From a2730a5bf0aebdc52eaabc08cb82e32e54129af8 Mon Sep 17 00:00:00 2001 From: Stephan Mueller Date: Fri, 18 Jun 2021 08:08:20 +0200 Subject: [PATCH] char/lrng: add common generic hash support The LRNG switchable DRNG support also allows the replacement of the hash implementation used as conditioning component. The common generic hash support code provides the required callbacks using the synchronous hash implementations of the kernel crypto API. All synchronous hash implementations supported by the kernel crypto API can be used as part of the LRNG with this generic support. The generic support is intended to be configured by separate switchable DRNG backends. CC: Torsten Duwe CC: "Eric W. Biederman" CC: "Alexander E. Patrakov" CC: "Ahmed S. Darwish" CC: "Theodore Y. Ts'o" CC: Willy Tarreau CC: Matthew Garrett CC: Vito Caputo CC: Andreas Dilger CC: Jan Kara CC: Ray Strode CC: William Jon McCann CC: zhangjs CC: Andy Lutomirski CC: Florian Weimer CC: Lennart Poettering CC: Nicolai Stange CC: "Peter, Matthias" CC: Marcelo Henrique Cerri CC: Neil Horman Reviewed-by: Alexander Lobakin Tested-by: Alexander Lobakin Signed-off-by: Stephan Mueller --- drivers/char/lrng/Kconfig | 8 +++ drivers/char/lrng/Makefile | 1 + drivers/char/lrng/lrng_kcapi_hash.c | 103 ++++++++++++++++++++++++++++ drivers/char/lrng/lrng_kcapi_hash.h | 20 ++++++ 4 files changed, 132 insertions(+) create mode 100644 drivers/char/lrng/lrng_kcapi_hash.c create mode 100644 drivers/char/lrng/lrng_kcapi_hash.h diff --git a/drivers/char/lrng/Kconfig b/drivers/char/lrng/Kconfig index c10a0c3f2015b..ab17c45a356b4 100644 --- a/drivers/char/lrng/Kconfig +++ b/drivers/char/lrng/Kconfig @@ -209,4 +209,12 @@ menuconfig LRNG_DRNG_SWITCH accessible via the external interfaces. With this configuration option other DRNGs can be selected and loaded at runtime. +if LRNG_DRNG_SWITCH + +config LRNG_KCAPI_HASH + bool + select CRYPTO_HASH + +endif # LRNG_DRNG_SWITCH + endif # LRNG diff --git a/drivers/char/lrng/Makefile b/drivers/char/lrng/Makefile index dc3ef329b2c46..299715bb0ec25 100644 --- a/drivers/char/lrng/Makefile +++ b/drivers/char/lrng/Makefile @@ -11,3 +11,4 @@ obj-y += lrng_es_mgr.o lrng_aux.o \ obj-$(CONFIG_NUMA) += lrng_numa.o obj-$(CONFIG_SYSCTL) += lrng_proc.o obj-$(CONFIG_LRNG_DRNG_SWITCH) += lrng_switch.o +obj-$(CONFIG_LRNG_KCAPI_HASH) += lrng_kcapi_hash.o diff --git a/drivers/char/lrng/lrng_kcapi_hash.c b/drivers/char/lrng/lrng_kcapi_hash.c new file mode 100644 index 0000000000000..9647d980e4683 --- /dev/null +++ b/drivers/char/lrng/lrng_kcapi_hash.c @@ -0,0 +1,103 @@ +// SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause +/* + * Backend for providing the hash primitive using the kernel crypto API. + * + * Copyright (C) 2021, Stephan Mueller + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include + +#include "lrng_kcapi_hash.h" + +struct lrng_hash_info { + struct crypto_shash *tfm; +}; + +static inline void _lrng_kcapi_hash_free(struct lrng_hash_info *lrng_hash) +{ + struct crypto_shash *tfm = lrng_hash->tfm; + + crypto_free_shash(tfm); + kfree(lrng_hash); +} + +void *lrng_kcapi_hash_alloc(const char *name) +{ + struct lrng_hash_info *lrng_hash; + struct crypto_shash *tfm; + int ret; + + if (!name) { + pr_err("Hash name missing\n"); + return ERR_PTR(-EINVAL); + } + + tfm = crypto_alloc_shash(name, 0, 0); + if (IS_ERR(tfm)) { + pr_err("could not allocate hash %s\n", name); + return ERR_CAST(tfm); + } + + ret = sizeof(struct lrng_hash_info); + lrng_hash = kmalloc(ret, GFP_KERNEL); + if (!lrng_hash) { + crypto_free_shash(tfm); + return ERR_PTR(-ENOMEM); + } + + lrng_hash->tfm = tfm; + + pr_info("Hash %s allocated\n", name); + + return lrng_hash; +} +EXPORT_SYMBOL(lrng_kcapi_hash_alloc); + +u32 lrng_kcapi_hash_digestsize(void *hash) +{ + struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash; + struct crypto_shash *tfm = lrng_hash->tfm; + + return crypto_shash_digestsize(tfm); +} +EXPORT_SYMBOL(lrng_kcapi_hash_digestsize); + +void lrng_kcapi_hash_dealloc(void *hash) +{ + struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash; + + _lrng_kcapi_hash_free(lrng_hash); + pr_info("Hash deallocated\n"); +} +EXPORT_SYMBOL(lrng_kcapi_hash_dealloc); + +int lrng_kcapi_hash_init(struct shash_desc *shash, void *hash) +{ + struct lrng_hash_info *lrng_hash = (struct lrng_hash_info *)hash; + struct crypto_shash *tfm = lrng_hash->tfm; + + shash->tfm = tfm; + return crypto_shash_init(shash); +} +EXPORT_SYMBOL(lrng_kcapi_hash_init); + +int lrng_kcapi_hash_update(struct shash_desc *shash, const u8 *inbuf, + u32 inbuflen) +{ + return crypto_shash_update(shash, inbuf, inbuflen); +} +EXPORT_SYMBOL(lrng_kcapi_hash_update); + +int lrng_kcapi_hash_final(struct shash_desc *shash, u8 *digest) +{ + return crypto_shash_final(shash, digest); +} +EXPORT_SYMBOL(lrng_kcapi_hash_final); + +void lrng_kcapi_hash_zero(struct shash_desc *shash) +{ + shash_desc_zero(shash); +} +EXPORT_SYMBOL(lrng_kcapi_hash_zero); diff --git a/drivers/char/lrng/lrng_kcapi_hash.h b/drivers/char/lrng/lrng_kcapi_hash.h new file mode 100644 index 0000000000000..2f94558d2dd64 --- /dev/null +++ b/drivers/char/lrng/lrng_kcapi_hash.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause */ +/* + * Copyright (C) 2020 - 2021, Stephan Mueller + */ + +#ifndef _LRNG_KCAPI_HASH_H +#define _LRNG_KCAPI_HASH_H + +#include + +void *lrng_kcapi_hash_alloc(const char *name); +u32 lrng_kcapi_hash_digestsize(void *hash); +void lrng_kcapi_hash_dealloc(void *hash); +int lrng_kcapi_hash_init(struct shash_desc *shash, void *hash); +int lrng_kcapi_hash_update(struct shash_desc *shash, const u8 *inbuf, + u32 inbuflen); +int lrng_kcapi_hash_final(struct shash_desc *shash, u8 *digest); +void lrng_kcapi_hash_zero(struct shash_desc *shash); + +#endif /* _LRNG_KCAPI_HASH_H */