Resolved Warning about in.proftpd: is it a problem?

[MMagnani]

Hello,

After some server uptime, dmesg command shows in last line:
[11615.673060] capability: warning: `in.proftpd' uses 32-bit capabilities (legacy support in use)

FTP seems to work fine, Debian 8.7‬, Plesk Onyx Version 17.0.17 Update #18

Could someone please explain if this is a problem?

Thanks in advance!

 

[Bitpalast]

Please refer to http://www.proftpd.org/docs/modules/mod_cap.html#FAQ for the answer

 

[MMagnani]

Please refer to http://www.proftpd.org/docs/modules/mod_cap.html#FAQ for the answer

Thank you, Peter
But that doesn't look right, since this is a fresh Debian 8 and Plesk installation.
Besides, I can't get why "in.proftpd" (and not "proftpd").
Any other hints?

 

[UFHH01]

Hi MMagnani,

since you seem to think, that even on a "fresh installation", there can't be any "old" libraries, let's have a look to your current installation then:

apt-cache policy libcap2
apt-cache policy libcap2-dev

apt-cache policy libcap-dev

 

[MMagnani]

Thank you, UFHH01

I am so far from being an expert, just trying some uneducated common sense. I am sorry if my questioning sounds rude.

# apt-cache policy libcap2
libcap2:
  Installed: 1:2.24-8
  Candidate: 1:2.24-8
  Version table:
 *** 1:2.24-8 0
        500 http://ftp.debian.org/debian/ jessie/main amd64 Packages
        100 /var/lib/dpkg/status


# apt-cache policy libcap2-dev
libcap2-dev:
  Installed: (none)
  Candidate: (none)
  Version table:


# apt-cache policy libcap-dev
libcap-dev:
  Installed: (none)
  Candidate: 1:2.24-8
  Version table:
     1:2.24-8 0
        500 http://ftp.debian.org/debian/ jessie/main amd64 Packages

As so, could you please explain me if above capability warning means any problem or risk and, if yes, how to solve it?

Thank you!

 

[UFHH01]

Hi MMagnani,

how to solve it?

hm... let me quote the answer from the provided link from @Peter Debik :

Question: Why do I see the following in my system logs?

warning: `proftpd' uses 32-bit capabilities (legacy support in use)

Answer: This warning is coming from the use of the libcap library. A newer version of the libcap library (called the "libcap2" or "libcap2-dev" package on some Linux distributions) is now available.
To remove the above warning, you will need to update/install the newer libcap2 or libcap2-dev package on your system, and re-build proftpd (using version 1.3.2rc1 or later) in order to compile and link against the newer libcap library.

Investigations:

=> https://packages.debian.org/de/jessie/proftpd-basic ( = proftpd-basic (1.3.5-1.1+deb8u1) ) => => => as you can see, the answered requirements "version 1.3.2rc1 or later" are already met.

apt-cache policy libcap2
libcap2: Installed: 1:2.24-8
Candidate: 1:2.24-8

But ( ! ) => https://launchpad.net/debian/+source/libcap2/+changelog states, that libcap2 version "2.25-1" was only published to Debian "Stretch" and "Sid" ( pls. see => https://launchpad.net/debian/+source/libcap2/1:2.25-1 ).​

Now looking for libcap-dev and libcap2-dev:

=> https://packages.debian.org/en/jessie/libcap-dev ( version 2.24-8 )
=> https://packages.debian.org/en/jessie/libcap2-dev ( Packages providing libcap2-dev => libcap-dev )

Conclusion: Is it WORTH to eliminate the warning by compiling and installing the newer, actual libcap2 - version 2.25-1 ???
Well, it's up to you, MMagnani.
Just be informed, that this "warning" doesn't harm your system, nor does it lead to issues/problems/failures with ProFTPD, as you already noticed. Some Linux distributions have a newer version, some don't... at the moment, Debian jessie works with 2.24-8, Ubuntu 16.04 with 2.24-12 and CentOS 7 comes with version 2.22-8 . The "warning" informs you as well, that is uses "32-bit capabilities (legacy support in use)"... but if you insist to compile and install the newest libcap2 - version, in order to get rid of that warning, pls. feel free to do that extra work. ​