From e68b9d00a6e05b3a941f63ffb696f91e554ac5ec Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel@debian.org>
Date: Fri, 18 Oct 2024 20:33:49 +0200
Subject: Adding upstream version 9.0.3.

Signed-off-by: Daniel Baumann <daniel@debian.org>
---
 modules/auth/password/hash/argon2.go       |  80 ++++++++++++
 modules/auth/password/hash/bcrypt.go       |  54 ++++++++
 modules/auth/password/hash/common.go       |  28 +++++
 modules/auth/password/hash/dummy.go        |  33 +++++
 modules/auth/password/hash/dummy_test.go   |  26 ++++
 modules/auth/password/hash/hash.go         | 189 ++++++++++++++++++++++++++++
 modules/auth/password/hash/hash_test.go    | 191 +++++++++++++++++++++++++++++
 modules/auth/password/hash/pbkdf2.go       |  67 ++++++++++
 modules/auth/password/hash/scrypt.go       |  67 ++++++++++
 modules/auth/password/hash/setting.go      |  76 ++++++++++++
 modules/auth/password/hash/setting_test.go |  38 ++++++
 modules/auth/password/password.go          | 136 ++++++++++++++++++++
 modules/auth/password/password_test.go     |  77 ++++++++++++
 modules/auth/password/pwn.go               |  52 ++++++++
 modules/auth/password/pwn/pwn.go           | 118 ++++++++++++++++++
 modules/auth/password/pwn/pwn_test.go      |  51 ++++++++
 16 files changed, 1283 insertions(+)
 create mode 100644 modules/auth/password/hash/argon2.go
 create mode 100644 modules/auth/password/hash/bcrypt.go
 create mode 100644 modules/auth/password/hash/common.go
 create mode 100644 modules/auth/password/hash/dummy.go
 create mode 100644 modules/auth/password/hash/dummy_test.go
 create mode 100644 modules/auth/password/hash/hash.go
 create mode 100644 modules/auth/password/hash/hash_test.go
 create mode 100644 modules/auth/password/hash/pbkdf2.go
 create mode 100644 modules/auth/password/hash/scrypt.go
 create mode 100644 modules/auth/password/hash/setting.go
 create mode 100644 modules/auth/password/hash/setting_test.go
 create mode 100644 modules/auth/password/password.go
 create mode 100644 modules/auth/password/password_test.go
 create mode 100644 modules/auth/password/pwn.go
 create mode 100644 modules/auth/password/pwn/pwn.go
 create mode 100644 modules/auth/password/pwn/pwn_test.go

(limited to 'modules/auth/password')

diff --git a/modules/auth/password/hash/argon2.go b/modules/auth/password/hash/argon2.go
new file mode 100644
index 0000000..0cd6472
--- /dev/null
+++ b/modules/auth/password/hash/argon2.go
@@ -0,0 +1,80 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"encoding/hex"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+
+	"golang.org/x/crypto/argon2"
+)
+
+func init() {
+	MustRegister("argon2", NewArgon2Hasher)
+}
+
+// Argon2Hasher implements PasswordHasher
+// and uses the Argon2 key derivation function, hybrant variant
+type Argon2Hasher struct {
+	time    uint32
+	memory  uint32
+	threads uint8
+	keyLen  uint32
+}
+
+// HashWithSaltBytes a provided password and salt
+func (hasher *Argon2Hasher) HashWithSaltBytes(password string, salt []byte) string {
+	if hasher == nil {
+		return ""
+	}
+	return hex.EncodeToString(argon2.IDKey([]byte(password), salt, hasher.time, hasher.memory, hasher.threads, hasher.keyLen))
+}
+
+// NewArgon2Hasher is a factory method to create an Argon2Hasher
+// The provided config should be either empty or of the form:
+// "<time>$<memory>$<threads>$<keyLen>", where <x> is the string representation
+// of an integer
+func NewArgon2Hasher(config string) *Argon2Hasher {
+	// This default configuration uses the following parameters:
+	// time=2, memory=64*1024, threads=8, keyLen=50.
+	// It will make two passes through the memory, using 64MiB in total.
+	// This matches the original configuration for `argon2` prior to storing hash parameters
+	// in the database.
+	// THESE VALUES MUST NOT BE CHANGED OR BACKWARDS COMPATIBILITY WILL BREAK
+	hasher := &Argon2Hasher{
+		time:    2,
+		memory:  1 << 16,
+		threads: 8,
+		keyLen:  50,
+	}
+
+	if config == "" {
+		return hasher
+	}
+
+	vals := strings.SplitN(config, "$", 4)
+	if len(vals) != 4 {
+		log.Error("invalid argon2 hash spec %s", config)
+		return nil
+	}
+
+	parsed, err := parseUIntParam(vals[0], "time", "argon2", config, nil)
+	hasher.time = uint32(parsed)
+
+	parsed, err = parseUIntParam(vals[1], "memory", "argon2", config, err)
+	hasher.memory = uint32(parsed)
+
+	parsed, err = parseUIntParam(vals[2], "threads", "argon2", config, err)
+	hasher.threads = uint8(parsed)
+
+	parsed, err = parseUIntParam(vals[3], "keyLen", "argon2", config, err)
+	hasher.keyLen = uint32(parsed)
+	if err != nil {
+		return nil
+	}
+
+	return hasher
+}
diff --git a/modules/auth/password/hash/bcrypt.go b/modules/auth/password/hash/bcrypt.go
new file mode 100644
index 0000000..4607c16
--- /dev/null
+++ b/modules/auth/password/hash/bcrypt.go
@@ -0,0 +1,54 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"golang.org/x/crypto/bcrypt"
+)
+
+func init() {
+	MustRegister("bcrypt", NewBcryptHasher)
+}
+
+// BcryptHasher implements PasswordHasher
+// and uses the bcrypt password hash function.
