)
+
+var externalTrackerRegex = regexp.MustCompile(`({?)(?:user|repo|index)+?(}?)`)
+
+func isLoopbackIP(ip string) bool {
+	return net.ParseIP(ip).IsLoopback()
+}
+
+// IsValidURL checks if URL is valid
+func IsValidURL(uri string) bool {
+	if u, err := url.ParseRequestURI(uri); err != nil ||
+		(u.Scheme != "http" && u.Scheme != "https") ||
+		!validPort(portOnly(u.Host)) {
+		return false
+	}
+
+	return true
+}
+
+// IsValidSiteURL checks if URL is valid
+func IsValidSiteURL(uri string) bool {
+	u, err := url.ParseRequestURI(uri)
+	if err != nil {
+		return false
+	}
+
+	if !validPort(portOnly(u.Host)) {
+		return false
+	}
+
+	for _, scheme := range setting.Service.ValidSiteURLSchemes {
+		if scheme == u.Scheme {
+			return true
+		}
+	}
+	return false
+}
+
+// IsEmailDomainListed checks whether the domain of an email address
+// matches a list of domains
+func IsEmailDomainListed(globs []glob.Glob, email string) bool {
+	if len(globs) == 0 {
+		return false
+	}
+
+	n := strings.LastIndex(email, "@")
+	if n <= 0 {
+		return false
+	}
+
+	domain := strings.ToLower(email[n+1:])
+
+	for _, g := range globs {
+		if g.Match(domain) {
+			return true
+		}
+	}
+
+	return false
+}
+
+// IsAPIURL checks if URL is current Gitea instance API URL
+func IsAPIURL(uri string) bool {
+	return strings.HasPrefix(strings.ToLower(uri), strings.ToLower(setting.AppURL+"api"))
+}
+
+// IsValidExternalURL checks if URL is valid external URL
+func IsValidExternalURL(uri string) bool {
+	if !IsValidURL(uri) || IsAPIURL(uri) {
+		return false
+	}
+
+	u, err := url.ParseRequestURI(uri)
+	if err != nil {
+		return false
+	}
+
+	// Currently check only if not loopback IP is provided to keep compatibility
+	if isLoopbackIP(u.Hostname()) || strings.ToLower(u.Hostname()) == "localhost" {
+		return false
+	}
+
+	// TODO: Later it should be added to allow local network IP addresses
+	//       only if allowed by special setting
+
+	return true
+}
+
+// IsValidExternalTrackerURLFormat checks if URL matches required syntax for external trackers
+func IsValidExternalTrackerURLFormat(uri string) bool {
+	if !IsValidExternalURL(uri) {
+		return false
+	}
+
+	// check for typoed variables like /{index/ or /[repo}
+	for _, match := range externalTrackerRegex.FindAllStringSubmatch(uri, -1) {
+		if (match[1] == "{" || match[2] == "}") && (match[1] != "{" || match[2] != "}") {
+			return false
+		}
+	}
+
+	return true
+}
+
+var (
+	validUsernamePatternWithDots    = regexp.MustCompile(`^[\da-zA-Z][-.\w]*$`)
+	validUsernamePatternWithoutDots = regexp.MustCompile(`^[\da-zA-Z][-\w]*$`)
+
+	// No consecutive or trailing non-alphanumeric chars, catches both cases
+	invalidUsernamePattern = regexp.MustCompile(`[-._]{2,}|[-._]$`)
+)
+
+// IsValidUsername checks if username is valid
+func IsValidUsername(name string) bool {
+	// It is difficult to find a single pattern that is both readable and effective,
+	// but it's easier to use positive and negative checks.
