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- /*
- * Copyright (c) 2016, Intel Corporation
- * Authors: Salvatore Benedetto <salvatore.benedetto@intel.com>
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public Licence
- * as published by the Free Software Foundation; either version
- * 2 of the Licence, or (at your option) any later version.
- */
- #include <linux/kernel.h>
- #include <linux/export.h>
- #include <linux/err.h>
- #include <linux/string.h>
- #include <crypto/dh.h>
- #include <crypto/kpp.h>
- #define DH_KPP_SECRET_MIN_SIZE (sizeof(struct kpp_secret) + 3 * sizeof(int))
- static inline u8 *dh_pack_data(void *dst, const void *src, size_t size)
- {
- memcpy(dst, src, size);
- return dst + size;
- }
- static inline const u8 *dh_unpack_data(void *dst, const void *src, size_t size)
- {
- memcpy(dst, src, size);
- return src + size;
- }
- static inline int dh_data_size(const struct dh *p)
- {
- return p->key_size + p->p_size + p->g_size;
- }
- int crypto_dh_key_len(const struct dh *p)
- {
- return DH_KPP_SECRET_MIN_SIZE + dh_data_size(p);
- }
- EXPORT_SYMBOL_GPL(crypto_dh_key_len);
- int crypto_dh_encode_key(char *buf, unsigned int len, const struct dh *params)
- {
- u8 *ptr = buf;
- struct kpp_secret secret = {
- .type = CRYPTO_KPP_SECRET_TYPE_DH,
- .len = len
- };
- if (unlikely(!buf))
- return -EINVAL;
- if (len != crypto_dh_key_len(params))
- return -EINVAL;
- ptr = dh_pack_data(ptr, &secret, sizeof(secret));
- ptr = dh_pack_data(ptr, ¶ms->key_size, sizeof(params->key_size));
- ptr = dh_pack_data(ptr, ¶ms->p_size, sizeof(params->p_size));
- ptr = dh_pack_data(ptr, ¶ms->g_size, sizeof(params->g_size));
- ptr = dh_pack_data(ptr, params->key, params->key_size);
- ptr = dh_pack_data(ptr, params->p, params->p_size);
- dh_pack_data(ptr, params->g, params->g_size);
- return 0;
- }
- EXPORT_SYMBOL_GPL(crypto_dh_encode_key);
- int crypto_dh_decode_key(const char *buf, unsigned int len, struct dh *params)
- {
- const u8 *ptr = buf;
- struct kpp_secret secret;
- if (unlikely(!buf || len < DH_KPP_SECRET_MIN_SIZE))
- return -EINVAL;
- ptr = dh_unpack_data(&secret, ptr, sizeof(secret));
- if (secret.type != CRYPTO_KPP_SECRET_TYPE_DH)
- return -EINVAL;
- ptr = dh_unpack_data(¶ms->key_size, ptr, sizeof(params->key_size));
- ptr = dh_unpack_data(¶ms->p_size, ptr, sizeof(params->p_size));
- ptr = dh_unpack_data(¶ms->g_size, ptr, sizeof(params->g_size));
- if (secret.len != crypto_dh_key_len(params))
- return -EINVAL;
- /*
- * Don't permit the buffer for 'key' or 'g' to be larger than 'p', since
- * some drivers assume otherwise.
- */
- if (params->key_size > params->p_size ||
- params->g_size > params->p_size)
- return -EINVAL;
- /* Don't allocate memory. Set pointers to data within
- * the given buffer
- */
- params->key = (void *)ptr;
- params->p = (void *)(ptr + params->key_size);
- params->g = (void *)(ptr + params->key_size + params->p_size);
- /*
- * Don't permit 'p' to be 0. It's not a prime number, and it's subject
- * to corner cases such as 'mod 0' being undefined or
- * crypto_kpp_maxsize() returning 0.
- */
- if (memchr_inv(params->p, 0, params->p_size) == NULL)
- return -EINVAL;
- return 0;
- }
- EXPORT_SYMBOL_GPL(crypto_dh_decode_key);
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