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Commit 38aede51 authored by Badhri Jagan Sridharan's avatar Badhri Jagan Sridharan Committed by Vikram Mulukutla
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ANDROID: dm: Mounting root as linear device when verity disabled 



This CL makes android-verity target to be added as linear
dm device if when bootloader is unlocked and verity is disabled.

Bug: 27175947
Change-Id: Ic41ca4b8908fb2777263799cf3a3e25934d70f18
Signed-off-by: default avatarBadhri Jagan Sridharan <Badhri@google.com>
Git-commit: 67ce4818
Git-repo: https://android.googlesource.com/kernel/common


Signed-off-by: default avatarVikram Mulukutla <markivx@codeaurora.org>
parent 03b451f7

drivers/md/dm-android-verity.c

+109 −22
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
 */



#include <linux/buffer_head.h>

#include <linux/debugfs.h>

#include <linux/delay.h>

#include <linux/device.h>

#include <linux/device-mapper.h>
@@ -43,6 +44,25 @@ 
static char verifiedbootstate[VERITY_COMMANDLINE_PARAM_LENGTH];

static char veritymode[VERITY_COMMANDLINE_PARAM_LENGTH];



static bool target_added;

static bool verity_enabled = true;

struct dentry *debug_dir;

static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv);



static struct target_type android_verity_target = {

	.name                   = "android-verity",

	.version                = {1, 0, 0},

	.module                 = THIS_MODULE,

	.ctr                    = android_verity_ctr,

	.dtr                    = verity_dtr,

	.map                    = verity_map,

	.status                 = verity_status,

	.ioctl                  = verity_ioctl,

	.merge                  = verity_merge,

	.iterate_devices        = verity_iterate_devices,

	.io_hints               = verity_io_hints,

};



static int __init verified_boot_state_param(char *line)

{

	strlcpy(verifiedbootstate, line, sizeof(verifiedbootstate));
@@ -549,6 +569,35 @@ static inline bool test_mult_overflow(sector_t a, u32 b) 
	return a > r;

}



static int add_as_linear_device(struct dm_target *ti, char *dev)

{

	/*Move to linear mapping defines*/

	char *linear_table_args[DM_LINEAR_ARGS];

	char offset[]  = "0";

	int err = 0;



	linear_table_args[0] = dev;

	linear_table_args[1] = offset;



	android_verity_target.dtr = linear_target.dtr,

	android_verity_target.map = linear_target.map,

	android_verity_target.status = linear_target.status,

	android_verity_target.ioctl = linear_target.ioctl,

	android_verity_target.merge = linear_target.merge,

	android_verity_target.iterate_devices = linear_target.iterate_devices,

	android_verity_target.io_hints = NULL;



	err = linear_target.ctr(ti, DM_LINEAR_ARGS, linear_table_args);



	if (!err) {

		DMINFO("Added android-verity as a linear target");

		target_added = true;

	} else

		DMERR("Failed to add android-verity as linear target");



	return err;

}



/*

 * Target parameters:

 *	<key id>	Key id of the public key in the system keyring.
@@ -613,13 +662,18 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv) 


	if (err == VERITY_STATE_DISABLE) {

		DMERR("Mounting root with verity disabled");

		return -EINVAL;

		verity_enabled = false;

		/* we would still have to parse the args to figure out

		 * the data blocks size. Or may be could map the entire

		 * partition similar to mounting the device.

		 */

	} else if (err) {

		DMERR("Verity header handle error");

		handle_error();

		goto free_metadata;

	}



	if (!verity_enabled) {

		err = verify_verity_signature(key_id, metadata);



		if (err) {
@@ -628,6 +682,7 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv) 
			goto free_metadata;

		} else

			DMINFO("Signature verification success");

	}



	table_ptr = metadata->verity_table;
@@ -683,6 +738,12 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv) 
	/* update target length */

	ti->len = data_sectors;



	/* Setup linear target and free */

	if (!verity_enabled) {

		err = add_as_linear_device(ti, argv[1]);

		goto free_metadata;

	}



	/*substitute data_dev and hash_dev*/

	verity_table_args[1] = argv[1];

	verity_table_args[2] = argv[1];
@@ -730,6 +791,13 @@ static int android_verity_ctr(struct dm_target *ti, unsigned argc, char **argv) 


	err = verity_ctr(ti, no_of_args, verity_table_args);



	if (err)

		DMERR("android-verity failed to mount as verity target");

	else {

		target_added = true;

		DMINFO("android-verity mounted as verity target");

	}



free_metadata:

	kfree(metadata->header);

	kfree(metadata->verity_table);
@@ -737,33 +805,52 @@ free_metadata: 
	return err;

}



static struct target_type android_verity_target = {

	.name			= "android-verity",

	.version		= {1, 0, 0},

	.module			= THIS_MODULE,

	.ctr			= android_verity_ctr,

	.dtr			= verity_dtr,

	.map			= verity_map,

	.status			= verity_status,

	.ioctl			= verity_ioctl,

	.merge			= verity_merge,

	.iterate_devices	= verity_iterate_devices,

	.io_hints		= verity_io_hints,

};



static int __init dm_android_verity_init(void)

{

	int r;

	struct dentry *file;



	r = dm_register_target(&android_verity_target);

	if (r < 0)

		DMERR("register failed %d", r);



	/* Tracks the status of the last added target */

	debug_dir = debugfs_create_dir("android_verity", NULL);



	if (IS_ERR_OR_NULL(debug_dir)) {

		DMERR("Cannot create android_verity debugfs directory: %ld",

			PTR_ERR(debug_dir));

		goto end;

	}



	file = debugfs_create_bool("target_added", S_IRUGO, debug_dir,

				(u32 *)&target_added);



	if (IS_ERR_OR_NULL(file)) {

		DMERR("Cannot create android_verity debugfs directory: %ld",

			PTR_ERR(debug_dir));

		debugfs_remove_recursive(debug_dir);

		goto end;

	}



	file = debugfs_create_bool("verity_enabled", S_IRUGO, debug_dir,

				(u32 *)&verity_enabled);



	if (IS_ERR_OR_NULL(file)) {

		DMERR("Cannot create android_verity debugfs directory: %ld",

			PTR_ERR(debug_dir));

		debugfs_remove_recursive(debug_dir);

	}



end:

	return r;

}



static void __exit dm_android_verity_exit(void)

{

	if (!IS_ERR_OR_NULL(debug_dir))

		debugfs_remove_recursive(debug_dir);



	dm_unregister_target(&android_verity_target);

}

drivers/md/dm-android-verity.h

+3 −0
Original line number Diff line number Diff line
@@ -44,6 +44,8 @@ 
#define VERITY_DEBUG 0



#define DM_MSG_PREFIX                   "android-verity"



#define DM_LINEAR_ARGS 2

/*

 * There can be two formats.

 * if fec is present
@@ -89,4 +91,5 @@ struct bio_read { 
	int number_of_pages;

};



extern struct target_type linear_target;

#endif /* DM_ANDROID_VERITY_H */

drivers/md/dm-linear.c

+1 −1
Original line number Diff line number Diff line
@@ -141,7 +141,7 @@ static int linear_iterate_devices(struct dm_target *ti, 
	return fn(ti, lc->dev, lc->start, ti->len, data);

}



static struct target_type linear_target = {

struct target_type linear_target = {

	.name   = "linear",

	.version = {1, 2, 1},

	.module = THIS_MODULE,