+type BcryptHasher struct {
+	cost int
+}
+
+// HashWithSaltBytes a provided password and salt
+func (hasher *BcryptHasher) HashWithSaltBytes(password string, salt []byte) string {
+	if hasher == nil {
+		return ""
+	}
+	hashedPassword, _ := bcrypt.GenerateFromPassword([]byte(password), hasher.cost)
+	return string(hashedPassword)
+}
+
+func (hasher *BcryptHasher) VerifyPassword(password, hashedPassword, salt string) bool {
+	return bcrypt.CompareHashAndPassword([]byte(hashedPassword), []byte(password)) == nil
+}
+
+// NewBcryptHasher is a factory method to create an BcryptHasher
+// The provided config should be either empty or the string representation of the "<cost>"
+// as an integer
+func NewBcryptHasher(config string) *BcryptHasher {
+	// This matches the original configuration for `bcrypt` prior to storing hash parameters
+	// in the database.
+	// THESE VALUES MUST NOT BE CHANGED OR BACKWARDS COMPATIBILITY WILL BREAK
+	hasher := &BcryptHasher{
+		cost: 10, // cost=10. i.e. 2^10 rounds of key expansion.
+	}
+
+	if config == "" {
+		return hasher
+	}
+	var err error
+	hasher.cost, err = parseIntParam(config, "cost", "bcrypt", config, nil)
+	if err != nil {
+		return nil
+	}
+
+	return hasher
+}
diff --git a/modules/auth/password/hash/common.go b/modules/auth/password/hash/common.go
new file mode 100644
index 0000000..487c073
--- /dev/null
+++ b/modules/auth/password/hash/common.go
@@ -0,0 +1,28 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"strconv"
+
+	"code.gitea.io/gitea/modules/log"
+)
+
+func parseIntParam(value, param, algorithmName, config string, previousErr error) (int, error) {
+	parsed, err := strconv.Atoi(value)
+	if err != nil {
+		log.Error("invalid integer for %s representation in %s hash spec %s", param, algorithmName, config)
+		return 0, err
+	}
+	return parsed, previousErr // <- Keep the previous error as this function should still return an error once everything has been checked if any call failed
+}
+
+func parseUIntParam(value, param, algorithmName, config string, previousErr error) (uint64, error) { //nolint:unparam
+	parsed, err := strconv.ParseUint(value, 10, 64)
+	if err != nil {
+		log.Error("invalid integer for %s representation in %s hash spec %s", param, algorithmName, config)
+		return 0, err
+	}
+	return parsed, previousErr // <- Keep the previous error as this function should still return an error once everything has been checked if any call failed
+}
diff --git a/modules/auth/password/hash/dummy.go b/modules/auth/password/hash/dummy.go
new file mode 100644
index 0000000..22f2e2f
--- /dev/null
+++ b/modules/auth/password/hash/dummy.go
@@ -0,0 +1,33 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"encoding/hex"
+)
+
+// DummyHasher implements PasswordHasher and is a dummy hasher that simply
+// puts the password in place with its salt
+// This SHOULD NOT be used in production and is provided to make the integration
+// tests faster only
+type DummyHasher struct{}
+
+// HashWithSaltBytes a provided password and salt
+func (hasher *DummyHasher) HashWithSaltBytes(password string, salt []byte) string {
+	if hasher == nil {
+		return ""
+	}
+
+	if len(salt) == 10 {
+		return string(salt) + ":" + password
+	}
+
+	return hex.EncodeToString(salt) + ":" + password
+}
+
+// NewDummyHasher is a factory method to create a DummyHasher
+// Any provided configuration is ignored
+func NewDummyHasher(_ string) *DummyHasher {
+	return &DummyHasher{}
+}
diff --git a/modules/auth/password/hash/dummy_test.go b/modules/auth/password/hash/dummy_test.go
new file mode 100644
index 0000000..35d1249
--- /dev/null
+++ b/modules/auth/password/hash/dummy_test.go
@@ -0,0 +1,26 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestDummyHasher(t *testing.T) {
+	dummy := &PasswordHashAlgorithm{
+		PasswordSaltHasher: NewDummyHasher(""),
+		Specification:      "dummy",
+	}
+
+	password, salt := "password", "ZogKvWdyEx"
+
+	hash, err := dummy.Hash(password, salt)
+	require.NoError(t, err)
+	assert.Equal(t, hash, salt+":"+password)
+
+	assert.True(t, dummy.VerifyPassword(password, hash, salt))
+}
diff --git a/modules/auth/password/hash/hash.go b/modules/auth/password/hash/hash.go
new file mode 100644
index 0000000..459320e
--- /dev/null
+++ b/modules/auth/password/hash/hash.go
@@ -0,0 +1,189 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"crypto/subtle"
+	"encoding/hex"
+	"fmt"
+	"strings"
+	"sync/atomic"
+
+	"code.gitea.io/gitea/modules/log"
+)
+
+// This package takes care of hashing passwords, verifying passwords, defining
+// available password algorithms, defining recommended password algorithms and
+// choosing the default password algorithm.
+
+// PasswordSaltHasher will hash a provided password with the provided saltBytes
+type PasswordSaltHasher interface {
+	HashWithSaltBytes(password string, saltBytes []byte) string
+}
+
+// PasswordHasher will hash a provided password with the salt
+type PasswordHasher interface {
+	Hash(password, salt string) (string, error)
+}
+
+// PasswordVerifier will ensure that a providedPassword matches the hashPassword when hashed with the salt
+type PasswordVerifier interface {
+	VerifyPassword(providedPassword, hashedPassword, salt string) bool
+}
+
+// PasswordHashAlgorithms are named PasswordSaltHashers with a default verifier and hash function
+type PasswordHashAlgorithm struct {
+	PasswordSaltHasher
+	Specification string // The specification that is used to create the internal PasswordSaltHasher
+}
+
+// Hash the provided password with the salt and return the hash
+func (algorithm *PasswordHashAlgorithm) Hash(password, salt string) (string, error) {
+	var saltBytes []byte
+
+	// There are two formats for the salt value:
+	// * The new format is a (32+)-byte hex-encoded string
+	// * The old format was a 10-byte binary format
+	// We have to tolerate both here.
+	if len(salt) == 10 {
+		saltBytes = []byte(salt)
+	} else {
+		var err error
+		saltBytes, err = hex.DecodeString(salt)
+		if err != nil {
+			return "", err
+		}
+	}
+
+	return algorithm.HashWithSaltBytes(password, saltBytes), nil
+}
+
+// Verify the provided password matches the hashPassword when hashed with the salt
+func (algorithm *PasswordHashAlgorithm) VerifyPassword(providedPassword, hashedPassword, salt string) bool {
+	// Some PasswordSaltHashers have their own specialised compare function that takes into
+	// account the stored parameters within the hash. e.g. bcrypt
+	if verifier, ok := algorithm.PasswordSaltHasher.(PasswordVerifier); ok {
+		return verifier.VerifyPassword(providedPassword, hashedPassword, salt)
+	}
+
+	// Compute the hash of the password.
