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Vadim Bendebury bc927107a0 tpm2: avoid comparison between signed and unsigned ints
The marshaling/unmarshaling code is using integer values to represent
room left in the buffer, to be able to communicate three conditions:
positive number means there is room left in the buffer, zero means
that the exact amount of data in the buffer was unmarshaled and
negative value means that the result of the operation did not fit into
the buffer.

The implementation is wrong though, as it compares directly signed and
unsigned values, which is illegal, as signed values get promoted to
unsigned by the compiler.

This patch changes the marshaling code to use size_t for the size, and
use zero as marshaling failure indication - after all the buffer where
the data is marshaled to should definitely be large enough, and it is
reasonable to expect at least some room left in it after marshaling.

The unmarshaling situation is different: we sure want to communicate
errors to the caller, but do not want to propagate error return values
through multiple layers. This patch keeps the size value in int, but
checks if it is negative separately, before comparing with positive
values.

BRANCH=none
BUG=chrome-os-partner:50645
TEST=with the rest of the patches applied kevin successfully boots up.

Change-Id: Ibfbd1b351e35e37c8925a78d095e4e8492805bad
Signed-off-by: Martin Roth <martinroth@chromium.org>
Original-Commit-Id: b1e862c2a650fa5f6cb25a01fe61e848a696cf17
Original-Change-Id: Ie7552b333afaff9a1234c948caf9d9a64447b2e1
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/358772
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/15610
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2016-07-13 23:58:32 +02:00
3rdparty 3rdparty/arm-trusted-firmware: Update to Jun 8, 2016 master 2016-06-12 12:14:06 +02:00
Documentation Documentation: Fix doxygen errors 2016-07-12 22:41:02 +02:00
payloads payloads/iPXE: Fix PXE Kconfig question 2016-07-12 19:24:03 +02:00
src tpm2: avoid comparison between signed and unsigned ints 2016-07-13 23:58:32 +02:00
util kconfig: add olddefconfig target to help 2016-07-12 19:23:36 +02:00
.clang-format
.gitignore .gitignore: add build and libpayload dirs for nvramcui payload 2016-05-03 04:16:45 +02:00
.gitmodules git modules: rename git submodules to avoid hierarchies 2016-02-11 20:55:55 +01:00
.gitreview add .gitreview 2012-11-01 23:13:39 +01:00
COPYING
MAINTAINERS MAINTAINERS: Add myself as tpm support maintainer. 2016-07-07 17:04:29 +02:00
Makefile Makefile: Make printall target more readable 2016-06-07 23:31:17 +02:00
Makefile.inc flashmap: Use CONFIG_ROM_SIZE as flash size in flashmap 2016-06-21 17:51:54 +02:00
README
toolchain.inc toolchain.inc: test IASL by version string instead of number 2016-03-04 16:36:25 +01:00

README

-------------------------------------------------------------------------------
coreboot README
-------------------------------------------------------------------------------

coreboot is a Free Software project aimed at replacing the proprietary BIOS
(firmware) found in most computers.  coreboot performs a little bit of
hardware initialization and then executes additional boot logic, called a
payload.

With the separation of hardware initialization and later boot logic,
coreboot can scale from specialized applications that run directly
firmware, run operating systems in flash, load custom
bootloaders, or implement firmware standards, like PC BIOS services or
UEFI. This allows for systems to only include the features necessary
in the target application, reducing the amount of code and flash space
required.

coreboot was formerly known as LinuxBIOS.


Payloads
--------

After the basic initialization of the hardware has been performed, any
desired "payload" can be started by coreboot.

See http://www.coreboot.org/Payloads for a list of supported payloads.


Supported Hardware
------------------

coreboot supports a wide range of chipsets, devices, and mainboards.

For details please consult:

 * http://www.coreboot.org/Supported_Motherboards
 * http://www.coreboot.org/Supported_Chipsets_and_Devices


Build Requirements
------------------

 * make
 * gcc / g++
   Because Linux distribution compilers tend to use lots of patches. coreboot
   does lots of "unusual" things in its build system, some of which break due
   to those patches, sometimes by gcc aborting, sometimes - and that's worse -
   by generating broken object code.
   Two options: use our toolchain (eg. make crosstools-i386) or enable the
   ANY_TOOLCHAIN Kconfig option if you're feeling lucky (no support in this
   case).
 * iasl (for targets with ACPI support)

Optional:

 * doxygen (for generating/viewing documentation)
 * gdb (for better debugging facilities on some targets)
 * ncurses (for 'make menuconfig' and 'make nconfig')
 * flex and bison (for regenerating parsers)


Building coreboot
-----------------

Please consult http://www.coreboot.org/Build_HOWTO for details.


Testing coreboot Without Modifying Your Hardware
------------------------------------------------

If you want to test coreboot without any risks before you really decide
to use it on your hardware, you can use the QEMU system emulator to run
coreboot virtually in QEMU.

Please see http://www.coreboot.org/QEMU for details.


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

Further details on the project, a FAQ, many HOWTOs, news, development
guidelines and more can be found on the coreboot website:

  http://www.coreboot.org

You can contact us directly on the coreboot mailing list:

  http://www.coreboot.org/Mailinglist


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

The copyright on coreboot is owned by quite a large number of individual
developers and companies. Please check the individual source files for details.

coreboot is licensed under the terms of the GNU General Public License (GPL).
Some files are licensed under the "GPL (version 2, or any later version)",
and some files are licensed under the "GPL, version 2". For some parts, which
were derived from other projects, other (GPL-compatible) licenses may apply.
Please check the individual source files for details.

This makes the resulting coreboot images licensed under the GPL, version 2.