Introduce ahash support for the "internal hash" algorithm.
Rework the dm-integrity code to be able to run the "internal hash"
either with a synchronous ("shash") or asynchronous ("ahash") hash
algorithm implementation.
The get_mac() function now tries to decide which of the digest
implemenations to use if there is a choice:
- If an ahash and shash tfm is available and both are backed by the
same driver name it is assumed that the shash is the faster
implementation and thus the shash tfm is delivered to the caller.
- If an ahash and shash tfm is available but the backing device driver
divers (different driver names) it is assumed that the ahash
implementation is a "better" hardware based implementation and thus
the ahash tfm is delivered to the caller.
- If there is no choice, for example only an ahash or an shash
implementation is available then this tfm is delivered to the
caller. Especially in cases where only an ahash implementation is
available this is now used instead of failing.
- The caller can steer this choice by passing a NULL to the ahash or
shash parameter, thus enforcing to only allocate an algorithm of the
remaining possibility.
The function integrity_sector_checksum() is now only a dispatcher
function calling one of the two new functions
integrity_ahash_sector_checksum() or integrity_shash_sector_checksum()
based on which tfm is allocated based on the two new fields
internal_shash and internal_ahash in struct dm_integrity_c.
Together with this comes some slight rework around availability and
digest size of the internal hash in use.
Signed-off-by: Harald Freudenberger <freude@xxxxxxxxxxxxx>
---
drivers/md/dm-integrity.c | 215 +++++++++++++++++++++++++++++---------
1 file changed, 168 insertions(+), 47 deletions(-)
diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index af0276ad84bd..a1ffc85ae6a7 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -221,7 +221,9 @@ struct dm_integrity_c {
int failed;
- struct crypto_shash *internal_hash;
+ bool have_internal_hash;
+ struct crypto_shash *internal_shash;
+ struct crypto_ahash *internal_ahash;
unsigned int internal_hash_digestsize;
struct dm_target *ti;
@@ -1635,57 +1637,128 @@ static void integrity_end_io(struct bio *bio)
dec_in_flight(dio);
}
-static void integrity_sector_checksum(struct dm_integrity_c *ic, sector_t sector,
- const char *data, char *result)
+static bool integrity_shash_sector_checksum(struct dm_integrity_c *ic,
+ sector_t sector, const char *data,
+ char *result)
{
__le64 sector_le = cpu_to_le64(sector);
- SHASH_DESC_ON_STACK(req, ic->internal_hash);
+ SHASH_DESC_ON_STACK(req, ic->internal_shash);
int r;
- unsigned int digest_size;
- req->tfm = ic->internal_hash;
+ req->tfm = ic->internal_shash;
r = crypto_shash_init(req);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_init", r);
- goto failed;
+ return false;
}
if (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) {
r = crypto_shash_update(req, (__u8 *)&ic->sb->salt, SALT_SIZE);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_update", r);
- goto failed;
+ return false;
}
}
r = crypto_shash_update(req, (const __u8 *)§or_le, sizeof(sector_le));
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_update", r);
- goto failed;
+ return false;
}
r = crypto_shash_update(req, data, ic->sectors_per_block << SECTOR_SHIFT);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_update", r);
- goto failed;
+ return false;
}
r = crypto_shash_final(req, result);
