Validate JWT signing method #51
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This is a fix for the vulnerability outlined here: https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/ CVEs for other vendors: CVE-2015-2964 CVE-2015-2951
crewjam
reviewed
Mar 14, 2017
| @@ -195,6 +195,11 @@ func (m *Middleware) getPossibleRequestIDs(r *http.Request) []string { | |||
| log.Printf("... invalid token %s", err) | |||
| continue | |||
| } | |||
| // Validate token signing method | |||
| if token.Method != jwt.SigningMethodHS256 { | |||
| log.Printf("EROR: invalid jwt signing method: %s", token.Method) | |||
| @@ -235,6 +240,12 @@ func (m *Middleware) Authorize(w http.ResponseWriter, r *http.Request, assertion | |||
| http.Error(w, http.StatusText(http.StatusForbidden), http.StatusForbidden) | |||
| return | |||
| } | |||
| // Validate token signing method | |||
| if state.Method != jwt.SigningMethodHS256 { | |||
| log.Printf("EROR: invalid jwt signing method: %s (%s)", state.Method, stateCookie.Value) | |||
| @@ -310,6 +321,11 @@ func (m *Middleware) IsAuthorized(r *http.Request) bool { | |||
| log.Printf("ERROR: invalid token: %s", err) | |||
| return false | |||
| } | |||
| // Validate token signing method | |||
| if token.Method != jwt.SigningMethodHS256 { | |||
| log.Printf("EROR: invalid jwt signing method: %s", token.Method) | |||
|
so actually, I've had a look at the implementation of jwt-go and it looks fairly resistant to this problem. For example, if Ref: https://github.com/dgrijalva/jwt-go/blob/master/none.go#L28 Nevertheless, there might still be downgrade attacks possible in the future, so it makes sense to address the algorithm issue. go-jwt has a facility for this by setting Parser.ValidMethods (https://github.com/dgrijalva/jwt-go/blob/master/parser.go#L11) Could you please take a stab at a change that uses that instead? And even better if we can craft a test? |
crewjam
added a commit
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this pull request
Apr 23, 2017
|
superseded by #63 |
crewjam
added a commit
that referenced
this pull request
Apr 23, 2017
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This is a fix for the vulnerability outlined here: https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/
CVEs for other vendors: CVE-2015-2964 CVE-2015-2951