[PATCH 2/6] crypto: ahash - Handle partial blocks in API

Herbert Xu
2025-05-05T12:32:45Z

Provide an option to handle the partial blocks in the ahash API.
Almost every hash algorithm has a block size and are only able
to hash partial blocks on finalisation.

As a first step disable virtual address support for algorithms
with state sizes larger than HASH_MAX_STATESIZE. This is OK as
virtual addresses are currently only used on synchronous fallbacks.

This means ahash_do_req_chain only needs to handle synchronous
fallbacks, removing the complexities of saving the request state.

Also move the saved request state into the ahash_request object
as nesting is no longer possible.

Add a scatterlist to ahash_request to store the partial block.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
crypto/ahash.c | 542 ++++++++++++++++++++----------------------
include/crypto/hash.h | 12 +-
2 files changed, 265 insertions(+), 289 deletions(-)

diff --git a/crypto/ahash.c b/crypto/ahash.c
index 344bf1b43e71..2a29c4a73d36 100644
--- a/crypto/ahash.c
+++ b/crypto/ahash.c
@@ -12,11 +12,13 @@
* Copyright (c) 2008 Loc Ho <lho@amcc.com>
*/

+#include <crypto/scatterwalk.h>
#include <linux/cryptouser.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
+#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/seq_file.h>
#include <linux/string.h>
@@ -40,24 +42,47 @@ struct crypto_hash_walk {
struct scatterlist *sg;
};

-struct ahash_save_req_state {
- struct ahash_request *req0;
- crypto_completion_t compl;
- void *data;
- struct scatterlist sg;
- const u8 *src;
- u8 *page;
- unsigned int offset;
- unsigned int nbytes;
- bool update;
-};
-
-static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt);
-static void ahash_restore_req(struct ahash_request *req);
-static void ahash_def_finup_done1(void *data, int err);
-static int ahash_def_finup_finish1(struct ahash_request *req, int err);
static int ahash_def_finup(struct ahash_request *req);

+static inline bool crypto_ahash_block_only(struct crypto_ahash *tfm)
+{
+ return crypto_ahash_alg(tfm)->halg.base.cra_flags &
+ CRYPTO_AHASH_ALG_BLOCK_ONLY;
+}
+
+static inline bool crypto_ahash_final_nonzero(struct crypto_ahash *tfm)
+{
+ return crypto_ahash_alg(tfm)->halg.base.cra_flags &
+ CRYPTO_AHASH_ALG_FINAL_NONZERO;
+}
+
+static inline bool crypto_ahash_need_fallback(struct crypto_ahash *tfm)
+{
+ return crypto_ahash_alg(tfm)->halg.base.cra_flags &
+ CRYPTO_ALG_NEED_FALLBACK;
+}
+
+static inline void ahash_op_done(void *data, int err,
+ int (*finish)(struct ahash_request *, int))
+{
+ struct ahash_request *areq = data;
+ crypto_completion_t compl;
+
+ compl = areq->saved_complete;
+ data = areq->saved_data;
+ if (err == -EINPROGRESS)
+ goto out;
+
+ areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
+
+ err = finish(areq, err);
+ if (err == -EINPROGRESS || err == -EBUSY)
+ return;
+
+out:
+ compl(data, err);
+}
+
static int hash_walk_next(struct crypto_hash_walk *walk)
{
unsigned int offset = walk->offset;
@@ -298,7 +323,7 @@ int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
int err;

err = alg->setkey(tfm, key, keylen);
- if (!err && ahash_is_async(tfm))
+ if (!err && crypto_ahash_need_fallback(tfm))
err = crypto_ahash_setkey(crypto_ahash_fb(tfm),
key, keylen);
if (unlikely(err)) {
@@ -311,159 +336,46 @@ int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
}
EXPORT_SYMBOL_GPL(crypto_ahash_setkey);

