Bug Id
SUNBUG: 6857395

Product
Solaris 10 Operating System
OpenSolaris

Date of Resolved Release
02-Sep-2009

Security Vulnerability with the Solaris IPv6 Networking Stack :

1. Impact

A security vulnerability with the Solaris IPv6 networking stack involving the
Cassini Gigabit-Ethernet Device Driver (ce(7D)) and jumbo frames may allow
a remote user to panic the system. This is a type of Denial of Service (DoS) condition.

Note: A similar issue exists for systems using IPv4 networking. See Sun Alert 257008 for details:

            http://sunsolve.sun.com/search/document.do?assetkey=1-66-257008-1

2. Contributing Factors

This issue can occur in the following releases:

SPARC platform

• Solaris 10 without patch 141414-10
• OpenSolaris based upon builds snv_01 through snv_82, and snv_111 through snv_123
  

x86 platform

• Solaris 10 without patch 141415-10
• OpenSolaris based upon builds snv_01 through snv_82, and snv_111 through snv_123
  

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

A system is only vulnerable to this issue if it is using a GigaSwift Ethernet Adapter (CE)
interface (ce(7D)) which has been configured to accept jumbo frames and
is configured for IPv6 and hardware checksumming is enabled.

To determine if there are any active CE interfaces present on a system,
run the following command:

	$ /sbin/ifconfig -a inet6 | /bin/grep ^ce
	ce1: flags=2004841<UP,RUNNING,MULTICAST,DHCP,IPv6> mtu 9194 index 3

To determine if jumbo frames are in use on a CE interface, use the following ndd commands:

	 # ndd -set /dev/ce instance 1
	 # ndd -get /dev/ce accept_jumbo
	 1

The above two commands must be repeated for each CE interface present on
the system (adjusting the instance number in the first command accordingly).

The file /kernel/drv/ce.conf may also include the accept_jumbo=1
directive, either globally or for a subset of interfaces, but the above
ndd commands will give the current state of the running interfaces.

To determine whether hardware checksumming is enabled, run the following
command as root:

	# echo "dohwcksum/X" | /usr/bin/mdb -k
	dohwcksum:
	dohwcksum:      1      

A value of 1 indicates that hardware checksumming is enabled (default value).
A value of 0 indicates hardware checksumming is disabled.

Note 3: Some third party storage systems have been seen to generate
jumbo ethernet packets which may trigger this issue and cause the
Solaris system to panic.

Note 4: The use of the kernel memory debugging facility 'kmem_flags'
will greatly increase the likelihood of a panic. To determine if
kmem_flags is set, run the following command as root:

	# echo "kmem_flags/X" | /usr/bin/mdb -k
	kmem_flags:
	kmem_flags:     0             

A value of zero indicates kmem_flags is not set. Any other value
indicates one or more of the kmem debugging facilities is active.

3. Symptoms

If the described issue occurs, the system will panic with a BAD TRAP
type 31, and a stack trace similar to the following:

	panic[cpu0]/thread=2a1008a1ca0: BAD TRAP: type=31 rp=2a1008a1270 
	addr=310cf2e6000 mmu_fsr=0

	bcksum+20 ()
	ip_rput_data_v6+1238 ()
 	ip_rput_v6+870 ()
 	putnext+208 ()

4. Relief/Workaround

There are two possible workarounds known at this time.

Workaround A:
Disable hardware checksumming. To do this, place the following line
in /etc/system and reboot:

     set ip:dohwcksum = 0

Note: This may impact performance.

Workaround B:
Prevent the network from sending jumbo frames to this host by disabling jumbo frames on the entire subnet.

Note: This may impact performance.

5. Resolution

This issue is addressed in the following releases:

SPARC Platform

• Solaris 10 with patch 141414-10 or later
• OpenSolaris based upon build snv_124 or later
  

x86 platform

• Solaris 10 with patch 141415-10 or later
• OpenSolaris based upon build snv_124 or later
  

5. Modification History

16-Jun-2010: Minor update to remove incorrect link for SunBug

For more information on Security Sun Alerts, see

References

SUNPATCH:141414-10
SUNPATCH:141415-10



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