#include "dm-audit.h"
#include <linux/module.h>
#include <linux/reboot.h>
-#include <linux/scatterlist.h>
#include <linux/string.h>
#include <linux/jump_label.h>
#include <linux/security.h>
static DEFINE_STATIC_KEY_FALSE(use_bh_wq_enabled);
-/* Is at least one dm-verity instance using ahash_tfm instead of shash_tfm? */
-static DEFINE_STATIC_KEY_FALSE(ahash_enabled);
-
struct dm_verity_prefetch_work {
struct work_struct work;
struct dm_verity *v;
return block >> (level * v->hash_per_block_bits);
}
-static int verity_ahash_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);
- }
-
- 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_ahash_init(struct dm_verity *v, struct ahash_request *req,
- struct crypto_wait *wait, bool may_sleep)
-{
- int r;
-
- ahash_request_set_tfm(req, v->ahash_tfm);
- ahash_request_set_callback(req,
- may_sleep ? CRYPTO_TFM_REQ_MAY_SLEEP | CRYPTO_TFM_REQ_MAY_BACKLOG : 0,
- crypto_req_done, (void *)wait);
- crypto_init_wait(wait);
-
- r = crypto_wait_req(crypto_ahash_init(req), wait);
-
- if (unlikely(r < 0)) {
- if (r != -ENOMEM)
- DMERR("crypto_ahash_init failed: %d", r);
- return r;
- }
-
- if (likely(v->salt_size && (v->version >= 1)))
- r = verity_ahash_update(v, req, v->salt, v->salt_size, wait);
-
- return r;
-}
-
-static int verity_ahash_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_ahash_update(v, req, v->salt, v->salt_size, wait);
-
- if (r < 0) {
- DMERR("%s failed updating salt: %d", __func__, 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 dm_verity_io *io,
- const u8 *data, size_t len, u8 *digest, bool may_sleep)
+ const u8 *data, size_t len, u8 *digest)
{
+ struct shash_desc *desc = &io->hash_desc;
int r;
- if (static_branch_unlikely(&ahash_enabled) && !v->shash_tfm) {
- struct ahash_request *req = verity_io_hash_req(v, io);
- struct crypto_wait wait;
-
- r = verity_ahash_init(v, req, &wait, may_sleep) ?:
- verity_ahash_update(v, req, data, len, &wait) ?:
- verity_ahash_final(v, req, digest, &wait);
+ 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 {
- struct shash_desc *desc = verity_io_hash_req(v, io);
-
- desc->tfm = v->shash_tfm;
+ /* Version 1: salt at beginning */
r = crypto_shash_import(desc, v->initial_hashstate) ?:
crypto_shash_finup(desc, data, len, digest);
}
}
r = verity_hash(v, io, data, 1 << v->hash_dev_block_bits,
- verity_io_real_digest(v, io), !io->in_bh);
+ verity_io_real_digest(v, io));
if (unlikely(r < 0))
goto release_ret_r;
goto free_ret;
r = verity_hash(v, io, buffer, 1 << v->data_dev_block_bits,
- verity_io_real_digest(v, io), true);
+ verity_io_real_digest(v, io));
if (unlikely(r))
goto free_ret;
}
r = verity_hash(v, io, data, block_size,
- verity_io_real_digest(v, io), !io->in_bh);
+ verity_io_real_digest(v, io));
if (unlikely(r < 0)) {
kunmap_local(data);
return r;
kfree(v->zero_digest);
verity_free_sig(v);
- if (v->ahash_tfm) {
- static_branch_dec(&ahash_enabled);
- crypto_free_ahash(v->ahash_tfm);
- } else {
- crypto_free_shash(v->shash_tfm);
- }
+ crypto_free_shash(v->shash_tfm);
kfree(v->alg_name);
if (!v->zero_digest)
return r;
- io = kmalloc(sizeof(*io) + v->hash_reqsize, GFP_KERNEL);
+ io = kmalloc(sizeof(*io) + crypto_shash_descsize(v->shash_tfm),
+ GFP_KERNEL);
if (!io)
return r; /* verity_dtr will free zero_digest */
goto out;
r = verity_hash(v, io, zero_data, 1 << v->data_dev_block_bits,
- v->zero_digest, true);
+ v->zero_digest);
out:
kfree(io);
static int verity_setup_hash_alg(struct dm_verity *v, const char *alg_name)
{
struct dm_target *ti = v->ti;
- struct crypto_ahash *ahash;
- struct crypto_shash *shash = NULL;
- const char *driver_name;
+ struct crypto_shash *shash;
v->alg_name = kstrdup(alg_name, GFP_KERNEL);
if (!v->alg_name) {
return -ENOMEM;
}
- /*
- * Allocate the hash transformation object that this dm-verity instance
- * will use. The vast majority of dm-verity users use CPU-based
- * hashing, so when possible use the shash API to minimize the crypto
- * API overhead. If the ahash API resolves to a different driver
- * (likely an off-CPU hardware offload), use ahash instead. Also use
- * ahash if the obsolete dm-verity format with the appended salt is
- * being used, so that quirk only needs to be handled in one place.