-static int ahash_reqchain_virt(struct ahash_save_req_state *state,
- int err, u32 mask)
-{
- struct ahash_request *req = state->req0;
- struct crypto_ahash *tfm;
-
- tfm = crypto_ahash_reqtfm(req);
-
- for (;;) {
- unsigned len = state->nbytes;
-
- if (!state->offset)
- break;
-
- if (state->offset == len || err) {
- u8 *result = req->result;
-
- ahash_request_set_virt(req, state->src, result, len);
- state->offset = 0;
- break;
- }
-
- len -= state->offset;
-
- len = min(PAGE_SIZE, len);
- memcpy(state->page, state->src + state->offset, len);
- state->offset += len;
- req->nbytes = len;
-
- err = crypto_ahash_alg(tfm)->update(req);
- if (err == -EINPROGRESS) {
- if (state->offset < state->nbytes)
- err = -EBUSY;
- break;
- }
-
- if (err == -EBUSY)
- break;
- }
-
- return err;
-}
-
-static int ahash_reqchain_finish(struct ahash_request *req0,
- struct ahash_save_req_state *state,
- int err, u32 mask)
-{
- u8 *page;
-
- err = ahash_reqchain_virt(state, err, mask);
- if (err == -EINPROGRESS || err == -EBUSY)
- goto out;
-
- page = state->page;
- if (page) {
- memset(page, 0, PAGE_SIZE);
- free_page((unsigned long)page);
- }
- ahash_restore_req(req0);
-
-out:
- return err;
-}
-
-static void ahash_reqchain_done(void *data, int err)
-{
- struct ahash_save_req_state *state = data;
- crypto_completion_t compl = state->compl;
-
- data = state->data;
-
- if (err == -EINPROGRESS) {
- if (state->offset < state->nbytes)
- return;
- goto notify;
- }
-
- err = ahash_reqchain_finish(state->req0, state, err,
- CRYPTO_TFM_REQ_MAY_BACKLOG);
- if (err == -EBUSY)
- return;
-
-notify:
- compl(data, err);
-}
-
static int ahash_do_req_chain(struct ahash_request *req,
- int (*op)(struct ahash_request *req))
+ int (*const *op)(struct ahash_request *req))
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
- bool update = op == crypto_ahash_alg(tfm)->update;
- struct ahash_save_req_state *state;
- struct ahash_save_req_state state0;
- u8 *page = NULL;
int err;

- if (crypto_ahash_req_virt(tfm) ||
- !update || !ahash_request_isvirt(req))
- return op(req);
+ if (crypto_ahash_req_virt(tfm) || !ahash_request_isvirt(req))
+ return (*op)(req);

- if (update && ahash_request_isvirt(req)) {
- page = (void *)__get_free_page(GFP_ATOMIC);
- err = -ENOMEM;
- if (!page)
- goto out;
- }
+ if (crypto_ahash_statesize(tfm) > HASH_MAX_STATESIZE)
+ return -ENOSYS;

- state = &state0;
- if (ahash_is_async(tfm)) {
- err = ahash_save_req(req, ahash_reqchain_done);
- if (err)
- goto out_free_page;
+ {
+ u8 state[HASH_MAX_STATESIZE];

- state = req->base.data;
- }
+ if (op == &crypto_ahash_alg(tfm)->digest) {
+ ahash_request_set_tfm(req, crypto_ahash_fb(tfm));
+ err = crypto_ahash_digest(req);
+ goto out_no_state;
+ }

- state->update = update;
- state->page = page;
- state->offset = 0;
- state->nbytes = 0;
+ err = crypto_ahash_export(req, state);
+ ahash_request_set_tfm(req, crypto_ahash_fb(tfm));
+ err = err ?: crypto_ahash_import(req, state);

- if (page)
- sg_init_one(&state->sg, page, PAGE_SIZE);
+ if (op == &crypto_ahash_alg(tfm)->finup) {
+ err = err ?: crypto_ahash_finup(req);
+ goto out_no_state;
+ }

- if (update && ahash_request_isvirt(req) && req->nbytes) {
- unsigned len = req->nbytes;
- u8 *result = req->result;
+ err = err ?: crypto_ahash_update(req);
+ crypto_ahash_export(req, state);

- state->src = req->svirt;
- state->nbytes = len;
+ ahash_request_set_tfm(req, tfm);
+ return err ?: crypto_ahash_import(req, state);

