Under CONFIG_FORTIFY_SOURCE=y and CONFIG_UBSAN_BOUNDS=y, Clang is bugged
here for calculating the size of the destination buffer (0x10 instead of
0x14). This copy is a fixed size (sizeof(struct fw_section_info_st)), with
the source and dest being struct fw_section_info_st, so the memcpy should
be safe, assuming the index is within bounds, which is UBSAN_BOUNDS's
responsibility to figure out.

Avoid the whole thing and just do a direct assignment. This results in
no change to the executable code.

[This is a duplicate of commit 2c0ab32b ("hinic: Replace memcpy()
 with direct assignment") which was applied to net-next.]

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: llvm@lists.linux.dev
Link: https://github.com/ClangBuiltLinux/linux/issues/1592Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org> # build
Link: https://lore.kernel.org/r/20220616052312.292861-1-keescook@chromium.orgSigned-off-by: Jakub Kicinski <kuba@kernel.org>