From: Harsh Jain Date: Mon, 15 Sep 2025 13:30:25 +0000 (+0530) Subject: crypto: drbg - Export CTR DRBG DF functions X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6c4fed5fee42f5785e881ef2c28359724b18b80e;p=thirdparty%2Flinux.git crypto: drbg - Export CTR DRBG DF functions Export drbg_ctr_df() derivative function to new module df_sp80090. Signed-off-by: Harsh Jain Signed-off-by: Herbert Xu --- diff --git a/crypto/Kconfig b/crypto/Kconfig index a04595f9d0ca4..b9afd8505b89c 100644 --- a/crypto/Kconfig +++ b/crypto/Kconfig @@ -1205,8 +1205,7 @@ config CRYPTO_DRBG_HASH config CRYPTO_DRBG_CTR bool "CTR_DRBG" - select CRYPTO_AES - select CRYPTO_CTR + select CRYPTO_DF80090A help CTR_DRBG variant as defined in NIST SP800-90A. @@ -1342,6 +1341,11 @@ config CRYPTO_KDF800108_CTR select CRYPTO_HMAC select CRYPTO_SHA256 +config CRYPTO_DF80090A + tristate + select CRYPTO_AES + select CRYPTO_CTR + endmenu menu "Userspace interface" diff --git a/crypto/Makefile b/crypto/Makefile index e430e6e99b6a2..c47f2bf5db61a 100644 --- a/crypto/Makefile +++ b/crypto/Makefile @@ -209,4 +209,6 @@ obj-$(CONFIG_CRYPTO_SIMD) += crypto_simd.o # obj-$(CONFIG_CRYPTO_KDF800108_CTR) += kdf_sp800108.o +obj-$(CONFIG_CRYPTO_DF80090A) += df_sp80090a.o + obj-$(CONFIG_CRYPTO_KRB5) += krb5/ diff --git a/crypto/df_sp80090a.c b/crypto/df_sp80090a.c new file mode 100644 index 0000000000000..8309e62abe270 --- /dev/null +++ b/crypto/df_sp80090a.c @@ -0,0 +1,247 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * NIST SP800-90A DRBG derivation function + * + * Copyright (C) 2014, Stephan Mueller + */ + +#include +#include +#include +#include +#include +#include + +static void drbg_kcapi_symsetkey(struct crypto_cipher *tfm, + const unsigned char *key, + u8 keylen); +static int drbg_kcapi_sym(struct crypto_cipher *tfm, unsigned char *outval, + const struct drbg_string *in, u8 blocklen_bytes); + +static void drbg_kcapi_symsetkey(struct crypto_cipher *tfm, + const unsigned char *key, u8 keylen) +{ + crypto_cipher_setkey(tfm, key, keylen); +} + +static int drbg_kcapi_sym(struct crypto_cipher *tfm, unsigned char *outval, + const struct drbg_string *in, u8 blocklen_bytes) +{ + /* there is only component in *in */ + BUG_ON(in->len < blocklen_bytes); + crypto_cipher_encrypt_one(tfm, outval, in->buf); + return 0; +} + +/* BCC function for CTR DRBG as defined in 10.4.3 */ + +static int drbg_ctr_bcc(struct crypto_cipher *tfm, + unsigned char *out, const unsigned char *key, + struct list_head *in, + u8 blocklen_bytes, + u8 keylen) +{ + int ret = 0; + struct drbg_string *curr = NULL; + struct drbg_string data; + short cnt = 0; + + drbg_string_fill(&data, out, blocklen_bytes); + + /* 10.4.3 step 2 / 4 */ + drbg_kcapi_symsetkey(tfm, key, keylen); + list_for_each_entry(curr, in, list) { + const unsigned char *pos = curr->buf; + size_t len = curr->len; + /* 10.4.3 step 4.1 */ + while (len) { + /* 10.4.3 step 4.2 */ + if (blocklen_bytes == cnt) { + cnt = 0; + ret = drbg_kcapi_sym(tfm, out, &data, blocklen_bytes); + if (ret) + return ret; + } + out[cnt] ^= *pos; + pos++; + cnt++; + len--; + } + } + /* 10.4.3 step 4.2 for last block */ + if (cnt) + ret = drbg_kcapi_sym(tfm, out, &data, blocklen_bytes); + + return ret; +} + +/* + * scratchpad usage: drbg_ctr_update is interlinked with crypto_drbg_ctr_df + * (and drbg_ctr_bcc, but this function does not need any temporary buffers), + * the scratchpad is used as follows: + * drbg_ctr_update: + * temp + * start: drbg->scratchpad + * length: drbg_statelen(drbg) + drbg_blocklen(drbg) + * note: the cipher writing into this variable works + * blocklen-wise. Now, when