+	if setting.Service.AllowDotsInUsernames {
+		return validUsernamePatternWithDots.MatchString(name) && !invalidUsernamePattern.MatchString(name)
+	}
+
+	return validUsernamePatternWithoutDots.MatchString(name) && !invalidUsernamePattern.MatchString(name)
+}
diff --git a/modules/validation/helpers_test.go b/modules/validation/helpers_test.go
new file mode 100644
index 0000000..a1bdf2a
--- /dev/null
+++ b/modules/validation/helpers_test.go
@@ -0,0 +1,216 @@
+// Copyright 2018 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/modules/setting"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_IsValidURL(t *testing.T) {
+	cases := []struct {
+		description string
+		url         string
+		valid       bool
+	}{
+		{
+			description: "Empty URL",
+			url:         "",
+			valid:       false,
+		},
+		{
+			description: "Loopback IPv4 URL",
+			url:         "http://127.0.1.1:5678/",
+			valid:       true,
+		},
+		{
+			description: "Loopback IPv6 URL",
+			url:         "https://[::1]/",
+			valid:       true,
+		},
+		{
+			description: "Missing semicolon after schema",
+			url:         "http//meh/",
+			valid:       false,
+		},
+	}
+
+	for _, testCase := range cases {
+		t.Run(testCase.description, func(t *testing.T) {
+			assert.Equal(t, testCase.valid, IsValidURL(testCase.url))
+		})
+	}
+}
+
+func Test_IsValidExternalURL(t *testing.T) {
+	setting.AppURL = "https://try.gitea.io/"
+
+	cases := []struct {
+		description string
+		url         string
+		valid       bool
+	}{
+		{
+			description: "Current instance URL",
+			url:         "https://try.gitea.io/test",
+			valid:       true,
+		},
+		{
+			description: "Loopback IPv4 URL",
+			url:         "http://127.0.1.1:5678/",
+			valid:       false,
+		},
+		{
+			description: "Current instance API URL",
+			url:         "https://try.gitea.io/api/v1/user/follow",
+			valid:       false,
+		},
+		{
+			description: "Local network URL",
+			url:         "http://192.168.1.2/api/v1/user/follow",
+			valid:       true,
+		},
+		{
+			description: "Local URL",
+			url:         "http://LOCALHOST:1234/whatever",
+			valid:       false,
+		},
+	}
+
+	for _, testCase := range cases {
+		t.Run(testCase.description, func(t *testing.T) {
+			assert.Equal(t, testCase.valid, IsValidExternalURL(testCase.url))
+		})
+	}
+}
+
+func Test_IsValidExternalTrackerURLFormat(t *testing.T) {
+	setting.AppURL = "https://try.gitea.io/"
+
+	cases := []struct {
+		description string
+		url         string
+		valid       bool
+	}{
+		{
+			description: "Correct external tracker URL with all placeholders",
+			url:         "https://github.com/{user}/{repo}/issues/{index}",
+			valid:       true,
+		},
+		{
+			description: "Local external tracker URL with all placeholders",
+			url:         "https://127.0.0.1/{user}/{repo}/issues/{index}",
+			valid:       false,
+		},
+		{
+			description: "External tracker URL with typo placeholder",
+			url:         "https://github.com/{user}/{repo/issues/{index}",
+			valid:       false,
+		},
+		{
+			description: "External tracker URL with typo placeholder",
+			url:         "https://github.com/[user}/{repo/issues/{index}",
+			valid:       false,
+		},
+		{
+			description: "External tracker URL with typo placeholder",
+			url:         "https://github.com/{user}/repo}/issues/{index}",
+			valid:       false,
+		},
+		{
+			description: "External tracker URL missing optional placeholder",
+			url:         "https://github.com/{user}/issues/{index}",
+			valid:       true,
+		},
+		{
+			description: "External tracker URL missing optional placeholder",
+			url:         "https://github.com/{repo}/issues/{index}",
+			valid:       true,
+		},
+		{
+			description: "External tracker URL missing optional placeholder",
+			url:         "https://github.com/issues/{index}",
+			valid:       true,
+		},
+		{
+			description: "External tracker URL missing optional placeholder",
+			url:         "https://github.com/issues/{user}",
+			valid:       true,
+		},
+		{
+			description: "External tracker URL with similar placeholder names test",
+			url:         "https://github.com/user/repo/issues/{index}",
+			valid:       true,
+		},
+	}
+
+	for _, testCase := range cases {
