Files
system76-coreboot/payloads/libpayload
Julius Werner 7124788b33 libpayload: usbmsc: Set correct allocation length for REQUEST SENSE
So I was debugging this faulty USB SD card reader that would just fail
it's REQUEST SENSE response for some reason (sending the CSW immediately
without the data), cursing those damn device vendors for building
non-compliant crap like I always do... when I noticed that we do not
actually set the Allocation Length field in our REQUEST SENSE command
block at all! We set a length in the CBW, but the SCSI command still has
its own length field and the SCSI spec specifically says that the device
has to return the exact amount of bytes listed there (even if it's 0). I
don't know what's more suprising: that we had such a blatant bug in this
stack for so long, or that this card reader is really the first device
to actually be spec compliant in that regard.

This patch fixes the bug and changes the command block structures to be
a little easier to read (why that field was called 'lun' before is
beyond me... LUN is a transport level thing and should never appear in
the command block at all, for any command). It also fixes a memcpy() in
wrap_cbw() to avoid a read buffer overflow that might expose stack frame
data to the device.

BRANCH=rambi?,nyan
BUG=chrome-os-partner:28437
TEST=The card reader works now (for it's first LUN at least).

Original-Change-Id: I86fdcae2ea4d2e2939e3676d31d8b6a4e797873b
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/198100
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
(cherry picked from commit 88943d9715994a14c50e74170f2453cceca0983b)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I3097c223248c07c866a33d4ab8f3db1a7082a815
Reviewed-on: http://review.coreboot.org/7903
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
2014-12-30 19:00:38 +01:00
..
2014-09-08 18:59:23 +02:00
2014-11-13 06:22:25 +01:00
2014-08-10 22:25:07 +02:00
2012-04-04 00:40:31 +02:00

-------------------------------------------------------------------------------
libpayload README
-------------------------------------------------------------------------------

libpayload is a minimal library to support standalone payloads
that can be booted with firmware like coreboot. It handles the setup
code, and provides common C library symbols such as malloc() and printf().

Note: This is _not_ a standard library for use with an operating system,
rather it's only useful for coreboot payload development!
See http://coreboot.org for details on coreboot.


Installation
------------

 $ git clone http://review.coreboot.org/p/coreboot.git

 $ cd coreboot/payloads/libpayload

 $ make menuconfig

 $ make

 $ sudo make install (optional, will install into /opt per default)

As libpayload is for 32bit x86 systems only, you might have to install the
32bit libgcc version, otherwise your payloads will fail to compile.
On Debian systems you'd do 'apt-get install gcc-multilib' for example.


Usage
-----

Here's an example of a very simple payload (hello.c) and how to build it:

 #include <libpayload.h>

 int main(void)
 {
     printf("Hello, world!\n");
     return 0;
 }

Building the payload using the 'lpgcc' compiler wrapper:

 $ lpgcc -o hello.elf hello.c

Please see the sample/ directory for details.


Website and Mailing List
------------------------

The main website is http://www.coreboot.org/Libpayload.

For additional information, patches, and discussions, please join the
coreboot mailing list at http://coreboot.org/Mailinglist, where most
libpayload developers are subscribed.


Copyright and License
---------------------

See LICENSES.