Incorrect header in useHttpBasicAuthForPasswordFlow

[Rzpeg]

Hello,

When configuring the basic authentication header for password flow you are using "Authentication" and the correct header for the scheme is "Authorization"

const header = btoa(`${this.clientId}:${this.dummyClientSecret}`);
                headers = headers.set(
                    'Authentication',
                    'BASIC ' + header);

[joelmuskwe]

Has this been sorted yet

[jeroenheijmans]

@joelmuskwe Don't think so. I've created a PR to fix things. If you need it right away I suggest making a custom build (or very maybe a http interceptor might give a workaround?), otherwise will have to wait a bit until a bugfix lands.

[vogoltsov]

I would also suggest changing header value prefix from 'BASIC ' to 'Basic ' as most frameworks check value using a case-sensitive startsWith method.

[jeroenheijmans]

@vogoltsov They do? Which ones? All servers I've worked with are case insensitive I think. Also, IIRC, the RFC specifies that the auth scheme should be treated in a case insensitive manner.

If you have an example server (or reference that it should be case sensitive) then it should probably be changed or made configurable. If so, I think creating a seperate issue would be good too?

[vinliangx]

Hello,
@jeroenheijmans I'm having the same issue I'm using Spring Security...

org.springframework.security.web.authentication.www.BasicAuthenticationFilter.java // line:175
if (header == null || !header.startsWith("Basic ")) {
...

Thanks,
Vin

[jeroenheijmans]

@vinliangx Well, oh my, you're right I see the same in the source for latest release of Spring.

I think that might be a bug in Spring though. Looking at RFC 7617 specifically section 2 it's stated that (emphasis mine):

Note that both scheme and parameter names are matched case-insensitively.

Disclaimer: I'm not great at estimating if I was looking at the right spec/rfc, so someone might correct me on this.

On the other hand:

• Everywhere in that RFC the scheme name is literally "Basic", so it's understandable that implementors use that.
• This Github issue here noted that the entire header is wrong anyways, so I don't think it would break anything more than it is already broken if we change the casing in angular-oauth2-oidc

so I'll update my PR accordingly.

[jeroenheijmans]

Note that this code in IdentityServer4 (a notable .NET server side framework) does the StartsWith in a case insensitive manner (AFAICT). It does also follow the RFC in that itself it seems to default to the "Basic" casing for examples and output and soforth.

[vinliangx]

I read in a few places that should be case insensitive, so the issue may go to Spring Framework, but I figure it would be easier to here. Meanwhile I did a workaround with a filter to modify the request in my service so everything goes smoothly from the web app.

I think this change won't cause major issues to anyone.

Thanks @jeroenheijmans!

[jeroenheijmans]

@vinliangx Nice, good to hear you found a workaround. It might be worth sharing here so others can use it too while the issue remains unfixed.

[vinliangx]

This is the workaround I've implemented for Spring Security:

The filter

import org.springframework.web.filter.OncePerRequestFilter;

@Component
public class BasicAuthHeaderFilter extends OncePerRequestFilter {
   @Override
   protected void doFilterInternal(HttpServletRequest request, 
                                                     HttpServletResponse response, 
                                                     FilterChain chain) throws ServletException, IOException {
      HttpServletRequestWrapper requestWrapper = new HttpServletRequestWrapper(request) {
                @Override
                public String getHeader(String name) {
                    String header = super.getHeader(name);                    
                    if (header == null && name.equalsIgnoreCase("authorization")){
                        header = super.getHeader("authentication");
                    }
                    if (header != null && header.toLowerCase().startsWith("basic")) {
                        return header.replaceAll("^[Bb][Aa][Ss][Ii][Cc]", "Basic");
                    }
                    return header;
                }
       };
      chain.doFilter(requestWrapper, response);
   }
}

Registering the Filter:

import org.springframework.boot.web.servlet.FilterRegistrationBean;

@Bean
public FilterRegistrationBean<BasicAuthHeaderFilter> filterFilterRegistrationBean(BasicAuthHeaderFilter filter) {
    FilterRegistrationBean<BasicAuthHeaderFilter> reg = new FilterRegistrationBean<>(filter);
    reg.setOrder(Ordered.HIGHEST_PRECEDENCE);
    return reg;
}

Thanks again @jeroenheijmans