coreboot-kgpe-d16/payloads/libpayload
Alex Rebert e5e24107f9 libpayload: cbfs: fix infinite loop in cbfs_get_{handle,attr}
cbfs_get_handle() and cbfs_get_attr() are both looping over elements to
find a particular one. Each element header contains the element's
length, which is used to compute the next element's offset. Invalid or
corrupted CBFS files could lead to infinite loops where the offset would
remain constant across iterations, due to 0-length elements or integer
overflows in the computation of the next offset.

This patch makes both functions more robust by adding a check that
ensure offsets are strictly monotonic. Instead of infinite looping, the
functions are now printing an ERROR and returning a NULL value.

Change-Id: I440e82fa969b8c2aacc5800e7e26450c3b97c74a
Signed-off-by: Alex Rebert <alexandre.rebert@gmail.com>
Found-by: Mayhem
Reviewed-on: https://review.coreboot.org/c/coreboot/+/39177
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
2020-03-02 15:00:24 +00:00
..
arch libpayload: arm64: Keep instruction cache enabled at all times 2020-02-17 15:42:34 +00:00
bin Remove MIPS architecture 2019-11-20 10:10:48 +00:00
configs trogdor: libpayload USB support 2019-12-05 17:57:31 +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 treewide: capitalize 'USB' 2020-02-26 17:06:40 +00:00
gdb libpayload: gdb: Factor out gdb_handle_reentrant_exception() from arm32 2018-10-12 20:17:40 +00:00
include treewide: capitalize 'USB' 2020-02-26 17:06:40 +00:00
libc payloads: Fix typos 2020-02-17 16:01:50 +00:00
libcbfs libpayload: cbfs: fix infinite loop in cbfs_get_{handle,attr} 2020-03-02 15:00:24 +00:00
liblz4
liblzma libpayload: Fix out-of-bounds read 2020-02-24 12:53:25 +00:00
libpci libpayload: Make pci and endian handling -Wconversion safe 2020-02-05 21:48:36 +00:00
sample Remove MIPS architecture 2019-11-20 10:10:48 +00:00
tests
Doxyfile payloads: Remove/fix trailing whitespace 2018-09-04 12:38:40 +00:00
Kconfig libpayload/drivers/i8042: Remove obsolete flag 2019-12-12 22:03:31 +00:00
LICENSES
LICENSE_GPL
Makefile Makefile: Remove romcc 2019-12-27 08:59:59 +00:00
Makefile.inc Remove MIPS architecture 2019-11-20 10:10:48 +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.