[PATCH v7 2/4] bootconfig: Check the checksum before removing the bootconfig from initrd

[Masami Hiramatsu <mhiramat@xxxxxxxxxx>]

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@xxxxxxxxxx>
---
 init/main.c |   22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/init/main.c b/init/main.c
index 98182c3c2c4b..266d61bc67b0 100644
--- a/init/main.c
+++ b/init/main.c
@@ -266,7 +266,7 @@ 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;
@@ -300,17 +300,20 @@ 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;
 }
@@ -409,12 +412,12 @@ 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,
@@ -438,11 +441,6 @@ 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)
@@ -471,7 +469,7 @@ 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)