+	providedPasswordHash, err := algorithm.Hash(providedPassword, salt)
+	if err != nil {
+		log.Error("passwordhash: %v.Hash(): %v", algorithm.Specification, err)
+		return false
+	}
+
+	// Compare it against the hashed password in constant-time.
+	return subtle.ConstantTimeCompare([]byte(hashedPassword), []byte(providedPasswordHash)) == 1
+}
+
+var (
+	lastNonDefaultAlgorithm  atomic.Value
+	availableHasherFactories = map[string]func(string) PasswordSaltHasher{}
+)
+
+// MustRegister registers a PasswordSaltHasher with the availableHasherFactories
+// Caution: This is not thread safe.
+func MustRegister[T PasswordSaltHasher](name string, newFn func(config string) T) {
+	if err := Register(name, newFn); err != nil {
+		panic(err)
+	}
+}
+
+// Register registers a PasswordSaltHasher with the availableHasherFactories
+// Caution: This is not thread safe.
+func Register[T PasswordSaltHasher](name string, newFn func(config string) T) error {
+	if _, has := availableHasherFactories[name]; has {
+		return fmt.Errorf("duplicate registration of password salt hasher: %s", name)
+	}
+
+	availableHasherFactories[name] = func(config string) PasswordSaltHasher {
+		n := newFn(config)
+		return n
+	}
+	return nil
+}
+
+// In early versions of gitea the password hash algorithm field of a user could be
+// empty. At that point the default was `pbkdf2` without configuration values
+//
+// Please note this is not the same as the DefaultAlgorithm which is used
+// to determine what an empty PASSWORD_HASH_ALGO setting in the app.ini means.
+// These are not the same even if they have the same apparent value and they mean different things.
+//
+// DO NOT COALESCE THESE VALUES
+const defaultEmptyHashAlgorithmSpecification = "pbkdf2"
+
+// Parse will convert the provided algorithm specification in to a PasswordHashAlgorithm
+// If the provided specification matches the DefaultHashAlgorithm Specification it will be
+// used.
+// In addition the last non-default hasher will be cached to help reduce the load from
+// parsing specifications.
+//
+// NOTE: No de-aliasing is done in this function, thus any specification which does not
+// contain a configuration will use the default values for that hasher. These are not
+// necessarily the same values as those obtained by dealiasing. This allows for
+// seamless backwards compatibility with the original configuration.
+//
+// To further labour this point, running `Parse("pbkdf2")` does not obtain the
+// same algorithm as setting `PASSWORD_HASH_ALGO=pbkdf2` in app.ini, nor is it intended to.
+// A user that has `password_hash_algo='pbkdf2'` in the db means get the original, unconfigured algorithm
+// Users will be migrated automatically as they log-in to have the complete specification stored
+// in their `password_hash_algo` fields by other code.
+func Parse(algorithmSpec string) *PasswordHashAlgorithm {
+	if algorithmSpec == "" {
+		algorithmSpec = defaultEmptyHashAlgorithmSpecification
+	}
+
+	if DefaultHashAlgorithm != nil && algorithmSpec == DefaultHashAlgorithm.Specification {
+		return DefaultHashAlgorithm
+	}
+
+	ptr := lastNonDefaultAlgorithm.Load()
+	if ptr != nil {
+		hashAlgorithm, ok := ptr.(*PasswordHashAlgorithm)
+		if ok && hashAlgorithm.Specification == algorithmSpec {
+			return hashAlgorithm
+		}
+	}
+
+	// Now convert the provided specification in to a hasherType +/- some configuration parameters
+	vals := strings.SplitN(algorithmSpec, "$", 2)
+	var hasherType string
+	var config string
+
+	if len(vals) == 0 {
+		// This should not happen as algorithmSpec should not be empty
+		// due to it being assigned to defaultEmptyHashAlgorithmSpecification above
+		// but we should be absolutely cautious here
+		return nil
+	}
+
+	hasherType = vals[0]
+	if len(vals) > 1 {
+		config = vals[1]
+	}
+
+	newFn, has := availableHasherFactories[hasherType]
+	if !has {
+		// unknown hasher type
+		return nil
+	}
+
+	ph := newFn(config)
+	if ph == nil {
+		// The provided configuration is likely invalid - it will have been logged already
+		// but we cannot hash safely
+		return nil
+	}
+
+	hashAlgorithm := &PasswordHashAlgorithm{
+		PasswordSaltHasher: ph,
+		Specification:      algorithmSpec,
+	}
+
+	lastNonDefaultAlgorithm.Store(hashAlgorithm)
+
+	return hashAlgorithm
+}
diff --git a/modules/auth/password/hash/hash_test.go b/modules/auth/password/hash/hash_test.go
new file mode 100644
index 0000000..03d08a8
--- /dev/null
+++ b/modules/auth/password/hash/hash_test.go
@@ -0,0 +1,191 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"encoding/hex"
+	"strconv"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type testSaltHasher string
+
+func (t testSaltHasher) HashWithSaltBytes(password string, salt []byte) string {
+	return password + "$" + string(salt) + "$" + string(t)
+}
+
+func Test_registerHasher(t *testing.T) {
+	MustRegister("Test_registerHasher", func(config string) testSaltHasher {
+		return testSaltHasher(config)
+	})
+
+	assert.Panics(t, func() {
+		MustRegister("Test_registerHasher", func(config string) testSaltHasher {
+			return testSaltHasher(config)
+		})
+	})
+
