Bug Id
6793049

Product
Solaris 10 Operating System
OpenSolaris

Date of Resolved Release
6-Mar-2009

A security vulnerability in NFSv4 Server Kernel Module:

1. Impact

A security vulnerability in the NFSv4 Server Kernel Module may allow a local unprivileged user to hang an NFSv4 server if that server is sharing an hsfs(7FS) file system (CD-ROM, DVD media). This is a type of  Denial of Service (DoS).

2. Contributing Factors

This issue can occur in the following releases:

SPARC Platform

• Solaris 10 without patch 139462-02
  
• OpenSolaris based upon builds snv_01 through snv_110
  

x86 Platform

• Solaris 10 without patch 139463-02
  
• OpenSolaris based upon builds snv_01 through snv_110
  

Note 1: Solaris 8 and Solaris 9 are not impacted by this issue.

Note 2: OpenSolaris distributions may include additional bug fixes above and beyond the build from which it was derived.  To determine the base build of OpenSolaris, the following command can be used:

    $ uname -v
    snv_86

Note 3: This issue only occurs on systems that are configured as a NFSv4 server and share a hsfs(7FS) file system. To determine if a system is configured as a NFSv4 server, the following command can be used:

    # rpcinfo -l localhost nfs 4

    program vers  tp_family/name/class    address             service
    100003  4    inet/tcp/cots_ord       127.0.0.1.8.1        nfs

To determine if a NFSv4 server is sharing a hsfs(7FS) file system, the following command can be used:

    # df -F hsfs `cut -f1 /etc/dfs/sharetab` 2>/dev/null
    /cdrom/s10_software_companion(/vol/dev/dsk/c0t0d0/s10_software_companion): 0 blocks 0 files

3. Symptoms

If the described issue is exploited, the NFSv4 server and possibly the entire system may become unresponsive. This may lead to a system hang on the NFSv4 server.

4. Workaround

If the hsfs(7FS) file system is shared, the NFS server system can be configured not to use NFSv4 by setting "NFS_SERVER_VERSMAX=3" in "/etc/default/nfs". For additional information, please refer to the nfs(4) documentation.

5. Resolution

This issue is addressed in the following releases:

SPARC Platform

• Solaris 10 with patch 139462-02 or later
  
• OpenSolaris based upon builds snv_111 or later
  

x86 Platform

• Solaris 10 with patch 139463-02 or later
  
• OpenSolaris based upon builds snv_111 or later

For more information on Security Sun Alerts, see 1009886.1.

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References

139462-02
139463-02





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