[PATCH v2 1/3] bootconfig: Check the checksum before removing the bootconfig from initrd

Masami Hiramatsu
2022-03-14T09:08:43Z

Check the bootconfig's checksum before removing the bootcinfig data
from initrd to avoid modifying initrd by mistake.
This will also simplifies the get_boot_config_from_initrd() interface.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
---
init/main.c | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/init/main.c b/init/main.c
index 65fa2e41a9c0..421050be5039 100644
--- a/init/main.c
+++ b/init/main.c
@@ -265,7 +265,7 @@ static int __init loglevel(char *str)
early_param("loglevel", loglevel);

#ifdef CONFIG_BLK_DEV_INITRD
-static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
+static void * __init get_boot_config_from_initrd(u32 *_size)
{
u32 size, csum;
char *data;
@@ -299,17 +299,20 @@ static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
return NULL;
}

+ if (xbc_calc_checksum(data, size) != csum) {
+ pr_err("bootconfig checksum failed\n");
+ return NULL;
+ }
+
/* Remove bootconfig from initramfs/initrd */
initrd_end = (unsigned long)data;
if (_size)
*_size = size;
- if (_csum)
- *_csum = csum;

return data;
}
#else
-static void * __init get_boot_config_from_initrd(u32 *_size, u32 *_csum)
+static void * __init get_boot_config_from_initrd(u32 *_size)
{
return NULL;
}
@@ -408,12 +411,12 @@ static void __init setup_boot_config(void)
static char tmp_cmdline[COMMAND_LINE_SIZE] __initdata;
const char *msg;
int pos;
- u32 size, csum;
+ u32 size;
char *data, *err;
int ret;

/* Cut out the bootconfig data even if we have no bootconfig option */
- data = get_boot_config_from_initrd(&size, &csum);
+ data = get_boot_config_from_initrd(&size);

strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);
err = parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,
@@ -437,11 +440,6 @@ static void __init setup_boot_config(void)
return;
}

- if (xbc_calc_checksum(data, size) != csum) {
- pr_err("bootconfig checksum failed\n");
- return;
- }
-
ret = xbc_init(data, size, &msg, &pos);
if (ret < 0) {
if (pos < 0)
@@ -470,7 +468,7 @@ static void __init exit_boot_config(void)
static void __init setup_boot_config(void)
{
/* Remove bootconfig data from initrd */
- get_boot_config_from_initrd(NULL, NULL);
+ get_boot_config_from_initrd(NULL);
}

static int __init warn_bootconfig(char *str)