if (unlikely(r < 0)) {
dm_integrity_io_error(ic, "crypto_shash_final", r);
- goto failed;
+ return false;
}
- digest_size = ic->internal_hash_digestsize;
- if (unlikely(digest_size < ic->tag_size))
- memset(result + digest_size, 0, ic->tag_size - digest_size);
+ if (unlikely(ic->internal_hash_digestsize < ic->tag_size))
+ memset(result + ic->internal_hash_digestsize,
+ 0, ic->tag_size - ic->internal_hash_digestsize);
- return;
+ return true;
+}
+
+static bool integrity_ahash_sector_checksum(struct dm_integrity_c *ic,
+ sector_t sector, const char *data,
+ char *result)
+{
+ struct ahash_request *req = NULL;
+ struct scatterlist sg[3], *s;
+ DECLARE_CRYPTO_WAIT(wait);
+ __le64 *sector_le = NULL;
+ unsigned int nbytes = 0;
+ int r = -ENOMEM;
+
+ req = ahash_request_alloc(ic->internal_ahash, GFP_KERNEL);
+ if (unlikely(!req)) {
+ dm_integrity_io_error(ic, "ahash_request_alloc", r);
+ return false;
+ }
+ ahash_request_set_callback(req, 0, crypto_req_done, &wait);
+
+ s = sg;
+ if (ic->sb->flags & cpu_to_le32(SB_FLAG_FIXED_HMAC)) {
+ sg_init_table(sg, 3);
+ sg_set_buf(s, (const __u8 *)&ic->sb->salt, SALT_SIZE);
+ nbytes += SALT_SIZE;
+ s++;
+ } else {
+ sg_init_table(sg, 2);
+ }
+
+ sector_le = kmalloc(sizeof(__le64), GFP_KERNEL);
+ if (unlikely(!sector_le)) {
+ dm_integrity_io_error(ic, "kmalloc(sizeof(__le64))", r);
+ goto out;
+ }
+ *sector_le = cpu_to_le64(sector);
+ sg_set_buf(s, (const __u8 *)sector_le, sizeof(*sector_le));
+ nbytes += sizeof(*sector_le);
+ s++;
+
+ sg_set_buf(s, data, ic->sectors_per_block << SECTOR_SHIFT);
+ nbytes += ic->sectors_per_block << SECTOR_SHIFT;
+
+ ahash_request_set_crypt(req, sg, result, nbytes);
+
+ r = crypto_wait_req(crypto_ahash_digest(req), &wait);
+ if (r) {
+ dm_integrity_io_error(ic, "crypto_ahash_digest", r);
+ goto out;
+ }
+
+ if (unlikely(ic->internal_hash_digestsize < ic->tag_size))
+ memset(result + ic->internal_hash_digestsize,
+ 0, ic->tag_size - ic->internal_hash_digestsize);
-failed:
- /* this shouldn't happen anyway, the hash functions have no reason to fail */
- get_random_bytes(result, ic->tag_size);
+out:
+ ahash_request_free(req);
+ kfree(sector_le);
+
+ return r ? false : true;
+}
+
+static void integrity_sector_checksum(struct dm_integrity_c *ic,
+ sector_t sector, const char *data,
+ char *result)
+{
+ bool r;
+
+ if (likely(ic->internal_shash))
+ r = integrity_shash_sector_checksum(ic, sector, data, result);
+ else
+ r = integrity_ahash_sector_checksum(ic, sector, data, result);
+
+ if (unlikely(!r))
+ get_random_bytes(result, ic->tag_size);
}
static noinline void integrity_recheck(struct dm_integrity_io *dio, char *checksum)
@@ -1774,7 +1847,7 @@ static void integrity_metadata(struct work_struct *w)
int r;
- if (ic->internal_hash) {
+ if (ic->have_internal_hash) {
struct bvec_iter iter;
struct bio_vec bv;
unsigned int digest_size = ic->internal_hash_digestsize;
@@ -1992,7 +2065,7 @@ static int dm_integrity_map(struct dm_target *ti, struct bio *bio)
return DM_MAPIO_KILL;
bip = bio_integrity(bio);
- if (!ic->internal_hash) {
+ if (!ic->have_internal_hash) {
if (bip) {
unsigned int wanted_tag_size = bio_sectors(bio) >> ic->sb->log2_sectors_per_block;
@@ -2073,7 +2146,7 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio,
mem_ptr += 1 << SECTOR_SHIFT;
} while (++s < ic->sectors_per_block);
#ifdef INTERNAL_VERIFY
- if (ic->internal_hash) {
+ if (ic->have_internal_hash) {
char checksums_onstack[MAX_T(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