+		t.Run(testCase.description, func(t *testing.T) {
+			assert.Equal(t, testCase.valid, IsValidExternalTrackerURLFormat(testCase.url))
+		})
+	}
+}
+
+func TestIsValidUsernameAllowDots(t *testing.T) {
+	setting.Service.AllowDotsInUsernames = true
+	tests := []struct {
+		arg  string
+		want bool
+	}{
+		{arg: "a", want: true},
+		{arg: "abc", want: true},
+		{arg: "0.b-c", want: true},
+		{arg: "a.b-c_d", want: true},
+		{arg: "", want: false},
+		{arg: ".abc", want: false},
+		{arg: "abc.", want: false},
+		{arg: "a..bc", want: false},
+		{arg: "a...bc", want: false},
+		{arg: "a.-bc", want: false},
+		{arg: "a._bc", want: false},
+		{arg: "a_-bc", want: false},
+		{arg: "a/bc", want: false},
+		{arg: "☁️", want: false},
+		{arg: "-", want: false},
+		{arg: "--diff", want: false},
+		{arg: "-im-here", want: false},
+		{arg: "a space", want: false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.arg, func(t *testing.T) {
+			assert.Equalf(t, tt.want, IsValidUsername(tt.arg), "IsValidUsername(%v)", tt.arg)
+		})
+	}
+}
+
+func TestIsValidUsernameBanDots(t *testing.T) {
+	setting.Service.AllowDotsInUsernames = false
+	defer func() {
+		setting.Service.AllowDotsInUsernames = true
+	}()
+
+	tests := []struct {
+		arg  string
+		want bool
+	}{
+		{arg: "a", want: true},
+		{arg: "abc", want: true},
+		{arg: "0.b-c", want: false},
+		{arg: "a.b-c_d", want: false},
+		{arg: ".abc", want: false},
+		{arg: "abc.", want: false},
+		{arg: "a..bc", want: false},
+		{arg: "a...bc", want: false},
+		{arg: "a.-bc", want: false},
+		{arg: "a._bc", want: false},
+	}
+	for _, tt := range tests {
+		t.Run(tt.arg, func(t *testing.T) {
+			assert.Equalf(t, tt.want, IsValidUsername(tt.arg), "IsValidUsername[AllowDotsInUsernames=false](%v)", tt.arg)
+		})
+	}
+}
diff --git a/modules/validation/refname_test.go b/modules/validation/refname_test.go
new file mode 100644
index 0000000..3af7387
--- /dev/null
+++ b/modules/validation/refname_test.go
@@ -0,0 +1,265 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"testing"
+
+	"gitea.com/go-chi/binding"
+)
+
+var gitRefNameValidationTestCases = []validationTestCase{
+	{
+		description: "Reference name contains only characters",
+		data: TestForm{
+			BranchName: "test",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "Reference name contains single slash",
+		data: TestForm{
+			BranchName: "feature/test",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "Reference name has allowed special characters",
+		data: TestForm{
+			BranchName: "debian/1%1.6.0-2",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "Reference name contains backslash",
+		data: TestForm{
+			BranchName: "feature\\test",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name starts with dot",
+		data: TestForm{
+			BranchName: ".test",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name ends with dot",
+		data: TestForm{
+			BranchName: "test.",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name starts with slash",
+		data: TestForm{
+			BranchName: "/test",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name ends with slash",
+		data: TestForm{
+			BranchName: "test/",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name ends with .lock",
+		data: TestForm{
+			BranchName: "test.lock",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name contains multiple consecutive dots",
+		data: TestForm{
+			BranchName: "te..st",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name contains multiple consecutive slashes",
+		data: TestForm{
+			BranchName: "te//st",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name is single @",
+		data: TestForm{
+			BranchName: "@",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has @{",
+		data: TestForm{
+			BranchName: "branch@{",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has unallowed special character ~",
+		data: TestForm{
+			BranchName: "~debian/1%1.6.0-2",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has unallowed special character *",
+		data: TestForm{
+			BranchName: "*debian/1%1.6.0-2",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has unallowed special character ?",
+		data: TestForm{
