[Devel] UAC module and parse error

[Bogdan-Andrei Iancu]

Hi Chris,

thanks for your input. Looking into RFC 2617, it looks like not all the 
fields may be not-quoted:

   

      digest-challenge  = 1#( realm | [ domain ] | nonce |
                          [ opaque ] |[ stale ] | [ algorithm ] |
                          [ qop-options ] | [auth-param] )


      domain            = "domain" "=" <"> URI ( 1*SP URI ) <">
      URI               = absoluteURI | abs_path
      nonce             = "nonce" "=" nonce-value
      nonce-value       = quoted-string
      opaque            = "opaque" "=" quoted-string
      stale             = "stale" "=" ( "true" | "false" )
      algorithm         = "algorithm" "=" ( "MD5" | "MD5-sess" |
                           token )
      qop-options       = "qop" "=" <"> 1#qop-value <">
      qop-value         = "auth" | "auth-int" | token

      realm       = "realm" "=" realm-value
      realm-value = quoted-string


So, only stale and algorithm can not be qouted.

regards,
bogdan


Christophe Irles wrote:

> Hi,
>
> I found a parse error bug in the UAC module. It's slightly the same 
> bug as describe in the 1448453 bug but it concerns the parse of the 
> field "stale" this time.
>
> Here is the log of openser:
>  4(19621) DEBUG:uac:uac_auth: picked reply is 0x816cfe8, code 407
>  4(19621) DEBUG:uac:get_autenticate_hdr: looking for header 
> "Proxy-Authenticate"
>  4(19621) parse_headers: flags=ffffffffffffffff
>  4(19621) DEBUG: get_hdr_body : content_length=0
>  4(19621) found end of header
>  4(19621) DEBUG:uac:uac_auth: header found; body=<Digest 
> realm="freephonie.net",nonce="028183054212a08209186424557a08f7",opaque="027fb3fb0f14a5b",stale=false,algorithm=MD5>
>
>  4(19621) DEBUG:uac:parse_authenticate_body: <realm>="freephonie.net" 
> state=2
>  4(19621) DEBUG:uac:parse_authenticate_body: 
> <nonce>="028183054212a08209186424557a08f7" state=3
>  4(19621) DEBUG:uac:parse_authenticate_body: 
> <opaque>="027fb3fb0f14a5b" state=6
>  4(19621) ERROR:uac:parse_authenticate_body: parse error in <Digest 
> realm="freephonie.net",nonce="028183054212a08209186424557a08f7",opaque="027fb3fb0f14a5b",stale=false,algorithm=MD5> 
> around 102
>
>  4(19621) ERROR:uac:uac_auth: failed to parse auth hdr body
>  4(19621) CONNTRACK: ct_destroy_connection(): 
> callId=MTUzMzAxOGNmYmZjM2ZmZWYyMzY3NjMyNDk0ZDVlYTY.
>  4(19621) DEBUG:tm:relay_reply: branch=0, save=0, relay=0
>  
>
> The bug is in the file "auth_hdr.c". Some fields (realm, nonce, stale, 
> domain, opaque) are specifically designed to have values between 
> double quote. I change it to accept values with or without double 
> quote.  In fact I made few changes since the code is already ready to 
> manage that, it just force the use of double quote. Perhaps some of 
> this fields in RFC must have double quoted value ?
>
> Here is mypatch file to resolve my problem:
> --- ./modules/uac/auth_hdr.c
> +++ ./patch/modules/uac/auth_hdr.c
> @@ -133,11 +133,11 @@
>                         n = LOWER4B( GET4B(p) );
>                         switch(n)
>                         {
> -                               CASE_5B( 0x7265616c, 'm', REALM_STATE, 
> 1); /*realm*/
> -                               CASE_5B( 0x6e6f6e63, 'e', NONCE_STATE, 
> 1); /*nonce*/
> -                               CASE_5B( 0x7374616c, 'e', STALE_STATE, 
> 1); /*stale*/
> -                               CASE_6B( 0x646f6d62, 'i', 'n', 
> DOMAIN_STATE, 1); /*domain*/
> -                               CASE_6B( 0x6f706171, 'u', 'e', 
> OPAQUE_STATE, 1); /*opaque*/
> +                               CASE_5B( 0x7265616c, 'm', REALM_STATE, 
> 0); /*realm*/
> +                               CASE_5B( 0x6e6f6e63, 'e', NONCE_STATE, 
> 0); /*nonce*/
> +                               CASE_5B( 0x7374616c, 'e', STALE_STATE, 
> 0); /*stale*/
> +                               CASE_6B( 0x646f6d62, 'i', 'n', 
> DOMAIN_STATE, 0); /*domain*/
> +                               CASE_6B( 0x6f706171, 'u', 'e', 
> OPAQUE_STATE, 0); /*opaque*/
>                                 case 0x616c676f: /*algo*/
>                                         if (p+9<end && 
> LOWER4B(GET4B(p+4))==0x72697468
>                                                 && LOWER1B(*(p+8))=='m' )
>
> Regards,
> Christophe
>
>------------------------------------------------------------------------
>
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