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: Badhri Jagan Sridharan <Badhri@google.com>
diff --git a/drivers/md/dm-android-verity.c b/drivers/md/dm-android-verity.c
index aeb5045..db4ddf7 100644
--- a/drivers/md/dm-android-verity.c
+++ b/drivers/md/dm-android-verity.c
@@ -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 @@
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.
@@ -613,21 +662,27 @@
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;
}
- err = verify_verity_signature(key_id, metadata);
+ if (!verity_enabled) {
+ err = verify_verity_signature(key_id, metadata);
- if (err) {
- DMERR("Signature verification failed");
- handle_error();
- goto free_metadata;
- } else
- DMINFO("Signature verification success");
+ if (err) {
+ DMERR("Signature verification failed");
+ handle_error();
+ goto free_metadata;
+ } else
+ DMINFO("Signature verification success");
+ }
table_ptr = metadata->verity_table;
@@ -683,6 +738,12 @@
/* 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 @@
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 @@
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);
}
diff --git a/drivers/md/dm-android-verity.h b/drivers/md/dm-android-verity.h
index 11477ff..2cf7de1 100644
--- a/drivers/md/dm-android-verity.h
+++ b/drivers/md/dm-android-verity.h
@@ -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 @@
int number_of_pages;
};
+extern struct target_type linear_target;
#endif /* DM_ANDROID_VERITY_H */
diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
index 4788b0b..6376fd0 100644
--- a/drivers/md/dm-linear.c
+++ b/drivers/md/dm-linear.c
@@ -159,7 +159,7 @@
return ret;
}
-static struct target_type linear_target = {
+struct target_type linear_target = {
.name = "linear",
.version = {1, 3, 0},
.module = THIS_MODULE,