Introduce a per-CPU pool of async crypto requests that can be used in bh-disabled contexts (designed with net RX/TX softirqs as users in mind). Allocation can sleep and is a slow-path. Initial implementation has only ahash as a backend and a fix-sized array of possible algorithms used in parallel. Signed-off-by: Dmitry Safonov <dima@xxxxxxxxxx> --- crypto/Kconfig | 6 + crypto/Makefile | 1 + crypto/crypto_pool.c | 291 ++++++++++++++++++++++++++++++++++++++++++ include/crypto/pool.h | 34 +++++ 4 files changed, 332 insertions(+) create mode 100644 crypto/crypto_pool.c create mode 100644 include/crypto/pool.h diff --git a/crypto/Kconfig b/crypto/Kconfig index 9c86f7045157..ba8d4a1f10f9 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -1388,6 +1388,12 @@ endmenu config CRYPTO_HASH_INFO bool +config CRYPTO_POOL + tristate "Per-CPU crypto pool" + default n + help + Per-CPU pool of crypto requests ready for usage in atomic contexts. + if !KMSAN # avoid false positives from assembly if ARM source "arch/arm/crypto/Kconfig" diff --git a/crypto/Makefile b/crypto/Makefile index d0126c915834..eed8f61bc93b 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -63,6 +63,7 @@ obj-$(CONFIG_CRYPTO_ACOMP2) += crypto_acompress.o cryptomgr-y := algboss.o testmgr.o obj-$(CONFIG_CRYPTO_MANAGER2) += cryptomgr.o +obj-$(CONFIG_CRYPTO_POOL) += crypto_pool.o obj-$(CONFIG_CRYPTO_USER) += crypto_user.o crypto_user-y := crypto_user_base.o crypto_user-$(CONFIG_CRYPTO_STATS) += crypto_user_stat.o diff --git a/crypto/crypto_pool.c b/crypto/crypto_pool.c new file mode 100644 index 000000000000..37131952c5a7 --- /dev/null +++ b/crypto/crypto_pool.c @@ -0,0 +1,291 @@ +// SPDX-License-Identifier: GPL-2.0-or-later + +#include <crypto/pool.h> +#include <linux/kref.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/percpu.h> +#include <linux/workqueue.h> + +static unsigned long scratch_size = DEFAULT_CRYPTO_POOL_SCRATCH_SZ; +static DEFINE_PER_CPU(void *, crypto_pool_scratch); + +struct crypto_pool_entry { + struct ahash_request * __percpu *req; + const char *alg; + struct kref kref; + bool needs_key; +}; + +#define CPOOL_SIZE (PAGE_SIZE/sizeof(struct crypto_pool_entry)) +static struct crypto_pool_entry cpool[CPOOL_SIZE]; +static unsigned int cpool_populated; +static DEFINE_MUTEX(cpool_mutex); + +static int crypto_pool_scratch_alloc(void) +{ + int cpu; + + lockdep_assert_held(&cpool_mutex); + + for_each_possible_cpu(cpu) { + void *scratch = per_cpu(crypto_pool_scratch, cpu); + + if (scratch) + continue; + + scratch = kmalloc_node(scratch_size, GFP_KERNEL, + cpu_to_node(cpu)); + if (!scratch) + return -ENOMEM; + per_cpu(crypto_pool_scratch, cpu) = scratch; + } + return 0; +} + +static void crypto_pool_scratch_free(void) +{ + int cpu; + + lockdep_assert_held(&cpool_mutex); + + for_each_possible_cpu(cpu) { + void *scratch = per_cpu(crypto_pool_scratch, cpu); + + if (!scratch) + continue; + per_cpu(crypto_pool_scratch, cpu) = NULL; + kfree(scratch); + } +} + +static int __cpool_alloc_ahash(struct crypto_pool_entry *e, const char *alg) +{ + struct crypto_ahash *hash; + int cpu, ret = -ENOMEM; + + e->alg = kstrdup(alg, GFP_KERNEL); + if (!e->alg) + return -ENOMEM; + + e->req = alloc_percpu(struct ahash_request *); + if (!e->req) + goto out_free_alg; + + hash = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hash)) { + ret = PTR_ERR(hash); + goto out_free_req; + } + + /* If hash has .setkey(), allocate ahash per-cpu, not only request */ + e->needs_key = crypto_ahash_get_flags(hash) & CRYPTO_TFM_NEED_KEY; + + for_each_possible_cpu(cpu) { + struct ahash_request *req; + + if (!hash) + hash = crypto_alloc_ahash(alg, 0, CRYPTO_ALG_ASYNC); + if (IS_ERR(hash)) + goto out_free; + + req = ahash_request_alloc(hash, GFP_KERNEL); + if (!req) + goto out_free; + + ahash_request_set_callback(req, 0, NULL, NULL); + + *per_cpu_ptr(e->req, cpu) = req; + + if (e->needs_key) + hash = NULL; + } + kref_init(&e->kref); + return 0; + +out_free: + if (!IS_ERR_OR_NULL(hash) && e->needs_key) + crypto_free_ahash(hash); + + for_each_possible_cpu(cpu) { + if (*per_cpu_ptr(e->req, cpu) == NULL) + break; + hash = crypto_ahash_reqtfm(*per_cpu_ptr(e->req, cpu)); + ahash_request_free(*per_cpu_ptr(e->req, cpu)); + if (e->needs_key) { + crypto_free_ahash(hash); + hash = NULL; + } + } + + if (hash) + crypto_free_ahash(hash); +out_free_req: + free_percpu(e->req); +out_free_alg: + kfree(e->alg); + e->alg = NULL; + return ret; +} + +/** + * crypto_pool_alloc_ahash - allocates pool for ahash requests + * @alg: name of async hash algorithm + */ +int crypto_pool_alloc_ahash(const char *alg) +{ + int i, ret; + + /* slow-path */ + mutex_lock(&cpool_mutex); + + for (i = 0; i < cpool_populated; i++) { + if (cpool[i].alg && !strcmp(cpool[i].alg, alg)) { + if (kref_read(&cpool[i].kref) > 0) { + kref_get(&cpool[i].kref); + ret = i; + goto out; + } else { + break; + } + } + } + + for (i = 0; i < cpool_populated; i++) { + if (!cpool[i].alg) + break; + } + if (i >= CPOOL_SIZE) { + ret = -ENOSPC; + goto out; + } + + ret = __cpool_alloc_ahash(&cpool[i], alg); + if (!ret) { + ret = i; + if (i == cpool_populated) + cpool_populated++; + } +out: + mutex_unlock(&cpool_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(crypto_pool_alloc_ahash); + +static void __cpool_free_entry(struct crypto_pool_entry *e) +{ + struct crypto_ahash *hash = NULL; + int cpu; + + for_each_possible_cpu(cpu) { + if (*per_cpu_ptr(e->req, cpu) == NULL) + continue; + + hash = crypto_ahash_reqtfm(*per_cpu_ptr(e->req, cpu)); + ahash_request_free(*per_cpu_ptr(e->req, cpu)); + if (e->needs_key) { + crypto_free_ahash(hash); + hash = NULL; + } + } + if (hash) + crypto_free_ahash(hash); + free_percpu(e->req); + kfree(e->alg); + memset(e, 0, sizeof(*e)); +} + +static void cpool_cleanup_work_cb(struct work_struct *work) +{ + unsigned int i; + bool free_scratch = true; + + mutex_lock(&cpool_mutex); + for (i = 0; i < cpool_populated; i++) { + if (kref_read(&cpool[i].kref) > 0) { + free_scratch = false; + continue; + } + if (!cpool[i].alg) + continue; + __cpool_free_entry(&cpool[i]); + } + if (free_scratch) + crypto_pool_scratch_free(); + mutex_unlock(&cpool_mutex); +} + +static DECLARE_WORK(cpool_cleanup_work, cpool_cleanup_work_cb); +static void cpool_schedule_cleanup(struct