On Mon, Aug 6, 2018 at 4:32 PM, Kees Cook <keescook@xxxxxxxxxxxx> wrote: > In preparing to remove all stack VLA usage from the kernel[1], this > removes the discouraged use of AHASH_REQUEST_ON_STACK in favor of > the smaller SHASH_DESC_ON_STACK by converting from ahash-wrapped-shash > to direct shash. By removing a layer of indirection this both improves > performance and reduces stack usage. The stack allocation will be made > a fixed size in a later patch to the crypto subsystem. > > The bulk of the lines in this change are simple s/ahash/shash/, but the > main logic differences are in drbd_csum_ee() and drbd_csum_bio(), which > externalizes the page walking with k(un)map_atomic() instead of using > scattergather. Hi Lars! How does this look to you? If you can Ack I assume Jens would be able to take this. Thanks! -Kees > > [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@xxxxxxxxxxxxxx > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > I'm calling this "v7" just for general sanity over the naming of the > patch when it was part of the large crypto series of changes. Really, > it's v2. > > v7: use kmap for possible highmem page addresses (Lars). > --- > drivers/block/drbd/drbd_int.h | 13 +++--- > drivers/block/drbd/drbd_main.c | 14 +++---- > drivers/block/drbd/drbd_nl.c | 39 ++++++------------ > drivers/block/drbd/drbd_receiver.c | 35 +++++++++-------- > drivers/block/drbd/drbd_worker.c | 63 +++++++++++++++--------------- > 5 files changed, 76 insertions(+), 88 deletions(-) > > diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h > index bc4ed2ed40a2..97d8e290c2be 100644 > --- a/drivers/block/drbd/drbd_int.h > +++ b/drivers/block/drbd/drbd_int.h > @@ -726,10 +726,10 @@ struct drbd_connection { > struct list_head transfer_log; /* all requests not yet fully processed */ > > struct crypto_shash *cram_hmac_tfm; > - struct crypto_ahash *integrity_tfm; /* checksums we compute, updates protected by connection->data->mutex */ > - struct crypto_ahash *peer_integrity_tfm; /* checksums we verify, only accessed from receiver thread */ > - struct crypto_ahash *csums_tfm; > - struct crypto_ahash *verify_tfm; > + struct crypto_shash *integrity_tfm; /* checksums we compute, updates protected by connection->data->mutex */ > + struct crypto_shash *peer_integrity_tfm; /* checksums we verify, only accessed from receiver thread */ > + struct crypto_shash *csums_tfm; > + struct crypto_shash *verify_tfm; > void *int_dig_in; > void *int_dig_vv; > > @@ -1533,8 +1533,9 @@ static inline void ov_out_of_sync_print(struct drbd_device *device) > } > > > -extern void drbd_csum_bio(struct crypto_ahash *, struct bio *, void *); > -extern void drbd_csum_ee(struct crypto_ahash *, struct drbd_peer_request *, void *); > +extern void drbd_csum_bio(struct crypto_shash *, struct bio *, void *); > +extern void drbd_csum_ee(struct crypto_shash *, struct drbd_peer_request *, > + void *); > /* worker callbacks */ > extern int w_e_end_data_req(struct drbd_work *, int); > extern int w_e_end_rsdata_req(struct drbd_work *, int); > diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c > index a80809bd3057..ccb54791d39c 100644 > --- a/drivers/block/drbd/drbd_main.c > +++ b/drivers/block/drbd/drbd_main.c > @@ -1377,7 +1377,7 @@ void drbd_send_ack_dp(struct drbd_peer_device *peer_device, enum drbd_packet cmd > struct p_data *dp, int data_size) > { > if (peer_device->connection->peer_integrity_tfm) > - data_size -= crypto_ahash_digestsize(peer_device->connection->peer_integrity_tfm); > + data_size -= crypto_shash_digestsize(peer_device->connection->peer_integrity_tfm); > _drbd_send_ack(peer_device, cmd, dp->sector, cpu_to_be32(data_size), > dp->block_id); > } > @@ -1690,7 +1690,7 @@ int drbd_send_dblock(struct drbd_peer_device *peer_device, struct drbd_request * > sock = &peer_device->connection->data; > p = drbd_prepare_command(peer_device, sock); > digest_size = peer_device->connection->integrity_tfm ? > - crypto_ahash_digestsize(peer_device->connection->integrity_tfm) : 0; > + crypto_shash_digestsize(peer_device->connection->integrity_tfm) : 0; > > if (!p) > return -EIO; > @@ -1796,7 +1796,7 @@ int drbd_send_block(struct drbd_peer_device *peer_device, enum drbd_packet cmd, > p = drbd_prepare_command(peer_device, sock); > > digest_size = peer_device->connection->integrity_tfm ? > - crypto_ahash_digestsize(peer_device->connection->integrity_tfm) : 0; > + crypto_shash_digestsize(peer_device->connection->integrity_tfm) : 0; > > if (!p) > return -EIO; > @@ -2561,11 +2561,11 @@ void conn_free_crypto(struct drbd_connection *connection) > { > drbd_free_sock(connection); > > - crypto_free_ahash(connection->csums_tfm); > - crypto_free_ahash(connection->verify_tfm); > + crypto_free_shash(connection->csums_tfm); > + crypto_free_shash(connection->verify_tfm); > crypto_free_shash(connection->cram_hmac_tfm); > - crypto_free_ahash(connection->integrity_tfm); > - crypto_free_ahash(connection->peer_integrity_tfm); > + crypto_free_shash(connection->integrity_tfm); > + crypto_free_shash(connection->peer_integrity_tfm); > kfree(connection->int_dig_in); > kfree(connection->int_dig_vv); > > diff --git a/drivers/block/drbd/drbd_nl.c b/drivers/block/drbd/drbd_nl.c > index b4f02768ba47..d15703b1ffe8 100644 > --- a/drivers/block/drbd/drbd_nl.c > +++ b/drivers/block/drbd/drbd_nl.c > @@ -2303,10 +2303,10 @@ check_net_options(struct drbd_connection *connection, struct net_conf *new_net_c > } > > struct crypto { > - struct crypto_ahash *verify_tfm; > - struct crypto_ahash *csums_tfm; > + struct crypto_shash *verify_tfm; > + struct crypto_shash *csums_tfm; > struct crypto_shash *cram_hmac_tfm; > - struct crypto_ahash *integrity_tfm; > + struct crypto_shash *integrity_tfm; > }; > > static int > @@ -2324,36 +2324,21 @@ alloc_shash(struct crypto_shash **tfm, char *tfm_name, int err_alg) > return NO_ERROR; > } > > -static int > -alloc_ahash(struct crypto_ahash **tfm, char *tfm_name, int err_alg) > -{ > - if (!tfm_name[0]) > - return NO_ERROR; > - > - *tfm = crypto_alloc_ahash(tfm_name, 0, CRYPTO_ALG_ASYNC); > - if (IS_ERR(*tfm)) { > - *tfm = NULL; > - return err_alg; > - } > - > - return NO_ERROR; > -} > - > static enum drbd_ret_code > alloc_crypto(struct crypto *crypto, struct net_conf *new_net_conf) > { > char hmac_name[CRYPTO_MAX_ALG_NAME]; > enum drbd_ret_code rv; > > - rv = alloc_ahash(&crypto->csums_tfm, new_net_conf->csums_alg, > + rv = alloc_shash(&crypto->csums_tfm, new_net_conf->csums_alg, > ERR_CSUMS_ALG); > if (rv != NO_ERROR) > return rv; > - rv = alloc_ahash(&crypto->verify_tfm, new_net_conf->verify_alg, > + rv = alloc_shash(&crypto->verify_tfm, new_net_conf->verify_alg, > ERR_VERIFY_ALG); > if (rv != NO_ERROR) > return rv; > - rv = alloc_ahash(&crypto->integrity_tfm, new_net_conf->integrity_alg, > + rv = alloc_shash(&crypto->integrity_tfm, new_net_conf->integrity_alg, > ERR_INTEGRITY_ALG); > if (rv != NO_ERROR) > return rv; > @@ -2371,9 +2356,9 @@ alloc_crypto(struct crypto *crypto, struct net_conf *new_net_conf) > static void free_crypto(struct crypto *crypto) > { > crypto_free_shash(crypto->cram_hmac_tfm); > - crypto_free_ahash(crypto->integrity_tfm); > - crypto_free_ahash(crypto->csums_tfm); > - crypto_free_ahash(crypto->verify_tfm); > + crypto_free_shash(crypto->integrity_tfm); > + crypto_free_shash(crypto->csums_tfm); > + crypto_free_shash(crypto->verify_tfm); > } > > int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info) > @@ -2450,17 +2435,17 @@ int drbd_adm_net_opts(struct sk_buff *skb, struct genl_info *info) > rcu_assign_pointer(connection->net_conf, new_net_conf); > > if (!rsr) { > - crypto_free_ahash(connection->csums_tfm); > + crypto_free_shash(connection->csums_tfm); > connection->csums_tfm = crypto.csums_tfm; > crypto.csums_tfm = NULL; > } > if (!ovr) { > - crypto_free_ahash(connection->verify_tfm); > + crypto_free_shash(connection->verify_tfm); > connection->verify_tfm = crypto.verify_tfm; > crypto.verify_tfm = NULL; > } > > - crypto_free_ahash(connection->integrity_tfm); > + crypto_free_shash(connection->integrity_tfm); > connection->integrity_tfm = crypto.integrity_tfm; > if (connection->cstate >= C_WF_REPORT_PARAMS && connection->agreed_pro_version >= 100) > /* Do this without trying to take connection->data.mutex again. */ > diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c > index be9450f5ad1c..76243e9ef277 100644 > --- a/drivers/block/drbd/drbd_receiver.c > +++ b/drivers/block/drbd/drbd_receiver.c > @@ -1732,7 +1732,7 @@ static int receive_Barrier(struct drbd_connection *connection, struct packet_inf > } > > /* quick wrapper in case payload size != request_size (write same) */ > -static void drbd_csum_ee_size(struct crypto_ahash *h, > +static void drbd_csum_ee_size(struct crypto_shash *h, > struct drbd_peer_request *r, void *d, > unsigned int payload_size) > { > @@ -1769,7 +1769,7 @@ read_in_block(struct drbd_peer_device *peer_device, u64 id, sector_t sector, > > digest_size = 0; > if (!trim && peer_device->connection->peer_integrity_tfm) { > - digest_size = crypto_ahash_digestsize(peer_device->connection->peer_integrity_tfm); > + digest_size = crypto_shash_digestsize(peer_device->connection->peer_integrity_tfm); > /* > * FIXME: Receive the incoming digest into the receive buffer > * here, together with its struct p_data? > @@ -1905,7 +1905,7 @@ static int recv_dless_read(struct drbd_peer_device *peer_device, struct drbd_req > > digest_size = 0; > if (peer_device->connection->peer_integrity_tfm) { > - digest_size = crypto_ahash_digestsize(peer_device->connection->peer_integrity_tfm); > + digest_size = crypto_shash_digestsize(peer_device->connection->peer_integrity_tfm); > err = drbd_recv_all_warn(peer_device->connection, dig_in, digest_size); > if (err) > return err; > @@ -3540,7 +3540,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in > int p_proto, p_discard_my_data, p_two_primaries, cf; > struct net_conf *nc, *old_net_conf, *new_net_conf = NULL; > char integrity_alg[SHARED_SECRET_MAX] = ""; > - struct crypto_ahash *peer_integrity_tfm = NULL; > + struct crypto_shash *peer_integrity_tfm = NULL; > void *int_dig_in = NULL, *int_dig_vv = NULL; > > p_proto = be32_to_cpu(p->protocol); > @@ -3621,7 +3621,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in > * change. > */ > > - peer_integrity_tfm = crypto_alloc_ahash(integrity_alg, 0, CRYPTO_ALG_ASYNC); > + peer_integrity_tfm = crypto_alloc_shash(integrity_alg, 0, CRYPTO_ALG_ASYNC); > if (IS_ERR(peer_integrity_tfm)) { > peer_integrity_tfm = NULL; > drbd_err(connection, "peer data-integrity-alg %s not supported\n", > @@ -3629,7 +3629,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in > goto disconnect; > } > > - hash_size = crypto_ahash_digestsize(peer_integrity_tfm); > + hash_size = crypto_shash_digestsize(peer_integrity_tfm); > int_dig_in = kmalloc(hash_size, GFP_KERNEL); > int_dig_vv = kmalloc(hash_size, GFP_KERNEL); > if (!