From 08debaa5cb31da50725a8cb2f06d3f617a9caa98 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 18 Oct 2023 15:34:55 -0700 Subject: [PATCH] crypto: shash - eliminate indirect call for default import and export Most shash algorithms don't have custom ->import and ->export functions, resulting in the memcpy() based default being used. Yet, crypto_shash_import() and crypto_shash_export() still make an indirect call, which is expensive. Therefore, change how the default import and export are called to make it so that crypto_shash_import() and crypto_shash_export() don't do an indirect call in this case. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- crypto/shash.c | 41 +++++++++++++++++++++++++++++++++-------- include/crypto/hash.h | 15 ++------------- 2 files changed, 35 insertions(+), 21 deletions(-) diff --git a/crypto/shash.c b/crypto/shash.c index 15fee57cca8ef..52420c41db44a 100644 --- a/crypto/shash.c +++ b/crypto/shash.c @@ -277,17 +277,34 @@ int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data, } EXPORT_SYMBOL_GPL(crypto_shash_tfm_digest); -static int shash_default_export(struct shash_desc *desc, void *out) +int crypto_shash_export(struct shash_desc *desc, void *out) { - memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm)); + struct crypto_shash *tfm = desc->tfm; + struct shash_alg *shash = crypto_shash_alg(tfm); + + if (shash->export) + return shash->export(desc, out); + + memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(tfm)); return 0; } +EXPORT_SYMBOL_GPL(crypto_shash_export); -static int shash_default_import(struct shash_desc *desc, const void *in) +int crypto_shash_import(struct shash_desc *desc, const void *in) { - memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm)); + struct crypto_shash *tfm = desc->tfm; + struct shash_alg *shash = crypto_shash_alg(tfm); + + if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) + return -ENOKEY; + + if (shash->import) + return shash->import(desc, in); + + memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(tfm)); return 0; } +EXPORT_SYMBOL_GPL(crypto_shash_import); static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key, unsigned int keylen) @@ -666,15 +683,23 @@ static int shash_prepare_alg(struct shash_alg *alg) base->cra_type = &crypto_shash_type; base->cra_flags |= CRYPTO_ALG_TYPE_SHASH; + /* + * Handle missing optional functions. For each one we can either + * install a default here, or we can leave the pointer as NULL and check + * the pointer for NULL in crypto_shash_*(), avoiding an indirect call + * when the default behavior is desired. For ->finup and ->digest we + * install defaults, since for optimal performance algorithms should + * implement these anyway. On the other hand, for ->import and + * ->export the common case and best performance comes from the simple + * memcpy of the shash_desc_ctx, so when those pointers are NULL we + * leave them NULL and provide the memcpy with no indirect call. + */ if (!alg->finup) alg->finup = shash_default_finup; if (!alg->digest) alg->digest = shash_default_digest; - if (!alg->export) { - alg->export = shash_default_export; - alg->import = shash_default_import; + if (!alg->export) alg->halg.statesize = alg->descsize; - } if (!alg->setkey) alg->setkey = shash_no_setkey; diff --git a/include/crypto/hash.h b/include/crypto/hash.h index f7c2a22cd776d..52e57e93b2f59 100644 --- a/include/crypto/hash.h +++ b/include/crypto/hash.h @@ -952,10 +952,7 @@ int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data, * Context: Any context. * Return: 0 if the export creation was successful; < 0 if an error occurred */ -static inline int crypto_shash_export(struct shash_desc *desc, void *out) -{ - return crypto_shash_alg(desc->tfm)->export(desc, out); -} +int crypto_shash_export(struct shash_desc *desc, void *out); /** * crypto_shash_import() - import operational state @@ -969,15 +966,7 @@ static inline int crypto_shash_export(struct shash_desc *desc, void *out) * Context: Any context. * Return: 0 if the import was successful; < 0 if an error occurred */ -static inline int crypto_shash_import(struct shash_desc *desc, const void *in) -{ - struct crypto_shash *tfm = desc->tfm; - - if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) - return -ENOKEY; - - return crypto_shash_alg(tfm)->import(desc, in); -} +int crypto_shash_import(struct shash_desc *desc, const void *in); /** * crypto_shash_init() - (re)initialize message digest -- 2.39.2