[Sun] Schwachstelle im Cassini Gigabit-Ethernet Treiber - Sun Alert ID 257008

19.06.2009 11:02

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Sun Bug ID 6803523 - Schwachstelle im Cassini Gigabit-Ethernet Treiber
bei der Verarbeitung von Jumbo-Frames

Im Solaris Cassini Gigabit-Ethernet Treiber (ce(7D)) werden Jumbo
Frames nicht korrekt verarbeitet, wenn die Pruefsummenverifikation in
der Hardware durchgefuehrt wird. Ein Angreifer kann diese
Schwachstelle ueber das Netzwerk dazu ausnutzen, eine Kernel-Panic
auszuloesen (Denial of Service), indem er entsprechend aufgebaute
Jumbo-Frames an das System sendet.

Die Existenz der Schwachstelle koennen Sie wie folgt erkennen:

Um festzustellen, ob Jumbo Frames und Hardware Checksumming fuer eine
Cassini Karte aktiviert sind, benutzen Sie fuer jede Cassini Karte die
folgenden Kommandos:

# ndd -set /dev/ce instance 0
# ndd -get /dev/ce accept_jumbo

Ein Rueckgabewert von 1 zeigt an, dasx die Verarbeitung von Jumbo
Frames aktiviert ist.

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

Ein Rueckgabewert von 1 zeigt an, das Hardware Checksumming aktiviert
ist.

Falls die Schwachstelle ausgenutzt wurde, zeigt sich ein Stack-Trace
aehnlich dem folgenden:

panic[cpu3]/thread=2a10423dca0: BAD TRAP: type=31 rp=2a10423d360
addr=3002e530000 mmu_fsr=0
ip_ocsum_long+0xe4()
bcksum()
ip_tcp_input+0x448()
ip_input+0xa68()
ip_rput()
putnext+0x218()
ce_intr+0x764c()
pci_intr_wrapper+0xb8()
intr_thread+0x168()
ktl0+0x48()
ip_ocsum_long+0xe4()
bcksum()
ip_tcp_input+0x448()
ip_input+0xa68()
ip_rput()
putnext+0x218()
ce_drain_fifo+0x57e4()
thread_start+0x4()


Betroffen sind die folgenden Software Pakete und Plattformen:

Solaris 10
OpenSolaris

SPARC Plattform
* Solaris 10 ohne Patch 141414-01
* OpenSolaris basierend auf den Builds snv_01 bis snv_82, und snv_111
bis snv_117

x86 Plattform
* Solaris 10 ohne Patch 141415-01
* OpenSolaris basierend auf den Builds snv_01 bis snv_82, und snv_111
bis snv_117

Vom Hersteller werden ueberarbeitete Pakete zur Verfuegung gestellt.

Weiterhin existieren Workarounds:

Deaktivieren Sie Hardware Checksumming indem Sie die folgende Zeile in
/etc/system einfuegen und das System rebooten:

set ip:dohwcksum = 0


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


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Solution Type Sun Alert
Solution 257008 : Security Vulnerability with the Solaris TCP/IP
Networking Stack Involving the Cassini Gigabit-Ethernet Device Driver
and Jumbo Frames
Related Categories

* Home>Content>Sun Alert Criteria Categories>Security
* Home>Content>Sun Alert Release Phase>Resolved

Bug ID
6803523


Product
Solaris 10 Operating System
OpenSolaris


Date of Resolved Release
18-Jun-2009


SA Document Body
A security vulnerability with the Solaris TCP/IP networking stack involving the
Cassini Gigabit-Ethernet Device Driver (ce(7D)) and jumbo frames:

1. Impact
A security vulnerability with the Solaris TCP/IP 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.
2. Contributing Factors
This issue can occur in the following releases:
SPARC Platform
* Solaris 10 without patch 141414-01
* OpenSolaris based upon builds snv_01 through snv_82, and snv_111
through snv_117

x86 Platform
* Solaris 10 without patch 141415-01
* OpenSolaris based upon builds snv_01 through snv_82, and snv_111
through snv_117

Note 1: Solaris 8 and Solaris 9 are not impacted by this issue.
Note 2: 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 hardware checksumming is
enabled.
To determine if there are any active CE interfaces present on a system,
run the following command:
# /sbin/ifconfig -a | /bin/grep ^ce
ce0: flags=1001000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4,FIXEDMTU> mtu 150
0 index 2
ce1: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> 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 0
# 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" | 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" | 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.
Note 5: 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


3. Symptoms
If the described issue occurs, the system will panic with a BAD TRAP
type 31, and the stack trace will be similar to one of the following:
panic[cpu3]/thread=2a10423dca0: BAD TRAP: type=31 rp=2a10423d360 addr=3002e
530000 mmu_fsr=0
ip_ocsum_long+0xe4()
bcksum()
ip_tcp_input+0x448()
ip_input+0xa68()
ip_rput()
putnext+0x218()
ce_intr+0x764c()
pci_intr_wrapper+0xb8()
intr_thread+0x168()
ktl0+0x48()
ip_ocsum_long+0xe4()
bcksum()
ip_tcp_input+0x448()
ip_input+0xa68()
ip_rput()
putnext+0x218()
ce_drain_fifo+0x57e4()
thread_start+0x4()

4. Workaround
There are two possible workarounds for this issue:
1. Disable hardware checksumming by putting the following line in
"/etc/system" and rebooting the system:
set ip:dohwcksum = 0

2. Prevent the network from sending jumbo frames to this host by
disabling jumbo frames on the entire subnet.
Note: These workarounds may impact system performance.
5. Resolution
This issue is addressed in the following releases:
SPARC Platform
* Solaris 10 with patch 141414-01 or later
* OpenSolaris based upon builds snv_118 or later

x86 Platform
* Solaris 10 with patch 141415-01 or later
* OpenSolaris based upon builds snv_118 or later

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