integrity_sector_checksum(ic, logical_sector, mem + bv.bv_offset, checksums_onstack);
@@ -2087,7 +2160,7 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio,
#endif
}
- if (!ic->internal_hash) {
+ if (!ic->have_internal_hash) {
struct bio_integrity_payload *bip = bio_integrity(bio);
unsigned int tag_todo = ic->tag_size;
char *tag_ptr = journal_entry_tag(ic, je);
@@ -2124,7 +2197,7 @@ static bool __journal_read_write(struct dm_integrity_io *dio, struct bio *bio,
je->last_bytes[s] = js[s].commit_id;
} while (++s < ic->sectors_per_block);
- if (ic->internal_hash) {
+ if (ic->have_internal_hash) {
unsigned int digest_size = ic->internal_hash_digestsize;
if (unlikely(digest_size > ic->tag_size)) {
@@ -2187,7 +2260,7 @@ static void dm_integrity_map_continue(struct dm_integrity_io *dio, bool from_map
sector_t recalc_sector;
struct completion read_comp;
bool discard_retried = false;
- bool need_sync_io = ic->internal_hash && dio->op == REQ_OP_READ;
+ bool need_sync_io = ic->have_internal_hash && dio->op == REQ_OP_READ;
if (unlikely(dio->op == REQ_OP_DISCARD) && ic->mode != 'D')
need_sync_io = true;
@@ -2908,7 +2981,7 @@ static void do_journal_write(struct dm_integrity_c *ic, unsigned int write_start
#ifndef INTERNAL_VERIFY
unlikely(from_replay) &&
#endif
- ic->internal_hash) {
+ ic->have_internal_hash) {
char test_tag[MAX_T(size_t, HASH_MAX_DIGESTSIZE, MAX_TAG_SIZE)];
integrity_sector_checksum(ic, sec + ((l - j) << ic->sb->log2_sectors_per_block),
@@ -3905,7 +3978,7 @@ static void dm_integrity_io_hints(struct dm_target *ti, struct queue_limits *lim
limits->discard_granularity = ic->sectors_per_block << SECTOR_SHIFT;
}
- if (!ic->internal_hash) {
+ if (!ic->have_internal_hash) {
struct blk_integrity *bi = &limits->integrity;
memset(bi, 0, sizeof(*bi));
@@ -4213,32 +4286,76 @@ static int get_alg_and_key(const char *arg, struct alg_spec *a, char **error, ch
return -ENOMEM;
}
-static int get_mac(struct crypto_shash **hash, struct alg_spec *a, char **error,
+static int get_mac(struct crypto_shash **shash, struct crypto_ahash **ahash,
+ struct alg_spec *a, char **error,
char *error_alg, char *error_key)
{
+ const char *ahash_driver_name = NULL;
int r;
- if (a->alg_string) {
- *hash = crypto_alloc_shash(a->alg_string, 0, CRYPTO_ALG_ALLOCATES_MEMORY);
- if (IS_ERR(*hash)) {
+ if (!a->alg_string || !(shash || ahash))
+ return 0;
+
+ if (ahash) {
+ *ahash = crypto_alloc_ahash(a->alg_string, 0, 0);
+ if (IS_ERR(*ahash)) {
*error = error_alg;
- r = PTR_ERR(*hash);
- *hash = NULL;
+ r = PTR_ERR(*ahash);
+ *ahash = NULL;
return r;
}
+ ahash_driver_name = crypto_ahash_driver_name(*ahash);
+ }
- if (a->key) {
- r = crypto_shash_setkey(*hash, a->key, a->key_size);
- if (r) {
- *error = error_key;
- return r;
+ if (shash) {
+ *shash = crypto_alloc_shash(a->alg_string, 0, CRYPTO_ALG_ALLOCATES_MEMORY);
+ if (IS_ERR(*shash) && !ahash_driver_name) {
+ *error = error_alg;
+ r = PTR_ERR(*shash);
+ *shash = NULL;
+ return r;
+ }
+ if (!IS_ERR(shash) && ahash_driver_name) {
+ if (strcmp(crypto_shash_driver_name(*shash), ahash_driver_name)) {
+ /*
+ * 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;
+ } else {
+ /* ahash and shash are same driver. Use shash. */
+ crypto_free_ahash(*ahash);
+ *ahash = NULL;
}
- } else if (crypto_shash_get_flags(*hash) & CRYPTO_TFM_NEED_KEY) {
+ }
+ }
+
+ /* either *ahash or *shash is set now */
+
+ if (a->key) {
+ r = shash && *shash ?