the statelen is not a multiple + * of blocklen, the generateion loop below "spills over" + * by at most blocklen. Thus, we need to give sufficient + * memory. + * df_data + * start: drbg->scratchpad + + * drbg_statelen(drbg) + drbg_blocklen(drbg) + * length: drbg_statelen(drbg) + * + * crypto_drbg_ctr_df: + * pad + * start: df_data + drbg_statelen(drbg) + * length: drbg_blocklen(drbg) + * iv + * start: pad + drbg_blocklen(drbg) + * length: drbg_blocklen(drbg) + * temp + * start: iv + drbg_blocklen(drbg) + * length: drbg_satelen(drbg) + drbg_blocklen(drbg) + * note: temp is the buffer that the BCC function operates + * on. BCC operates blockwise. drbg_statelen(drbg) + * is sufficient when the DRBG state length is a multiple + * of the block size. For AES192 (and maybe other ciphers) + * this is not correct and the length for temp is + * insufficient (yes, that also means for such ciphers, + * the final output of all BCC rounds are truncated). + * Therefore, add drbg_blocklen(drbg) to cover all + * possibilities. + * refer to crypto_drbg_ctr_df_datalen() to get required length + */ + +/* Derivation Function for CTR DRBG as defined in 10.4.2 */ +int crypto_drbg_ctr_df(struct crypto_cipher *tfm, + unsigned char *df_data, size_t bytes_to_return, + struct list_head *seedlist, + u8 blocklen_bytes, + u8 statelen) +{ + int ret = -EFAULT; + unsigned char L_N[8]; + /* S3 is input */ + struct drbg_string S1, S2, S4, cipherin; + LIST_HEAD(bcc_list); + unsigned char *pad = df_data + statelen; + unsigned char *iv = pad + blocklen_bytes; + unsigned char *temp = iv + blocklen_bytes; + size_t padlen = 0; + unsigned int templen = 0; + /* 10.4.2 step 7 */ + unsigned int i = 0; + /* 10.4.2 step 8 */ + const unsigned char *K = (unsigned char *) + "\x00\x01\x02\x03\x04\x05\x06\x07" + "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" + "\x10\x11\x12\x13\x14\x15\x16\x17" + "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"; + unsigned char *X; + size_t generated_len = 0; + size_t inputlen = 0; + struct drbg_string *seed = NULL; + u8 keylen; + + memset(pad, 0, blocklen_bytes); + memset(iv, 0, blocklen_bytes); + keylen = statelen - blocklen_bytes; + /* 10.4.2 step 1 is implicit as we work byte-wise */ + + /* 10.4.2 step 2 */ + if ((512 / 8) < bytes_to_return) + return -EINVAL; + + /* 10.4.2 step 2 -- calculate the entire length of all input data */ + list_for_each_entry(seed, seedlist, list) + inputlen += seed->len; + drbg_cpu_to_be32(inputlen, &L_N[0]); + + /* 10.4.2 step 3 */ + drbg_cpu_to_be32(bytes_to_return, &L_N[4]); + + /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */ + padlen = (inputlen + sizeof(L_N) + 1) % (blocklen_bytes); + /* wrap the padlen appropriately */ + if (padlen) + padlen = blocklen_bytes - padlen; + /* + * pad / padlen contains the 0x80 byte and the following zero bytes. + * As the calculated padlen value only covers the number of zero + * bytes, this value has to be incremented by one for the 0x80 byte. + */ + padlen++; + pad[0] = 0x80; + + /* 10.4.2 step 4 -- first fill the linked list and then order it */ + drbg_string_fill(&S1, iv, blocklen_bytes); + list_add_tail(&S1.list, &bcc_list); + drbg_string_fill(&S2, L_N, sizeof(L_N)); + list_add_tail(&S2.list, &bcc_list); + list_splice_tail(seedlist, &bcc_list); + drbg_string_fill(&S4, pad, padlen); + list_add_tail(&S4.list, &bcc_list); + + /* 10.4.2 step 9 */ + while (templen < (keylen + (blocklen_bytes))) { + /* + * 10.4.2 step 9.1 - the padding is implicit as the buffer + * holds zeros after allocation -- even the increment of i + * is irrelevant as the increment