init/main.c: Fix potential static_command_line memory overflow

init/main.c: Fix potential static_command_line memory overflow

commit 46dad3c1e57897ab9228332f03e1c14798d2d3b9 upstream.

We allocate memory of size 'xlen + strlen(boot_command_line) + 1' for
static_command_line, but the strings copied into static_command_line are
extra_command_line and command_line, rather than extra_command_line and
boot_command_line.

When strlen(command_line) > strlen(boot_command_line), static_command_line
will overflow.

This patch just recovers strlen(command_line) which was miss-consolidated
with strlen(boot_command_line) in the commit f5c7310ac73e ("init/main: add
checks for the return value of memblock_alloc*()")

Link: https://lore.kernel.org/all/20240412081733.35925-2-ytcoode@gmail.com/
Fixes: f5c7310ac73e ("init/main: add checks for the return value of memblock_alloc*()")
Cc: stable@vger.kernel.org
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>