+	require.Error(t, Register("Test_registerHasher", func(config string) testSaltHasher {
+		return testSaltHasher(config)
+	}))
+
+	assert.Equal(t, "password$salt$",
+		Parse("Test_registerHasher").PasswordSaltHasher.HashWithSaltBytes("password", []byte("salt")))
+
+	assert.Equal(t, "password$salt$config",
+		Parse("Test_registerHasher$config").PasswordSaltHasher.HashWithSaltBytes("password", []byte("salt")))
+
+	delete(availableHasherFactories, "Test_registerHasher")
+}
+
+func TestParse(t *testing.T) {
+	hashAlgorithmsToTest := []string{}
+	for plainHashAlgorithmNames := range availableHasherFactories {
+		hashAlgorithmsToTest = append(hashAlgorithmsToTest, plainHashAlgorithmNames)
+	}
+	for _, aliased := range aliasAlgorithmNames {
+		if strings.Contains(aliased, "$") {
+			hashAlgorithmsToTest = append(hashAlgorithmsToTest, aliased)
+		}
+	}
+	for _, algorithmName := range hashAlgorithmsToTest {
+		t.Run(algorithmName, func(t *testing.T) {
+			algo := Parse(algorithmName)
+			assert.NotNil(t, algo, "Algorithm %s resulted in an empty algorithm", algorithmName)
+		})
+	}
+}
+
+func TestHashing(t *testing.T) {
+	hashAlgorithmsToTest := []string{}
+	for plainHashAlgorithmNames := range availableHasherFactories {
+		hashAlgorithmsToTest = append(hashAlgorithmsToTest, plainHashAlgorithmNames)
+	}
+	for _, aliased := range aliasAlgorithmNames {
+		if strings.Contains(aliased, "$") {
+			hashAlgorithmsToTest = append(hashAlgorithmsToTest, aliased)
+		}
+	}
+
+	runTests := func(password, salt string, shouldPass bool) {
+		for _, algorithmName := range hashAlgorithmsToTest {
+			t.Run(algorithmName, func(t *testing.T) {
+				output, err := Parse(algorithmName).Hash(password, salt)
+				if shouldPass {
+					require.NoError(t, err)
+					assert.NotEmpty(t, output, "output for %s was empty", algorithmName)
+				} else {
+					require.Error(t, err)
+				}
+
+				assert.Equal(t, Parse(algorithmName).VerifyPassword(password, output, salt), shouldPass)
+			})
+		}
+	}
+
+	// Test with new salt format.
+	runTests(strings.Repeat("a", 16), hex.EncodeToString([]byte{0x01, 0x02, 0x03}), true)
+
+	// Test with legacy salt format.
+	runTests(strings.Repeat("a", 16), strings.Repeat("b", 10), true)
+
+	// Test with invalid salt.
+	runTests(strings.Repeat("a", 16), "a", false)
+}
+
+// vectors were generated using the current codebase.
+var vectors = []struct {
+	algorithms []string
+	password   string
+	salt       string
+	output     string
+	shouldfail bool
+}{
+	{
+		algorithms: []string{"bcrypt", "bcrypt$10"},
+		password:   "abcdef",
+		salt:       strings.Repeat("a", 10),
+		output:     "$2a$10$fjtm8BsQ2crym01/piJroenO3oSVUBhSLKaGdTYJ4tG0ePVCrU0G2",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"scrypt", "scrypt$65536$16$2$50"},
+		password:   "abcdef",
+		salt:       strings.Repeat("a", 10),
+		output:     "3b571d0c07c62d42b7bad3dbf18fb0cd67d4d8cd4ad4c6928e1090e5b2a4a84437c6fd2627d897c0e7e65025ca62b67a0002",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"argon2", "argon2$2$65536$8$50"},
+		password:   "abcdef",
+		salt:       strings.Repeat("a", 10),
+		output:     "551f089f570f989975b6f7c6a8ff3cf89bc486dd7bbe87ed4d80ad4362f8ee599ec8dda78dac196301b98456402bcda775dc",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"pbkdf2", "pbkdf2$10000$50"},
+		password:   "abcdef",
+		salt:       strings.Repeat("a", 10),
+		output:     "ab48d5471b7e6ed42d10001db88c852ff7303c788e49da5c3c7b63d5adf96360303724b74b679223a3dea8a242d10abb1913",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"bcrypt", "bcrypt$10"},
+		password:   "abcdef",
+		salt:       hex.EncodeToString([]byte{0x01, 0x02, 0x03, 0x04}),
+		output:     "$2a$10$qhgm32w9ZpqLygugWJsLjey8xRGcaq9iXAfmCeNBXxddgyoaOC3Gq",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"scrypt", "scrypt$65536$16$2$50"},
+		password:   "abcdef",
+		salt:       hex.EncodeToString([]byte{0x01, 0x02, 0x03, 0x04}),
+		output:     "25fe5f66b43fa4eb7b6717905317cd2223cf841092dc8e0a1e8c75720ad4846cb5d9387303e14bc3c69faa3b1c51ef4b7de1",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"argon2", "argon2$2$65536$8$50"},
+		password:   "abcdef",
+		salt:       hex.EncodeToString([]byte{0x01, 0x02, 0x03, 0x04}),
+		output:     "9c287db63a91d18bb1414b703216da4fc431387c1ae7c8acdb280222f11f0929831055dbfd5126a3b48566692e83ec750d2a",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"pbkdf2", "pbkdf2$10000$50"},
+		password:   "abcdef",
+		salt:       hex.EncodeToString([]byte{0x01, 0x02, 0x03, 0x04}),
+		output:     "45d6cdc843d65cf0eda7b90ab41435762a282f7df013477a1c5b212ba81dbdca2edf1ecc4b5cb05956bb9e0c37ab29315d78",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"pbkdf2$320000$50"},
+		password:   "abcdef",
+		salt:       hex.EncodeToString([]byte{0x01, 0x02, 0x03, 0x04}),
+		output:     "84e233114499e8721da80e85568e5b7b5900b3e49a30845fcda9d1e1756da4547d70f8740ac2b4a5d82f88cebcd27f21bfe2",
+		shouldfail: false,
+	},
+	{
+		algorithms: []string{"pbkdf2", "pbkdf2$10000$50"},
+		password:   "abcdef",
+		salt:       "",
+		output:     "",
+		shouldfail: true,
+	},
+}
+
+// Ensure that the current code will correctly verify against the test vectors.
