[OpenJDK 2D-Dev] [10] RFR JDK-8190332: PngReader throws NegativeArraySizeException/OOM error when IHDR width is very large

[Phil Race]

+1

-phil.

On 11/16/2017 02:52 AM, Jayathirth D V wrote:
> Hi Prahalad,
>
> Thanks for the approval after review.
>
> I explicitly added "{" in new line because of multiline condition in catch block. I was advised previously to do so when there are multiline conditions before a block from readability perspective(http://mail.openjdk.java.net/pipermail/2d-dev/2016-April/006677.html ).
> If Phil/Others can also give clarification on this, if needed I will make this minor correction.
>
> Regards,
> Jay
>
> -----Original Message-----
> From: Prahalad Kumar Narayanan
> Sent: Thursday, November 16, 2017 2:11 PM
> To: Jayathirth D V; Philip Race; 2d-dev
> Subject: RE: [OpenJDK 2D-Dev] [10] RFR JDK-8190332: PngReader throws NegativeArraySizeException/OOM error when IHDR width is very large
>
> Hello Jay
>
> The change looks good.
>
> I just noticed the braces ' { ' for the first catch block is on a new line.
> It's a minor observation, does not need another webrev.
>
> Thanks
> Have a good day
>
> Prahalad
>
>
> -----Original Message-----
> From: Jayathirth D V
> Sent: Thursday, November 16, 2017 2:06 PM
> To: Prahalad Kumar Narayanan; Philip Race; 2d-dev
> Subject: RE: [OpenJDK 2D-Dev] [10] RFR JDK-8190332: PngReader throws NegativeArraySizeException/OOM error when IHDR width is very large
>
> Hi Prahalad,
>
> Thanks for your inputs.
> I have updated comments in PNGImageReader and updated the jtreg comment in test case.
> Please find updated webrev for review:
> http://cr.openjdk.java.net/~jdv/8190332/webrev.02/
>
> Thanks,
> Jay
>
> -----Original Message-----
> From: Prahalad Kumar Narayanan
> Sent: Wednesday, November 15, 2017 6:22 PM
> To: Jayathirth D V; Philip Race; 2d-dev
> Subject: RE: [OpenJDK 2D-Dev] [10] RFR JDK-8190332: PngReader throws NegativeArraySizeException/OOM error when IHDR width is very large
>
> Hello Jay
>
> Good day to you.
> Overall, the code change looks good.
>
> Few minor changes to the comment lines:
> . You may re-phrase the new comments introduced at Line 1366.
> . Please include the comments that explained recover strategy. This got deleted in your change.
>        . The new comments imply that OOM is wrapped and thrown to the caller.
>        . However, the deleted comments substantiate why such a decision was taken (we will not estimate memory requirements). Helps the programmer in future.
>
> . Modified comments lines (for reference)
> 1365              *
> 1366              * If the read operation triggers OutOfMemoryError, the same
> 1367              * will be wrapped in an IIOException at PNGImageReader.read
> 1368              * method.
> 1369              *
> 1370              * The recovery strategy for this case should be
> 1371              * defined on the level of application, so we will not
> 1372              * try to estimate the required amount of the memory and/or
> 1373              * handle OOM in any way
> 1374              */
>
> . The jtreg comments in the test-case have a Javadoc comment style rather than multi-line comment.
>        . You may change it or retain the current style- as I do see many test files in repo with Javadoc style comments.
>        . Reference link: http://openjdk.java.net/jtreg/faq.html#question3.1
>    
> Thanks
> Have a good day
>
> Prahalad
>
> ----- Original Message -----
> From: Jayathirth D V
> Sent: Tuesday, November 14, 2017 3:44 PM
> To: Philip Race; Prahalad Kumar Narayanan; 2d-dev
> Subject: RE: [OpenJDK 2D-Dev] [10] RFR JDK-8190332: PngReader throws NegativeArraySizeException/OOM error when IHDR width is very large
>
> Hi,
>
> Thanks for the review Phil and Prahalad.
>
> Based on the suggestions I have updated the code to wrap underlying Exception/Error in IIOException instead of overriding the message content and removed the check for IndexOutOfBoundsException.
> Corresponding test case changes are also done.
>
> Please find updated webrev for review:
> http://cr.openjdk.java.net/~jdv/8190332/webrev.01/
>
> Thanks,
> Jay
>
> From: Phil Race
> Sent: Tuesday, November 14, 2017 12:06 AM
> To: Jayathirth D V; 2d-dev
> Subject: Re: [OpenJDK 2D-Dev] [10] RFR JDK-8190332: PngReader throws NegativeArraySizeException/OOM error when IHDR width is very large
>
> 1676                  IndexOutOfBoundsException |
>
>
> IndexOutOfBoundsException is a specified exception but as such is thrown outside this try block
>
> so I think you should not re-throw it here but should let it be handled by the block below.
>
>    throw new IIOException("BufferOverflow/OOM while reading"
> 1683                     + " the image");
>
> Whilst that's the issue here I think this message will look quite odd if what we actually had thrown is something like ClassCastException so I think you should leave it to the underlying exception to report the issue.
>
> Also I had said to wrap the original exception, so what I expected was
>
> throw new IIOException("Caught exception during read: ", e);
>
> -phil.
>
> On 11/13/2017 01:23 AM, Jayathirth D V wrote:
> Hello All,
>   
> Please review the following fix in JDK10 :
>   
> Bug : https://bugs.openjdk.java.net/browse/JDK-8190332
> Webrev : http://cr.openjdk.java.net/~jdv/8190332/webrev.00/
>   
> Issue :
>         Two types of issues are fixed under the same solution, so JDK-8190511 is closed as duplicate of this issue.
>         1) PNGImageReader throws OOM error when IHDR width equals/or greater than VM's array size limit.
>         2) PNGImageReader throws NegativeArraySizeException when IHDR width value is very high.
>   
> Root cause :
> 1) VM doesn't allow creation of array with Size >= ((2 to the power of 31) - 2) so we throw OOM error.
> 2) We use width from IHDR to calculate needed "bytesPerRow" value as "(inputBands*passWidth*bitDepth + 7)/8". When IHDR width is very high we overflow the integer size of bytesPerRow and when we try to create array using bytesPerRow it throws NegativeArraySizeException.
>   
> Solution :
>         According to PNG spec maximum value that can be stored in IHDR width/height is (2 to the power of 31). We can't support PNG images with so large height/width, because based on other parameters like inputsBands, bitDepth we will definitely           overflow than the maximum buffer value of VM. Also PNG is not a preferred format for such kind of large images.
>                  Instead of catching these OOMError/NegativeArraySizeException at many different levels in PNGImageReader we can catch Throwable at higher level and convert OOMError/ NegativeArraySizeException into IIOException.
>   
> Thanks,
> Jay
>