1 files changed, 852 insertions, 343 deletions

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index f4c31ffaa88e..66a00a8ccb39 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012 Red Hat, Inc.
  *
@@ -5,8 +6,6 @@
  *
  * Based on Chromium dm-verity driver (C) 2011 The Chromium OS Authors
  *
- * This file is released under the GPLv2.
- *
  * In the file "/sys/module/dm_verity/parameters/prefetch_cluster" you can set
  * default prefetch value. Data are read in "prefetch_cluster" chunks from the
  * hash device. Setting this greatly improves performance when data and hash
@@ -16,9 +15,13 @@
 
 #include "dm-verity.h"
 #include "dm-verity-fec.h"
-
+#include "dm-verity-verify-sig.h"
+#include "dm-audit.h"
 #include <linux/module.h>
 #include <linux/reboot.h>
+#include <linux/string.h>
+#include <linux/jump_label.h>
+#include <linux/security.h>
 
 #define DM_MSG_PREFIX			"verity"
 
@@ -26,25 +29,43 @@
 #define DM_VERITY_ENV_VAR_NAME		"DM_VERITY_ERR_BLOCK_NR"
 
 #define DM_VERITY_DEFAULT_PREFETCH_SIZE	262144
+#define DM_VERITY_USE_BH_DEFAULT_BYTES	8192
 
 #define DM_VERITY_MAX_CORRUPTED_ERRS	100
 
 #define DM_VERITY_OPT_LOGGING		"ignore_corruption"
 #define DM_VERITY_OPT_RESTART		"restart_on_corruption"
+#define DM_VERITY_OPT_PANIC		"panic_on_corruption"
+#define DM_VERITY_OPT_ERROR_RESTART	"restart_on_error"
+#define DM_VERITY_OPT_ERROR_PANIC	"panic_on_error"
 #define DM_VERITY_OPT_IGN_ZEROES	"ignore_zero_blocks"
 #define DM_VERITY_OPT_AT_MOST_ONCE	"check_at_most_once"
+#define DM_VERITY_OPT_TASKLET_VERIFY	"try_verify_in_tasklet"
+
+#define DM_VERITY_OPTS_MAX		(5 + DM_VERITY_OPTS_FEC + \
+					 DM_VERITY_ROOT_HASH_VERIFICATION_OPTS)
+
+static unsigned int dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
 
-#define DM_VERITY_OPTS_MAX		(2 + DM_VERITY_OPTS_FEC)
+module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, 0644);
 
-static unsigned dm_verity_prefetch_cluster = DM_VERITY_DEFAULT_PREFETCH_SIZE;
+static unsigned int dm_verity_use_bh_bytes[4] = {
+	DM_VERITY_USE_BH_DEFAULT_BYTES,	// IOPRIO_CLASS_NONE
+	DM_VERITY_USE_BH_DEFAULT_BYTES,	// IOPRIO_CLASS_RT
+	DM_VERITY_USE_BH_DEFAULT_BYTES,	// IOPRIO_CLASS_BE
+	0				// IOPRIO_CLASS_IDLE
+};
+
+module_param_array_named(use_bh_bytes, dm_verity_use_bh_bytes, uint, NULL, 0644);
 
-module_param_named(prefetch_cluster, dm_verity_prefetch_cluster, uint, S_IRUGO | S_IWUSR);
+static DEFINE_STATIC_KEY_FALSE(use_bh_wq_enabled);
 
 struct dm_verity_prefetch_work {
 	struct work_struct work;
 	struct dm_verity *v;
+	unsigned short ioprio;
 	sector_t block;
-	unsigned n_blocks;
+	unsigned int n_blocks;
 };
 
 /*
@@ -78,7 +99,7 @@ static void dm_bufio_alloc_callback(struct dm_buffer *buf)
  */
 static sector_t verity_map_sector(struct dm_verity *v, sector_t bi_sector)
 {
-	return v->data_start + dm_target_offset(v->ti, bi_sector);
+	return dm_target_offset(v->ti, bi_sector);
 }
 
 /*
@@ -93,106 +114,34 @@ static sector_t verity_position_at_level(struct dm_verity *v, sector_t block,
 	return block >> (level * v->hash_per_block_bits);
 }
 
-static int verity_hash_update(struct dm_verity *v, struct ahash_request *req,
-				const u8 *data, size_t len,
-				struct crypto_wait *wait)
-{
-	struct scatterlist sg;
-
-	if (likely(!is_vmalloc_addr(data))) {
-		sg_init_one(&sg, data, len);
-		ahash_request_set_crypt(req, &sg, NULL, len);
-		return crypto_wait_req(crypto_ahash_update(req), wait);
-	} else {
-		do {
-			int r;
-			size_t this_step = min_t(size_t, len, PAGE_SIZE - offset_in_page(data));
-			flush_kernel_vmap_range((void *)data, this_step);
-			sg_init_table(&sg, 1);
-			sg_set_page(&sg, vmalloc_to_page(data), this_step, offset_in_page(data));
-			ahash_request_set_crypt(req, &sg, NULL, this_step);
-			r = crypto_wait_req(crypto_ahash_update(req), wait);
-			if (unlikely(r))
-				return r;
-			data += this_step;
-			len -= this_step;
-		} while (len);
-		return 0;
-	}
-}
-
-/*
- * Wrapper for crypto_ahash_init, which handles verity salting.
- */
-static int verity_hash_init(struct dm_verity *v, struct ahash_request *req,
-				struct crypto_wait *wait)
-{
-	int r;
-
-	ahash_request_set_tfm(req, v->tfm);
-	ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP |
-					CRYPTO_TFM_REQ_MAY_BACKLOG,
-					crypto_req_done, (void *)wait);
-	crypto_init_wait(wait);
-
-	r = crypto_wait_req(crypto_ahash_init(req), wait);
-
-	if (unlikely(r < 0)) {
-		DMERR("crypto_ahash_init failed: %d", r);
-		return r;
-	}
-
-	if (likely(v->salt_size && (v->version >= 1)))
-		r = verity_hash_update(v, req, v->salt, v->salt_size, wait);
-
-	return r;
-}
-
-static int verity_hash_final(struct dm_verity *v, struct ahash_request *req,
-			     u8 *digest, struct crypto_wait *wait)
-{
-	int r;
-
-	if (unlikely(v->salt_size && (!v->version))) {
-		r = verity_hash_update(v, req, v->salt, v->salt_size, wait);
-
-		if (r < 0) {
-			DMERR("verity_hash_final failed updating salt: %d", r);
-			goto out;
-		}
-	}
-
-	ahash_request_set_crypt(req, NULL, digest, 0);
-	r = crypto_wait_req(crypto_ahash_final(req), wait);
-out:
-	return r;
-}
-
-int verity_hash(struct dm_verity *v, struct ahash_request *req,
+int verity_hash(struct dm_verity *v, struct dm_verity_io *io,
 		const u8 *data, size_t len, u8 *digest)
 {
+	struct shash_desc *desc = &io->hash_desc;
 	int r;
-	struct crypto_wait wait;
-
-	r = verity_hash_init(v, req, &wait);
-	if (unlikely(r < 0))
-		goto out;
-
-	r = verity_hash_update(v, req, data, len, &wait);
-	if (unlikely(r < 0))
-		goto out;
-
-	r = verity_hash_final(v, req, digest, &wait);
 
