[Bug 997096] Re: nscd segmentation fault

Tue Oct 22 10:45:29 UTC 2013

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On 2013-05-12T19:28:28+00:00 Twild wrote:

nscd[2320]: segfault at 0 ip 00007f911bd87741 sp 00007f910e202188 error
4 in libc-2.17.so[7f911bc38000+1a3000]

I get frequently the error in syslog files:

nscd[2320]: segfault at 0 ip 00007f911bd87741 sp 00007f910e202188 error
4 in libc-2.17.so

fortunately the systemd re-spawns the nscd immediately. After my quick
core dump analysis I'm quite sure that the problem comes from:

glibc-2.17-4.4.1, nscd netgroupcache.c in line 205:

size_t userlen = strlen (nuser) + 1; <------ core dump

because nuser in the triple code is 0 in case of (host,,) entries in
NIS! This may causes the core dump.

I found two work arounds to avoid a nscd crash:

1.) switch off netgroup in nscd.conf 
        enable-cache netgroup yes -> no
or

2.) in NIS change entries in netgroup 
        (host,,) -> (host,-,<youdomain>

regards Thomas

Reply at:
https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/997096/comments/10

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On 2013-07-04T15:03:19+00:00 E-kuemmerle wrote:

I can confirm that bug, I observe exactly the same segfaults on my
server:

(gdb) where
#0  0x00007f32fd360741 in __strlen_sse2_pminub () from /lib64/libc.so.6
#1  0x00007f32fde513cd in addgetnetgrentX (db=db at entry=0x7f32fe059640 <dbs+1440>, 
    fd=fd at entry=-1, req=req at entry=0x7f32f19977a0, 
    key=key at entry=0x7f32f19979e0 "asslgc", uid=uid at entry=4294967295, he=he at entry=0x0, 
    dh=dh at entry=0x0, resultp=resultp at entry=0x7f32f1997798) at netgroupcache.c:205
#2  0x00007f32fde51eb5 in addinnetgrX (db=db at entry=0x7f32fe059640 <dbs+1440>, 
    fd=fd at entry=15, req=req at entry=0x7f32f1997860, key=<optimized out>, 
    key at entry=0x7f32f19979e0 "asslgc", uid=uid at entry=4294967295, he=he at entry=0x0, 
    dh=dh at entry=0x0) at netgroupcache.c:487
#3  0x00007f32fde52074 in addinnetgr (db=db at entry=0x7f32fe059640 <dbs+1440>, 
    fd=fd at entry=15, req=req at entry=0x7f32f1997860, key=key at entry=0x7f32f19979e0, 
    uid=uid at entry=4294967295) at netgroupcache.c:652
#4  0x00007f32fde3ed36 in handle_request (pid=<optimized out>, key=0x7f32f19979e0, 
    req=0x7f32f1997860, fd=15, uid=<optimized out>) at connections.c:1326
#5  nscd_run_worker (p=<optimized out>) at connections.c:1792
#6  0x00007f32fd9fde0f in start_thread () from /lib64/libpthread.so.0
#7  0x00007f32fd2f97dd in clone () from /lib64/libc.so.6

(gdb) print data.val.triple
$3 = {host = 0x7f32f19971c8 "ass801", user = 0x0, domain = 0x0}

Reply at:
https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/997096/comments/11

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On 2013-09-30T16:05:48+00:00 Swamp-a wrote:

openSUSE-SU-2013:1510-1: An update that solves 6 vulnerabilities and has
5 fixes is now available.

Category: security (moderate)
Bug References: 779320,801246,805054,813121,813306,819383,819524,824046,830257,834594,839870
CVE References: CVE-2012-4412,CVE-2013-0242,CVE-2013-1914,CVE-2013-2207,CVE-2013-4237,CVE-2013-4332
Sources used:
openSUSE 12.3 (src):    glibc-2.17-4.7.1, glibc-testsuite-2.17-4.7.2, glibc-testsuite-2.17-4.7.3, glibc-utils-2.17-4.7.1

Reply at:
https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/997096/comments/12

------------------------------------------------------------------------
On 2013-10-01T06:49:23+00:00 Schwab-5 wrote:

Fixed.

Reply at:
https://bugs.launchpad.net/ubuntu/+source/eglibc/+bug/997096/comments/13

** Changed in: eglibc (openSUSE)
       Status: Unknown => Fix Released

** Changed in: eglibc (openSUSE)
   Importance: Unknown => Low

** CVE added: http://www.cve.mitre.org/cgi-
bin/cvename.cgi?name=2012-4412

** CVE added: http://www.cve.mitre.org/cgi-
bin/cvename.cgi?name=2013-0242

** CVE added: http://www.cve.mitre.org/cgi-
bin/cvename.cgi?name=2013-1914

** CVE added: http://www.cve.mitre.org/cgi-
bin/cvename.cgi?name=2013-2207

** CVE added: http://www.cve.mitre.org/cgi-
bin/cvename.cgi?name=2013-4237

** CVE added: http://www.cve.mitre.org/cgi-
bin/cvename.cgi?name=2013-4332

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https://bugs.launchpad.net/bugs/997096

Title:
  nscd segmentation fault

Status in “eglibc” package in Ubuntu:
  Confirmed
Status in “eglibc” package in openSUSE:
  Fix Released

Bug description:
  nscd segfaults a few seconds after every getent netgroup requests:

  root at cmo-cluster2:~# nscd -d 
  Wed 09 May 2012 12:59:54 PM UTC - 13953: register trace file /etc/passwd for database passwd
  Wed 09 May 2012 12:59:54 PM UTC - 13953: register trace file /etc/group for database group
  Wed 09 May 2012 12:59:54 PM UTC - 13953: register trace file /etc/services for database services
  Wed 09 May 2012 12:59:54 PM UTC - 13953: register trace file /etc/netgroup for database netgroup
  Wed 09 May 2012 12:59:54 PM UTC - 13953: cannot stat() file `/etc/netgroup': No such file or directory
  Wed 09 May 2012 12:59:56 PM UTC - 13953: handle_request: request received (Version = 2) from PID 13962
  Wed 09 May 2012 12:59:56 PM UTC - 13953: 	GETFDNETGR
  Wed 09 May 2012 12:59:56 PM UTC - 13953: handle_request: request received (Version = 2) from PID 13962
  Wed 09 May 2012 12:59:56 PM UTC - 13953: 	GETNETGRENT (cmo-nfs-netgroup)
  Wed 09 May 2012 12:59:56 PM UTC - 13953: Haven't found "cmo-nfs-netgroup" in netgroup cache!
  Wed 09 May 2012 12:59:56 PM UTC - 13953: provide access to FD 11, for netgroup
  Segmentation fault (core dumped)

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