remains within length of i + */ + drbg_cpu_to_be32(i, iv); + /* 10.4.2 step 9.2 -- BCC and concatenation with temp */ + ret = drbg_ctr_bcc(tfm, temp + templen, K, &bcc_list, + blocklen_bytes, keylen); + if (ret) + goto out; + /* 10.4.2 step 9.3 */ + i++; + templen += blocklen_bytes; + } + + /* 10.4.2 step 11 */ + X = temp + (keylen); + drbg_string_fill(&cipherin, X, blocklen_bytes); + + /* 10.4.2 step 12: overwriting of outval is implemented in next step */ + + /* 10.4.2 step 13 */ + drbg_kcapi_symsetkey(tfm, temp, keylen); + while (generated_len < bytes_to_return) { + short blocklen = 0; + /* + * 10.4.2 step 13.1: the truncation of the key length is + * implicit as the key is only drbg_blocklen in size based on + * the implementation of the cipher function callback + */ + ret = drbg_kcapi_sym(tfm, X, &cipherin, blocklen_bytes); + if (ret) + goto out; + blocklen = (blocklen_bytes < + (bytes_to_return - generated_len)) ? + blocklen_bytes : + (bytes_to_return - generated_len); + /* 10.4.2 step 13.2 and 14 */ + memcpy(df_data + generated_len, X, blocklen); + generated_len += blocklen; + } + + ret = 0; + +out: + memset(iv, 0, blocklen_bytes); + memset(temp, 0, statelen + blocklen_bytes); + memset(pad, 0, blocklen_bytes); + return ret; +} +EXPORT_SYMBOL_GPL(crypto_drbg_ctr_df); + +MODULE_IMPORT_NS("CRYPTO_INTERNAL"); +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Stephan Mueller "); +MODULE_DESCRIPTION("Derivation Function conformant to SP800-90A"); diff --git a/crypto/drbg.c b/crypto/drbg.c index dbe4c8bb5ceb7..bad005eef03d6 100644 --- a/crypto/drbg.c +++ b/crypto/drbg.c @@ -98,6 +98,7 @@ */ #include +#include #include #include #include @@ -261,26 +262,6 @@ static int drbg_fips_continuous_test(struct drbg_state *drbg, return 0; } -/* - * Convert an integer into a byte representation of this integer. - * The byte representation is big-endian - * - * @val value to be converted - * @buf buffer holding the converted integer -- caller must ensure that - * buffer size is at least 32 bit - */ -#if (defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR)) -static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf) -{ - struct s { - __be32 conv; - }; - struct s *conversion = (struct s *) buf; - - conversion->conv = cpu_to_be32(val); -} -#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */ - /****************************************************************** * CTR DRBG callback functions ******************************************************************/ @@ -294,10 +275,6 @@ MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes192"); MODULE_ALIAS_CRYPTO("drbg_pr_ctr_aes128"); MODULE_ALIAS_CRYPTO("drbg_nopr_ctr_aes128"); -static void drbg_kcapi_symsetkey(struct drbg_state *drbg, - const unsigned char *key); -static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval, - const struct drbg_string *in); static int drbg_init_sym_kernel(struct drbg_state *drbg); static int drbg_fini_sym_kernel(struct drbg_state *drbg); static int drbg_kcapi_sym_ctr(struct drbg_state *drbg, @@ -305,202 +282,12 @@ static int drbg_kcapi_sym_ctr(struct drbg_state *drbg, u8 *outbuf, u32 outlen); #define DRBG_OUTSCRATCHLEN 256 -/* BCC function for CTR DRBG as defined in 10.4.3 */ -static int drbg_ctr_bcc(struct drbg_state *drbg, - unsigned char *out, const unsigned char *key, - struct list_head *in) -{ - int ret = 0; - struct drbg_string *curr = NULL; - struct drbg_string data; - short cnt = 0; - - drbg_string_fill(&data, out, drbg_blocklen(drbg)); - - /* 10.4.3 step 2 / 4 */ - drbg_kcapi_symsetkey(drbg, key); - list_for_each_entry(curr, in, list) { - const