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From: David Sterba <dsterba@suse.cz>
To: Krzysztof Kolasa <kkolasa@winsoft.pl>
Cc: tom.yeon@windriver.com, gregkh@linuxfoundation.org,
	linux-kernel@vger.kernel.org
Subject: Re: lz4: fix system halted at boot kernel x86_64 compressed lz4
Date: Wed, 25 Mar 2015 01:44:58 +0100	[thread overview]
Message-ID: <20150325004458.GA20767@suse.cz> (raw)
In-Reply-To: <55114A1D.7030508@winsoft.pl>

On Tue, Mar 24, 2015 at 12:27:25PM +0100, Krzysztof Kolasa wrote:
> lz4: fix system halted at boot kernel x86_64 compressed lz4
> 
> Decompression process ends with an error when loading kernel:
> 
> Decoding failed
>  -- System halted

Serious regression detected ...

> 
> This condition is probably not needed ( from the last commit d5e7caf) :

The offending patch is on the way to stable trees, so it would be best
to postpone it for now.

> if( ... ||
>     (op + COPYLENGTH) > oend)
>     goto _output_error
> 
> macro LZ4_SECURE_COPY() tests op and does not copy any data
> when op exceeds the value, decompression process is continued.
> 
> added by analogy security for the ref:
> 
> if ((ref + COPYLENGTH) > oend...
> 
> to lz4_uncompress_unknownoutputsize(...)

I did only a quick check, your analysis seems correct. Reviewing the lz4
patches is tedious as the kernel implementations do not match the
upstream one line-by-line besides that I've missed the side effects of
the macro.

       reply	other threads:[~2015-03-25  0:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <55114A1D.7030508@winsoft.pl>
2015-03-25  0:44 ` David Sterba [this message]
2015-03-25  7:04   ` lz4: fix system halted at boot kernel x86_64 compressed lz4 Krzysztof Kolasa
2015-03-31 15:22     ` Greg KH
2015-04-03 11:33       ` Krzysztof Kolasa
2015-04-03 13:17         ` Greg KH
2015-04-03 13:58           ` Krzysztof Kolasa
2015-04-03 14:17             ` Alexander Kuleshov
2015-04-03 14:23               ` Greg KH
2015-04-03 14:30                 ` Krzysztof Kolasa
2015-04-03 14:44                   ` Greg KH
2015-04-03 15:12                     ` [PATCHv2] " Krzysztof Kolasa
2015-04-03 17:36                       ` Greg KH
2015-04-03 18:03                         ` Krzysztof Kolasa
2015-04-03 18:06                           ` Greg KH
2015-04-03 18:18                         ` Alexander Kuleshov
2015-04-03 19:01                           ` Greg KH

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