coreboot-kgpe-d16/payloads/libpayload
Julius Werner 182fea717e libpayload: usbmsc: Skip zero-length packets at end of data
Some broken USB mass storage devices send another zero-length packet at
the end of the data part of a transfer if the amount of data was evenly
divisible by the packet size (which is pretty much always the case for
block reads). This packet will get interpreted as the CSW and screw up
the MSC state machine.

This patch works around this issue by retrying the CSW transfer when it
was received as exactly 0 bytes. This is the same mitigation the Linux
kernel uses and harmless for correctly behaving devices. Also tighten
validation of the CSW a little, making sure we verify the length before
we read any fields and checking the signature in addition to the tag.

Change-Id: I24f183f27b2c4f0142ba6c4b35b490c5798d0d21
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34485
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2019-08-22 10:36:48 +00:00
..
arch libpayload: Align main() data types 2019-04-05 22:37:19 +00:00
bin libpayload: Move base address, stack and heap size to Kconfig 2016-03-15 20:53:38 +01:00
configs payloads/libpayload: Update a Makefile for sample libpayload 2019-06-21 09:16:36 +00:00
crypto payloads: Replace all IS_ENABLED(CONFIG_XXX) with CONFIG(XXX) 2019-03-07 17:15:30 +00:00
curses libpayload: Enable -Wimplicit-fallthrough 2019-07-21 17:17:42 +00:00
drivers libpayload: usbmsc: Skip zero-length packets at end of data 2019-08-22 10:36:48 +00:00
gdb libpayload: gdb: Factor out gdb_handle_reentrant_exception() from arm32 2018-10-12 20:17:40 +00:00
include Add buffer_to/from_fifo32(_prefix) helpers 2019-08-22 10:36:22 +00:00
libc Add buffer_to/from_fifo32(_prefix) helpers 2019-08-22 10:36:22 +00:00
libcbfs payloads: Replace all IS_ENABLED(CONFIG_XXX) with CONFIG(XXX) 2019-03-07 17:15:30 +00:00
liblz4 Rename __attribute__((packed)) --> __packed 2017-07-13 19:45:59 +00:00
liblzma libpayload: lzma: Allocate scratchpad on the heap 2016-08-08 19:02:07 +02:00
libpci libpayload: Add pci_free_dev() and some boilerplate 2017-12-07 21:51:24 +00:00
sample payloads/libpayload: Update a Makefile for sample libpayload 2019-06-21 09:16:36 +00:00
tests
Doxyfile payloads: Remove/fix trailing whitespace 2018-09-04 12:38:40 +00:00
Kconfig libpayload: Add UART for qcs405 2019-06-04 14:14:58 +00:00
LICENSES libpayload: Add LZ4 decompression algorithm 2015-07-09 00:10:16 +02:00
LICENSE_GPL
Makefile libpayload: Make libpayload compile using gnu11 2018-07-16 07:44:03 +00:00
Makefile.inc Makefile.inc, payloads: Enable -Wvla 2019-08-20 20:57:01 +00:00
README payloads/libpayload: Update a Makefile for sample libpayload 2019-06-21 09:16:36 +00:00

README

-------------------------------------------------------------------------------
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 https://www.coreboot.org for details on coreboot.


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

 $ git clone https://review.coreboot.org/coreboot.git

 $ cd coreboot/payloads/libpayload

 $ make menuconfig

 $ make

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

On x86 systems, libpayload will always be 32-bit even if your host OS runs
in 64-bit, so you might have to install the 32-bit libgcc version.
On Debian systems you'd do 'apt-get install gcc-multilib' for example.

Run 'make distclean' before switching boards. This command will remove
your current .config file, so you need 'make menuconfig' again or
'make defconfig' in order to set up configuration. Default configuration
is based on 'configs/defconfig'. See the configs/ directory for examples
of configuration.


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 https://www.coreboot.org/Libpayload.

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


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

See LICENSES.