- len = min(PAGE_SIZE, len);
-
- memcpy(page, req->svirt, len);
- state->offset = len;
-
- ahash_request_set_crypt(req, &state->sg, result, len);
- }
-
- err = op(req);
- if (err == -EINPROGRESS || err == -EBUSY) {
- if (state->offset < state->nbytes)
- err = -EBUSY;
+out_no_state:
+ ahash_request_set_tfm(req, tfm);
return err;
}
-
- return ahash_reqchain_finish(req, state, err, ~0);
-
-out_free_page:
- free_page((unsigned long)page);
-
-out:
- return err;
}

int crypto_ahash_init(struct ahash_request *req)
@@ -476,144 +388,191 @@ int crypto_ahash_init(struct ahash_request *req)
return -ENOKEY;
if (ahash_req_on_stack(req) && ahash_is_async(tfm))
return -EAGAIN;
- return ahash_do_req_chain(req, crypto_ahash_alg(tfm)->init);
+ if (crypto_ahash_block_only(tfm)) {
+ u8 *buf = ahash_request_ctx(req);
+
+ buf += crypto_ahash_reqsize(tfm) - 1;
+ *buf = 0;
+ }
+ return crypto_ahash_alg(tfm)->init(req);
}
EXPORT_SYMBOL_GPL(crypto_ahash_init);

-static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
+static void ahash_save_req(struct ahash_request *req, crypto_completion_t cplt)
{
- struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
- struct ahash_save_req_state *state;
-
- if (!ahash_is_async(tfm))
- return 0;
-
- state = kmalloc(sizeof(*state), GFP_ATOMIC);
- if (!state)
- return -ENOMEM;
-
- state->compl = req->base.complete;
- state->data = req->base.data;
+ req->saved_complete = req->base.complete;
+ req->saved_data = req->base.data;
req->base.complete = cplt;
- req->base.data = state;
- state->req0 = req;
-
- return 0;
+ req->base.data = req;
}

static void ahash_restore_req(struct ahash_request *req)
{
- struct ahash_save_req_state *state;
- struct crypto_ahash *tfm;
+ req->base.complete = req->saved_complete;
+ req->base.data = req->saved_data;
+}

- tfm = crypto_ahash_reqtfm(req);
- if (!ahash_is_async(tfm))
- return;
+static int ahash_update_finish(struct ahash_request *req, int err)
+{
+ struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ bool nonzero = crypto_ahash_final_nonzero(tfm);
+ int bs = crypto_ahash_blocksize(tfm);
+ u8 *blenp = ahash_request_ctx(req);
+ int blen;
+ u8 *buf;

- state = req->base.data;
+ blenp += crypto_ahash_reqsize(tfm) - 1;
+ blen = *blenp;
+ buf = blenp - bs;

- req->base.complete = state->compl;
- req->base.data = state->data;
- kfree(state);
+ if (blen) {
+ req->src = req->sg_head + 1;
+ if (sg_is_chain(req->src))
+ req->src = sg_chain_ptr(req->src);
+ }
+
+ req->nbytes += nonzero - blen;
+
+ blen = err < 0 ? 0 : err + nonzero;
+ if (ahash_request_isvirt(req))
+ memcpy(buf, req->svirt + req->nbytes - blen, blen);
+ else
+ memcpy_from_sglist(buf, req->src, req->nbytes - blen, blen);
+ *blenp = blen;
+
+ ahash_restore_req(req);
+
+ return err;
+}
+
+static void ahash_update_done(void *data, int err)
+{
+ ahash_op_done(data, err, ahash_update_finish);
}

int crypto_ahash_update(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ bool nonzero = crypto_ahash_final_nonzero(tfm);
+ int bs = crypto_ahash_blocksize(tfm);
+ u8 *blenp = ahash_request_ctx(req);
+ int blen, err;
+ u8 *buf;

if (likely(tfm->using_shash))
return shash_ahash_update(req, ahash_request_ctx(req));
if (ahash_req_on_stack(req) && ahash_is_async(tfm))
return -EAGAIN;
- return ahash_do_req_chain(req, crypto_ahash_alg(tfm)->update);
+ if (!crypto_ahash_block_only(tfm))
+ return ahash_do_req_chain(req, &crypto_ahash_alg(tfm)->update);
+
+ blenp += crypto_ahash_reqsize(tfm) - 1;
+ blen = *blenp;
+ buf = blenp - bs;
+
+ if (blen + req->nbytes < bs + nonzero) {
+ if (ahash_request_isvirt(req))
+ memcpy(buf + blen, req->svirt, req->nbytes);
+ else
+ memcpy_from_sglist(buf + blen, req->src, 0,
+ req->nbytes);
+
+ *blenp += req->nbytes;
+ return 0;
+ }
+
+ if (blen) {
+ memset(req->sg_head, 0, sizeof(req->sg_head[0]));
+ sg_set_buf(req->sg_head, buf, blen);
+ if (req->src != req->sg_head + 1)
+ sg_chain(req->sg_head, 2, req->src);
+ req->src = req->sg_head;
+ req->nbytes += blen;
+ }
+ req->nbytes -= nonzero;
+
+ ahash_save_req(req, ahash_update_done);
+
+ err = ahash_do_req_chain(req, &crypto_ahash_alg(tfm)->update);
+ if (err == -EINPROGRESS || err == -EBUSY)
+ return err;
+
+ return ahash_update_finish(req, err);
}
EXPORT_SYMBOL_GPL(crypto_ahash_update);

