mc 4.8.19: segfaults while searching for contents

mc 4.8.19: segfaults while searching for contents

[Matthias Fischer]

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Hi,

Suddenly 'mc 4.8.19' starts throwing segfaults each time I search for contents in multiple files, e.g. in a directory structure like '/usr/local/bin'. Searching in SINGLE files or in a directory which contains only *.sh-files is ok):

...
07:42:32	kernel: 	mc[17515]: segfault at a39349a0 ip a2fbdf81 sp b0f41af4 error 4 in libpcre.so.1.2.9[a2f94000+44000]
07:42:32	kernel: 	grsec: From 192.168.100.1: Segmentation fault occurred at a39349a0 in /usr/bin/m c[mc:17515] uid/euid:0/0 gid/egid:0/0, parent /bin/bash[bash:16795] uid/euid:0/0 gid/egid:0/0
07:42:32	kernel: 	grsec: From 192.168.100.1: denied resource overstep by requesting 4096 for RLIMIT_CORE against limit 0 for /usr/bin/mc[mc:17515] uid/euid:0/0 gid/egid:0/0, parent /bin/bash[bash:16795] uid/euid:0/0 gid/egid:0/0
...

The same happens on a fresh test installation.

Right now I'm  thinking about using 'paxctl' on '/usr/bin/mc', but I'm not really sure...:

1. If this would be a solution
2. Which options to use - and
3. On which parts ('/usr/bin/mc'?) exactly.

I'm testing with:

...
paxctl -cm /usr/bin/mc
...

But had no luck until now.

Anybody got a hint or experiencing the same?

Best,
Matthias

Re: mc 4.8.19: segfaults while searching for contents

[Matthias Fischer]

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Hi,

On 03.10.2017 08:50, Matthias Fischer wrote:
> ...
> 
> Suddenly 'mc 4.8.19' starts throwing segfaults...
> 
> ...

This is weird.

As soon as directory (e.g. '/usr/local/bin') contains the file
'ipfirereboot', 'mc' crashes while searching for content 'flush' (e.g.).

Thus, I would say, 'mc' has problems searching in (specific) binaries -
searching in '/usr/bin' has the same effect.

And:

The following 'paxctl'-options had NO effect:

...
root(a)ipfire: /usr/bin # paxctl -v /usr/bin/mc
PaX control v0.9
Copyright 2004,2005,2006,2007,2009,2010,2011,2012,2014 PaX Team
<pageexec(a)freemail.hu>

- PaX flags: -p-s-m-x-e-- [/usr/bin/mc]
        PAGEEXEC is disabled
        SEGMEXEC is disabled
        MPROTECT is disabled
        RANDEXEC is disabled
        EMUTRAMP is disabled
...

Searching in text-only files is ok, but as soon as directory contains
the above file (or something similar), 'mc' crashes.

This does NOT happen on my devel with 'mc 4.8.15'... ;-)

Best,
Matthias

Re: mc 4.8.19: segfaults while searching for contents

[Michael Tremer]

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Hi,

this doesn't have anything to do with PaX. It's just a bug in mc.

Probably has this problem with files that have the SUID bit set?!

Did you try to update mc?

-Michael

On Tue, 2017-10-03 at 09:24 +0200, Matthias Fischer wrote:
> Hi,
> 
> On 03.10.2017 08:50, Matthias Fischer wrote:
> > ...
> > 
> > Suddenly 'mc 4.8.19' starts throwing segfaults...
> > 
> > ...
> 
> This is weird.
> 
> As soon as directory (e.g. '/usr/local/bin') contains the file
> 'ipfirereboot', 'mc' crashes while searching for content 'flush' (e.g.).
> 
> Thus, I would say, 'mc' has problems searching in (specific) binaries -
> searching in '/usr/bin' has the same effect.
> 
> And:
> 
> The following 'paxctl'-options had NO effect:
> 
> ...
> root(a)ipfire: /usr/bin # paxctl -v /usr/bin/mc
> PaX control v0.9
> Copyright 2004,2005,2006,2007,2009,2010,2011,2012,2014 PaX Team
> <pageexec(a)freemail.hu>
> 
> - PaX flags: -p-s-m-x-e-- [/usr/bin/mc]
>         PAGEEXEC is disabled
>         SEGMEXEC is disabled
>         MPROTECT is disabled
>         RANDEXEC is disabled
>         EMUTRAMP is disabled
> ...
> 
> Searching in text-only files is ok, but as soon as directory contains
> the above file (or something similar), 'mc' crashes.
> 
> This does NOT happen on my devel with 'mc 4.8.15'... ;-)
> 
> Best,
> Matthias

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Re: mc 4.8.19: segfaults while searching for contents

[Matthias Fischer]

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On 04.10.2017 17:41, Michael Tremer wrote:
> Hi,

Hello,

> this doesn't have anything to do with PaX. It's just a bug in mc.
> 
> Probably has this problem with files that have the SUID bit set?!

Perhaps. Will look at this when I have the time again.

> Did you try to update mc?

I tested with several versions and clean compilations - its always the
same. On the 'Devel' machine (Ubuntu, mc 4.8.15, no PaX) everything works.

Best,
Matthias

> -Michael
> 
> On Tue, 2017-10-03 at 09:24 +0200, Matthias Fischer wrote:
>> Hi,
>> 
>> On 03.10.2017 08:50, Matthias Fischer wrote:
>> > ...
>> > 
>> > Suddenly 'mc 4.8.19' starts throwing segfaults...
>> > 
>> > ...
>> 
>> This is weird.
>> 
>> As soon as directory (e.g. '/usr/local/bin') contains the file
>> 'ipfirereboot', 'mc' crashes while searching for content 'flush' (e.g.).
>> 
>> Thus, I would say, 'mc' has problems searching in (specific) binaries -
>> searching in '/usr/bin' has the same effect.
>> 
>> And:
>> 
>> The following 'paxctl'-options had NO effect:
>> 
>> ...
>> root(a)ipfire: /usr/bin # paxctl -v /usr/bin/mc
>> PaX control v0.9
>> Copyright 2004,2005,2006,2007,2009,2010,2011,2012,2014 PaX Team
>> <pageexec(a)freemail.hu>
>> 
>> - PaX flags: -p-s-m-x-e-- [/usr/bin/mc]
>>         PAGEEXEC is disabled
>>         SEGMEXEC is disabled
>>         MPROTECT is disabled
>>         RANDEXEC is disabled
>>         EMUTRAMP is disabled
>> ...
>> 
>> Searching in text-only files is ok, but as soon as directory contains
>> the above file (or something similar), 'mc' crashes.
>> 
>> This does NOT happen on my devel with 'mc 4.8.15'... ;-)
>> 
>> Best,
>> Matthias
>