-out:
+	desc->tfm = v->shash_tfm;
+	if (unlikely(v->initial_hashstate == NULL)) {
+		/* Version 0: salt at end */
+		r = crypto_shash_init(desc) ?:
+		    crypto_shash_update(desc, data, len) ?:
+		    crypto_shash_update(desc, v->salt, v->salt_size) ?:
+		    crypto_shash_final(desc, digest);
+	} else {
+		/* Version 1: salt at beginning */
+		r = crypto_shash_import(desc, v->initial_hashstate) ?:
+		    crypto_shash_finup(desc, data, len, digest);
+	}
+	if (unlikely(r))
+		DMERR("Error hashing block: %d", r);
 	return r;
 }
 
 static void verity_hash_at_level(struct dm_verity *v, sector_t block, int level,
-				 sector_t *hash_block, unsigned *offset)
+				 sector_t *hash_block, unsigned int *offset)
 {
 	sector_t position = verity_position_at_level(v, block, level);
-	unsigned idx;
+	unsigned int idx;
 
 	*hash_block = v->hash_level_block[level] + (position >> v->hash_per_block_bits);
 
@@ -218,7 +167,7 @@ static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
 	struct mapped_device *md = dm_table_get_md(v->ti->table);
 
 	/* Corruption should be visible in device status in all modes */
-	v->hash_failed = 1;
+	v->hash_failed = true;
 
 	if (v->corrupted_errs >= DM_VERITY_MAX_CORRUPTED_ERRS)
 		goto out;
@@ -236,11 +185,13 @@ static int verity_handle_err(struct dm_verity *v, enum verity_block_type type,
 		BUG();
 	}
 
-	DMERR("%s: %s block %llu is corrupted", v->data_dev->name, type_str,
-		block);
+	DMERR_LIMIT("%s: %s block %llu is corrupted", v->data_dev->name,
+		    type_str, block);
 
-	if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS)
+	if (v->corrupted_errs == DM_VERITY_MAX_CORRUPTED_ERRS) {
 		DMERR("%s: reached maximum errors", v->data_dev->name);
+		dm_audit_log_target(DM_MSG_PREFIX, "max-corrupted-errors", v->ti, 0);
+	}
 
 	snprintf(verity_env, DM_VERITY_ENV_LENGTH, "%s=%d,%llu",
 		DM_VERITY_ENV_VAR_NAME, type, block);
@@ -254,6 +205,9 @@ out:
 	if (v->mode == DM_VERITY_MODE_RESTART)
 		kernel_restart("dm-verity device corrupted");
 
+	if (v->mode == DM_VERITY_MODE_PANIC)
+		panic("dm-verity device corrupted");
+
 	return 1;
 }
 
@@ -277,13 +231,44 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
 	u8 *data;
 	int r;
 	sector_t hash_block;
-	unsigned offset;
+	unsigned int offset;
+	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
 
 	verity_hash_at_level(v, block, level, &hash_block, &offset);
 
-	data = dm_bufio_read(v->bufio, hash_block, &buf);
-	if (IS_ERR(data))
-		return PTR_ERR(data);
+	if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
+		data = dm_bufio_get(v->bufio, hash_block, &buf);
+		if (IS_ERR_OR_NULL(data)) {
+			/*
+			 * In tasklet and the hash was not in the bufio cache.
+			 * Return early and resume execution from a work-queue
+			 * to read the hash from disk.
+			 */
+			return -EAGAIN;
+		}
+	} else {
+		data = dm_bufio_read_with_ioprio(v->bufio, hash_block,
+						&buf, bio->bi_ioprio);
+	}
+
+	if (IS_ERR(data)) {
+		if (skip_unverified)
+			return 1;
+		r = PTR_ERR(data);
+		data = dm_bufio_new(v->bufio, hash_block, &buf);
+		if (IS_ERR(data))
+			return r;
+		if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_METADATA,
+				      hash_block, data) == 0) {
+			aux = dm_bufio_get_aux_data(buf);
+			aux->hash_verified = 1;
+			goto release_ok;
+		} else {
+			dm_bufio_release(buf);
+			dm_bufio_forget(v->bufio, hash_block);
+			return r;
+		}
+	}
 
 	aux = dm_bufio_get_aux_data(buf);
 
@@ -293,8 +278,7 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
 			goto release_ret_r;
 		}
 
-		r = verity_hash(v, verity_io_hash_req(v, io),
-				data, 1 << v->hash_dev_block_bits,
+		r = verity_hash(v, io, data, 1 << v->hash_dev_block_bits,
 				verity_io_real_digest(v, io));
 		if (unlikely(r < 0))
 			goto release_ret_r;
@@ -302,18 +286,30 @@ static int verity_verify_level(struct dm_verity *v, struct dm_verity_io *io,
 		if (likely(memcmp(verity_io_real_digest(v, io), want_digest,
 				  v->digest_size) == 0))
 			aux->hash_verified = 1;
-		else if (verity_fec_decode(v, io,
-					   DM_VERITY_BLOCK_TYPE_METADATA,
-					   hash_block, data, NULL) == 0)
+		else if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
+			/*
+			 * Error handling code (FEC included) cannot be run in a
+			 * tasklet since it may sleep, so fallback to work-queue.
+			 */
+			r = -EAGAIN;
+			goto release_ret_r;
+		} else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_METADATA,
+					     hash_block, data) == 0)
 			aux->hash_verified = 1;
 		else if (verity_handle_err(v,
 					   DM_VERITY_BLOCK_TYPE_METADATA,
 					   hash_block)) {
+			struct bio *bio;
+			io->had_mismatch = true;
+			bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
+			dm_audit_log_bio(DM_MSG_PREFIX, "verify-metadata", bio,
+					 block, 0);
 			r = -EIO;
 			goto release_ret_r;
 		}
 	}
 
+release_ok:
 	data += offset;
 	memcpy(want_digest, data, v->digest_size);
 	r = 0;
@@ -361,127 +357,115 @@ out:
 	return r;
 }
 
-/*
- * Calculates the digest for the given bio
- */
-static int verity_for_io_block(struct dm_verity *v, struct dm_verity_io *io,
-			       struct bvec_iter *iter, struct crypto_wait *wait)
+static noinline int verity_recheck(struct dm_verity *v, struct dm_verity_io *io,
+				   sector_t cur_block, u8 *dest)
 {
-	unsigned int todo = 1 << v->data_dev_block_bits;
-	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
-	struct scatterlist sg;
-	struct ahash_request *req = verity_io_hash_req(v, io);
-
-	do {
-		int r;
-		unsigned int len;
-		struct bio_vec bv = bio_iter_iovec(bio, *iter);
-
-		sg_init_table(&sg, 1);
-
-		len = bv.bv_len;
-
-		if (likely(len >= todo))
-			len = todo;
-		/*
-		 * Operating on a single page at a time looks suboptimal
-		 * until you consider the typical block size is 4,096B.
-		 * Going through this loops twice should be very rare.
-		 */
-		sg_set_page(&sg, bv.bv_page, len, bv.bv_offset);
-		ahash_request_set_crypt(req, &sg, NULL, len);
-		r = crypto_wait_req(crypto_ahash_update(req), wait);
-
-		if (unlikely(r < 0)) {
-			DMERR("verity_for_io_block crypto op failed: %d", r);
-			return r;
-		}
-
-		bio_advance_iter(bio, iter, len);
-		todo -= len;
-	} while (todo);
-
-	return 0;
-}
-
-/*
- * Calls function process for 1 << v->data_dev_block_bits bytes in the bio_vec
- * starting from iter.
- */
-int verity_for_bv_block(struct dm_verity *v, struct dm_verity_io *io,
-			struct bvec_iter *iter,
-			int (*process)(struct dm_verity *v,
-				       struct dm_verity_io *io, u8 *data,
-				       size_t len))
-{
-	unsigned todo = 1 << v->data_dev_block_bits;
-	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
-
-	do {
-		int r;
-		u8 *page;
-		unsigned len;
-		struct bio_vec bv = bio_iter_iovec(bio, *iter);
-
-		page = kmap_atomic(bv.bv_page);
-		len = bv.bv_len;
-
-		if (likely(len >= todo))
-			len = todo;
-
-		r = process(v, io, page + bv.bv_offset, len);
-		kunmap_atomic(page);
-
-		if (r < 0)
-			return r;
+	struct page *page;
+	void *buffer;
+	int r;
+	struct dm_io_request io_req;
+	struct dm_io_region io_loc;
+
+	page = mempool_alloc(&v->recheck_pool, GFP_NOIO);
+	buffer = page_to_virt(page);
+
+	io_req.bi_opf = REQ_OP_READ;
+	io_req.mem.type = DM_IO_KMEM;
+	io_req.mem.ptr.addr = buffer;
+	io_req.notify.fn = NULL;
+	io_req.client = v->io;
+	io_loc.bdev = v->data_dev->bdev;
+	io_loc.sector = cur_block << (v->data_dev_block_bits - SECTOR_SHIFT);
+	io_loc.count = 1 << (v->data_dev_block_bits - SECTOR_SHIFT);
+	r = dm_io(&io_req, 1, &io_loc, NULL, IOPRIO_DEFAULT);
+	if (unlikely(r))
+		goto free_ret;
+
+	r = verity_hash(v, io, buffer, 1 << v->data_dev_block_bits,
+			verity_io_real_digest(v, io));
+	if (unlikely(r))
+		goto free_ret;
+
+	if (memcmp(verity_io_real_digest(v, io),
+		   verity_io_want_digest(v, io), v->digest_size)) {
+		r = -EIO;
+		goto free_ret;
+	}
 
