FS#39978 - [linux] module binfmt_aout disabled in 3.14.1 i686 version

Attached to Project: Arch Linux
Opened by patrick (potomac) - Sunday, 20 April 2014, 18:58 GMT
Last edited by Tobias Powalowski (tpowa) - Monday, 16 June 2014, 18:33 GMT
Task Type Feature Request
Category Kernel
Status Closed
Assigned To Tobias Powalowski (tpowa)
Thomas Bächler (brain0)
Architecture i686
Severity Low
Priority Normal
Reported Version
Due in Version Undecided
Due Date Undecided
Percent Complete 100%
Votes 0
Private No

Details

Description:

with kernel 3.14.1 (i686) package it's not possible to execute an "a.out" binary file,

because the "CONFIG_BINFMT_AOUT" option has not been set in config file,

with older kernel versions this option was enabled,

the solution is to re-enable this option :

CONFIG_BINFMT_AOUT=y

or

CONFIG_BINFMT_AOUT=m



Additional info:
* package version(s) linux 3.14.1 ( i686 )
* config and/or log files etc.


Steps to reproduce:

- install kernel 3.14.1 ( i686 version )
- try to execute an a.out binary format file
- this attempt will fail ( missing module binfmt_aout )

this bug may also concern the x64 version of linux 3.14.1 ( but I didn't test )
This task depends upon

Closed by  Tobias Powalowski (tpowa)
Monday, 16 June 2014, 18:33 GMT
Reason for closing:  Won't implement
Comment by Daniel Micay (thestinger) - Tuesday, 22 April 2014, 18:20 GMT
I'm curious about what the use case for this is, considering that it's a legacy feature around for backwards compatibility. The rationale for making this optional in the first place was a questionable use case, and worries about a needless security risk:

https://lwn.net/Articles/196295/

> The patch also changes CONFIG_BINFMT_AOUT to be disabled by default on
archs that had it default to enabled. The a.out support is similarly
risky and not audited/hardened with the same scrutiny that the ELF
support has received.
Comment by Thomas Bächler (brain0) - Tuesday, 22 April 2014, 19:51 GMT
I don't see why anyone would need a.out binaries. We also disable options for compatibility with libc5 and similarly old stuff, so I don't see why we should keep something as antique as a.out around.

What's the use case here?
Comment by patrick (potomac) - Tuesday, 22 April 2014, 21:14 GMT
I did the bug report for an user who has very old programs ( a.out formats ), and he has no source code available for these old programs ( he can not recompile these programs in elf binary format )
Comment by Daniel Micay (thestinger) - Tuesday, 22 April 2014, 21:17 GMT
I really doubt there are users with useful binaries dating from before Linux 1.2.
Comment by patrick (potomac) - Tuesday, 22 April 2014, 21:18 GMT
one alternative is to put the module binfmt_aout in a separate package for this use case ( old softwares )
Comment by Daniel Micay (thestinger) - Tuesday, 22 April 2014, 21:21 GMT
Is there actually a single user who has a useful binary that old? Filling an imagined use case doesn't make sense.
Comment by patrick (potomac) - Tuesday, 22 April 2014, 21:40 GMT
@Daniel_Micay: it's not so surprising to see in 2014 old software like a.out still running,

as long as software does the job well then an user ( or a company ) doesn't feel the need of change, I see this in bank business where cobol softwares, win3.x/MSDOS softwares are still running,

and if this software is a proprietary software then there is no easy alternatives
Comment by Daniel Micay (thestinger) - Tuesday, 22 April 2014, 21:46 GMT
I'm asking if there's actually an Arch Linux user with one of these mythical useful ancient binaries. I understand that a theoretical possibility of such a user existing, but I seriously doubt that anyone is running a pre Linux 1.2 binary (without available source code) on Arch Linux. Theoretical use cases with no actual users don't make sense to support.
Comment by Daniel Micay (thestinger) - Tuesday, 22 April 2014, 21:49 GMT
Keep in mind we're talking about binaries dating from *before* 1995 here... that's before Red Hat Linux (the predecessor to RHEL/Fedora) even existed. Is there even one example of useful proprietary Linux software from that era? And by useful I mean something a reasonable person (not an hobby software archaeologist) would run on Arch.
Comment by patrick (potomac) - Tuesday, 22 April 2014, 22:00 GMT
@Daniel_Micay : yes there is an actual archlinux user who needs the module binfmt_aout,

like I said I did this bug report because I know someone in the french forum of archlinux who can not run a.out format since the 3.14.x kernel version ( with 3.13.x version i686 there is no problem because the binfmt_aout option was enabled )
Comment by Johannes Löthberg (demize) - Tuesday, 22 April 2014, 22:06 GMT
You've said that he has binaries in a.out format but you haven't said why he does and why he can't just use a piece of software from.. this century?
Comment by patrick (potomac) - Tuesday, 22 April 2014, 22:23 GMT
@Johannes Löthberg : he said in the french forum of archlinux that he don't have the source code for these old programs ( he can not recompile these programs in elf binary format ), that's why he still uses these a.out binaries,

he didn't say more, so I don't know exactly what kind of old software he has and if it's possible to replace them with modern software equivalent,


Loading...