bootconfig: Add bootconfig magic word for indicating bootconfig explicitly
Add bootconfig magic word to the end of bootconfig on initrd
image for indicating explicitly the bootconfig is there.
Also tools/bootconfig treats wrong size or wrong checksum or
parse error as an error, because if there is a bootconfig magic
word, there must be a bootconfig.
The bootconfig magic word is "#BOOTCONFIG\n", 12 bytes word.
Thus the block image of the initrd file with bootconfig is
as follows.
[Initrd][bootconfig][size][csum][#BOOTCONFIG\n]
Link: http://lkml.kernel.org/r/158220112263.26565.3944814205960612841.stgit@devnote2
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/init/main.c b/init/main.c
index d96cc5f..2fe8dec 100644
--- a/init/main.c
+++ b/init/main.c
@@ -374,7 +374,11 @@ static void __init setup_boot_config(const char *cmdline)
if (!initrd_end)
goto not_found;
- hdr = (u32 *)(initrd_end - 8);
+ data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
+ if (memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
+ goto not_found;
+
+ hdr = (u32 *)(data - 8);
size = hdr[0];
csum = hdr[1];