-int crypto_ahash_final(struct ahash_request *req)
+static int ahash_finup_finish(struct ahash_request *req, int err)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ u8 *blenp = ahash_request_ctx(req);
+ int blen;

- if (likely(tfm->using_shash))
- return crypto_shash_final(ahash_request_ctx(req), req->result);
- if (ahash_req_on_stack(req) && ahash_is_async(tfm))
- return -EAGAIN;
- return ahash_do_req_chain(req, crypto_ahash_alg(tfm)->final);
+ blenp += crypto_ahash_reqsize(tfm) - 1;
+ blen = *blenp;
+
+ if (blen) {
+ if (sg_is_last(req->src))
+ req->src = NULL;
+ else {
+ req->src = req->sg_head + 1;
+ if (sg_is_chain(req->src))
+ req->src = sg_chain_ptr(req->src);
+ }
+ req->nbytes -= blen;
+ }
+
+ ahash_restore_req(req);
+
+ return err;
+}
+
+static void ahash_finup_done(void *data, int err)
+{
+ ahash_op_done(data, err, ahash_finup_finish);
}
-EXPORT_SYMBOL_GPL(crypto_ahash_final);

int crypto_ahash_finup(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+ int bs = crypto_ahash_blocksize(tfm);
+ u8 *blenp = ahash_request_ctx(req);
+ int blen, err;
+ u8 *buf;

if (likely(tfm->using_shash))
return shash_ahash_finup(req, ahash_request_ctx(req));
if (ahash_req_on_stack(req) && ahash_is_async(tfm))
return -EAGAIN;
- if (!crypto_ahash_alg(tfm)->finup ||
- (!crypto_ahash_req_virt(tfm) && ahash_request_isvirt(req)))
+ if (!crypto_ahash_alg(tfm)->finup)
return ahash_def_finup(req);
- return ahash_do_req_chain(req, crypto_ahash_alg(tfm)->finup);
+ if (!crypto_ahash_block_only(tfm))
+ return ahash_do_req_chain(req, &crypto_ahash_alg(tfm)->finup);
+
+ blenp += crypto_ahash_reqsize(tfm) - 1;
+ blen = *blenp;
+ buf = blenp - bs;
+
+ if (blen) {
+ memset(req->sg_head, 0, sizeof(req->sg_head[0]));
+ sg_set_buf(req->sg_head, buf, blen);
+ if (!req->src)
+ sg_mark_end(req->sg_head);
+ else if (req->src != req->sg_head + 1)
+ sg_chain(req->sg_head, 2, req->src);
+ req->src = req->sg_head;
+ req->nbytes += blen;
+ }
+
+ ahash_save_req(req, ahash_finup_done);
+
+ err = ahash_do_req_chain(req, &crypto_ahash_alg(tfm)->finup);
+ if (err == -EINPROGRESS || err == -EBUSY)
+ return err;
+
+ return ahash_finup_finish(req, err);
}
EXPORT_SYMBOL_GPL(crypto_ahash_finup);