(int_dig_in && int_dig_vv)) { > @@ -3659,7 +3659,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in > mutex_unlock(&connection->resource->conf_update); > mutex_unlock(&connection->data.mutex); > > - crypto_free_ahash(connection->peer_integrity_tfm); > + crypto_free_shash(connection->peer_integrity_tfm); > kfree(connection->int_dig_in); > kfree(connection->int_dig_vv); > connection->peer_integrity_tfm = peer_integrity_tfm; > @@ -3677,7 +3677,7 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in > disconnect_rcu_unlock: > rcu_read_unlock(); > disconnect: > - crypto_free_ahash(peer_integrity_tfm); > + crypto_free_shash(peer_integrity_tfm); > kfree(int_dig_in); > kfree(int_dig_vv); > conn_request_state(connection, NS(conn, C_DISCONNECTING), CS_HARD); > @@ -3689,15 +3689,16 @@ static int receive_protocol(struct drbd_connection *connection, struct packet_in > * return: NULL (alg name was "") > * ERR_PTR(error) if something goes wrong > * or the crypto hash ptr, if it worked out ok. */ > -static struct crypto_ahash *drbd_crypto_alloc_digest_safe(const struct drbd_device *device, > +static struct crypto_shash *drbd_crypto_alloc_digest_safe( > + const struct drbd_device *device, > const char *alg, const char *name) > { > - struct crypto_ahash *tfm; > + struct crypto_shash *tfm; > > if (!alg[0]) > return NULL; > > - tfm = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC); > + tfm = crypto_alloc_shash(alg, 0, 0); > if (IS_ERR(tfm)) { > drbd_err(device, "Can not allocate \"%s\" as %s (reason: %ld)\n", > alg, name, PTR_ERR(tfm)); > @@ -3750,8 +3751,8 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i > struct drbd_device *device; > struct p_rs_param_95 *p; > unsigned int header_size, data_size, exp_max_sz; > - struct crypto_ahash *verify_tfm = NULL; > - struct crypto_ahash *csums_tfm = NULL; > + struct crypto_shash *verify_tfm = NULL; > + struct crypto_shash *csums_tfm = NULL; > struct net_conf *old_net_conf, *new_net_conf = NULL; > struct disk_conf *old_disk_conf = NULL, *new_disk_conf = NULL; > const int apv = connection->agreed_pro_version; > @@ -3898,14 +3899,14 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i > if (verify_tfm) { > strcpy(new_net_conf->verify_alg, p->verify_alg); > new_net_conf->verify_alg_len = strlen(p->verify_alg) + 1; > - crypto_free_ahash(peer_device->connection->verify_tfm); > + crypto_free_shash(peer_device->connection->verify_tfm); > peer_device->connection->verify_tfm = verify_tfm; > drbd_info(device, "using verify-alg: \"%s\"\n", p->verify_alg); > } > if (csums_tfm) { > strcpy(new_net_conf->csums_alg, p->csums_alg); > new_net_conf->csums_alg_len = strlen(p->csums_alg) + 1; > - crypto_free_ahash(peer_device->connection->csums_tfm); > + crypto_free_shash(peer_device->connection->csums_tfm); > peer_device->connection->csums_tfm = csums_tfm; > drbd_info(device, "using csums-alg: \"%s\"\n", p->csums_alg); > } > @@ -3949,9 +3950,9 @@ static int receive_SyncParam(struct drbd_connection *connection, struct packet_i > mutex_unlock(&connection->resource->conf_update); > /* just for completeness: actually not needed, > * as this is not reached if csums_tfm was ok. */ > - crypto_free_ahash(csums_tfm); > + crypto_free_shash(csums_tfm); > /* but free the verify_tfm again, if csums_tfm did not work out */ > - crypto_free_ahash(verify_tfm); > + crypto_free_shash(verify_tfm); > conn_request_state(peer_device->connection, NS(conn, C_DISCONNECTING), CS_HARD); > return -EIO; > } > diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c > index 5e793dd7adfb..0b41fb0181a6 100644 > --- a/drivers/block/drbd/drbd_worker.c > +++ b/drivers/block/drbd/drbd_worker.c > @@ -295,60 +295,61 @@ void drbd_request_endio(struct bio *bio) > complete_master_bio(device, &m); > } > > -void drbd_csum_ee(struct crypto_ahash *tfm, struct drbd_peer_request *peer_req, void *digest) > +void drbd_csum_ee(struct crypto_shash *tfm, struct drbd_peer_request *peer_req, void *digest) > { > - AHASH_REQUEST_ON_STACK(req, tfm); > - struct scatterlist sg; > + SHASH_DESC_ON_STACK(desc, tfm); > struct page *page = peer_req->pages; > struct page *tmp; > unsigned len; > + void *src; > > - ahash_request_set_tfm(req, tfm); > - ahash_request_set_callback(req, 0, NULL, NULL); > + desc->tfm = tfm; > + desc->flags = 0; > > - sg_init_table(&sg, 1); > - crypto_ahash_init(req); > + crypto_shash_init(desc); > > + src = kmap_atomic(page); > while ((tmp = page_chain_next(page))) { > /* all but the last page will be fully used */ > - sg_set_page(&sg, page, PAGE_SIZE, 0); > - ahash_request_set_crypt(req, &sg, NULL, sg.length); > - crypto_ahash_update(req); > + crypto_shash_update(desc, src, PAGE_SIZE); > + kunmap_atomic(src); > page = tmp; > + src = kmap_atomic(page); > } > /* and now the last, possibly only partially used page */ > len = peer_req->i.size & (PAGE_SIZE - 1); > - sg_set_page(&sg, page, len ?: PAGE_SIZE, 0); > - ahash_request_set_crypt(req, &sg, digest, sg.length); > - crypto_ahash_finup(req); > - ahash_request_zero(req); > + crypto_shash_update(desc, src, len ?: PAGE_SIZE); > + kunmap_atomic(src); > + > + crypto_shash_final(desc, digest); > + shash_desc_zero(desc); > } > > -void drbd_csum_bio(struct crypto_ahash *tfm, struct bio *bio, void *digest) > +void drbd_csum_bio(struct crypto_shash *tfm, struct bio *bio, void *digest) > { > - AHASH_REQUEST_ON_STACK(req, tfm); > - struct scatterlist sg; > + SHASH_DESC_ON_STACK(desc, tfm); > struct bio_vec bvec; > struct bvec_iter iter; > > - ahash_request_set_tfm(req, tfm); > - ahash_request_set_callback(req, 0, NULL, NULL); > + desc->tfm = tfm; > + desc->flags = 0; > > - sg_init_table(&sg, 1); > - crypto_ahash_init(req); > + crypto_shash_init(desc); > > bio_for_each_segment(bvec, bio, iter) { > - sg_set_page(&sg, bvec.bv_page, bvec.bv_len, bvec.bv_offset); > - ahash_request_set_crypt(req, &sg, NULL, sg.length); > - crypto_ahash_update(req); > + u8 *src; > + > + src = kmap_atomic(bvec.bv_page); > + crypto_shash_update(desc, src + bvec.bv_offset, bvec.bv_len); > + kunmap_atomic(src); > + > /* REQ_OP_WRITE_SAME has only one segment, > * checksum the payload only once. */ > if (bio_op(bio) == REQ_OP_WRITE_SAME) > break; > } > - ahash_request_set_crypt(req, NULL, digest, 0); > - crypto_ahash_final(req); > - ahash_request_zero(req); > + crypto_shash_final(desc, digest); > + shash_desc_zero(desc); > } > > /* MAYBE merge common code with w_e_end_ov_req */ > @@ -367,7 +368,7 @@ static int w_e_send_csum(struct drbd_work *w, int cancel) > if (unlikely((peer_req->flags & EE_WAS_ERROR) != 0)) > goto out; > > - digest_size = crypto_ahash_digestsize(peer_device->connection->csums_tfm); > + digest_size = crypto_shash_digestsize(peer_device->connection->csums_tfm); > digest = kmalloc(digest_size, GFP_NOIO); > if (digest) { > sector_t sector = peer_req->i.sector; > @@ -1205,7 +1206,7 @@ int w_e_end_csum_rs_req(struct drbd_work *w, int cancel) > * a real fix would be much more involved, > * introducing more locking mechanisms */ > if (peer_device->connection->csums_tfm) { > - digest_size = crypto_ahash_digestsize(peer_device->connection->csums_tfm); > + digest_size = crypto_shash_digestsize(peer_device->connection->csums_tfm); > D_ASSERT(device, digest_size == di->digest_size); > digest = kmalloc(digest_size, GFP_NOIO); > } > @@ -1255,7 +1256,7 @@ int w_e_end_ov_req(struct drbd_work *w, int cancel) > if (unlikely(cancel)) > goto out; > > - digest_size = crypto_ahash_digestsize(peer_device->connection->verify_tfm); > + digest_size = crypto_shash_digestsize(peer_device->connection->verify_tfm); > digest = kmalloc(digest_size, GFP_NOIO); > if (!digest) { > err = 1; /* terminate the connection in case the allocation failed */ > @@ -1327,7 +1328,7 @@ int w_e_end_ov_reply(struct drbd_work *w, int cancel) > di = peer_req->digest; > > if (likely((peer_req->flags & EE_WAS_ERROR) == 0)) { > - digest_size = crypto_ahash_digestsize(peer_device->connection->verify_tfm); > + digest_size = crypto_shash_digestsize(peer_device->connection->verify_tfm); > digest = kmalloc(digest_size, GFP_NOIO); > if (digest) { > drbd_csum_ee(peer_device->connection->verify_tfm, peer_req, digest); > -- > 2.17.1 > > > -- > Kees Cook > Pixel Security -- Kees Cook Pixel Security