- */
- ahash = crypto_alloc_ahash(alg_name, 0,
- v->use_bh_wq ? CRYPTO_ALG_ASYNC : 0);
- if (IS_ERR(ahash)) {
+ shash = crypto_alloc_shash(alg_name, 0, 0);
+ if (IS_ERR(shash)) {
ti->error = "Cannot initialize hash function";
- return PTR_ERR(ahash);
- }
- driver_name = crypto_ahash_driver_name(ahash);
- if (v->version >= 1 /* salt prepended, not appended? */) {
- shash = crypto_alloc_shash(alg_name, 0, 0);
- if (!IS_ERR(shash) &&
- strcmp(crypto_shash_driver_name(shash), driver_name) != 0) {
- /*
- * ahash gave a different driver than shash, so probably
- * this is a case of real hardware offload. Use ahash.
- */
- crypto_free_shash(shash);
- shash = NULL;
- }
- }
- if (!IS_ERR_OR_NULL(shash)) {
- crypto_free_ahash(ahash);
- ahash = NULL;
- v->shash_tfm = shash;
- v->digest_size = crypto_shash_digestsize(shash);
- v->hash_reqsize = sizeof(struct shash_desc) +
- crypto_shash_descsize(shash);
- DMINFO("%s using shash \"%s\"", alg_name, driver_name);
- } else {
- v->ahash_tfm = ahash;
- static_branch_inc(&ahash_enabled);
- v->digest_size = crypto_ahash_digestsize(ahash);
- v->hash_reqsize = sizeof(struct ahash_request) +
- crypto_ahash_reqsize(ahash);
- DMINFO("%s using ahash \"%s\"", alg_name, driver_name);
+ 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 -EINVAL;
}
}
- if (v->shash_tfm) {
+ if (v->version) { /* Version 1: salt at beginning */
SHASH_DESC_ON_STACK(desc, v->shash_tfm);
int r;
goto bad;
}
- ti->per_io_data_size = sizeof(struct dm_verity_io) + v->hash_reqsize;
+ ti->per_io_data_size = sizeof(struct dm_verity_io) +
+ crypto_shash_descsize(v->shash_tfm);
r = verity_fec_ctr(v);
if (r)
bdev = dm_disk(dm_table_get_md(ti->table))->part0;
root_digest.digest = v->root_digest;
root_digest.digest_len = v->digest_size;
- if (static_branch_unlikely(&ahash_enabled) && !v->shash_tfm)
- root_digest.alg = crypto_ahash_alg_name(v->ahash_tfm);
- else
- root_digest.alg = crypto_shash_alg_name(v->shash_tfm);
+ root_digest.alg = crypto_shash_alg_name(v->shash_tfm);
r = security_bdev_setintegrity(bdev, LSM_INT_DMVERITY_ROOTHASH, &root_digest,
sizeof(root_digest));
.name = "verity",
/* Note: the LSMs depend on the singleton and immutable features */
.features = DM_TARGET_SINGLETON | DM_TARGET_IMMUTABLE,
- .version = {1, 11, 0},
+ .version = {1, 12, 0},
.module = THIS_MODULE,
.ctr = verity_ctr,
.dtr = verity_dtr,
struct dm_target *ti;
struct dm_bufio_client *bufio;
char *alg_name;
- struct crypto_ahash *ahash_tfm; /* either this or shash_tfm is set */
- struct crypto_shash *shash_tfm; /* either this or ahash_tfm is set */
+ struct crypto_shash *shash_tfm;
u8 *root_digest; /* digest of the root block */
u8 *salt; /* salt: its size is salt_size */
- u8 *initial_hashstate; /* salted initial state, if shash_tfm is set */
+ u8 *initial_hashstate; /* salted initial state, if version >= 1 */
u8 *zero_digest; /* digest for a zero block */
#ifdef CONFIG_SECURITY
u8 *root_digest_sig; /* signature of the root digest */
bool hash_failed:1; /* set if hash of any block failed */
bool use_bh_wq:1; /* try to verify in BH wq before normal work-queue */
unsigned int digest_size; /* digest size for the current hash algorithm */
- unsigned int hash_reqsize; /* the size of temporary space for crypto */
enum verity_mode mode; /* mode for handling verification errors */
enum verity_mode error_mode;/* mode for handling I/O errors */
unsigned int corrupted_errs;/* Number of errors for corrupted blocks */
u8 want_digest[HASH_MAX_DIGESTSIZE];
/*
- * This struct is followed by a variable-sized hash request of size
- * v->hash_reqsize, either a struct ahash_request or a struct shash_desc
- * (depending on whether ahash_tfm or shash_tfm is being used). To
- * access it, use verity_io_hash_req().
+ * Temporary space for hashing. This is variable-length and must be at
+ * the end of the struct. struct shash_desc is just the fixed part;
+ * it's followed by a context of size crypto_shash_descsize(shash_tfm).
*/
+ struct shash_desc hash_desc;
};
-static inline void *verity_io_hash_req(struct dm_verity *v,
- struct dm_verity_io *io)
-{
- return io + 1;
-}
-
static inline u8 *verity_io_real_digest(struct dm_verity *v,
struct dm_verity_io *io)
{
}
extern int verity_hash(struct dm_verity *v, struct dm_verity_io *io,
- const u8 *data, size_t len, u8 *digest, bool may_sleep);
+ const u8 *data, size_t len, u8 *digest);
extern int verity_hash_for_block(struct dm_verity *v, struct dm_verity_io *io,
sector_t block, u8 *digest, bool *is_zero);
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