-static int ahash_def_digest_finish(struct ahash_request *req, int err)
-{
- struct crypto_ahash *tfm;
-
- if (err)
- goto out;
-
- tfm = crypto_ahash_reqtfm(req);
- if (ahash_is_async(tfm))
- req->base.complete = ahash_def_finup_done1;
-
- err = crypto_ahash_update(req);
- if (err == -EINPROGRESS || err == -EBUSY)
- return err;
-
- return ahash_def_finup_finish1(req, err);
-
-out:
- ahash_restore_req(req);
- return err;
-}
-
-static void ahash_def_digest_done(void *data, int err)
-{
- struct ahash_save_req_state *state0 = data;
- struct ahash_save_req_state state;
- struct ahash_request *areq;
-
- state = *state0;
- areq = state.req0;
- if (err == -EINPROGRESS)
- goto out;
-
- areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
-
- err = ahash_def_digest_finish(areq, err);
- if (err == -EINPROGRESS || err == -EBUSY)
- return;
-
-out:
- state.compl(state.data, err);
-}
-
-static int ahash_def_digest(struct ahash_request *req)
-{
- int err;
-
- err = ahash_save_req(req, ahash_def_digest_done);
- if (err)
- return err;
-
- err = crypto_ahash_init(req);
- if (err == -EINPROGRESS || err == -EBUSY)
- return err;
-
- return ahash_def_digest_finish(req, err);
-}
-
int crypto_ahash_digest(struct ahash_request *req)
{
struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
@@ -622,18 +581,15 @@ int crypto_ahash_digest(struct ahash_request *req)
return shash_ahash_digest(req, prepare_shash_desc(req, tfm));
if (ahash_req_on_stack(req) && ahash_is_async(tfm))
return -EAGAIN;
- if (!crypto_ahash_req_virt(tfm) && ahash_request_isvirt(req))
- return ahash_def_digest(req);
if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
return -ENOKEY;
- return ahash_do_req_chain(req, crypto_ahash_alg(tfm)->digest);
+ return ahash_do_req_chain(req, &crypto_ahash_alg(tfm)->digest);
}
EXPORT_SYMBOL_GPL(crypto_ahash_digest);

static void ahash_def_finup_done2(void *data, int err)
{
- struct ahash_save_req_state *state = data;
- struct ahash_request *areq = state->req0;
+ struct ahash_request *areq = data;

if (err == -EINPROGRESS)
return;
@@ -644,14 +600,10 @@ static void ahash_def_finup_done2(void *data, int err)

static int ahash_def_finup_finish1(struct ahash_request *req, int err)
{
- struct crypto_ahash *tfm;
-
if (err)
goto out;

- tfm = crypto_ahash_reqtfm(req);
- if (ahash_is_async(tfm))
- req->base.complete = ahash_def_finup_done2;
+ req->base.complete = ahash_def_finup_done2;

err = crypto_ahash_final(req);
if (err == -EINPROGRESS || err == -EBUSY)
@@ -664,32 +616,14 @@ static int ahash_def_finup_finish1(struct ahash_request *req, int err)

static void ahash_def_finup_done1(void *data, int err)
{
- struct ahash_save_req_state *state0 = data;
- struct ahash_save_req_state state;
- struct ahash_request *areq;
-
- state = *state0;
- areq = state.req0;
- if (err == -EINPROGRESS)
- goto out;
-
- areq->base.flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
-
- err = ahash_def_finup_finish1(areq, err);
- if (err == -EINPROGRESS || err == -EBUSY)
- return;
-
-out:
- state.compl(state.data, err);
+ ahash_op_done(data, err, ahash_def_finup_finish1);
}

static int ahash_def_finup(struct ahash_request *req)
{
int err;

- err = ahash_save_req(req, ahash_def_finup_done1);
- if (err)
- return err;
+ ahash_save_req(req, ahash_def_finup_done1);

err = crypto_ahash_update(req);
if (err == -EINPROGRESS || err == -EBUSY)
@@ -714,6 +648,14 @@ int crypto_ahash_export(struct ahash_request *req, void *out)

if (likely(tfm->using_shash))
return crypto_shash_export(ahash_request_ctx(req), out);
+ if (crypto_ahash_block_only(tfm)) {
+ unsigned int plen = crypto_ahash_blocksize(tfm) + 1;
+ unsigned int reqsize = crypto_ahash_reqsize(tfm);
+ unsigned int ss = crypto_ahash_statesize(tfm);
+ u8 *buf = ahash_request_ctx(req);
+
+ memcpy(out + ss - plen, buf + reqsize - plen, plen);
+ }
return crypto_ahash_alg(tfm)->export(req, out);
}
EXPORT_SYMBOL_GPL(crypto_ahash_export);
@@ -737,8 +679,12 @@ int crypto_ahash_import(struct ahash_request *req, const void *in)

if (likely(tfm->using_shash))
return crypto_shash_import(prepare_shash_desc(req, tfm), in);
- if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
- return -ENOKEY;
+ if (crypto_ahash_block_only(tfm)) {
+ unsigned int reqsize = crypto_ahash_reqsize(tfm);
+ u8 *buf = ahash_request_ctx(req);
+
+ buf[reqsize - 1] = 0;
+ }
return crypto_ahash_import_core(req, in);
}
EXPORT_SYMBOL_GPL(crypto_ahash_import);
@@ -753,7 +699,7 @@ static void crypto_ahash_exit_tfm(struct crypto_tfm *tfm)
else if (tfm->__crt_alg->cra_exit)
tfm->__crt_alg->cra_exit(tfm);

