On Thu, 2016-10-06 at 02:26 +0200, deloptes wrote:
> Patrick Ohly wrote:
>
> > + // The Nokia N9 vCalendar implementation sends ==0A=0D= at the
> > end of + // the line when it should send just the =. Apparently the
> > CRLF octets + // get inserted before quoted-printable encoding and
> > then get encoded. + // Such a sequence is invalid because = cannot
> > be used literally + // and must be followed by characters
> > representing the hex value, + // i.e. == is already invalid.
> > + //
> > + // We must skip over the entire sequence and continue at the last
> > + // = in ==0A=0D=, otherwise the code below would insert
> > additional + // characters into the decoded text.
>
> This seems to magically work
I don't like magic - at least not in software engineering ;-}
So let's try to understand this a bit better. Compared to my proposed
patch, you added "p=nextunfolded(p,aMimeMode,true)" before the
"continue".
Without it, we enter the next loop iteration:
c=*p; // c should be = now
if (isEndOfLineOrText(c) || (!escaped && aStructSep!=0 && (c==aStructSep ||
c==aAltSep))) break; // We haven't changed any of these, so it should continue.
escaped=(!escaped) && (c=='\\'); // No change either.
if (c=='=') {
s=nextunfolded(p,aMimeMode,true); // Hmm, not quite the same...
Okay, I think I understand. The loop expects to start after skipping
over line folding, so when we enter it pointing towards the soft line
break =, it does the wrong thing. The additional nextunfolded() avoids
that.
> @@ -1937,6 +1938,23 @@ static void decodeValue(
> uInt16 code;
> const char *s;
> char hex[2];
> +
> + // The Nokia N9 vCalendar implementation sends ==0D=0A= at the end
> of
> + // the line when it should send just the =. Apparently the CRLF
> octets
> + // get inserted before quoted-printable encoding and then get
> encoded.
> + // Such a sequence is invalid because = cannot be used literally
> + // and must be followed by characters representing the hex value,
> + // i.e. == is already invalid.
> + //
> + // We must skip over the entire sequence and continue at the last
> + // = in ==0D=0A=, otherwise the code below would insert additional
> + // characters into the decoded text.
> + if (strncmp(p,"==0D=0A=",8)==0) {
> + p += strlen("==0D=0A")-1;
> + // put the cursor at the next useful =
> + p=nextunfolded(p,aMimeMode,true);
> + continue;
> + }
> s=nextunfolded(p,aMimeMode,true);
> if (*s==0) break; // end of string
> hex[0]=*s; // first digit
I'll add that patch to the next test run. Thanks for testing and the
correction.
--
Best Regards, Patrick Ohly
The content of this message is my personal opinion only and although
I am an employee of Intel, the statements I make here in no way
represent Intel's position on the issue, nor am I authorized to speak
on behalf of Intel on this matter.
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