DefineFont2/3 tag parsing bug

Thanks Naoki,

I imagine swftools.org's library would need to detect and special case
non-null-terminated strings for this field to maintain backwards
compatibility.

Please note that the font name in the new SWF 9 DefineFontName tag is
different from the equivalent field in DefineFontInfo, DefineFont2 and
DefineFont3 in that the DefineFontName tags' font name field is not null
terminated.

Pete

________________________________

From: Naoki INADA [mailto:member@adobeforums.com]
Sent: Wednesday, May 21, 2008 2:44 AM
To: flexsdk-dev@adobeforums.com
Subject: Re: DefineFont2/3 tag parsing bug


A new message was posted by Naoki INADA in

Developers --
DefineFont2/3 tag parsing bug

Hi Peter.

The swf file that I encountered the crash was made by swftools
(http://www.swftools.org/) but not Flash or Flex.
I'll fix swftools.

Thank you a lot for your research.


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Hi Peter.

The swf file that I encountered the crash was made by swftools (http://www.swftools.org/) but not Flash or Flex.
I'll fix swftools.

Thank you a lot for your research.

Hi Naoki,

Flex matches what Flash Authoring generates and it works in the player, so it is likely that the SWF specification is wrong. The fontName field for a DefineFontInfo or DefineFont2 or DefineFont3 tag is a null terminated String.

Pete

<DIV dir=ltr align=left><SPAN class=126172614-13052008><FONT face=Arial <br />color=#0000ff size=2>The code explicitly comments that removal of the null <br />terminator needs to be done, but as you said, this seems to contradict the <br />specification for fontName in DefineFontInfo or DefineFont2/3. Thankfully, <br />it seems readLengthString() is only used for font names.</FONT></SPAN></DIV><br /><DIV dir=ltr align=left><SPAN class=126172614-13052008><FONT face=Arial <br />color=#0000ff size=2></FONT></SPAN> </DIV><br /><DIV dir=ltr align=left><SPAN class=126172614-13052008><FONT face=Arial <br />color=#0000ff size=2>Before we change the code we'll ask the Flash team to <br />confirm whether the spec or our code is wrong. </FONT></SPAN><SPAN <br />class=126172614-13052008><FONT face=Arial color=#0000ff size=2>(However, from <br />the error message reported, it seems that an empty string (0 length) was <br />encountered for the font name and that seems invalid to <br />me...).</FONT></SPAN></DIV><br /><DIV dir=ltr align=left><SPAN class=126172614-13052008><FONT face=Arial <br />color=#0000ff size=2></FONT></SPAN> </DIV><br /><DIV dir=ltr align=left><SPAN class=126172614-13052008><FONT face=Arial <br />color=#0000ff size=2>Pete</FONT></SPAN></DIV>

Are attached files removed in this forum?

Following is the patch I attached previous message.

Index: modules/swfutils/src/java/flash/swf/SwfDecoder.java
===================================================================
--- modules/swfutils/src/java/flash/swf/SwfDecoder.java (revision 1678)
+++ modules/swfutils/src/java/flash/swf/SwfDecoder.java (working copy)
@@ -268,16 +268,15 @@
byte[] b = new byte[length];
readFully(b);

- // [paul] Flash Authoring and the player null terminate the
- // string, so ignore the last byte when constructing the String.
+ // In string with length, strings are not null-terminated.
if (swfVersion >= 6)
{
- return new String(b, 0, length - 1, "UTF8").intern();
+ return new String(b, 0, length, "UTF8").intern();
}
else
{
// use platform encoding
- return new String(b, 0, length - 1).intern();
+ return new String(b, 0, length).intern();
}
}