CVE-2021-47288

In the Linux kernel, the following vulnerability has been resolved: 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().