htpasswd: clean up errors

Signed-off-by: Alejandro Mery <amery@jpi.io>

.vscode/settings.json

@@ -0,0 +1,7 @@
+{
+    "cSpell.words": [
+        "hasher",
+        "htpasswd",
+        "Passwds"
+    ]
+}

go.mod

@@ -1,6 +1,6 @@
 module asciigoat.org/httools
 
-go 1.21.1
+go 1.20
 
 require github.com/mgechev/revive v1.3.3
 

go.sum

@@ -40,7 +40,6 @@ github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXl
 golang.org/x/crypto v0.13.0 h1:mvySKfSWJ+UKUii46M40LOvyWfN0s2U+46/jDd0e6Ck=
 golang.org/x/crypto v0.13.0/go.mod h1:y6Z2r+Rw4iayiXXAIxJIDAJ1zMW4yaTpebo8fPOliYc=
 golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
-golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
 golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

htpasswd/errors.go

@@ -0,0 +1,49 @@
+package htpasswd
+
+import (
+	"errors"
+	"strings"
+)
+
+var (
+	// ErrExists indicates the specified user already exists
+	ErrExists = errors.New("user already exists")
+	// ErrNotExists indicates the specified user does not exist
+	ErrNotExists = errors.New("user does not exist")
+	// ErrInvalidAlgorithm indicates the htpasswd entry doesn't contain a
+	// valid algorithm signature
+	ErrInvalidAlgorithm = errors.New("invalid algorithm")
+	// ErrInvalidPassword indicates the offered password doesn't match
+	ErrInvalidPassword = errors.New("invalid password")
+)
+
+// UserError indicates an error associated to the specified user
+type UserError struct {
+	Name string
+	Hint string
+	Err  error
+}
+
+func (e *UserError) Error() string {
+	var buf strings.Builder
+	var reason string
+
+	if e.Hint != "" {
+		reason = e.Hint
+	} else {
+		reason = e.Err.Error()
+	}
+
+	if e.Name == "" {
+		return reason
+	}
+
+	_, _ = buf.WriteString(e.Name)
+	_, _ = buf.WriteString(": ")
+	_, _ = buf.WriteString(reason)
+	return buf.String()
+}
+
+func (e *UserError) Unwrap() error {
+	return e.Err
+}

htpasswd/htpasswd.go

@@ -19,18 +19,18 @@ type Hasher interface {
 	Prefix() string
 }
 
-// ParseHtpasswdFile parses a .htpasswd file
+// ParseFile parses a .htpasswd file
 // and returns a Passwd type
-func ParseHtpasswdFile(file string) (Passwds, error) {
+func ParseFile(file string) (Passwds, error) {
 	htpasswdBytes, err := os.ReadFile(file)
 	if err != nil {
 		return nil, err
 	}
-	return ParseHtpasswd(htpasswdBytes)
+	return Parse(htpasswdBytes)
 }
 
-// ParseHtpasswd parses a slice of bytes in htpasswd style
-func ParseHtpasswd(htpasswdBytes []byte) (Passwds, error) {
+// Parse parses a slice of bytes in htpasswd style
+func Parse(htpasswdBytes []byte) (Passwds, error) {
 	lines := strings.Split(string(htpasswdBytes), "\n")
 	passwords := make(map[string]string)
 	var err error
@@ -51,8 +51,10 @@ func ParseHtpasswd(htpasswdBytes []byte) (Passwds, error) {
 		_, exists := passwords[parts[0]]
 
 		if exists {
-			err = errors.New("invalid htpasswords file - user " +
-				parts[0] + " defined more than once")
+			err = &UserError{
+				Name: parts[0],
+				Err:  ErrExists,
+			}
 			return passwords, err
 		}
 		passwords[parts[0]] = parts[1]
@@ -63,7 +65,7 @@ func ParseHtpasswd(htpasswdBytes []byte) (Passwds, error) {
 // CreateUser creates a record in the named file with
 // the named password and hash algorithm
 func CreateUser(file, user, passwd string, algo Hasher) error {
-	pp, err := ParseHtpasswdFile(file)
+	pp, err := ParseFile(file)
 	if err != nil {
 		return err
 	}
@@ -71,15 +73,19 @@ func CreateUser(file, user, passwd string, algo Hasher) error {
 	if err != nil {
 		return err
 	}
-	return pp.Write(file)
+	return pp.WriteFile(file)
 }
 
 // CreateUser will create a new user in the given Passwd object
 // using the given name, password and hashing algorithm
 func (pp Passwds) CreateUser(user, passwd string, algo Hasher) error {
 	if _, exists := pp[user]; exists {
-		return fmt.Errorf("user %s already exists", user)
+		return &UserError{
+			Name: user,
+			Err:  ErrExists,
+		}
 	}
+
 	h, err := algo.Hash(passwd)
 	if err != nil {
 		return err
@@ -91,7 +97,7 @@ func (pp Passwds) CreateUser(user, passwd string, algo Hasher) error {
 // UpdateUser will update the password for the named user
 // in the named file
 func UpdateUser(file, user, passwd string, algo Hasher) error {
-	pp, err := ParseHtpasswdFile(file)
+	pp, err := ParseFile(file)
 	if err != nil {
 		return err
 	}
@@ -99,15 +105,19 @@ func UpdateUser(file, user, passwd string, algo Hasher) error {
 	if err != nil {
 		return err
 	}
-	return pp.Write(file)
+	return pp.WriteFile(file)
 }
 
