Revision e6838a29ecb484c97e4efef9429643b9851fba6e authored by J. Bruce Fields on 21 April 2017, 20:10:18 UTC, committed by J. Bruce Fields on 25 April 2017, 20:34:37 UTC
A client can append random data to the end of an NFSv2 or NFSv3 RPC call
without our complaining; we'll just stop parsing at the end of the
expected data and ignore the rest.

Encoded arguments and replies are stored together in an array of pages,
and if a call is too large it could leave inadequate space for the
reply.  This is normally OK because NFS RPC's typically have either
short arguments and long replies (like READ) or long arguments and short
replies (like WRITE).  But a client that sends an incorrectly long reply
can violate those assumptions.  This was observed to cause crashes.

Also, several operations increment rq_next_page in the decode routine
before checking the argument size, which can leave rq_next_page pointing
well past the end of the page array, causing trouble later in
svc_free_pages.

So, following a suggestion from Neil Brown, add a central check to
enforce our expectation that no NFSv2/v3 call has both a large call and
a large reply.

As followup we may also want to rewrite the encoding routines to check
more carefully that they aren't running off the end of the page array.

We may also consider rejecting calls that have any extra garbage
appended.  That would be safer, and within our rights by spec, but given
the age of our server and the NFS protocol, and the fact that we've
never enforced this before, we may need to balance that against the
possibility of breaking some oddball client.

Reported-by: Tuomas Haanpää <thaan@synopsys.com>
Reported-by: Ari Kauppi <ari@synopsys.com>
Cc: stable@vger.kernel.org
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
1 parent 5a7ad11
Raw File
bt8xxgpio.txt
===============================================================
==  BT8XXGPIO driver                                         ==
==                                                           ==
==  A driver for a selfmade cheap BT8xx based PCI GPIO-card  ==
==                                                           ==
==  For advanced documentation, see                          ==
==  http://www.bu3sch.de/btgpio.php                          ==
===============================================================


A generic digital 24-port PCI GPIO card can be built out of an ordinary
Brooktree bt848, bt849, bt878 or bt879 based analog TV tuner card. The
Brooktree chip is used in old analog Hauppauge WinTV PCI cards. You can easily
find them used for low prices on the net.

The bt8xx chip does have 24 digital GPIO ports.
These ports are accessible via 24 pins on the SMD chip package.


==============================================
==  How to physically access the GPIO pins  ==
==============================================

The are several ways to access these pins. One might unsolder the whole chip
and put it on a custom PCI board, or one might only unsolder each individual
GPIO pin and solder that to some tiny wire. As the chip package really is tiny
there are some advanced soldering skills needed in any case.

The physical pinouts are drawn in the following ASCII art.
The GPIO pins are marked with G00-G23

                                           G G G G G G G G G G G G     G G G G G G
                                           0 0 0 0 0 0 0 0 0 0 1 1     1 1 1 1 1 1
                                           0 1 2 3 4 5 6 7 8 9 0 1     2 3 4 5 6 7
           | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
           ---------------------------------------------------------------------------
         --|                               ^                                     ^   |--
         --|                               pin 86                           pin 67   |--
         --|                                                                         |--
         --|                                                               pin 61 >  |-- G18
         --|                                                                         |-- G19
         --|                                                                         |-- G20
         --|                                                                         |-- G21
         --|                                                                         |-- G22
         --|                                                               pin 56 >  |-- G23
         --|                                                                         |--
         --|                           Brooktree 878/879                             |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|                                                                         |--
         --|   O                                                                     |--
         --|                                                                         |--
           ---------------------------------------------------------------------------
           | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
           ^
           This is pin 1

back to top