Integrated: JDK-8361748 : Enforce limits on the size of an XBM image

[Harshitha Onkar]

On Fri, 25 Jul 2025 23:37:27 GMT, Harshitha Onkar <honkar at openjdk.org> wrote:

> XBM (X Bitmap) images are small one-bit deep images that were developed as a simple uncompressed format that could easily be included in C source files as include files.
> 
> Format of XBM image:
> 
> 
>  #define width w
>  #define height h
>  static char foo_bits[] = {
>  0xnn,0xnn,0xnn,0xnn,0xnn, .......
>  0xnn,0xnn,0xnn,0xnn, .........
>  0xnn,0xnn,0xnn,0xnn};
> 
> 
> The first two #defines statements specify the width and height of the bitmap in pixels followed by hex byte array which represent pixel data itself.
> 
> The current implementation allows an arbitrarily large XBM which is not a valid use case for any XBM.
> Also it doesn't validate that the provided byte array is sufficient to populate the specified WxH. Since these are small one-bit mono images a reasonable size limit is set to `MAX_XBM_SIZE = 16384 bytes`. It can be set to a larger limit if someone thinks it is necessary.
> 
> The XBMDecoder's produceImage() has outdated logic, it has been restructured by adding more efficient parser logic and better error handling checks.

This pull request has now been integrated.

Changeset: c71be802
Author:    Harshitha Onkar <honkar at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/c71be802b530034169d17325478dba6e2f1c3238
Stats:     245 lines in 7 files changed: 157 ins; 33 del; 55 mod

8361748: Enforce limits on the size of an XBM image

Reviewed-by: prr, jdv

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PR: https://git.openjdk.org/jdk/pull/26488