-		bio_advance_iter(bio, iter, len);
-		todo -= len;
-	} while (todo);
+	memcpy(dest, buffer, 1 << v->data_dev_block_bits);
+	r = 0;
+free_ret:
+	mempool_free(page, &v->recheck_pool);
 
-	return 0;
+	return r;
 }
 
-static int verity_bv_zero(struct dm_verity *v, struct dm_verity_io *io,
-			  u8 *data, size_t len)
+static int verity_handle_data_hash_mismatch(struct dm_verity *v,
+					    struct dm_verity_io *io,
+					    struct bio *bio, sector_t blkno,
+					    u8 *data)
 {
-	memset(data, 0, len);
+	if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
+		/*
+		 * Error handling code (FEC included) cannot be run in the
+		 * BH workqueue, so fallback to a standard workqueue.
+		 */
+		return -EAGAIN;
+	}
+	if (verity_recheck(v, io, blkno, data) == 0) {
+		if (v->validated_blocks)
+			set_bit(blkno, v->validated_blocks);
+		return 0;
+	}
+#if defined(CONFIG_DM_VERITY_FEC)
+	if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA, blkno,
+			      data) == 0)
+		return 0;
+#endif
+	if (bio->bi_status)
+		return -EIO; /* Error correction failed; Just return error */
+
+	if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA, blkno)) {
+		io->had_mismatch = true;
+		dm_audit_log_bio(DM_MSG_PREFIX, "verify-data", bio, blkno, 0);
+		return -EIO;
+	}
 	return 0;
 }
 
 /*
- * Moves the bio iter one data block forward.
- */
-static inline void verity_bv_skip_block(struct dm_verity *v,
-					struct dm_verity_io *io,
-					struct bvec_iter *iter)
-{
-	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
-
-	bio_advance_iter(bio, iter, 1 << v->data_dev_block_bits);
-}
-
-/*
  * Verify one "dm_verity_io" structure.
  */
 static int verity_verify_io(struct dm_verity_io *io)
 {
-	bool is_zero;
 	struct dm_verity *v = io->v;
-	struct bvec_iter start;
-	unsigned b;
-	struct crypto_wait wait;
+	const unsigned int block_size = 1 << v->data_dev_block_bits;
+	struct bvec_iter iter_copy;
+	struct bvec_iter *iter;
+	struct bio *bio = dm_bio_from_per_bio_data(io, v->ti->per_io_data_size);
+	unsigned int b;
 
-	for (b = 0; b < io->n_blocks; b++) {
+	if (static_branch_unlikely(&use_bh_wq_enabled) && io->in_bh) {
+		/*
+		 * Copy the iterator in case we need to restart
+		 * verification in a work-queue.
+		 */
+		iter_copy = io->iter;
+		iter = &iter_copy;
+	} else
+		iter = &io->iter;
+
+	for (b = 0; b < io->n_blocks;
+	     b++, bio_advance_iter(bio, iter, block_size)) {
 		int r;
 		sector_t cur_block = io->block + b;
-		struct ahash_request *req = verity_io_hash_req(v, io);
+		bool is_zero;
+		struct bio_vec bv;
+		void *data;
 
-		if (v->validated_blocks &&
-		    likely(test_bit(cur_block, v->validated_blocks))) {
-			verity_bv_skip_block(v, io, &io->iter);
+		if (v->validated_blocks && bio->bi_status == BLK_STS_OK &&
+		    likely(test_bit(cur_block, v->validated_blocks)))
 			continue;
-		}
 
 		r = verity_hash_for_block(v, io, cur_block,
 					  verity_io_want_digest(v, io),
@@ -489,51 +473,69 @@ static int verity_verify_io(struct dm_verity_io *io)
 		if (unlikely(r < 0))
 			return r;
 
+		bv = bio_iter_iovec(bio, *iter);
+		if (unlikely(bv.bv_len < block_size)) {
+			/*
+			 * Data block spans pages.  This should not happen,
+			 * since dm-verity sets dma_alignment to the data block
+			 * size minus 1, and dm-verity also doesn't allow the
+			 * data block size to be greater than PAGE_SIZE.
+			 */
+			DMERR_LIMIT("unaligned io (data block spans pages)");
+			return -EIO;
+		}
+
+		data = bvec_kmap_local(&bv);
+
 		if (is_zero) {
 			/*
 			 * If we expect a zero block, don't validate, just
 			 * return zeros.
 			 */
-			r = verity_for_bv_block(v, io, &io->iter,
-						verity_bv_zero);
-			if (unlikely(r < 0))
-				return r;
-
+			memset(data, 0, block_size);
+			kunmap_local(data);
 			continue;
 		}
 
-		r = verity_hash_init(v, req, &wait);
-		if (unlikely(r < 0))
-			return r;
-
-		start = io->iter;
-		r = verity_for_io_block(v, io, &io->iter, &wait);
-		if (unlikely(r < 0))
-			return r;
-
-		r = verity_hash_final(v, req, verity_io_real_digest(v, io),
-					&wait);
-		if (unlikely(r < 0))
+		r = verity_hash(v, io, data, block_size,
+				verity_io_real_digest(v, io));
+		if (unlikely(r < 0)) {
+			kunmap_local(data);
 			return r;
+		}
 
 		if (likely(memcmp(verity_io_real_digest(v, io),
 				  verity_io_want_digest(v, io), v->digest_size) == 0)) {
 			if (v->validated_blocks)
 				set_bit(cur_block, v->validated_blocks);
+			kunmap_local(data);
 			continue;
 		}
-		else if (verity_fec_decode(v, io, DM_VERITY_BLOCK_TYPE_DATA,
-					   cur_block, NULL, &start) == 0)
-			continue;
-		else if (verity_handle_err(v, DM_VERITY_BLOCK_TYPE_DATA,
-					   cur_block))
-			return -EIO;
+		r = verity_handle_data_hash_mismatch(v, io, bio, cur_block,
+						     data);
+		kunmap_local(data);
+		if (unlikely(r))
+			return r;
 	}
 
 	return 0;
 }
 
 /*
+ * Skip verity work in response to I/O error when system is shutting down.
+ */
+static inline bool verity_is_system_shutting_down(void)
+{
+	return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
+		|| system_state == SYSTEM_RESTART;
+}
+
+static void restart_io_error(struct work_struct *w)
+{
+	kernel_restart("dm-verity device has I/O error");
+}
+
+/*
  * End one "io" structure with a given error.
  */
 static void verity_finish_io(struct dm_verity_io *io, blk_status_t status)
@@ -544,7 +546,26 @@ static void verity_finish_io(struct dm_verity_io *io, blk_status_t status)
 	bio->bi_end_io = io->orig_bi_end_io;
 	bio->bi_status = status;
 
