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Re: [reSIProcate] Uri escaping

Why not just fix Uri::shouldEscapeUserChar so that if c < 0 then return true, instead of false?

inline bool 
Uri::shouldEscapeUserChar(char c)
{
   if(!mEncodingReady)
   {
      initialiseEncodingTables();
   }

   if(c < 0)
   {
      return false;
   }

   return mUriEncodingUserTable[c];
}

Scott

2010/4/9 Jeremy Geras <jgeras@xxxxxxxxxxxxxxx>

Here's an attempt at fixing escapeToStream(..) which seems to work OK...

 

template<class Predicate> EncodeStream&

Data::escapeToStream(EncodeStream& str, Predicate shouldEscape) const

{

   static char hex[] = "0123456789ABCDEF";

 

   if (empty())

   {

      return str;

   }

  

   const char* p = mBuf;

   const char* e = mBuf + mSize;

 

   while (p < e)

   {

      // ?abr? Why is this special cased? Removing this code

      // does not change the behavior of this method.

      if (*p == '%'

          && e - p > 2

          && isHex(*(p+1))

          && isHex(*(p+2)))

      {

         str.write(p, 3);

         p+=3;

      }

      else if (shouldEscape(*p))

      {

         int hi = (*p & 0xF0)>>4;

         int low = (*p & 0x0F);

        

         str << '%' << hex[hi] << hex[low];

         p++;

      }

// BEGIN NEW

      else if ((*p) < 0)

      {

         // count the number of UTF-8 bytes

         if (((*p) | 0x1F) == ~0x20)

         {

            Data utf8(Data::Borrow, p, 2);

            utf8.urlEncode(str);

            p+=2;

         }

         else if (((*p) | 0x0F) == ~0x10)

         {

            Data utf8(Data::Borrow, p, 3);

            utf8.urlEncode(str);

            p+=3;

         }

         else if (((*p) | 0x07) == ~0x08)

         {

            Data utf8(Data::Borrow, p, 4);

            utf8.urlEncode(str);

            p+=4;

         }

         else

         {

            str.put(*p++);

         }

      }

// END NEW

      else

      {

         str.put(*p++);

      }

   }

   return str;

}

 

From: resiprocate-devel-bounces@xxxxxxxxxxxxxxx [mailto:resiprocate-devel-bounces@xxxxxxxxxxxxxxx] On Behalf Of Jeremy Geras
Sent: April-08-10 4:05 PM


To: Scott Godin
Cc: resiprocate-devel@xxxxxxxxxxxxxxx
Subject: Re: [reSIProcate] Uri escaping

 

So my latest thinking is that my attempted fix is definitely bad, since it doesn't take into account the special 3261 rules (like + being a valid user character).

 

So I guess the real fix is to fix escapeToStream(..) so that it can detect UTF-8 characters and % HEX HEX encode them...?

 

From: Jeremy Geras
Sent: April-08-10 2:41 PM
To: 'Scott Godin'
Cc: resiprocate-devel@xxxxxxxxxxxxxxx
Subject: RE: [reSIProcate] Uri escaping

 

Hmmm... Won't Uri::shouldEscapeUserChar return false with non-US ASCII characters?  (That's what I'm seeing... c == -60) when the URI contains a character like Ă.

 

From: slgodin@xxxxxxxxx [mailto:slgodin@xxxxxxxxx] On Behalf Of Scott Godin
Sent: April-08-10 2:31 PM
To: Jeremy Geras
Cc: resiprocate-devel@xxxxxxxxxxxxxxx
Subject: Re: [reSIProcate] Uri escaping

 

I agree that RFC3261 specifies the user part should be escaped (ie. % HEXDIG HEXDIG):

 
user             =  1*( unreserved / escaped / user-unreserved )

However looking at the Data::escapeToStream method - it should be escaping using (% HEXDIG HEXDIG) - it's not really clear to me how you are ending up with non-escaped characters in the encoding.  We should figure out why escapeToStream is not working for you.

 

Scott

 

On Thu, Apr 8, 2010 at 4:59 PM, Jeremy Geras <jgeras@xxxxxxxxxxxxxxx> wrote:

Hi,

 

General question:  How should URIs be escaped?

 

See the attached trace for an example of what we're seeing with resip -- note the Contact header in the NOTIFY, and the subsequent Request-URI in the re-SUBSCRIBE.  Should the URI in the request line be URL-encoded?  (Pouring through the BNF in 3261 leads me to think that it should...)

 

Note that this is a trace from a deployment where the re-SUBSCRIBE actually fails because of the lack of proper escaping.  I tried making the following change in Uri.cxx, and with that in place the re-SUBSCRIBE works.  However I'm not sure if this is correct, or if this is the right spot.  Thoughts?

 

Thanks,

Jeremy

 

// should not encode user parameters unless its a tel?

EncodeStream&

Uri::encodeParsed(EncodeStream& str) const

{

   str << mScheme << Symbols::COLON;

   if (!mUser.empty())

   {

#ifdef HANDLE_CHARACTER_ESCAPING

      //mUser.escapeToStream(str, shouldEscapeUserChar); <== ORIGINAL CODE

      mUser.urlEncode(str);

#else

      str << mUser;

#endif

 

 ... snip ...

 

 


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