+func TestVectors(t *testing.T) {
+	for i, vector := range vectors {
+		for _, algorithm := range vector.algorithms {
+			t.Run(strconv.Itoa(i)+": "+algorithm, func(t *testing.T) {
+				pa := Parse(algorithm)
+				assert.Equal(t, !vector.shouldfail, pa.VerifyPassword(vector.password, vector.output, vector.salt))
+			})
+		}
+	}
+}
diff --git a/modules/auth/password/hash/pbkdf2.go b/modules/auth/password/hash/pbkdf2.go
new file mode 100644
index 0000000..27382fe
--- /dev/null
+++ b/modules/auth/password/hash/pbkdf2.go
@@ -0,0 +1,67 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+
+	"golang.org/x/crypto/pbkdf2"
+)
+
+func init() {
+	MustRegister("pbkdf2", NewPBKDF2Hasher)
+}
+
+// PBKDF2Hasher implements PasswordHasher
+// and uses the PBKDF2 key derivation function.
+type PBKDF2Hasher struct {
+	iter, keyLen int
+}
+
+// HashWithSaltBytes a provided password and salt
+func (hasher *PBKDF2Hasher) HashWithSaltBytes(password string, salt []byte) string {
+	if hasher == nil {
+		return ""
+	}
+	return hex.EncodeToString(pbkdf2.Key([]byte(password), salt, hasher.iter, hasher.keyLen, sha256.New))
+}
+
+// NewPBKDF2Hasher is a factory method to create an PBKDF2Hasher
+// config should be either empty or of the form:
+// "<iter>$<keyLen>", where <x> is the string representation
+// of an integer
+func NewPBKDF2Hasher(config string) *PBKDF2Hasher {
+	// This default configuration uses the following parameters:
+	// iter=10000, keyLen=50.
+	// This matches the original configuration for `pbkdf2` prior to storing parameters
+	// in the database.
+	// THESE VALUES MUST NOT BE CHANGED OR BACKWARDS COMPATIBILITY WILL BREAK
+	hasher := &PBKDF2Hasher{
+		iter:   10_000,
+		keyLen: 50,
+	}
+
+	if config == "" {
+		return hasher
+	}
+
+	vals := strings.SplitN(config, "$", 2)
+	if len(vals) != 2 {
+		log.Error("invalid pbkdf2 hash spec %s", config)
+		return nil
+	}
+
+	var err error
+	hasher.iter, err = parseIntParam(vals[0], "iter", "pbkdf2", config, nil)
+	hasher.keyLen, err = parseIntParam(vals[1], "keyLen", "pbkdf2", config, err)
+	if err != nil {
+		return nil
+	}
+
+	return hasher
+}
diff --git a/modules/auth/password/hash/scrypt.go b/modules/auth/password/hash/scrypt.go
new file mode 100644
index 0000000..f3d38f7
--- /dev/null
+++ b/modules/auth/password/hash/scrypt.go
@@ -0,0 +1,67 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"encoding/hex"
+	"strings"
+
+	"code.gitea.io/gitea/modules/log"
+
+	"golang.org/x/crypto/scrypt"
+)
+
+func init() {
+	MustRegister("scrypt", NewScryptHasher)
+}
+
+// ScryptHasher implements PasswordHasher
+// and uses the scrypt key derivation function.
+type ScryptHasher struct {
+	n, r, p, keyLen int
+}
+
+// HashWithSaltBytes a provided password and salt
+func (hasher *ScryptHasher) HashWithSaltBytes(password string, salt []byte) string {
+	if hasher == nil {
+		return ""
+	}
+	hashedPassword, _ := scrypt.Key([]byte(password), salt, hasher.n, hasher.r, hasher.p, hasher.keyLen)
+	return hex.EncodeToString(hashedPassword)
+}
+
+// NewScryptHasher is a factory method to create an ScryptHasher
+// The provided config should be either empty or of the form:
+// "<n>$<r>$<p>$<keyLen>", where <x> is the string representation
+// of an integer
+func NewScryptHasher(config string) *ScryptHasher {
+	// This matches the original configuration for `scrypt` prior to storing hash parameters
+	// in the database.
+	// THESE VALUES MUST NOT BE CHANGED OR BACKWARDS COMPATIBILITY WILL BREAK
+	hasher := &ScryptHasher{
+		n:      1 << 16,
+		r:      16,
+		p:      2, // 2 passes through memory - this default config will use 128MiB in total.
+		keyLen: 50,
+	}
+
+	if config == "" {
+		return hasher
+	}
+
+	vals := strings.SplitN(config, "$", 4)
+	if len(vals) != 4 {
+		log.Error("invalid scrypt hash spec %s", config)
+		return nil
+	}
+	var err error
+	hasher.n, err = parseIntParam(vals[0], "n", "scrypt", config, nil)
+	hasher.r, err = parseIntParam(vals[1], "r", "scrypt", config, err)
+	hasher.p, err = parseIntParam(vals[2], "p", "scrypt", config, err)
+	hasher.keyLen, err = parseIntParam(vals[3], "keyLen", "scrypt", config, err)
+	if err != nil {
+		return nil
+	}
+	return hasher
+}
diff --git a/modules/auth/password/hash/setting.go b/modules/auth/password/hash/setting.go
new file mode 100644
index 0000000..05cd36f
--- /dev/null
+++ b/modules/auth/password/hash/setting.go
@@ -0,0 +1,76 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+// DefaultHashAlgorithmName represents the default value of PASSWORD_HASH_ALGO
+// configured in app.ini.
+//
+// It is NOT the same and does NOT map to the defaultEmptyHashAlgorithmSpecification.
+//
+// It will be dealiased as per aliasAlgorithmNames whereas
+// defaultEmptyHashAlgorithmSpecification does not undergo dealiasing.
+const DefaultHashAlgorithmName = "pbkdf2_hi"
+
+var DefaultHashAlgorithm *PasswordHashAlgorithm
+
+// aliasAlgorithNames provides a mapping between the value of PASSWORD_HASH_ALGO
+// configured in the app.ini and the parameters used within the hashers internally.
+//
+// If it is necessary to change the default parameters for any hasher in future you
+// should change these values and not those in argon2.go etc.
+var aliasAlgorithmNames = map[string]string{
+	"argon2":    "argon2$2$65536$8$50",
+	"bcrypt":    "bcrypt$10",
+	"scrypt":    "scrypt$65536$16$2$50",
+	"pbkdf2":    "pbkdf2_v2", // pbkdf2 should default to pbkdf2_v2
+	"pbkdf2_v1": "pbkdf2$10000$50",
+	// The latest PBKDF2 password algorithm is used as the default since it doesn't
+	// use a lot of  memory and is safer to use on less powerful devices.