-	verity_fec_finish_io(io);
+	if (!static_branch_unlikely(&use_bh_wq_enabled) || !io->in_bh)
+		verity_fec_finish_io(io);
+
+	if (unlikely(status != BLK_STS_OK) &&
+	    unlikely(!(bio->bi_opf & REQ_RAHEAD)) &&
+	    !io->had_mismatch &&
+	    !verity_is_system_shutting_down()) {
+		if (v->error_mode == DM_VERITY_MODE_PANIC) {
+			panic("dm-verity device has I/O error");
+		}
+		if (v->error_mode == DM_VERITY_MODE_RESTART) {
+			static DECLARE_WORK(restart_work, restart_io_error);
+			queue_work(v->verify_wq, &restart_work);
+			/*
+			 * We deliberately don't call bio_endio here, because
+			 * the machine will be restarted anyway.
+			 */
+			return;
+		}
+	}
 
 	bio_endio(bio);
 }
@@ -553,20 +574,61 @@ static void verity_work(struct work_struct *w)
 {
 	struct dm_verity_io *io = container_of(w, struct dm_verity_io, work);
 
+	io->in_bh = false;
+
 	verity_finish_io(io, errno_to_blk_status(verity_verify_io(io)));
 }
 
+static void verity_bh_work(struct work_struct *w)
+{
+	struct dm_verity_io *io = container_of(w, struct dm_verity_io, bh_work);
+	int err;
+
+	io->in_bh = true;
+	err = verity_verify_io(io);
+	if (err == -EAGAIN || err == -ENOMEM) {
+		/* fallback to retrying with work-queue */
+		INIT_WORK(&io->work, verity_work);
+		queue_work(io->v->verify_wq, &io->work);
+		return;
+	}
+
+	verity_finish_io(io, errno_to_blk_status(err));
+}
+
+static inline bool verity_use_bh(unsigned int bytes, unsigned short ioprio)
+{
+	return ioprio <= IOPRIO_CLASS_IDLE &&
+		bytes <= READ_ONCE(dm_verity_use_bh_bytes[ioprio]) &&
+		!need_resched();
+}
+
 static void verity_end_io(struct bio *bio)
 {
 	struct dm_verity_io *io = bio->bi_private;
+	unsigned short ioprio = IOPRIO_PRIO_CLASS(bio->bi_ioprio);
+	unsigned int bytes = io->n_blocks << io->v->data_dev_block_bits;
 
-	if (bio->bi_status && !verity_fec_is_enabled(io->v)) {
+	if (bio->bi_status &&
+	    (!verity_fec_is_enabled(io->v) ||
+	     verity_is_system_shutting_down() ||
+	     (bio->bi_opf & REQ_RAHEAD))) {
 		verity_finish_io(io, bio->bi_status);
 		return;
 	}
 
-	INIT_WORK(&io->work, verity_work);
-	queue_work(io->v->verify_wq, &io->work);
+	if (static_branch_unlikely(&use_bh_wq_enabled) && io->v->use_bh_wq &&
+		verity_use_bh(bytes, ioprio)) {
+		if (in_hardirq() || irqs_disabled()) {
+			INIT_WORK(&io->bh_work, verity_bh_work);
+			queue_work(system_bh_wq, &io->bh_work);
+		} else {
+			verity_bh_work(&io->bh_work);
+		}
+	} else {
+		INIT_WORK(&io->work, verity_work);
+		queue_work(io->v->verify_wq, &io->work);
+	}
 }
 
 /*
@@ -584,10 +646,12 @@ static void verity_prefetch_io(struct work_struct *work)
 	for (i = v->levels - 2; i >= 0; i--) {
 		sector_t hash_block_start;
 		sector_t hash_block_end;
+
 		verity_hash_at_level(v, pw->block, i, &hash_block_start, NULL);
 		verity_hash_at_level(v, pw->block + pw->n_blocks - 1, i, &hash_block_end, NULL);
+
 		if (!i) {
-			unsigned cluster = READ_ONCE(dm_verity_prefetch_cluster);
+			unsigned int cluster = READ_ONCE(dm_verity_prefetch_cluster);
 
 			cluster >>= v->data_dev_block_bits;
 			if (unlikely(!cluster))
@@ -602,17 +666,33 @@ static void verity_prefetch_io(struct work_struct *work)
 				hash_block_end = v->hash_blocks - 1;
 		}
 no_prefetch_cluster:
-		dm_bufio_prefetch(v->bufio, hash_block_start,
-				  hash_block_end - hash_block_start + 1);
+		dm_bufio_prefetch_with_ioprio(v->bufio, hash_block_start,
+					hash_block_end - hash_block_start + 1,
+					pw->ioprio);
 	}
 
 	kfree(pw);
 }
 
-static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
+static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io,
+				   unsigned short ioprio)
 {
+	sector_t block = io->block;
+	unsigned int n_blocks = io->n_blocks;
 	struct dm_verity_prefetch_work *pw;
 
+	if (v->validated_blocks) {
+		while (n_blocks && test_bit(block, v->validated_blocks)) {
+			block++;
+			n_blocks--;
+		}
+		while (n_blocks && test_bit(block + n_blocks - 1,
+					    v->validated_blocks))
+			n_blocks--;
+		if (!n_blocks)
+			return;
+	}
+
 	pw = kmalloc(sizeof(struct dm_verity_prefetch_work),
 		GFP_NOIO | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
 
@@ -621,8 +701,9 @@ static void verity_submit_prefetch(struct dm_verity *v, struct dm_verity_io *io)
 
 	INIT_WORK(&pw->work, verity_prefetch_io);
 	pw->v = v;
-	pw->block = io->block;
-	pw->n_blocks = io->n_blocks;
+	pw->block = block;
+	pw->n_blocks = n_blocks;
+	pw->ioprio = ioprio;
 	queue_work(v->verify_wq, &pw->work);
 }
 
@@ -638,7 +719,7 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
 	bio_set_dev(bio, v->data_dev->bdev);
 	bio->bi_iter.bi_sector = verity_map_sector(v, bio->bi_iter.bi_sector);
 
-	if (((unsigned)bio->bi_iter.bi_sector | bio_sectors(bio)) &
+	if (((unsigned int)bio->bi_iter.bi_sector | bio_sectors(bio)) &
 	    ((1 << (v->data_dev_block_bits - SECTOR_SHIFT)) - 1)) {
 		DMERR_LIMIT("unaligned io");
 		return DM_MAPIO_KILL;
@@ -658,6 +739,7 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
 	io->orig_bi_end_io = bio->bi_end_io;
 	io->block = bio->bi_iter.bi_sector >> (v->data_dev_block_bits - SECTOR_SHIFT);
 	io->n_blocks = bio->bi_iter.bi_size >> v->data_dev_block_bits;
+	io->had_mismatch = false;
 
 	bio->bi_end_io = verity_end_io;
 	bio->bi_private = io;
@@ -665,23 +747,30 @@ static int verity_map(struct dm_target *ti, struct bio *bio)
 
 	verity_fec_init_io(io);
 
-	verity_submit_prefetch(v, io);
+	verity_submit_prefetch(v, io, bio->bi_ioprio);
 
