Commit de462e5f authored by Masami Hiramatsu's avatar Masami Hiramatsu Committed by Steven Rostedt (VMware)
Browse files

bootconfig: Fix to remove bootconfig data from initrd while boot 

If there is a bootconfig data in the tail of initrd/initramfs,
initrd image sanity check caused an error while decompression
stage as follows.

[    0.883882] Unpacking initramfs...
[    2.696429] Initramfs unpacking failed: invalid magic at start of compressed archive

This error will be ignored if CONFIG_BLK_DEV_RAM=n,
but CONFIG_BLK_DEV_RAM=y the kernel failed to mount rootfs
and causes a panic.

To fix this issue, shrink down the initrd_end for removing
tailing bootconfig data while boot the kernel.

Link: http://lkml.kernel.org/r/158788401014.24243.17424755854115077915.stgit@devnote2



Cc: Borislav Petkov <bp@alien8.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 7684b858 ("bootconfig: Load boot config from the tail of initrd")
Signed-off-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 6a8b55ed

init/main.c

+52 −17
Original line number Diff line number Diff line
@@ -257,6 +257,47 @@ 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)

{

	u32 size, csum;

	char *data;

	u32 *hdr;



	if (!initrd_end)

		return NULL;



	data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;

	if (memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))

		return NULL;



	hdr = (u32 *)(data - 8);

	size = hdr[0];

	csum = hdr[1];



	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);

		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)

{

	return NULL;

}

#endif



#ifdef CONFIG_BOOT_CONFIG



char xbc_namebuf[XBC_KEYLEN_MAX] __initdata;
@@ -357,9 +398,12 @@ static void __init setup_boot_config(const char *cmdline) 
	int pos;

	u32 size, csum;

	char *data, *copy;

	u32 *hdr;

	int ret;



	data = get_boot_config_from_initrd(&size, &csum);

	if (!data)

		goto not_found;



	strlcpy(tmp_cmdline, boot_command_line, COMMAND_LINE_SIZE);

	parse_args("bootconfig", tmp_cmdline, NULL, 0, 0, 0, NULL,

		   bootconfig_params);
@@ -367,27 +411,12 @@ static void __init setup_boot_config(const char *cmdline) 
	if (!bootconfig_found)

		return;



	if (!initrd_end)

		goto not_found;



	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];



	if (size >= XBC_DATA_MAX) {

		pr_err("bootconfig size %d greater than max size %d\n",

			size, XBC_DATA_MAX);

		return;

	}



	data = ((void *)hdr) - size;

	if ((unsigned long)data < initrd_start)

		goto not_found;



	if (boot_config_checksum((unsigned char *)data, size) != csum) {

		pr_err("bootconfig checksum failed\n");

		return;
@@ -420,8 +449,14 @@ static void __init setup_boot_config(const char *cmdline) 
not_found:

	pr_err("'bootconfig' found on command line, but no bootconfig found\n");

}



#else

#define setup_boot_config(cmdline)	do { } while (0)



static void __init setup_boot_config(const char *cmdline)

{

	/* Remove bootconfig data from initrd */

	get_boot_config_from_initrd(NULL, NULL);

}



static int __init warn_bootconfig(char *str)

{

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