[RFC PATCH 1/3] bootconfig: Use hexadecimal ASCII string for size and checksum

Masami Hiramatsu
2020-11-19T14:32:01Z

To make the bootconfig format more platform independent, use
8-bytes hexadecimal ASCII string for size and checksum field
in the footer. This will allow us to apply bootconfig to the
cross build initrd without caring the endianness.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
init/main.c | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/init/main.c b/init/main.c
index 20baced721ad..b82f23cff709 100644
--- a/init/main.c
+++ b/init/main.c
@@ -267,8 +267,8 @@ early_param("loglevel", loglevel);
static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
{
u32 size, csum;
+ char buf[9];
char *data;
- u32 *hdr;
int i;

if (!initrd_end)
@@ -287,11 +287,21 @@ static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
return NULL;

found:
- hdr = (u32 *)(data - 8);
- size = hdr[0];
- csum = hdr[1];
+ buf[8] = '\0';
+ data -= 8;
+ memcpy(buf, data, 8);
+ if (kstrtou32(buf, 16, &csum) != 0) {
+ pr_err("bootconfig checksum field is invalid\n");
+ return NULL;
+ }
+ data -= 8;
+ memcpy(buf, data, 8);
+ if (kstrtou32(buf, 16, &size) != 0) {
+ pr_err("bootconfig size field is invalid\n");
+ return NULL;
+ }
+ data -= size;

- data = ((void *)hdr) - size;
if ((unsigned long)data < initrd_start) {
pr_err("bootconfig size %d is greater than initrd size %ld\n",
size, initrd_end - initrd_start);