+			BranchName: "?debian/1%1.6.0-2",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has unallowed special character ^",
+		data: TestForm{
+			BranchName: "^debian/1%1.6.0-2",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has unallowed special character :",
+		data: TestForm{
+			BranchName: "debian:jessie",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has unallowed special character (whitespace)",
+		data: TestForm{
+			BranchName: "debian jessie",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+	{
+		description: "Reference name has unallowed special character [",
+		data: TestForm{
+			BranchName: "debian[jessie",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"BranchName"},
+				Classification: ErrGitRefName,
+				Message:        "GitRefName",
+			},
+		},
+	},
+}
+
+func Test_GitRefNameValidation(t *testing.T) {
+	AddBindingRules()
+
+	for _, testCase := range gitRefNameValidationTestCases {
+		t.Run(testCase.description, func(t *testing.T) {
+			performValidationTest(t, testCase)
+		})
+	}
+}
diff --git a/modules/validation/regex_pattern_test.go b/modules/validation/regex_pattern_test.go
new file mode 100644
index 0000000..efcb276
--- /dev/null
+++ b/modules/validation/regex_pattern_test.go
@@ -0,0 +1,59 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"regexp"
+	"testing"
+
+	"gitea.com/go-chi/binding"
+)
+
+func getRegexPatternErrorString(pattern string) string {
+	if _, err := regexp.Compile(pattern); err != nil {
+		return err.Error()
+	}
+	return ""
+}
+
+var regexValidationTestCases = []validationTestCase{
+	{
+		description: "Empty regex pattern",
+		data: TestForm{
+			RegexPattern: "",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "Valid regex",
+		data: TestForm{
+			RegexPattern: `(\d{1,3})+`,
+		},
+		expectedErrors: binding.Errors{},
+	},
+
+	{
+		description: "Invalid regex",
+		data: TestForm{
+			RegexPattern: "[a-",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"RegexPattern"},
+				Classification: ErrRegexPattern,
+				Message:        getRegexPatternErrorString("[a-"),
+			},
+		},
+	},
+}
+
+func Test_RegexPatternValidation(t *testing.T) {
+	AddBindingRules()
+
+	for _, testCase := range regexValidationTestCases {
+		t.Run(testCase.description, func(t *testing.T) {
+			performValidationTest(t, testCase)
+		})
+	}
+}
diff --git a/modules/validation/validatable.go b/modules/validation/validatable.go
new file mode 100644
index 0000000..94b5cc1
--- /dev/null
+++ b/modules/validation/validatable.go
@@ -0,0 +1,84 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// Copyright 2023 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"fmt"
+	"reflect"
+	"strings"
+	"unicode/utf8"
+
+	"code.gitea.io/gitea/modules/timeutil"
+)
+
+// ErrNotValid represents an validation error
+type ErrNotValid struct {
+	Message string
+}
+
+func (err ErrNotValid) Error() string {
+	return fmt.Sprintf("Validation Error: %v", err.Message)
+}
+
+// IsErrNotValid checks if an error is a ErrNotValid.
+func IsErrNotValid(err error) bool {
+	_, ok := err.(ErrNotValid)
+	return ok
+}
+
+type Validateable interface {
+	Validate() []string
+}
+
+func IsValid(v Validateable) (bool, error) {
+	if err := v.Validate(); len(err) > 0 {
+		typeof := reflect.TypeOf(v)
+		errString := strings.Join(err, "\n")
+		return false, ErrNotValid{fmt.Sprint(typeof, ": ", errString)}
+	}
+
+	return true, nil
+}
+
+func ValidateNotEmpty(value any, name string) []string {
+	isValid := true
+	switch v := value.(type) {
+	case string:
+		if v == "" {
+			isValid = false
+		}
+	case timeutil.TimeStamp:
+		if v.IsZero() {
+			isValid = false
+		}
+	case int64:
+		if v == 0 {
+			isValid = false
+		}
+	default:
+		isValid = false
+	}
+
+	if isValid {
+		return []string{}
+	}
+	return []string{fmt.Sprintf("%v should not be empty", name)}
+}
+
+func ValidateMaxLen(value string, maxLen int, name string) []string {
+	if utf8.RuneCountInString(value) > maxLen {
+		return []string{fmt.Sprintf("Value %v was longer than %v", name, maxLen)}
+	}
+	return []string{}
+}
+
+func ValidateOneOf(value any, allowed []any, name string) []string {
+	for _, allowedElem := range allowed {
+		if value == allowedElem {
+			return []string{}
+		}
+	}