-	generic_make_request(bio);
+	submit_bio_noacct(bio);
 
 	return DM_MAPIO_SUBMITTED;
 }
 
+static void verity_postsuspend(struct dm_target *ti)
+{
+	struct dm_verity *v = ti->private;
+	flush_workqueue(v->verify_wq);
+	dm_bufio_client_reset(v->bufio);
+}
+
 /*
  * Status: V (valid) or C (corruption found)
  */
 static void verity_status(struct dm_target *ti, status_type_t type,
-			  unsigned status_flags, char *result, unsigned maxlen)
+			  unsigned int status_flags, char *result, unsigned int maxlen)
 {
 	struct dm_verity *v = ti->private;
-	unsigned args = 0;
-	unsigned sz = 0;
-	unsigned x;
+	unsigned int args = 0;
+	unsigned int sz = 0;
+	unsigned int x;
 
 	switch (type) {
 	case STATUSTYPE_INFO:
@@ -708,12 +797,18 @@ static void verity_status(struct dm_target *ti, status_type_t type,
 				DMEMIT("%02x", v->salt[x]);
 		if (v->mode != DM_VERITY_MODE_EIO)
 			args++;
+		if (v->error_mode != DM_VERITY_MODE_EIO)
+			args++;
 		if (verity_fec_is_enabled(v))
 			args += DM_VERITY_OPTS_FEC;
 		if (v->zero_digest)
 			args++;
 		if (v->validated_blocks)
 			args++;
+		if (v->use_bh_wq)
+			args++;
+		if (v->signature_key_desc)
+			args += DM_VERITY_ROOT_HASH_VERIFICATION_OPTS;
 		if (!args)
 			return;
 		DMEMIT(" %u", args);
@@ -726,6 +821,22 @@ static void verity_status(struct dm_target *ti, status_type_t type,
 			case DM_VERITY_MODE_RESTART:
 				DMEMIT(DM_VERITY_OPT_RESTART);
 				break;
+			case DM_VERITY_MODE_PANIC:
+				DMEMIT(DM_VERITY_OPT_PANIC);
+				break;
+			default:
+				BUG();
+			}
+		}
+		if (v->error_mode != DM_VERITY_MODE_EIO) {
+			DMEMIT(" ");
+			switch (v->error_mode) {
+			case DM_VERITY_MODE_RESTART:
+				DMEMIT(DM_VERITY_OPT_ERROR_RESTART);
+				break;
+			case DM_VERITY_MODE_PANIC:
+				DMEMIT(DM_VERITY_OPT_ERROR_PANIC);
+				break;
 			default:
 				BUG();
 			}
@@ -734,19 +845,81 @@ static void verity_status(struct dm_target *ti, status_type_t type,
 			DMEMIT(" " DM_VERITY_OPT_IGN_ZEROES);
 		if (v->validated_blocks)
 			DMEMIT(" " DM_VERITY_OPT_AT_MOST_ONCE);
+		if (v->use_bh_wq)
+			DMEMIT(" " DM_VERITY_OPT_TASKLET_VERIFY);
 		sz = verity_fec_status_table(v, sz, result, maxlen);
+		if (v->signature_key_desc)
+			DMEMIT(" " DM_VERITY_ROOT_HASH_VERIFICATION_OPT_SIG_KEY
+				" %s", v->signature_key_desc);
+		break;
+
+	case STATUSTYPE_IMA:
+		DMEMIT_TARGET_NAME_VERSION(ti->type);
+		DMEMIT(",hash_failed=%c", v->hash_failed ? 'C' : 'V');
+		DMEMIT(",verity_version=%u", v->version);
+		DMEMIT(",data_device_name=%s", v->data_dev->name);
+		DMEMIT(",hash_device_name=%s", v->hash_dev->name);
+		DMEMIT(",verity_algorithm=%s", v->alg_name);
+
+		DMEMIT(",root_digest=");
+		for (x = 0; x < v->digest_size; x++)
+			DMEMIT("%02x", v->root_digest[x]);
+
+		DMEMIT(",salt=");
+		if (!v->salt_size)
+			DMEMIT("-");
+		else
+			for (x = 0; x < v->salt_size; x++)
+				DMEMIT("%02x", v->salt[x]);
+
+		DMEMIT(",ignore_zero_blocks=%c", v->zero_digest ? 'y' : 'n');
+		DMEMIT(",check_at_most_once=%c", v->validated_blocks ? 'y' : 'n');
+		if (v->signature_key_desc)
+			DMEMIT(",root_hash_sig_key_desc=%s", v->signature_key_desc);
+
+		if (v->mode != DM_VERITY_MODE_EIO) {
+			DMEMIT(",verity_mode=");
+			switch (v->mode) {
+			case DM_VERITY_MODE_LOGGING:
+				DMEMIT(DM_VERITY_OPT_LOGGING);
+				break;
+			case DM_VERITY_MODE_RESTART:
+				DMEMIT(DM_VERITY_OPT_RESTART);
+				break;
+			case DM_VERITY_MODE_PANIC:
+				DMEMIT(DM_VERITY_OPT_PANIC);
+				break;
+			default:
+				DMEMIT("invalid");
+			}
+		}
+		if (v->error_mode != DM_VERITY_MODE_EIO) {
+			DMEMIT(",verity_error_mode=");
+			switch (v->error_mode) {
+			case DM_VERITY_MODE_RESTART:
+				DMEMIT(DM_VERITY_OPT_ERROR_RESTART);
+				break;
+			case DM_VERITY_MODE_PANIC:
+				DMEMIT(DM_VERITY_OPT_ERROR_PANIC);
+				break;
+			default:
+				DMEMIT("invalid");
+			}
+		}
+		DMEMIT(";");
 		break;
 	}
 }
 
-static int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev)
+static int verity_prepare_ioctl(struct dm_target *ti, struct block_device **bdev,
+				unsigned int cmd, unsigned long arg,
+				bool *forward)
 {
 	struct dm_verity *v = ti->private;
 
 	*bdev = v->data_dev->bdev;
 
-	if (v->data_start ||
-	    ti->len != i_size_read(v->data_dev->bdev->bd_inode) >> SECTOR_SHIFT)
+	if (ti->len != bdev_nr_sectors(v->data_dev->bdev))
 		return 1;
 	return 0;
 }
@@ -756,7 +929,7 @@ static int verity_iterate_devices(struct dm_target *ti,
 {
 	struct dm_verity *v = ti->private;
 
-	return fn(ti, v->data_dev, v->data_start, ti->len, data);
+	return fn(ti, v->data_dev, 0, ti->len, data);
 }
 
 static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits)
@@ -769,9 +942,52 @@ static void verity_io_hints(struct dm_target *ti, struct queue_limits *limits)
 	if (limits->physical_block_size < 1 << v->data_dev_block_bits)
 		limits->physical_block_size = 1 << v->data_dev_block_bits;
 
-	blk_limits_io_min(limits, limits->logical_block_size);
+	limits->io_min = limits->logical_block_size;
+
+	/*
+	 * Similar to what dm-crypt does, opt dm-verity out of support for
+	 * direct I/O that is aligned to less than the traditional direct I/O
+	 * alignment requirement of logical_block_size.  This prevents dm-verity
+	 * data blocks from crossing pages, eliminating various edge cases.
+	 */
+	limits->dma_alignment = limits->logical_block_size - 1;
 }
 
+#ifdef CONFIG_SECURITY
+
+static int verity_init_sig(struct dm_verity *v, const void *sig,
+			   size_t sig_size)
+{
+	v->sig_size = sig_size;
+
+	if (sig) {
+		v->root_digest_sig = kmemdup(sig, v->sig_size, GFP_KERNEL);
+		if (!v->root_digest_sig)
+			return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void verity_free_sig(struct dm_verity *v)
+{
+	kfree(v->root_digest_sig);
+}
+
+#else
+
+static inline int verity_init_sig(struct dm_verity *v, const void *sig,
+				  size_t sig_size)
+{
+	return 0;
+}
+
+static inline void verity_free_sig(struct dm_verity *v)
+{
+}
+
+#endif /* CONFIG_SECURITY */
+
 static void verity_dtr(struct dm_target *ti)
 {
 	struct dm_verity *v = ti->private;
@@ -779,16 +995,21 @@ static void verity_dtr(struct dm_target *ti)
 	if (v->verify_wq)
 		destroy_workqueue(v->verify_wq);
 
