mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-05 10:02:47 +00:00
149 lines
4.6 KiB
Go
149 lines
4.6 KiB
Go
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package jwt
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import (
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"bytes"
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"encoding/json"
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"fmt"
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"strings"
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)
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type Parser struct {
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ValidMethods []string // If populated, only these methods will be considered valid
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UseJSONNumber bool // Use JSON Number format in JSON decoder
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SkipClaimsValidation bool // Skip claims validation during token parsing
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}
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// Parse, validate, and return a token.
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// keyFunc will receive the parsed token and should return the key for validating.
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// If everything is kosher, err will be nil
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func (p *Parser) Parse(tokenString string, keyFunc Keyfunc) (*Token, error) {
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return p.ParseWithClaims(tokenString, MapClaims{}, keyFunc)
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}
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func (p *Parser) ParseWithClaims(tokenString string, claims Claims, keyFunc Keyfunc) (*Token, error) {
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token, parts, err := p.ParseUnverified(tokenString, claims)
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if err != nil {
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return token, err
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}
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// Verify signing method is in the required set
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if p.ValidMethods != nil {
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var signingMethodValid = false
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var alg = token.Method.Alg()
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for _, m := range p.ValidMethods {
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if m == alg {
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signingMethodValid = true
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break
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}
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}
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if !signingMethodValid {
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// signing method is not in the listed set
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return token, NewValidationError(fmt.Sprintf("signing method %v is invalid", alg), ValidationErrorSignatureInvalid)
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}
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}
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// Lookup key
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var key interface{}
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if keyFunc == nil {
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// keyFunc was not provided. short circuiting validation
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return token, NewValidationError("no Keyfunc was provided.", ValidationErrorUnverifiable)
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}
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if key, err = keyFunc(token); err != nil {
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// keyFunc returned an error
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if ve, ok := err.(*ValidationError); ok {
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return token, ve
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}
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return token, &ValidationError{Inner: err, Errors: ValidationErrorUnverifiable}
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}
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vErr := &ValidationError{}
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// Validate Claims
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if !p.SkipClaimsValidation {
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if err := token.Claims.Valid(); err != nil {
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// If the Claims Valid returned an error, check if it is a validation error,
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// If it was another error type, create a ValidationError with a generic ClaimsInvalid flag set
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if e, ok := err.(*ValidationError); !ok {
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vErr = &ValidationError{Inner: err, Errors: ValidationErrorClaimsInvalid}
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} else {
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vErr = e
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}
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}
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}
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// Perform validation
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token.Signature = parts[2]
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if err = token.Method.Verify(strings.Join(parts[0:2], "."), token.Signature, key); err != nil {
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vErr.Inner = err
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vErr.Errors |= ValidationErrorSignatureInvalid
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}
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if vErr.valid() {
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token.Valid = true
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return token, nil
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}
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return token, vErr
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}
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// WARNING: Don't use this method unless you know what you're doing
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//
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// This method parses the token but doesn't validate the signature. It's only
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// ever useful in cases where you know the signature is valid (because it has
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// been checked previously in the stack) and you want to extract values from
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// it.
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func (p *Parser) ParseUnverified(tokenString string, claims Claims) (token *Token, parts []string, err error) {
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parts = strings.Split(tokenString, ".")
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if len(parts) != 3 {
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return nil, parts, NewValidationError("token contains an invalid number of segments", ValidationErrorMalformed)
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}
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token = &Token{Raw: tokenString}
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// parse Header
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var headerBytes []byte
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if headerBytes, err = DecodeSegment(parts[0]); err != nil {
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if strings.HasPrefix(strings.ToLower(tokenString), "bearer ") {
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return token, parts, NewValidationError("tokenstring should not contain 'bearer '", ValidationErrorMalformed)
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}
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return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
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}
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if err = json.Unmarshal(headerBytes, &token.Header); err != nil {
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return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
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}
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// parse Claims
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var claimBytes []byte
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token.Claims = claims
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if claimBytes, err = DecodeSegment(parts[1]); err != nil {
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return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
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}
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dec := json.NewDecoder(bytes.NewBuffer(claimBytes))
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if p.UseJSONNumber {
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dec.UseNumber()
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}
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// JSON Decode. Special case for map type to avoid weird pointer behavior
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if c, ok := token.Claims.(MapClaims); ok {
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err = dec.Decode(&c)
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} else {
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err = dec.Decode(&claims)
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}
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// Handle decode error
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if err != nil {
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return token, parts, &ValidationError{Inner: err, Errors: ValidationErrorMalformed}
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}
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// Lookup signature method
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if method, ok := token.Header["alg"].(string); ok {
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if token.Method = GetSigningMethod(method); token.Method == nil {
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return token, parts, NewValidationError("signing method (alg) is unavailable.", ValidationErrorUnverifiable)
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}
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} else {
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return token, parts, NewValidationError("signing method (alg) is unspecified.", ValidationErrorUnverifiable)
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}
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return token, parts, nil
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}
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