[OpenJDK 2D-Dev]  RFR JDK-8243674: Remove language tag length limit for iTXt chunk in PNGImageReader
Jayathirth D v
JAYATHIRTH.D.V at ORACLE.COM
Fri Jul 31 14:21:27 UTC 2020
Thanks for the review Sergey.
The extra check for length will hit only in case of corrupted chunk. Since we don’t know the exact length of “languageTag” or “Translated keyword” or “Text” we use chunkLength to calculate remaining length.
This fix is to comply with spec. Testcase throws appropriate “Found non null terminated string” IIOException without this fix(because languageTag can be more than 80) and works properly with fix.
> On 31-Jul-2020, at 4:25 AM, Sergey Bylokhov <Sergey.Bylokhov at oracle.com> wrote:
> Hi, Jay.
> The fix looks fine, but maybe we can to trigger added IIOException(remainingLen < 0) by the test?
> On 29.07.2020 02:41, Jayathirth D v wrote:
>> Hello All,
>> Please review the following fix for JDK 16:
>> Bug : https://bugs.openjdk.java.net/browse/JDK-8243674
>> Webrev : http://cr.openjdk.java.net/~jdv/8243674/webrev.00/
>> Issue : We have language tag length limit of 80 for iTXt chunk in PNGImageReader which is not spec compliant(http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html#C.iTXt). There should not be limit on length of language tag.
>> Solution : Remove language tag restriction of 80. In PNGImageWriter we don’t enforce any limit on language tag length.
> Best regards, Sergey.
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