+	mempool_exit(&v->recheck_pool);
+	if (v->io)
+		dm_io_client_destroy(v->io);
+
 	if (v->bufio)
 		dm_bufio_client_destroy(v->bufio);
 
 	kvfree(v->validated_blocks);
 	kfree(v->salt);
+	kfree(v->initial_hashstate);
 	kfree(v->root_digest);
 	kfree(v->zero_digest);
+	verity_free_sig(v);
 
-	if (v->tfm)
-		crypto_free_ahash(v->tfm);
+	crypto_free_shash(v->shash_tfm);
 
 	kfree(v->alg_name);
 
@@ -800,13 +1021,23 @@ static void verity_dtr(struct dm_target *ti)
 
 	verity_fec_dtr(v);
 
+	kfree(v->signature_key_desc);
+
+	if (v->use_bh_wq)
+		static_branch_dec(&use_bh_wq_enabled);
+
 	kfree(v);
+
+	dm_audit_log_dtr(DM_MSG_PREFIX, ti, 1);
 }
 
 static int verity_alloc_most_once(struct dm_verity *v)
 {
 	struct dm_target *ti = v->ti;
 
+	if (v->validated_blocks)
+		return 0;
+
 	/* the bitset can only handle INT_MAX blocks */
 	if (v->data_blocks > INT_MAX) {
 		ti->error = "device too large to use check_at_most_once";
@@ -827,17 +1058,21 @@ static int verity_alloc_most_once(struct dm_verity *v)
 static int verity_alloc_zero_digest(struct dm_verity *v)
 {
 	int r = -ENOMEM;
-	struct ahash_request *req;
+	struct dm_verity_io *io;
 	u8 *zero_data;
 
+	if (v->zero_digest)
+		return 0;
+
 	v->zero_digest = kmalloc(v->digest_size, GFP_KERNEL);
 
 	if (!v->zero_digest)
 		return r;
 
-	req = kmalloc(v->ahash_reqsize, GFP_KERNEL);
+	io = kmalloc(sizeof(*io) + crypto_shash_descsize(v->shash_tfm),
+		     GFP_KERNEL);
 
-	if (!req)
+	if (!io)
 		return r; /* verity_dtr will free zero_digest */
 
 	zero_data = kzalloc(1 << v->data_dev_block_bits, GFP_KERNEL);
@@ -845,20 +1080,63 @@ static int verity_alloc_zero_digest(struct dm_verity *v)
 	if (!zero_data)
 		goto out;
 
-	r = verity_hash(v, req, zero_data, 1 << v->data_dev_block_bits,
+	r = verity_hash(v, io, zero_data, 1 << v->data_dev_block_bits,
 			v->zero_digest);
 
 out:
-	kfree(req);
+	kfree(io);
 	kfree(zero_data);
 
 	return r;
 }
 
-static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
+static inline bool verity_is_verity_mode(const char *arg_name)
 {
-	int r;
-	unsigned argc;
+	return (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING) ||
+		!strcasecmp(arg_name, DM_VERITY_OPT_RESTART) ||
+		!strcasecmp(arg_name, DM_VERITY_OPT_PANIC));
+}
+
+static int verity_parse_verity_mode(struct dm_verity *v, const char *arg_name)
+{
+	if (v->mode)
+		return -EINVAL;
+
+	if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING))
+		v->mode = DM_VERITY_MODE_LOGGING;
+	else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART))
+		v->mode = DM_VERITY_MODE_RESTART;
+	else if (!strcasecmp(arg_name, DM_VERITY_OPT_PANIC))
+		v->mode = DM_VERITY_MODE_PANIC;
+
+	return 0;
+}
+
+static inline bool verity_is_verity_error_mode(const char *arg_name)
+{
+	return (!strcasecmp(arg_name, DM_VERITY_OPT_ERROR_RESTART) ||
+		!strcasecmp(arg_name, DM_VERITY_OPT_ERROR_PANIC));
+}
+
+static int verity_parse_verity_error_mode(struct dm_verity *v, const char *arg_name)
+{
+	if (v->error_mode)
+		return -EINVAL;
+
+	if (!strcasecmp(arg_name, DM_VERITY_OPT_ERROR_RESTART))
+		v->error_mode = DM_VERITY_MODE_RESTART;
+	else if (!strcasecmp(arg_name, DM_VERITY_OPT_ERROR_PANIC))
+		v->error_mode = DM_VERITY_MODE_PANIC;
+
+	return 0;
+}
+
+static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
+				 struct dm_verity_sig_opts *verify_args,
+				 bool only_modifier_opts)
+{
+	int r = 0;
+	unsigned int argc;
 	struct dm_target *ti = v->ti;
 	const char *arg_name;
 
@@ -877,15 +1155,29 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
 		arg_name = dm_shift_arg(as);
 		argc--;
 
-		if (!strcasecmp(arg_name, DM_VERITY_OPT_LOGGING)) {
-			v->mode = DM_VERITY_MODE_LOGGING;
+		if (verity_is_verity_mode(arg_name)) {
+			if (only_modifier_opts)
+				continue;
+			r = verity_parse_verity_mode(v, arg_name);
+			if (r) {
+				ti->error = "Conflicting error handling parameters";
+				return r;
+			}
 			continue;
 
-		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_RESTART)) {
-			v->mode = DM_VERITY_MODE_RESTART;
+		} else if (verity_is_verity_error_mode(arg_name)) {
+			if (only_modifier_opts)
+				continue;
+			r = verity_parse_verity_error_mode(v, arg_name);
+			if (r) {
+				ti->error = "Conflicting error handling parameters";
+				return r;
+			}
 			continue;
 
 		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_IGN_ZEROES)) {
+			if (only_modifier_opts)
+				continue;
 			r = verity_alloc_zero_digest(v);
 			if (r) {
 				ti->error = "Cannot allocate zero digest";
@@ -894,18 +1186,47 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
 			continue;
 
 		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_AT_MOST_ONCE)) {
+			if (only_modifier_opts)
+				continue;
 			r = verity_alloc_most_once(v);
 			if (r)
 				return r;
 			continue;
 
+		} else if (!strcasecmp(arg_name, DM_VERITY_OPT_TASKLET_VERIFY)) {
+			v->use_bh_wq = true;
+			static_branch_inc(&use_bh_wq_enabled);
+			continue;
+
 		} else if (verity_is_fec_opt_arg(arg_name)) {
+			if (only_modifier_opts)
+				continue;
 			r = verity_fec_parse_opt_args(as, v, &argc, arg_name);
 			if (r)
 				return r;
 			continue;
+
+		} else if (verity_verify_is_sig_opt_arg(arg_name)) {
+			if (only_modifier_opts)
+				continue;
+			r = verity_verify_sig_parse_opt_args(as, v,
+							     verify_args,
+							     &argc, arg_name);
+			if (r)
+				return r;
+			continue;
+
+		} else if (only_modifier_opts) {
+			/*
+			 * Ignore unrecognized opt, could easily be an extra
+			 * argument to an option whose parsing was skipped.
+			 * Normal parsing (@only_modifier_opts=false) will
+			 * properly parse all options (and their extra args).
+			 */
+			continue;
 		}
 
+		DMERR("Unrecognized verity feature request: %s", arg_name);
 		ti->error = "Unrecognized verity feature request";
 		return -EINVAL;
 	} while (argc && !r);
@@ -913,6 +1234,75 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
 	return r;
 }
 