+	"pbkdf2_v2": "pbkdf2$50000$50",
+	// The pbkdf2_hi password algorithm is offered as a stronger alternative to the
+	// slightly improved pbkdf2_v2 algorithm
+	"pbkdf2_hi": "pbkdf2$320000$50",
+}
+
+var RecommendedHashAlgorithms = []string{
+	"pbkdf2",
+	"argon2",
+	"bcrypt",
+	"scrypt",
+	"pbkdf2_hi",
+}
+
+// hashAlgorithmToSpec converts an algorithm name or a specification to a full algorithm specification
+func hashAlgorithmToSpec(algorithmName string) string {
+	if algorithmName == "" {
+		algorithmName = DefaultHashAlgorithmName
+	}
+	alias, has := aliasAlgorithmNames[algorithmName]
+	for has {
+		algorithmName = alias
+		alias, has = aliasAlgorithmNames[algorithmName]
+	}
+	return algorithmName
+}
+
+// SetDefaultPasswordHashAlgorithm will take a provided algorithmName and de-alias it to
+// a complete algorithm specification.
+func SetDefaultPasswordHashAlgorithm(algorithmName string) (string, *PasswordHashAlgorithm) {
+	algoSpec := hashAlgorithmToSpec(algorithmName)
+	// now we get a full specification, e.g. pbkdf2$50000$50 rather than pbdkf2
+	DefaultHashAlgorithm = Parse(algoSpec)
+	return algoSpec, DefaultHashAlgorithm
+}
+
+// ConfigHashAlgorithm will try to find a "recommended algorithm name" defined by RecommendedHashAlgorithms for config
+// This function is not fast and is only used for the installation page
+func ConfigHashAlgorithm(algorithm string) string {
+	algorithm = hashAlgorithmToSpec(algorithm)
+	for _, recommAlgo := range RecommendedHashAlgorithms {
+		if algorithm == hashAlgorithmToSpec(recommAlgo) {
+			return recommAlgo
+		}
+	}
+	return algorithm
+}
diff --git a/modules/auth/password/hash/setting_test.go b/modules/auth/password/hash/setting_test.go
new file mode 100644
index 0000000..548d87c
--- /dev/null
+++ b/modules/auth/password/hash/setting_test.go
@@ -0,0 +1,38 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package hash
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestCheckSettingPasswordHashAlgorithm(t *testing.T) {
+	t.Run("pbkdf2 is pbkdf2_v2", func(t *testing.T) {
+		pbkdf2v2Config, pbkdf2v2Algo := SetDefaultPasswordHashAlgorithm("pbkdf2_v2")
+		pbkdf2Config, pbkdf2Algo := SetDefaultPasswordHashAlgorithm("pbkdf2")
+
+		assert.Equal(t, pbkdf2v2Config, pbkdf2Config)
+		assert.Equal(t, pbkdf2v2Algo.Specification, pbkdf2Algo.Specification)
+	})
+
+	for a, b := range aliasAlgorithmNames {
+		t.Run(a+"="+b, func(t *testing.T) {
+			aConfig, aAlgo := SetDefaultPasswordHashAlgorithm(a)
+			bConfig, bAlgo := SetDefaultPasswordHashAlgorithm(b)
+
+			assert.Equal(t, bConfig, aConfig)
+			assert.Equal(t, aAlgo.Specification, bAlgo.Specification)
+		})
+	}
+
+	t.Run("pbkdf2_hi is the default when default password hash algorithm is empty", func(t *testing.T) {
+		emptyConfig, emptyAlgo := SetDefaultPasswordHashAlgorithm("")
+		pbkdf2hiConfig, pbkdf2hiAlgo := SetDefaultPasswordHashAlgorithm("pbkdf2_hi")
+
+		assert.Equal(t, pbkdf2hiConfig, emptyConfig)
+		assert.Equal(t, pbkdf2hiAlgo.Specification, emptyAlgo.Specification)
+	})
+}
diff --git a/modules/auth/password/password.go b/modules/auth/password/password.go
new file mode 100644
index 0000000..85f9780
--- /dev/null
+++ b/modules/auth/password/password.go
@@ -0,0 +1,136 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package password
+
+import (
+	"bytes"
+	"context"
+	"crypto/rand"
+	"errors"
+	"html/template"
+	"math/big"
+	"strings"
+	"sync"
+
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/translation"
+)
+
+var (
+	ErrComplexity = errors.New("password not complex enough")
+	ErrMinLength  = errors.New("password not long enough")
+)
+
+// complexity contains information about a particular kind of password complexity
+type complexity struct {
+	ValidChars string
+	TrNameOne  string
+}
+
+var (
+	matchComplexityOnce sync.Once
+	validChars          string
+	requiredList        []complexity
+
+	charComplexities = map[string]complexity{
+		"lower": {
+			`abcdefghijklmnopqrstuvwxyz`,
+			"form.password_lowercase_one",
+		},
+		"upper": {
+			`ABCDEFGHIJKLMNOPQRSTUVWXYZ`,
+			"form.password_uppercase_one",
+		},
+		"digit": {
+			`0123456789`,
+			"form.password_digit_one",
+		},
+		"spec": {
+			` !"#$%&'()*+,-./:;<=>?@[\]^_{|}~` + "`",
+			"form.password_special_one",
+		},
+	}
+)
+
+// NewComplexity for preparation
+func NewComplexity() {
+	matchComplexityOnce.Do(func() {
+		setupComplexity(setting.PasswordComplexity)
+	})
+}
+
+func setupComplexity(values []string) {
+	if len(values) != 1 || values[0] != "off" {
+		for _, val := range values {
+			if complexity, ok := charComplexities[val]; ok {
+				validChars += complexity.ValidChars
+				requiredList = append(requiredList, complexity)
+			}
+		}
+		if len(requiredList) == 0 {
+			// No valid character classes found; use all classes as default
+			for _, complexity := range charComplexities {
+				validChars += complexity.ValidChars
+				requiredList = append(requiredList, complexity)
+			}
+		}
+	}
+	if validChars == "" {
+		// No complexities to check; provide a sensible default for password generation