+ crypto_shash_setkey(*shash, a->key, a->key_size) :
+ crypto_ahash_setkey(*ahash, a->key, a->key_size);
+ if (r) {
*error = error_key;
- return -ENOKEY;
+ return r;
}
+ } else if ((shash && *shash ?
+ crypto_shash_get_flags(*shash) :
+ crypto_ahash_get_flags(*ahash))
+ & CRYPTO_TFM_NEED_KEY) {
+ *error = error_key;
+ return -ENOKEY;
}
+ pr_debug("Using %s %s (driver name %s)\n",
+ ahash && *ahash ? "ahash" : "shash",
+ a->alg_string,
+ ahash && *ahash ?
+ crypto_ahash_driver_name(*ahash) :
+ crypto_shash_driver_name(*shash));
+
return 0;
}
@@ -4693,18 +4810,20 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
buffer_sectors = 1;
ic->log2_buffer_sectors = min((int)__fls(buffer_sectors), 31 - SECTOR_SHIFT);
- r = get_mac(&ic->internal_hash, &ic->internal_hash_alg, &ti->error,
+ r = get_mac(&ic->internal_shash, &ic->internal_ahash,
+ &ic->internal_hash_alg, &ti->error,
"Invalid internal hash", "Error setting internal hash key");
if (r)
goto bad;
+ ic->have_internal_hash = ic->internal_shash || ic->internal_ahash;
- r = get_mac(&ic->journal_mac, &ic->journal_mac_alg, &ti->error,
+ r = get_mac(&ic->journal_mac, NULL, &ic->journal_mac_alg, &ti->error,
"Invalid journal mac", "Error setting journal mac key");
if (r)
goto bad;
if (!ic->tag_size) {
- if (!ic->internal_hash) {
+ if (!ic->have_internal_hash) {
ti->error = "Unknown tag size";
r = -EINVAL;
goto bad;
@@ -4768,13 +4887,13 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
}
}
- if (ic->mode == 'B' && !ic->internal_hash) {
+ if (ic->mode == 'B' && !ic->have_internal_hash) {
r = -EINVAL;
ti->error = "Bitmap mode can be only used with internal hash";
goto bad;
}
- if (ic->discard && !ic->internal_hash) {
+ if (ic->discard && !ic->have_internal_hash) {
r = -EINVAL;
ti->error = "Discard can be only used with internal hash";
goto bad;
@@ -5036,7 +5155,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
ic->sb->recalc_sector = cpu_to_le64(0);
}
- if (ic->internal_hash) {
+ if (ic->have_internal_hash) {
ic->recalc_wq = alloc_workqueue("dm-integrity-recalc", WQ_MEM_RECLAIM, 1);
if (!ic->recalc_wq) {
ti->error = "Cannot allocate workqueue";
@@ -5227,8 +5346,10 @@ static void dm_integrity_dtr(struct dm_target *ti)
if (ic->sb)
free_pages_exact(ic->sb, SB_SECTORS << SECTOR_SHIFT);
- if (ic->internal_hash)
- crypto_free_shash(ic->internal_hash);
+ if (ic->internal_shash)
+ crypto_free_shash(ic->internal_shash);
+ if (ic->internal_ahash)
+ crypto_free_ahash(ic->internal_ahash);
free_alg(&ic->internal_hash_alg);
if (ic->journal_crypt)
--
2.43.0