+static int verity_setup_hash_alg(struct dm_verity *v, const char *alg_name)
+{
+	struct dm_target *ti = v->ti;
+	struct crypto_shash *shash;
+
+	v->alg_name = kstrdup(alg_name, GFP_KERNEL);
+	if (!v->alg_name) {
+		ti->error = "Cannot allocate algorithm name";
+		return -ENOMEM;
+	}
+
+	shash = crypto_alloc_shash(alg_name, 0, 0);
+	if (IS_ERR(shash)) {
+		ti->error = "Cannot initialize hash function";
+		return PTR_ERR(shash);
+	}
+	v->shash_tfm = shash;
+	v->digest_size = crypto_shash_digestsize(shash);
+	DMINFO("%s using \"%s\"", alg_name, crypto_shash_driver_name(shash));
+	if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) {
+		ti->error = "Digest size too big";
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int verity_setup_salt_and_hashstate(struct dm_verity *v, const char *arg)
+{
+	struct dm_target *ti = v->ti;
+
+	if (strcmp(arg, "-") != 0) {
+		v->salt_size = strlen(arg) / 2;
+		v->salt = kmalloc(v->salt_size, GFP_KERNEL);
+		if (!v->salt) {
+			ti->error = "Cannot allocate salt";
+			return -ENOMEM;
+		}
+		if (strlen(arg) != v->salt_size * 2 ||
+		    hex2bin(v->salt, arg, v->salt_size)) {
+			ti->error = "Invalid salt";
+			return -EINVAL;
+		}
+	}
+	if (v->version) { /* Version 1: salt at beginning */
+		SHASH_DESC_ON_STACK(desc, v->shash_tfm);
+		int r;
+
+		/*
+		 * Compute the pre-salted hash state that can be passed to
+		 * crypto_shash_import() for each block later.
+		 */
+		v->initial_hashstate = kmalloc(
+			crypto_shash_statesize(v->shash_tfm), GFP_KERNEL);
+		if (!v->initial_hashstate) {
+			ti->error = "Cannot allocate initial hash state";
+			return -ENOMEM;
+		}
+		desc->tfm = v->shash_tfm;
+		r = crypto_shash_init(desc) ?:
+		    crypto_shash_update(desc, v->salt, v->salt_size) ?:
+		    crypto_shash_export(desc, v->initial_hashstate);
+		if (r) {
+			ti->error = "Cannot set up initial hash state";
+			return r;
+		}
+	}
+	return 0;
+}
+
 /*
  * Target parameters:
  *	<version>	The current format is version 1.
@@ -927,9 +1317,10 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v)
  *	<digest>
  *	<salt>		Hex string or "-" if no salt.
  */
-static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
+static int verity_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 {
 	struct dm_verity *v;
+	struct dm_verity_sig_opts verify_args = {0};
 	struct dm_arg_set as;
 	unsigned int num;
 	unsigned long long num_ll;
@@ -937,6 +1328,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	int i;
 	sector_t hash_position;
 	char dummy;
+	char *root_hash_digest_to_validate;
 
 	v = kzalloc(sizeof(struct dm_verity), GFP_KERNEL);
 	if (!v) {
@@ -950,7 +1342,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	if (r)
 		goto bad;
 
-	if ((dm_table_get_mode(ti->table) & ~FMODE_READ)) {
+	if ((dm_table_get_mode(ti->table) & ~BLK_OPEN_READ)) {
 		ti->error = "Device must be readonly";
 		r = -EINVAL;
 		goto bad;
@@ -962,6 +1354,15 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		goto bad;
 	}
 
+	/* Parse optional parameters that modify primary args */
+	if (argc > 10) {
+		as.argc = argc - 10;
+		as.argv = argv + 10;
+		r = verity_parse_opt_args(&as, v, &verify_args, true);
+		if (r < 0)
+			goto bad;
+	}
+
 	if (sscanf(argv[0], "%u%c", &num, &dummy) != 1 ||
 	    num > 1) {
 		ti->error = "Invalid version";
@@ -970,13 +1371,13 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	}
 	v->version = num;
 
-	r = dm_get_device(ti, argv[1], FMODE_READ, &v->data_dev);
+	r = dm_get_device(ti, argv[1], BLK_OPEN_READ, &v->data_dev);
 	if (r) {
 		ti->error = "Data device lookup failed";
 		goto bad;
 	}
 
-	r = dm_get_device(ti, argv[2], FMODE_READ, &v->hash_dev);
+	r = dm_get_device(ti, argv[2], BLK_OPEN_READ, &v->hash_dev);
 	if (r) {
 		ti->error = "Hash device lookup failed";
 		goto bad;
@@ -1026,37 +1427,9 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	}
 	v->hash_start = num_ll;
 
-	v->alg_name = kstrdup(argv[7], GFP_KERNEL);
-	if (!v->alg_name) {
-		ti->error = "Cannot allocate algorithm name";
-		r = -ENOMEM;
-		goto bad;
-	}
-
-	v->tfm = crypto_alloc_ahash(v->alg_name, 0, 0);
-	if (IS_ERR(v->tfm)) {
-		ti->error = "Cannot initialize hash function";
-		r = PTR_ERR(v->tfm);
-		v->tfm = NULL;
-		goto bad;
-	}
-
-	/*
-	 * dm-verity performance can vary greatly depending on which hash
-	 * algorithm implementation is used.  Help people debug performance
-	 * problems by logging the ->cra_driver_name.
-	 */
-	DMINFO("%s using implementation \"%s\"", v->alg_name,
-	       crypto_hash_alg_common(v->tfm)->base.cra_driver_name);
-
-	v->digest_size = crypto_ahash_digestsize(v->tfm);
-	if ((1 << v->hash_dev_block_bits) < v->digest_size * 2) {
-		ti->error = "Digest size too big";
-		r = -EINVAL;
+	r = verity_setup_hash_alg(v, argv[7]);
+	if (r)
 		goto bad;
-	}
-	v->ahash_reqsize = sizeof(struct ahash_request) +
-		crypto_ahash_reqsize(v->tfm);
 
 	v->root_digest = kmalloc(v->digest_size, GFP_KERNEL);
 	if (!v->root_digest) {
@@ -1070,22 +1443,11 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		r = -EINVAL;
 		goto bad;
 	}
+	root_hash_digest_to_validate = argv[8];
 
-	if (strcmp(argv[9], "-")) {
-		v->salt_size = strlen(argv[9]) / 2;
-		v->salt = kmalloc(v->salt_size, GFP_KERNEL);
-		if (!v->salt) {
-			ti->error = "Cannot allocate salt";
-			r = -ENOMEM;
-			goto bad;
-		}
-		if (strlen(argv[9]) != v->salt_size * 2 ||
-		    hex2bin(v->salt, argv[9], v->salt_size)) {
-			ti->error = "Invalid salt";
-			r = -EINVAL;
-			goto bad;
-		}
-	}
+	r = verity_setup_salt_and_hashstate(v, argv[9]);
+	if (r)
+		goto bad;
 
 	argv += 10;
 	argc -= 10;
@@ -1094,12 +1456,27 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	if (argc) {
 		as.argc = argc;
 		as.argv = argv;
-
-		r = verity_parse_opt_args(&as, v);
+		r = verity_parse_opt_args(&as, v, &verify_args, false);
 		if (r < 0)
 			goto bad;
 	}
 
+	/* Root hash signature is an optional parameter */
+	r = verity_verify_root_hash(root_hash_digest_to_validate,
+				    strlen(root_hash_digest_to_validate),
+				    verify_args.sig,
+				    verify_args.sig_size);
+	if (r < 0) {
+		ti->error = "Root hash verification failed";
+		goto bad;
+	}
+
+	r = verity_init_sig(v, verify_args.sig, verify_args.sig_size);
+	if (r < 0) {
+		ti->error = "Cannot allocate root digest signature";
+		goto bad;
+	}
+
 	v->hash_per_block_bits =
 		__fls((1 << v->hash_dev_block_bits) / v->digest_size);
 