+		validChars = charComplexities["lower"].ValidChars + charComplexities["upper"].ValidChars + charComplexities["digit"].ValidChars
+	}
+}
+
+// IsComplexEnough return True if password meets complexity settings
+func IsComplexEnough(pwd string) bool {
+	NewComplexity()
+	if len(validChars) > 0 {
+		for _, req := range requiredList {
+			if !strings.ContainsAny(req.ValidChars, pwd) {
+				return false
+			}
+		}
+	}
+	return true
+}
+
+// Generate a random password
+func Generate(n int) (string, error) {
+	NewComplexity()
+	buffer := make([]byte, n)
+	max := big.NewInt(int64(len(validChars)))
+	for {
+		for j := 0; j < n; j++ {
+			rnd, err := rand.Int(rand.Reader, max)
+			if err != nil {
+				return "", err
+			}
+			buffer[j] = validChars[rnd.Int64()]
+		}
+
+		if err := IsPwned(context.Background(), string(buffer)); err != nil {
+			if errors.Is(err, ErrIsPwned) {
+				continue
+			}
+			return "", err
+		}
+		if IsComplexEnough(string(buffer)) && string(buffer[0]) != " " && string(buffer[n-1]) != " " {
+			return string(buffer), nil
+		}
+	}
+}
+
+// BuildComplexityError builds the error message when password complexity checks fail
+func BuildComplexityError(locale translation.Locale) template.HTML {
+	var buffer bytes.Buffer
+	buffer.WriteString(locale.TrString("form.password_complexity"))
+	buffer.WriteString("<ul>")
+	for _, c := range requiredList {
+		buffer.WriteString("<li>")
+		buffer.WriteString(locale.TrString(c.TrNameOne))
+		buffer.WriteString("</li>")
+	}
+	buffer.WriteString("</ul>")
+	return template.HTML(buffer.String())
+}
diff --git a/modules/auth/password/password_test.go b/modules/auth/password/password_test.go
new file mode 100644
index 0000000..1fe3fb5
--- /dev/null
+++ b/modules/auth/password/password_test.go
@@ -0,0 +1,77 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package password
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestComplexity_IsComplexEnough(t *testing.T) {
+	matchComplexityOnce.Do(func() {})
+
+	testlist := []struct {
+		complexity  []string
+		truevalues  []string
+		falsevalues []string
+	}{
+		{[]string{"off"}, []string{"1", "-", "a", "A", "ñ", "日本語"}, []string{}},
+		{[]string{"lower"}, []string{"abc", "abc!"}, []string{"ABC", "123", "=!$", ""}},
+		{[]string{"upper"}, []string{"ABC"}, []string{"abc", "123", "=!$", "abc!", ""}},
+		{[]string{"digit"}, []string{"123"}, []string{"abc", "ABC", "=!$", "abc!", ""}},
+		{[]string{"spec"}, []string{"=!$", "abc!"}, []string{"abc", "ABC", "123", ""}},
+		{[]string{"off"}, []string{"abc", "ABC", "123", "=!$", "abc!", ""}, nil},
+		{[]string{"lower", "spec"}, []string{"abc!"}, []string{"abc", "ABC", "123", "=!$", "abcABC123", ""}},
+		{[]string{"lower", "upper", "digit"}, []string{"abcABC123"}, []string{"abc", "ABC", "123", "=!$", "abc!", ""}},
+		{[]string{""}, []string{"abC=1", "abc!9D"}, []string{"ABC", "123", "=!$", ""}},
+	}
+
+	for _, test := range testlist {
+		testComplextity(test.complexity)
+		for _, val := range test.truevalues {
+			assert.True(t, IsComplexEnough(val))
+		}
+		for _, val := range test.falsevalues {
+			assert.False(t, IsComplexEnough(val))
+		}
+	}
+
+	// Remove settings for other tests
+	testComplextity([]string{"off"})
+}
+
+func TestComplexity_Generate(t *testing.T) {
+	matchComplexityOnce.Do(func() {})
+
+	const maxCount = 50
+	const pwdLen = 50
+
+	test := func(t *testing.T, modes []string) {
+		testComplextity(modes)
+		for i := 0; i < maxCount; i++ {
+			pwd, err := Generate(pwdLen)
+			require.NoError(t, err)
+			assert.Len(t, pwd, pwdLen)
+			assert.True(t, IsComplexEnough(pwd), "Failed complexities with modes %+v for generated: %s", modes, pwd)
+		}
+	}
+
+	test(t, []string{"lower"})
+	test(t, []string{"upper"})
+	test(t, []string{"lower", "upper", "spec"})
+	test(t, []string{"off"})
+	test(t, []string{""})
+
+	// Remove settings for other tests
+	testComplextity([]string{"off"})
+}
+
+func testComplextity(values []string) {
+	// Cleanup previous values
+	validChars = ""
+	requiredList = make([]complexity, 0, len(values))
+	setupComplexity(values)
+}
diff --git a/modules/auth/password/pwn.go b/modules/auth/password/pwn.go
new file mode 100644
index 0000000..e00205e
--- /dev/null
+++ b/modules/auth/password/pwn.go
@@ -0,0 +1,52 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package password
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"code.gitea.io/gitea/modules/auth/password/pwn"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+var ErrIsPwned = errors.New("password has been pwned")
+
+type ErrIsPwnedRequest struct {
+	err error
+}
+
+func IsErrIsPwnedRequest(err error) bool {
+	_, ok := err.(ErrIsPwnedRequest)
+	return ok
+}
+
+func (err ErrIsPwnedRequest) Error() string {
+	return fmt.Sprintf("using Have-I-Been-Pwned service failed: %v", err.err)
+}
+
+func (err ErrIsPwnedRequest) Unwrap() error {
+	return err.err
+}
+
+// IsPwned checks whether a password has been pwned
+// If a password has not been pwned, no error is returned.
