Bug#659251: openssl: enc: Bad compression ration with -z (zlib compression)

[Roland Stigge]

Package: openssl
Version: 1.0.0g-1
Severity: normal

Hi,

consider symmetric encryption with "openssl enc":

$ openssl enc -bf -in /usr/share/common-licenses/GPL-3 -out GPL-3.enc
enter bf-cbc encryption password:
Verifying - enter bf-cbc encryption password:
$ openssl enc -bf -in /usr/share/common-licenses/GPL-3 -out GPL-3.enc-z -z
enter bf-cbc encryption password:
Verifying - enter bf-cbc encryption password:
$ gzip -c /usr/share/common-licenses/GPL-3 > GPL-3.gz
$ ls -l GPL-3* /usr/share/common-licenses/GPL-3
-rw-r--r-- 1 rst rst 35168 Feb 9 15:39 GPL-3.enc
-rw-r--r-- 1 rst rst 35189 Feb 9 15:39 GPL-3.enc-z
-rw-r--r-- 1 rst rst 12143 Feb 9 15:40 GPL-3.gz
-rw-r--r-- 1 root root 35147 Jul 2 2007 /usr/share/common-licenses/GPL-3
$

As you can see in the gzip compression case, the cleartext provides for quite
some compression. But when enabling zlib compression for "openssl enc" via
"-z", the resulting file is even bigger and it looks like there is no actual
compression done at all.

Thanks in advance,

Roland


-- System Information:
Debian Release: wheezy/sid
APT prefers unstable
APT policy: (500, 'unstable')
Architecture: i386 (x86_64)

Kernel: Linux 3.2.0-1-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.utf8, LC_CTYPE=en_US.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages openssl depends on:
ii libc6 2.13-24
ii libssl1.0.0 1.0.0g-1
ii zlib1g 1:1.2.3.4.dfsg-3

openssl recommends no packages.

Versions of packages openssl suggests:
ii ca-certificates 20111211

-- no debconf information



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[Sebastian Andrzej Siewior]

tags 659251 + patch
thanks

* Roland Stigge | 2012-02-09 15:52:21 [+0100]:

>$ openssl enc -bf -in /usr/share/common-licenses/GPL-3 -out GPL-3.enc
>enter bf-cbc encryption password:
>Verifying - enter bf-cbc encryption password:
>$ openssl enc -bf -in /usr/share/common-licenses/GPL-3 -out GPL-3.enc-z -z
>enter bf-cbc encryption password:
>Verifying - enter bf-cbc encryption password:
>$ gzip -c /usr/share/common-licenses/GPL-3 > GPL-3.gz
>$ ls -l GPL-3* /usr/share/common-licenses/GPL-3
>-rw-r--r-- 1 rst rst 35168 Feb 9 15:39 GPL-3.enc
>-rw-r--r-- 1 rst rst 35189 Feb 9 15:39 GPL-3.enc-z
>-rw-r--r-- 1 rst rst 12143 Feb 9 15:40 GPL-3.gz
>-rw-r--r-- 1 root root 35147 Jul 2 2007 /usr/share/common-licenses/GPL-3
>$

The problem is that openssl tries to compress encrypted content which
seems not to work. The patch attached changes the order to first
compress and then encrypt.

Sebastian