@@ -1119,6 +1496,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	hash_position = v->hash_start;
 	for (i = v->levels - 1; i >= 0; i--) {
 		sector_t s;
+
 		v->hash_level_block[i] = hash_position;
 		s = (v->data_blocks + ((sector_t)1 << ((i + 1) * v->hash_per_block_bits)) - 1)
 					>> ((i + 1) * v->hash_per_block_bits);
@@ -1131,9 +1509,24 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	}
 	v->hash_blocks = hash_position;
 
+	r = mempool_init_page_pool(&v->recheck_pool, 1, 0);
+	if (unlikely(r)) {
+		ti->error = "Cannot allocate mempool";
+		goto bad;
+	}
+
+	v->io = dm_io_client_create();
+	if (IS_ERR(v->io)) {
+		r = PTR_ERR(v->io);
+		v->io = NULL;
+		ti->error = "Cannot allocate dm io";
+		goto bad;
+	}
+
 	v->bufio = dm_bufio_client_create(v->hash_dev->bdev,
 		1 << v->hash_dev_block_bits, 1, sizeof(struct buffer_aux),
-		dm_bufio_alloc_callback, NULL);
+		dm_bufio_alloc_callback, NULL,
+		v->use_bh_wq ? DM_BUFIO_CLIENT_NO_SLEEP : 0);
 	if (IS_ERR(v->bufio)) {
 		ti->error = "Cannot initialize dm-bufio";
 		r = PTR_ERR(v->bufio);
@@ -1147,8 +1540,16 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 		goto bad;
 	}
 
-	/* WQ_UNBOUND greatly improves performance when running on ramdisk */
-	v->verify_wq = alloc_workqueue("kverityd", WQ_CPU_INTENSIVE | WQ_MEM_RECLAIM | WQ_UNBOUND, num_online_cpus());
+	/*
+	 * Using WQ_HIGHPRI improves throughput and completion latency by
+	 * reducing wait times when reading from a dm-verity device.
+	 *
+	 * Also as required for the "try_verify_in_tasklet" feature: WQ_HIGHPRI
+	 * allows verify_wq to preempt softirq since verification in BH workqueue
+	 * will fall-back to using it for error handling (or if the bufio cache
+	 * doesn't have required hashes).
+	 */
+	v->verify_wq = alloc_workqueue("kverityd", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
 	if (!v->verify_wq) {
 		ti->error = "Cannot allocate workqueue";
 		r = -ENOMEM;
@@ -1156,7 +1557,7 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	}
 
 	ti->per_io_data_size = sizeof(struct dm_verity_io) +
-				v->ahash_reqsize + v->digest_size * 2;
+			       crypto_shash_descsize(v->shash_tfm);
 
 	r = verity_fec_ctr(v);
 	if (r)
@@ -1165,46 +1566,154 @@ static int verity_ctr(struct dm_target *ti, unsigned argc, char **argv)
 	ti->per_io_data_size = roundup(ti->per_io_data_size,
 				       __alignof__(struct dm_verity_io));
 
+	verity_verify_sig_opts_cleanup(&verify_args);
+
+	dm_audit_log_ctr(DM_MSG_PREFIX, ti, 1);
+
 	return 0;
 
 bad:
+
+	verity_verify_sig_opts_cleanup(&verify_args);
+	dm_audit_log_ctr(DM_MSG_PREFIX, ti, 0);
 	verity_dtr(ti);
 
 	return r;
 }
 
+/*
+ * Get the verity mode (error behavior) of a verity target.
+ *
+ * Returns the verity mode of the target, or -EINVAL if 'ti' is not a verity
+ * target.
+ */
+int dm_verity_get_mode(struct dm_target *ti)
+{
+	struct dm_verity *v = ti->private;
+
+	if (!dm_is_verity_target(ti))
+		return -EINVAL;
+
+	return v->mode;
+}
+
+/*
+ * Get the root digest of a verity target.
+ *
+ * Returns a copy of the root digest, the caller is responsible for
+ * freeing the memory of the digest.
+ */
+int dm_verity_get_root_digest(struct dm_target *ti, u8 **root_digest, unsigned int *digest_size)
+{
+	struct dm_verity *v = ti->private;
+
+	if (!dm_is_verity_target(ti))
+		return -EINVAL;
+
+	*root_digest = kmemdup(v->root_digest, v->digest_size, GFP_KERNEL);
+	if (*root_digest == NULL)
+		return -ENOMEM;
+
+	*digest_size = v->digest_size;
+
+	return 0;
+}
+
+#ifdef CONFIG_SECURITY
+
+#ifdef CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG
+
+static int verity_security_set_signature(struct block_device *bdev,
+					 struct dm_verity *v)
+{
+	/*
+	 * if the dm-verity target is unsigned, v->root_digest_sig will
+	 * be NULL, and the hook call is still required to let LSMs mark
+	 * the device as unsigned. This information is crucial for LSMs to
+	 * block operations such as execution on unsigned files
+	 */
+	return security_bdev_setintegrity(bdev,
+					  LSM_INT_DMVERITY_SIG_VALID,
+					  v->root_digest_sig,
+					  v->sig_size);
+}
+
+#else
+
+static inline int verity_security_set_signature(struct block_device *bdev,
+						struct dm_verity *v)
+{
+	return 0;
+}
+
+#endif /* CONFIG_DM_VERITY_VERIFY_ROOTHASH_SIG */
+
+/*
+ * Expose verity target's root hash and signature data to LSMs before resume.
+ *
+ * Returns 0 on success, or -ENOMEM if the system is out of memory.
+ */
+static int verity_preresume(struct dm_target *ti)
+{
+	struct block_device *bdev;
+	struct dm_verity_digest root_digest;
+	struct dm_verity *v;
+	int r;
+
+	v = ti->private;
+	bdev = dm_disk(dm_table_get_md(ti->table))->part0;
+	root_digest.digest = v->root_digest;
+	root_digest.digest_len = v->digest_size;
+	root_digest.alg = crypto_shash_alg_name(v->shash_tfm);
+
+	r = security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, &root_digest,
+				       sizeof(root_digest));
+	if (r)
+		return r;
+
+	r =  verity_security_set_signature(bdev, v);
+	if (r)
+		goto bad;
+
+	return 0;
+
+bad:
+
+	security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, NULL, 0);
+
+	return r;
+}
+
+#endif /* CONFIG_SECURITY */
+
 static struct target_type verity_target = {
 	.name		= "verity",
-	.version	= {1, 4, 0},
+/* Note: the LSMs depend on the singleton and immutable features */
+	.features	= DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
+	.version	= {1, 12, 0},
 	.module		= THIS_MODULE,
 	.ctr		= verity_ctr,
 	.dtr		= verity_dtr,
 	.map		= verity_map,
+	.postsuspend	= verity_postsuspend,
 	.status		= verity_status,
 	.prepare_ioctl	= verity_prepare_ioctl,
 	.iterate_devices = verity_iterate_devices,
 	.io_hints	= verity_io_hints,
+#ifdef CONFIG_SECURITY
+	.preresume	= verity_preresume,
+#endif /* CONFIG_SECURITY */
 };
+module_dm(verity);
 
-static int __init dm_verity_init(void)
-{
-	int r;
-
-	r = dm_register_target(&verity_target);
-	if (r < 0)
-		DMERR("register failed %d", r);
-
-	return r;
-}
-
-static void __exit dm_verity_exit(void)
+/*
+ * Check whether a DM target is a verity target.
+ */
+bool dm_is_verity_target(struct dm_target *ti)
 {
-	dm_unregister_target(&verity_target);
+	return ti->type == &verity_target;
 }
 
-module_init(dm_verity_init);
-module_exit(dm_verity_exit);
-
 MODULE_AUTHOR("Mikulas Patocka <mpatocka@redhat.com>");
 MODULE_AUTHOR("Mandeep Baines <msb@chromium.org>");
 MODULE_AUTHOR("Will Drewry <wad@chromium.org>");