+func IsPwned(ctx context.Context, password string) error {
+	if !setting.PasswordCheckPwn {
+		return nil
+	}
+
+	client := pwn.New(pwn.WithContext(ctx))
+	count, err := client.CheckPassword(password, true)
+	if err != nil {
+		return ErrIsPwnedRequest{err}
+	}
+
+	if count > 0 {
+		return ErrIsPwned
+	}
+
+	return nil
+}
diff --git a/modules/auth/password/pwn/pwn.go b/modules/auth/password/pwn/pwn.go
new file mode 100644
index 0000000..f77ce9f
--- /dev/null
+++ b/modules/auth/password/pwn/pwn.go
@@ -0,0 +1,118 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package pwn
+
+import (
+	"context"
+	"crypto/sha1"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+
+	"code.gitea.io/gitea/modules/setting"
+)
+
+const passwordURL = "https://api.pwnedpasswords.com/range/"
+
+// ErrEmptyPassword is an empty password error
+var ErrEmptyPassword = errors.New("password cannot be empty")
+
+// Client is a HaveIBeenPwned client
+type Client struct {
+	ctx  context.Context
+	http *http.Client
+}
+
+// New returns a new HaveIBeenPwned Client
+func New(options ...ClientOption) *Client {
+	client := &Client{
+		ctx:  context.Background(),
+		http: http.DefaultClient,
+	}
+
+	for _, opt := range options {
+		opt(client)
+	}
+
+	return client
+}
+
+// ClientOption is a way to modify a new Client
+type ClientOption func(*Client)
+
+// WithHTTP will set the http.Client of a Client
+func WithHTTP(httpClient *http.Client) func(pwnClient *Client) {
+	return func(pwnClient *Client) {
+		pwnClient.http = httpClient
+	}
+}
+
+// WithContext will set the context.Context of a Client
+func WithContext(ctx context.Context) func(pwnClient *Client) {
+	return func(pwnClient *Client) {
+		pwnClient.ctx = ctx
+	}
+}
+
+func newRequest(ctx context.Context, method, url string, body io.ReadCloser) (*http.Request, error) {
+	req, err := http.NewRequestWithContext(ctx, method, url, body)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Add("User-Agent", "Gitea "+setting.AppVer)
+	return req, nil
+}
+
+// CheckPassword returns the number of times a password has been compromised
+// Adding padding will make requests more secure, however is also slower
+// because artificial responses will be added to the response
+// For more information, see https://www.troyhunt.com/enhancing-pwned-passwords-privacy-with-padding/
+func (c *Client) CheckPassword(pw string, padding bool) (int, error) {
+	if pw == "" {
+		return -1, ErrEmptyPassword
+	}
+
+	sha := sha1.New()
+	sha.Write([]byte(pw))
+	enc := hex.EncodeToString(sha.Sum(nil))
+	prefix, suffix := enc[:5], enc[5:]
+
+	req, err := newRequest(c.ctx, http.MethodGet, fmt.Sprintf("%s%s", passwordURL, prefix), nil)
+	if err != nil {
+		return -1, nil
+	}
+	if padding {
+		req.Header.Add("Add-Padding", "true")
+	}
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return -1, err
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return -1, err
+	}
+	defer resp.Body.Close()
+
+	for _, pair := range strings.Split(string(body), "\n") {
+		parts := strings.Split(pair, ":")
+		if len(parts) != 2 {
+			continue
+		}
+		if strings.EqualFold(suffix, parts[0]) {
+			count, err := strconv.ParseInt(strings.TrimSpace(parts[1]), 10, 64)
+			if err != nil {
+				return -1, err
+			}
+			return int(count), nil
+		}
+	}
+	return 0, nil
+}
diff --git a/modules/auth/password/pwn/pwn_test.go b/modules/auth/password/pwn/pwn_test.go
new file mode 100644
index 0000000..e510815
--- /dev/null
+++ b/modules/auth/password/pwn/pwn_test.go
@@ -0,0 +1,51 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package pwn
+
+import (
+	"net/http"
+	"testing"
+	"time"
+
+	"github.com/h2non/gock"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+var client = New(WithHTTP(&http.Client{
+	Timeout: time.Second * 2,
+}))
+
+func TestPassword(t *testing.T) {
+	defer gock.Off()
+
+	count, err := client.CheckPassword("", false)
+	require.ErrorIs(t, err, ErrEmptyPassword, "blank input should return ErrEmptyPassword")
+	assert.Equal(t, -1, count)
+
+	gock.New("https://api.pwnedpasswords.com").Get("/range/5c1d8").Times(1).Reply(200).BodyString("EAF2F254732680E8AC339B84F3266ECCBB5:1\r\nFC446EB88938834178CB9322C1EE273C2A7:2")
+	count, err = client.CheckPassword("pwned", false)
+	require.NoError(t, err)
+	assert.Equal(t, 1, count)
+
+	gock.New("https://api.pwnedpasswords.com").Get("/range/ba189").Times(1).Reply(200).BodyString("FD4CB34F0378BCB15D23F6FFD28F0775C9E:3\r\nFDF342FCD8C3611DAE4D76E8A992A3E4169:4")
+	count, err = client.CheckPassword("notpwned", false)
+	require.NoError(t, err)
+	assert.Equal(t, 0, count)
+
+	gock.New("https://api.pwnedpasswords.com").Get("/range/a1733").Times(1).Reply(200).BodyString("C4CE0F1F0062B27B9E2F41AF0C08218017C:1\r\nFC446EB88938834178CB9322C1EE273C2A7:2\r\nFE81480327C992FE62065A827429DD1318B:0")
+	count, err = client.CheckPassword("paddedpwned", true)
+	require.NoError(t, err)
+	assert.Equal(t, 1, count)
+
+	gock.New("https://api.pwnedpasswords.com").Get("/range/5617b").Times(1).Reply(200).BodyString("FD4CB34F0378BCB15D23F6FFD28F0775C9E:3\r\nFDF342FCD8C3611DAE4D76E8A992A3E4169:4\r\nFE81480327C992FE62065A827429DD1318B:0")
+	count, err = client.CheckPassword("paddednotpwned", true)
+	require.NoError(t, err)
+	assert.Equal(t, 0, count)
+
+	gock.New("https://api.pwnedpasswords.com").Get("/range/79082").Times(1).Reply(200).BodyString("FDF342FCD8C3611DAE4D76E8A992A3E4169:4\r\nFE81480327C992FE62065A827429DD1318B:0\r\nAFEF386F56EB0B4BE314E07696E5E6E6536:0")
+	count, err = client.CheckPassword("paddednotpwnedzero", true)
+	require.NoError(t, err)
+	assert.Equal(t, 0, count)
+}
-- 
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