+	return []string{fmt.Sprintf("Value %v is not contained in allowed values %v", value, allowed)}
+}
diff --git a/modules/validation/validatable_test.go b/modules/validation/validatable_test.go
new file mode 100644
index 0000000..919f5a3
--- /dev/null
+++ b/modules/validation/validatable_test.go
@@ -0,0 +1,69 @@
+// Copyright 2024 The Forgejo Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/modules/timeutil"
+)
+
+type Sut struct {
+	valid bool
+}
+
+func (sut Sut) Validate() []string {
+	if sut.valid {
+		return []string{}
+	}
+	return []string{"invalid"}
+}
+
+func Test_IsValid(t *testing.T) {
+	sut := Sut{valid: true}
+	if res, _ := IsValid(sut); !res {
+		t.Errorf("sut expected to be valid: %v\n", sut.Validate())
+	}
+	sut = Sut{valid: false}
+	res, err := IsValid(sut)
+	if res {
+		t.Errorf("sut expected to be invalid: %v\n", sut.Validate())
+	}
+	if err == nil || !IsErrNotValid(err) || err.Error() != "Validation Error: validation.Sut: invalid" {
+		t.Errorf("validation error expected, but was %v", err)
+	}
+}
+
+func Test_ValidateNotEmpty_ForString(t *testing.T) {
+	sut := ""
+	if len(ValidateNotEmpty(sut, "dummyField")) == 0 {
+		t.Errorf("sut should be invalid")
+	}
+	sut = "not empty"
+	if res := ValidateNotEmpty(sut, "dummyField"); len(res) > 0 {
+		t.Errorf("sut should be valid but was %q", res)
+	}
+}
+
+func Test_ValidateNotEmpty_ForTimestamp(t *testing.T) {
+	sut := timeutil.TimeStamp(0)
+	if res := ValidateNotEmpty(sut, "dummyField"); len(res) == 0 {
+		t.Errorf("sut should be invalid")
+	}
+	sut = timeutil.TimeStampNow()
+	if res := ValidateNotEmpty(sut, "dummyField"); len(res) > 0 {
+		t.Errorf("sut should be valid but was %q", res)
+	}
+}
+
+func Test_ValidateMaxLen(t *testing.T) {
+	sut := "0123456789"
+	if len(ValidateMaxLen(sut, 9, "dummyField")) == 0 {
+		t.Errorf("sut should be invalid")
+	}
+	sut = "0123456789"
+	if res := ValidateMaxLen(sut, 11, "dummyField"); len(res) > 0 {
+		t.Errorf("sut should be valid but was %q", res)
+	}
+}
diff --git a/modules/validation/validurl_test.go b/modules/validation/validurl_test.go
new file mode 100644
index 0000000..39f7fa5
--- /dev/null
+++ b/modules/validation/validurl_test.go
@@ -0,0 +1,110 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package validation
+
+import (
+	"testing"
+
+	"gitea.com/go-chi/binding"
+)
+
+var urlValidationTestCases = []validationTestCase{
+	{
+		description: "Empty URL",
+		data: TestForm{
+			URL: "",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "URL without port",
+		data: TestForm{
+			URL: "http://test.lan/",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "URL with port",
+		data: TestForm{
+			URL: "http://test.lan:3000/",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "URL with IPv6 address without port",
+		data: TestForm{
+			URL: "http://[::1]/",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "URL with IPv6 address with port",
+		data: TestForm{
+			URL: "http://[::1]:3000/",
+		},
+		expectedErrors: binding.Errors{},
+	},
+	{
+		description: "Invalid URL",
+		data: TestForm{
+			URL: "http//test.lan/",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"URL"},
+				Classification: binding.ERR_URL,
+				Message:        "Url",
+			},
+		},
+	},
+	{
+		description: "Invalid schema",
+		data: TestForm{
+			URL: "ftp://test.lan/",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"URL"},
+				Classification: binding.ERR_URL,
+				Message:        "Url",
+			},
+		},
+	},
+	{
+		description: "Invalid port",
+		data: TestForm{
+			URL: "http://test.lan:3x4/",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"URL"},
+				Classification: binding.ERR_URL,
+				Message:        "Url",
+			},
+		},
+	},
+	{
+		description: "Invalid port with IPv6 address",
+		data: TestForm{
+			URL: "http://[::1]:3x4/",
+		},
+		expectedErrors: binding.Errors{
+			binding.Error{
+				FieldNames:     []string{"URL"},
+				Classification: binding.ERR_URL,
+				Message:        "Url",
+			},
+		},
+	},
+}
+
+func Test_ValidURLValidation(t *testing.T) {
+	AddBindingRules()
+
+	for _, testCase := range urlValidationTestCases {
+		t.Run(testCase.description, func(t *testing.T) {
+			performValidationTest(t, testCase)
+		})
+	}
+}