WSL2-Linux-Kernel/drivers/media/pci/ngene
Gustavo A. R. Silva 8d4abca95e media: ngene: Fix out-of-bounds bug in ngene_command_config_free_buf()
Fix an 11-year old bug in ngene_command_config_free_buf() while
addressing the following warnings caught with -Warray-bounds:

arch/alpha/include/asm/string.h:22:16: warning: '__builtin_memcpy' offset [12, 16] from the object at 'com' is out of the bounds of referenced subobject 'config' with type 'unsigned char' at offset 10 [-Warray-bounds]
arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [12, 16] from the object at 'com' is out of the bounds of referenced subobject 'config' with type 'unsigned char' at offset 10 [-Warray-bounds]

The problem is that the original code is trying to copy 6 bytes of
data into a one-byte size member _config_ of the wrong structue
FW_CONFIGURE_BUFFERS, in a single call to memcpy(). This causes a
legitimate compiler warning because memcpy() overruns the length
of &com.cmd.ConfigureBuffers.config. It seems that the right
structure is FW_CONFIGURE_FREE_BUFFERS, instead, because it contains
6 more members apart from the header _hdr_. Also, the name of
the function ngene_command_config_free_buf() suggests that the actual
intention is to ConfigureFreeBuffers, instead of ConfigureBuffers
(which takes place in the function ngene_command_config_buf(), above).

Fix this by enclosing those 6 members of struct FW_CONFIGURE_FREE_BUFFERS
into new struct config, and use &com.cmd.ConfigureFreeBuffers.config as
the destination address, instead of &com.cmd.ConfigureBuffers.config,
when calling memcpy().

This also helps with the ongoing efforts to globally enable
-Warray-bounds and get us closer to being able to tighten the
FORTIFY_SOURCE routines on memcpy().

Link: https://github.com/KSPP/linux/issues/109
Fixes: dae52d009f ("V4L/DVB: ngene: Initial check-in")
Cc: stable@vger.kernel.org
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/linux-hardening/20210420001631.GA45456@embeddedor/
2021-07-19 19:33:46 -05:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile media: prefix header search paths with $(srctree)/ 2019-05-18 11:49:56 +09:00
ngene-cards.c media: ngene: simplify the return expression of eeprom_write_ushort() 2021-03-11 11:59:45 +01:00
ngene-core.c media: ngene: Fix out-of-bounds bug in ngene_command_config_free_buf() 2021-07-19 19:33:46 -05:00
ngene-dvb.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 461 2019-06-19 17:09:09 +02:00
ngene-i2c.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 461 2019-06-19 17:09:09 +02:00
ngene.h media: ngene: Fix out-of-bounds bug in ngene_command_config_free_buf() 2021-07-19 19:33:46 -05:00