unsigned char *pos = curr->buf; - size_t len = curr->len; - /* 10.4.3 step 4.1 */ - while (len) { - /* 10.4.3 step 4.2 */ - if (drbg_blocklen(drbg) == cnt) { - cnt = 0; - ret = drbg_kcapi_sym(drbg, out, &data); - if (ret) - return ret; - } - out[cnt] ^= *pos; - pos++; - cnt++; - len--; - } - } - /* 10.4.3 step 4.2 for last block */ - if (cnt) - ret = drbg_kcapi_sym(drbg, out, &data); - - return ret; -} - -/* - * scratchpad usage: drbg_ctr_update is interlinked with drbg_ctr_df - * (and drbg_ctr_bcc, but this function does not need any temporary buffers), - * the scratchpad is used as follows: - * drbg_ctr_update: - * temp - * start: drbg->scratchpad - * length: drbg_statelen(drbg) + drbg_blocklen(drbg) - * note: the cipher writing into this variable works - * blocklen-wise. Now, when the statelen is not a multiple - * of blocklen, the generateion loop below "spills over" - * by at most blocklen. Thus, we need to give sufficient - * memory. - * df_data - * start: drbg->scratchpad + - * drbg_statelen(drbg) + drbg_blocklen(drbg) - * length: drbg_statelen(drbg) - * - * drbg_ctr_df: - * pad - * start: df_data + drbg_statelen(drbg) - * length: drbg_blocklen(drbg) - * iv - * start: pad + drbg_blocklen(drbg) - * length: drbg_blocklen(drbg) - * temp - * start: iv + drbg_blocklen(drbg) - * length: drbg_satelen(drbg) + drbg_blocklen(drbg) - * note: temp is the buffer that the BCC function operates - * on. BCC operates blockwise. drbg_statelen(drbg) - * is sufficient when the DRBG state length is a multiple - * of the block size. For AES192 (and maybe other ciphers) - * this is not correct and the length for temp is - * insufficient (yes, that also means for such ciphers, - * the final output of all BCC rounds are truncated). - * Therefore, add drbg_blocklen(drbg) to cover all - * possibilities. - */ - -/* Derivation Function for CTR DRBG as defined in 10.4.2 */ static int drbg_ctr_df(struct drbg_state *drbg, unsigned char *df_data, size_t bytes_to_return, struct list_head *seedlist) { - int ret = -EFAULT; - unsigned char L_N[8]; - /* S3 is input */ - struct drbg_string S1, S2, S4, cipherin; - LIST_HEAD(bcc_list); - unsigned char *pad = df_data + drbg_statelen(drbg); - unsigned char *iv = pad + drbg_blocklen(drbg); - unsigned char *temp = iv + drbg_blocklen(drbg); - size_t padlen = 0; - unsigned int templen = 0; - /* 10.4.2 step 7 */ - unsigned int i = 0; - /* 10.4.2 step 8 */ - const unsigned char *K = (unsigned char *) - "\x00\x01\x02\x03\x04\x05\x06\x07" - "\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f" - "\x10\x11\x12\x13\x14\x15\x16\x17" - "\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"; - unsigned char *X; - size_t generated_len = 0; - size_t inputlen = 0; - struct drbg_string *seed = NULL; - - memset(pad, 0, drbg_blocklen(drbg)); - memset(iv, 0, drbg_blocklen(drbg)); - - /* 10.4.2 step 1 is implicit as we work byte-wise */ - - /* 10.4.2 step 2 */ - if ((512/8) < bytes_to_return) - return -EINVAL; - - /* 10.4.2 step 2 -- calculate the entire length of all input data */ - list_for_each_entry(seed, seedlist, list) - inputlen += seed->len; - drbg_cpu_to_be32(inputlen, &L_N[0]); - - /* 10.4.2 step 3 */ - drbg_cpu_to_be32(bytes_to_return, &L_N[4]); - - /* 10.4.2 step 5: length is L_N, input_string, one byte, padding */ - padlen = (inputlen + sizeof(L_N) + 1) % (drbg_blocklen(drbg)); - /* wrap the padlen appropriately */ - if (padlen) - padlen = drbg_blocklen(drbg) - padlen; - /* - * pad / padlen contains the 0x80 byte and the following zero bytes. - * As the calculated padlen value only covers the number of zero - * bytes, this