Security Vulnerability in Solaris sockfs Related to HTTP Request Handling May Allow Remote Users to Panic Web Servers Resulting in a Denial of Service (DoS)

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A security vulnerability in the Solaris sockfs kernel module:

1. Impact

A security vulnerability in the Solaris sockfs kernel module may allow a local or remote unprivileged HTTP client to panic a vulnerable Solaris web server thereby resulting in a Denial of Service (DoS) to the system as a whole.

2. Contributing Factors

This issue can occur in the following releases:

SPARC Platform

• Solaris 10 with patch 118833-25 or later and without patch 141690-02
• OpenSolaris based upon builds snv_41 through snv_122

x86 Platform

• Solaris 10 with patch 118855-25  or later and without patch 141691-02
• OpenSolaris based upon builds snv_41 through snv_122
  

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

Note 2: This issue only occurs if a system is configured as an HTTP server utilizing the Solaris Network Cache Accelerator (nca(1)) and has logging enabled.  To determine if NCA is enabled on the system, execute the following command:

    $ grep status=enabled /etc/nca/ncakmod.conf
    status=enabled

Please reference ncakmod.conf(4) for more information on configuring the NCA kernel module.

Physical interfaces registered to use the NCA feature are listed in the "/etc/nca/nca.if" file:

    $ cat /etc/nca/nca.if
    hme0
    hme1

Please reference nca.if(4) for more information on specifying the physical interfaces for NCA.

To determine if NCA logging is enabled, execute the following command:

    $ grep status=enabled /etc/nca/ncalogd.conf
    status=enabled

Note 3: 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_111

3. Symptoms

If the described issue occurs, the system will panic with a NULL pointer dereference on nl7c_http_log. The stack trace will be similar to the following:

   nl7c_http_log+0x9a()
   nl7c_logd_log+0x16f()
   nl7c_parse+0x49f()
   nl7c_process+0x141()
   sotpi_recvmsg+0x618()
   socktpi_read+0x84()
   fop_read+0x31()
   read+0x188()
   read32+0xe()
   _sys_sysenter_post_swapgs+0x14b()

4. Workaround

To work around the described issue until patches can be installed, disable logging of NCA by setting "status=disabled" in "/etc/nca/ncalogd.conf". Please refer to ncalogd.conf(4) for details.

A system reboot is required for the change to be effective. Please refer to reboot(1M) for more details.

5. Resolution

This issue is addressed in the following releases:

SPARC Platform

• Solaris 10 with patch 141690-02 or later
• OpenSolaris based upon builds snv_123 or later
  

x86 Platform

• Solaris 10 with patch 141691-02 or later
• OpenSolaris based upon builds snv_123 or later

For more information on Security Sun Alerts, see Technical Instruction ID 213557.

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Modification History

26-Aug-2009: Updated Contributing Factors and Resolution sections. Updated document release phase to Workaround.

10-Sep-2009: Updated the Contributing Factors and Resolution sections. Resolved.

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