Bug 4545 - rpc.mountd denial of service
rpc.mountd denial of service
Status: CLOSED CURRENTRELEASE
Product: Red Hat Linux
Classification: Retired
Component: nfs-server (Show other bugs)
5.2
i386 Linux
medium Severity medium
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Assigned To: David Lawrence
: Security
Depends On:
Blocks:
  Show dependency treegraph
 
Reported: 1999-08-16 12:04 EDT by ncb
Modified: 2008-05-01 11:37 EDT (History)
0 users

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Fixed In Version:
Doc Type: Bug Fix
Doc Text:
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Clone Of:
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Last Closed: 1999-08-26 18:57:33 EDT
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RHEL 7.3 requirements from Atomic Host:
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Description ncb 1999-08-16 12:04:07 EDT
nfs-server-2.2beta44 on Redhat 5.2, with kernel 2.2.9.

My /etc/exports looks like this:
/hj4    @all-cc(rw)

We've got some hosts that are not in the all-cc netgroup,
and should be denied access to /hj4.  rpc.mountd does deny
the mount to these systems, but suffers a SIGSEGV in the
process.

After inspecting auth.c:auth_unknown_clientbyaddr() this
behavior seems not to be strictly a YP problem, but rather
any unauthorized host requesting services from mountd.

Here is a (quite simple) patch:

*** nfs-server-2.2beta43/auth.c.OLD     Sat Aug 14 21:39:56
1999
--- nfs-server-2.2beta43/auth.c Sat Aug 14 21:40:18 1999
***************
*** 479,485 ****
                auth_add_mountlist(ncp, cp->m, 0);
        }

!       auth_sort_mountlist(ncp->m);
        return ncp;
  }

--- 479,485 ----
                auth_add_mountlist(ncp, cp->m, 0);
        }

!       if(ncp) auth_sort_mountlist(ncp->m);
        return ncp;
  }




------
Neil Bright
Computing and Networking Services
College of Computing
Georgia Institute of Technology
Comment 1 ncb 1999-08-19 14:33:59 EDT
Sorry, forgot to mention this isn't a problem with knfsd in 6.0.
Comment 2 Jeff Johnson 1999-08-26 18:57:59 EDT
Fixed in nfs-server-2.2beta44-2. Thanks for the patch.

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