[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=6634

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fweimer at redhat dot com
              Flags|                            |security-

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[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[halesh dot s at gmail dot com]

------- Additional Comments From halesh dot s at gmail dot com  2008-08-14 09:26 -------
Thanks.



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[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[drepper at redhat dot com]

------- Additional Comments From drepper at redhat dot com  2008-08-14 04:24 -------
I checked in a slightly modified patch.

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           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


http://sourceware.org/bugzilla/show_bug.cgi?id=6634

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[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[halesh dot s at gmail dot com]

------- Additional Comments From halesh dot s at gmail dot com  2008-06-27 07:22 -------
(In reply to comment #2)
> Created an attachment (id=2802)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=2802&action=view)
> Patch for the pututline() for fcntl() lock time out
> 
> 
> After applaying the attached patch..
> 
> who o/p Before Executing tests
> ==============================
> $who ./utmp
> chill	 tty1	      May 15 18:53
> halesh	 pts/4	      Jun 20 13:00 (43.88.101.161)
> 
> 
> who o/p After executing tests
> =============================
> $who ./utmp
> chill	 tty1	      May 15 18:53
> halesh	 pts/4	      Jun 20 13:00 

Last part of who(1) o/p of second entry got missed while copying in text box...

 who o/p After Executing tests
 ==============================
 $who ./utmp
 chill	 tty1	      May 15 18:53
 halesh	 pts/4	      Jun 20 13:00 (43.88.101.161)

> 
> I have tested regression tests for adding new entry and replacing entries 
using
> pututline() with patch and wroking fine.



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[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[halesh dot s at gmail dot com]

------- Additional Comments From halesh dot s at gmail dot com  2008-06-27 07:13 -------
Created an attachment (id=2802)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=2802&action=view)
Patch for the pututline() for fcntl() lock time out


After applaying the attached patch..

who o/p Before Executing tests
==============================
$who ./utmp
chill	 tty1	      May 15 18:53
halesh	 pts/4	      Jun 20 13:00 (43.88.101.161)


who o/p After executing tests
=============================
$who ./utmp
chill	 tty1	      May 15 18:53
halesh	 pts/4	      Jun 20 13:00 

I have tested regression tests for adding new entry and replacing entries using
pututline() with patch and wroking fine.

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[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[halesh dot s at gmail dot com]

------- Additional Comments From halesh dot s at gmail dot com  2008-06-26 07:01 -------
Created an attachment (id=2800)
 --> (http://sourceware.org/bugzilla/attachment.cgi?id=2800&action=view)
pututline() currupts the utmp file on fcntl() lock time out


In some scenarios pututline (3) may corrupt the utmp like with heavy system
load environment and using pututline frequently.

The failure analysis is in login/utmp_file.c internal_getut_r() function is not
retaining the  lock error because of fcntl() failure so, pututline() is failing
to differentiate between utline not exists and utmp lock time out. As its
returning -1 in both cases. In both cases it treats as utline not found it
appends at the last.

Copy /var/run/utmp to current directory where you are executing tests.

who o/p Before Executing tests
==============================

$ who ./utmp
chill	 tty1	      May 15 18:53
halesh	 pts/2	      Jun 20 12:28
halesh	 pts/4	      Jun 20 13:00

who o/p After executing tests
=============================

$ who ./utmp
chill	 tty1	      May 15 18:53
halesh	 pts/2	      Jun 20 12:28
halesh	 pts/4	      Jun 20 13:00
chill	 tty1	      May 15 18:53     <- ** THE FIRST LOGIN HAS BEEN APPENDED.


**utmp got currupted becuase of adding firstlogin entry again at the last
instead of replacing it.

If you are not able to reproduce please increase the LOOP macro in testcase. 


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[Bug libc/6634] pututline_file() corrupts utmp file when internal_getut_r() returns -1 due to LOCK_FILE timeout.

[garyhade at us dot ibm dot com]

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----------------------------------------------------------------------------
                 CC|                            |garyhade at us dot ibm dot
                   |                            |com


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