- if (ahash_is_async(hash))
+ if (crypto_ahash_need_fallback(hash))
crypto_free_ahash(crypto_ahash_fb(hash));
}

@@ -770,9 +716,14 @@ static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
if (tfm->__crt_alg->cra_type == &crypto_shash_type)
return crypto_init_ahash_using_shash(tfm);

- if (ahash_is_async(hash)) {
+ if (crypto_ahash_need_fallback(hash)) {
+ unsigned int block_only = crypto_ahash_block_only(hash) ?
+ CRYPTO_AHASH_ALG_BLOCK_ONLY : 0;
+
fb = crypto_alloc_ahash(crypto_ahash_alg_name(hash),
- 0, CRYPTO_ALG_ASYNC);
+ CRYPTO_ALG_REQ_VIRT | block_only,
+ CRYPTO_ALG_ASYNC |
+ CRYPTO_ALG_REQ_VIRT | block_only);
if (IS_ERR(fb))
return PTR_ERR(fb);

@@ -797,6 +748,10 @@ static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
MAX_SYNC_HASH_REQSIZE)
goto out_exit_tfm;

+ BUILD_BUG_ON(HASH_MAX_DESCSIZE > MAX_SYNC_HASH_REQSIZE);
+ if (crypto_ahash_reqsize(hash) < HASH_MAX_DESCSIZE)
+ crypto_ahash_set_reqsize(hash, HASH_MAX_DESCSIZE);
+
return 0;

out_exit_tfm:
@@ -941,7 +896,7 @@ struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
return nhash;
}

- if (ahash_is_async(hash)) {
+ if (crypto_ahash_need_fallback(hash)) {
fb = crypto_clone_ahash(crypto_ahash_fb(hash));
err = PTR_ERR(fb);
if (IS_ERR(fb))
@@ -993,9 +948,22 @@ static int ahash_prepare_alg(struct ahash_alg *alg)
base->cra_type = &crypto_ahash_type;
base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;

+ if ((base->cra_flags ^ CRYPTO_ALG_REQ_VIRT) &
+ (CRYPTO_ALG_ASYNC | CRYPTO_ALG_REQ_VIRT))
+ base->cra_flags |= CRYPTO_ALG_NEED_FALLBACK;
+
if (!alg->setkey)
alg->setkey = ahash_nosetkey;

+ if (base->cra_flags & CRYPTO_AHASH_ALG_BLOCK_ONLY) {
+ BUILD_BUG_ON(MAX_ALGAPI_BLOCKSIZE >= 256);
+ if (!alg->finup)
+ return -EINVAL;
+
+ base->cra_reqsize += base->cra_blocksize + 1;
+ alg->halg.statesize += base->cra_blocksize + 1;
+ }
+
return 0;
}

diff --git a/include/crypto/hash.h b/include/crypto/hash.h
index 9fc9daaaaab4..540e09ff395d 100644
--- a/include/crypto/hash.h
+++ b/include/crypto/hash.h
@@ -8,8 +8,8 @@
#ifndef _CRYPTO_HASH_H
#define _CRYPTO_HASH_H

-#include <linux/atomic.h>
#include <linux/crypto.h>
+#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <linux/string.h>

@@ -65,6 +65,10 @@ struct ahash_request {
};
u8 *result;

+ struct scatterlist sg_head[2];
+ crypto_completion_t saved_complete;
+ void *saved_data;
+
void *__ctx[] CRYPTO_MINALIGN_ATTR;
};

@@ -478,7 +482,11 @@ int crypto_ahash_finup(struct ahash_request *req);
* -EBUSY if queue is full and request should be resubmitted later;
* other < 0 if an error occurred
*/
-int crypto_ahash_final(struct ahash_request *req);
+static inline int crypto_ahash_final(struct ahash_request *req)
+{
+ req->nbytes = 0;
+ return crypto_ahash_finup(req);
+}

/**
* crypto_ahash_digest() - calculate message digest for a buffer
--
2.39.5