Fedora Users — Re: Corrupted gshadow files with many users in group

Mike Cisar wrote:

Have a system running FC2 and have recently noticed problems with the
gshadow file becoming corrupted on groups with a large number of members
(100+).

I seem to recall seeing a similar problem years back (RH7, RH8 era) which
affected both the group and gshadow files... a 3rd party made a patched
version of something which solved the problem, and then eventually the
problem was resolved in the distribution.  The details are all very fuzzy by
now :-)

After a certain period the gshadow becomes corrupted to such an extent that
using useradd, userdel, etc brings the machine to its knees for maybe 10
minutes using all swap and all ram and driving utilization through the roof
and then it thankfully recovers.

The corruption seems to be bits and pieces of the particular group repeated
over and over, with the valid entries all the way at the end of the line.
As an example, on this machine the netexplorer group has around 100 users...
after the line in gshadow became corrupted I simply snipped the whole line
leaving the entry as (the entry in the group file was fine with all users
intact).

netexplorer:!::

I then added a user "acall" to the group, it was added successfully to the group file, but gshadow now contained the following...

netexplorer:!::orer,lorer,,,er,,,lorer,,,lorer,,,orer,plorer,!,rer,orer,!,or
er,orer,!,,er,,,,,,,,,acall

adding a second user "gptest" leaves the gshadow entry in this state...

netexplorer:!::orer,lorer,,orer,er,,r,lorer,,orer,lorer,,orer,orer,plorer,!,
rer,orer,!,orer,orer,!,,er,rer,,,,lorer,lorer,er,r,orer,lorer,,,er,,,lorer,,
,lorer,,,orer,plorer,!,rer,orer,!,orer,orer,!,,er,,,,,,,,,acall,gptest

As you can see this can snowball the length of the line in no time.

Any ideas, suggestions?

Thanks,

Mike <<<<<

I bugzilla'd that problem a few days ago after I described the same issue on this list. I forget the bugzilla number. Its been assigned but there is no fix yet.

I manually fixed the gshadow file using sed, grep, and a bit of manual keying to put it in shape. The bulk of the file can be shrunk down by just removing consecutive commas.

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Bill Gradwohl
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