kref *kref) +{ + schedule_work(&cpool_cleanup_work); +} + +/** + * crypto_pool_release - decreases number of users for a pool. If it was + * the last user of the pool, releases any memory that was consumed. + * @id: crypto_pool that was previously allocated by crypto_pool_alloc_ahash() + */ +void crypto_pool_release(unsigned int id) +{ + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) + return; + + /* slow-path */ + kref_put(&cpool[id].kref, cpool_schedule_cleanup); +} +EXPORT_SYMBOL_GPL(crypto_pool_release); + +/** + * crypto_pool_add - increases number of users (refcounter) for a pool + * @id: crypto_pool that was previously allocated by crypto_pool_alloc_ahash() + */ +void crypto_pool_add(unsigned int id) +{ + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) + return; + kref_get(&cpool[id].kref); +} +EXPORT_SYMBOL_GPL(crypto_pool_add); + +/** + * crypto_pool_get - disable bh and start using crypto_pool + * @id: crypto_pool that was previously allocated by crypto_pool_alloc_ahash() + * @c: returned crypto_pool for usage (uninitialized on failure) + */ +int crypto_pool_get(unsigned int id, struct crypto_pool *c) +{ + struct crypto_pool_ahash *ret = (struct crypto_pool_ahash *)c; + + local_bh_disable(); + if (WARN_ON_ONCE(id > cpool_populated || !cpool[id].alg)) { + local_bh_enable(); + return -EINVAL; + } + ret->req = *this_cpu_ptr(cpool[id].req); + ret->base.scratch = this_cpu_read(crypto_pool_scratch); + return 0; +} +EXPORT_SYMBOL_GPL(crypto_pool_get); + +/** + * crypto_pool_algo - return algorithm of crypto_pool + * @id: crypto_pool that was previously allocated by crypto_pool_alloc_ahash() + * @buf: buffer to return name of algorithm + * @buf_len: size of @buf + */ +size_t crypto_pool_algo(unsigned int id, char *buf, size_t buf_len) +{ + size_t ret = 0; + + /* slow-path */ + mutex_lock(&cpool_mutex); + if (cpool[id].alg) + ret = strscpy(buf, cpool[id].alg, buf_len); + mutex_unlock(&cpool_mutex); + return ret; +} +EXPORT_SYMBOL_GPL(crypto_pool_algo); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("Per-CPU pool of crypto requests"); diff --git a/include/crypto/pool.h b/include/crypto/pool.h new file mode 100644 index 000000000000..2c61aa45faff --- /dev/null +++ b/include/crypto/pool.h @@ -0,0 +1,34 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +#ifndef _CRYPTO_POOL_H +#define _CRYPTO_POOL_H + +#include <crypto/hash.h> + +#define DEFAULT_CRYPTO_POOL_SCRATCH_SZ 128 + +struct crypto_pool { + void *scratch; +}; + +/* + * struct crypto_pool_ahash - per-CPU pool of ahash_requests + * @base: common members that can be used by any async crypto ops + * @req: pre-allocated ahash request + */ +struct crypto_pool_ahash { + struct crypto_pool base; + struct ahash_request *req; +}; + +int crypto_pool_alloc_ahash(const char *alg); +void crypto_pool_add(unsigned int id); +void crypto_pool_release(unsigned int id); + +int crypto_pool_get(unsigned int id, struct crypto_pool *c); +static inline void crypto_pool_put(void) +{ + local_bh_enable(); +} +size_t crypto_pool_algo(unsigned int id, char *buf, size_t buf_len); + +#endif /* _CRYPTO_POOL_H */ -- 2.39.0