 // UpdateUser will update the password for the named user
 // using the given name, password and hashing algorithm
 func (pp Passwds) UpdateUser(user, passwd string, algo Hasher) error {
 	if _, exists := pp[user]; !exists {
-		return fmt.Errorf("user %s does not exist", user)
+		return &UserError{
+			Name: user,
+			Err:  ErrNotExists,
+		}
 	}
+
 	h, err := algo.Hash(passwd)
 	if err != nil {
 		return err
@@ -118,7 +128,7 @@ func (pp Passwds) UpdateUser(user, passwd string, algo Hasher) error {
 
 // DeleteUser deletes the named user from the named file
 func DeleteUser(file, user string) error {
-	pp, err := ParseHtpasswdFile(file)
+	pp, err := ParseFile(file)
 	if err != nil {
 		return err
 	}
@@ -127,13 +137,16 @@ func DeleteUser(file, user string) error {
 		return err
 	}
 
-	return pp.Write(file)
+	return pp.WriteFile(file)
 }
 
 // DeleteUser deletes the named user from the named file
 func (pp Passwds) DeleteUser(user string) error {
 	if _, exists := pp[user]; !exists {
-		return fmt.Errorf("user %s does not exist", user)
+		return &UserError{
+			Name: user,
+			Err:  ErrNotExists,
+		}
 	}
 
 	delete(pp, user)
@@ -143,7 +156,7 @@ func (pp Passwds) DeleteUser(user string) error {
 // VerifyUser will check if the given user and password are matching
 // with the content of the given file
 func VerifyUser(file, user, passwd string) error {
-	pp, err := ParseHtpasswdFile(file)
+	pp, err := ParseFile(file)
 	if err != nil {
 		return err
 	}
@@ -154,17 +167,25 @@ func VerifyUser(file, user, passwd string) error {
 // with the given Passwd object
 func (pp Passwds) VerifyUser(user, passwd string) error {
 	if _, ok := pp[user]; !ok {
-		return fmt.Errorf("user %s does not exist", user)
+		return &UserError{
+			Name: user,
+			Err:  ErrNotExists,
+		}
 	}
-	alg, err := identifyHash(pp[user])
-	if err != nil {
-		return fmt.Errorf("cannot identify algo %v", alg)
+
+	alg := identifyHash(pp[user])
+	if alg == nil {
+		return &UserError{
+			Name: user,
+			Err:  ErrInvalidAlgorithm,
+		}
 	}
+
 	return alg.Match(passwd, pp[user])
 }
 
-// Write will cwrite the Passwd object to the given file
-func (pp Passwds) Write(file string) error {
+// WriteFile will write the Passwds object to the given file
+func (pp Passwds) WriteFile(file string) error {
 	return os.WriteFile(file, pp.Bytes(), os.ModePerm)
 }
 
@@ -177,24 +198,24 @@ func (pp Passwds) Bytes() []byte {
 	return pass
 }
 
-func identifyHash(h string) (Hasher, error) {
+func identifyHash(h string) Hasher {
 	switch {
 	case strings.HasPrefix(h, "$2a$"), strings.HasPrefix(h, "$2y$"),
 		strings.HasPrefix(h, "$2x$"), strings.HasPrefix(h, "$2b$"):
-		return new(Bcrypt), nil
+		return new(Bcrypt)
 	case strings.HasPrefix(h, "$apr1$"):
-		return new(Apr1), nil
+		return new(Apr1)
 	case strings.HasPrefix(h, "{SHA}"):
-		return new(Sha), nil
+		return new(Sha)
 	case strings.HasPrefix(h, "{SSHA}"):
-		return new(Ssha), nil
+		return new(Ssha)
 	case strings.HasPrefix(h, "$5$"):
-		return new(Sha256), nil
+		return new(Sha256)
 	case strings.HasPrefix(h, "$6$"):
-		return new(Sha512), nil
+		return new(Sha512)
+	default:
+		return nil
 	}
-
-	return nil, fmt.Errorf("unsupported hash algorithm")
 }
 
 func validLine(parts []string, lineNumber int, line string) (bool, error) {

htpasswd/htpasswd_test.go

@@ -6,7 +6,7 @@ import (
 )
 
 func TestParseHtpasswd(t *testing.T) {
-	passwords, err := ParseHtpasswd([]byte("sha:{SHA}IRRjboXT92QSYXm8lpGPCZUvU1E=\n"))
+	passwords, err := Parse([]byte("sha:{SHA}IRRjboXT92QSYXm8lpGPCZUvU1E=\n"))
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -51,7 +51,7 @@ func TestVerifyPassword(t *testing.T) {
 		TestCreateUser(t)
 	}
 
-	_, err = ParseHtpasswdFile(f.Name())
+	_, err = ParseFile(f.Name())
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -83,7 +83,7 @@ func TestVerifyUser(t *testing.T) {
 		TestCreateUser(t)
 	}
 
-	pp, err := ParseHtpasswdFile(f.Name())
+	pp, err := ParseFile(f.Name())
 	if err != nil {
 		t.Fatal(err)
 	}