Re: [PATCH] crypto: deflate - fix decompression window size

[Herbert Xu <herbert@gondor.apana.org.au>]

On Tue, Mar 24, 2026 at 06:08:58PM +0000, Giovanni Cabiddu wrote:
> deflate_decompress() initializes the inflate stream with windowBits set
> to -DEFLATE_DEF_WINBITS (11 bits, 2KB window). Valid raw DEFLATE streams
> allow window sizes up to MAX_WBITS (15 bits, 32KB).  Using a smaller
> window than the one used during compression causes decompression to fail
> for externally generated data. This might occur if data is compressed
> with a compressor that is not deflate-generic (i.e. this
> implementation).
> 
> Use -MAX_WBITS when calling zlib_inflateInit2() to accept all valid raw
> DEFLATE streams. The inflate workspace allocated in deflate_alloc_stream()
> is already sized using zlib_inflate_workspacesize(), which accounts for
> the maximum window size, so no allocation change is needed.
> 
> Fixes: 08cabc7d3c86 ("crypto: deflate - Convert to acomp")

That commit doesn't touch this at all.  I think you meant

commit 62a465c25e99b9a98259a6b7f5bb759f5296d501
Author: Herbert Xu <herbert@gondor.apana.org.au>
Date:   Wed Aug 30 17:56:25 2023 +0800

    crypto: deflate - Remove zlib-deflate

But this simply restored the status quo prior to

commit a368f43d6e3a001e684e9191a27df384fbff12f5
Author: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Date:   Fri Apr 21 21:54:30 2017 +0100

    crypto: scomp - add support for deflate rfc1950 (zlib)

So the commit message needs to be rewritten to clearly state
why this is needed for the "deflate" algorithm.

Thanks,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
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