value has to be incremented by one for the 0x80 byte. - */ - padlen++; - pad[0] = 0x80; - - /* 10.4.2 step 4 -- first fill the linked list and then order it */ - drbg_string_fill(&S1, iv, drbg_blocklen(drbg)); - list_add_tail(&S1.list, &bcc_list); - drbg_string_fill(&S2, L_N, sizeof(L_N)); - list_add_tail(&S2.list, &bcc_list); - list_splice_tail(seedlist, &bcc_list); - drbg_string_fill(&S4, pad, padlen); - list_add_tail(&S4.list, &bcc_list); - - /* 10.4.2 step 9 */ - while (templen < (drbg_keylen(drbg) + (drbg_blocklen(drbg)))) { - /* - * 10.4.2 step 9.1 - the padding is implicit as the buffer - * holds zeros after allocation -- even the increment of i - * is irrelevant as the increment remains within length of i - */ - drbg_cpu_to_be32(i, iv); - /* 10.4.2 step 9.2 -- BCC and concatenation with temp */ - ret = drbg_ctr_bcc(drbg, temp + templen, K, &bcc_list); - if (ret) - goto out; - /* 10.4.2 step 9.3 */ - i++; - templen += drbg_blocklen(drbg); - } - - /* 10.4.2 step 11 */ - X = temp + (drbg_keylen(drbg)); - drbg_string_fill(&cipherin, X, drbg_blocklen(drbg)); - - /* 10.4.2 step 12: overwriting of outval is implemented in next step */ - - /* 10.4.2 step 13 */ - drbg_kcapi_symsetkey(drbg, temp); - while (generated_len < bytes_to_return) { - short blocklen = 0; - /* - * 10.4.2 step 13.1: the truncation of the key length is - * implicit as the key is only drbg_blocklen in size based on - * the implementation of the cipher function callback - */ - ret = drbg_kcapi_sym(drbg, X, &cipherin); - if (ret) - goto out; - blocklen = (drbg_blocklen(drbg) < - (bytes_to_return - generated_len)) ? - drbg_blocklen(drbg) : - (bytes_to_return - generated_len); - /* 10.4.2 step 13.2 and 14 */ - memcpy(df_data + generated_len, X, blocklen); - generated_len += blocklen; - } - - ret = 0; - -out: - memset(iv, 0, drbg_blocklen(drbg)); - memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg)); - memset(pad, 0, drbg_blocklen(drbg)); - return ret; + return crypto_drbg_ctr_df(drbg->priv_data, df_data, drbg_statelen(drbg), + seedlist, drbg_blocklen(drbg), drbg_statelen(drbg)); } /* @@ -1310,10 +1097,8 @@ static inline int drbg_alloc_state(struct drbg_state *drbg) sb_size = 0; else if (drbg->core->flags & DRBG_CTR) sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg) + /* temp */ - drbg_statelen(drbg) + /* df_data */ - drbg_blocklen(drbg) + /* pad */ - drbg_blocklen(drbg) + /* iv */ - drbg_statelen(drbg) + drbg_blocklen(drbg); /* temp */ + crypto_drbg_ctr_df_datalen(drbg_statelen(drbg), + drbg_blocklen(drbg)); else sb_size = drbg_statelen(drbg) + drbg_blocklen(drbg); @@ -1800,25 +1585,6 @@ static int drbg_init_sym_kernel(struct drbg_state *drbg) return alignmask; } -static void drbg_kcapi_symsetkey(struct drbg_state *drbg, - const unsigned char *key) -{ - struct crypto_cipher *tfm = drbg->priv_data; - - crypto_cipher_setkey(tfm, key, (drbg_keylen(drbg))); -} - -static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval, - const struct drbg_string *in) -{ - struct crypto_cipher *tfm = drbg->priv_data; - - /* there is only component in *in */ - BUG_ON(in->len < drbg_blocklen(drbg)); - crypto_cipher_encrypt_one(tfm, outval, in->buf); - return 0; -} - static int drbg_kcapi_sym_ctr(struct drbg_state *drbg, u8 *inbuf, u32 inlen, u8 *outbuf, u32 outlen) diff --git a/drivers/crypto/Kconfig b/drivers/crypto/Kconfig index a6688d54984c4..8d3b5d2890f8b 100644 --- a/drivers/crypto/Kconfig +++ b/drivers/crypto/Kconfig @@ -728,6 +728,7 @@ config CRYPTO_DEV_TEGRA config CRYPTO_DEV_XILINX_TRNG tristate "Support for Xilinx True Random Generator" depends on ZYNQMP_FIRMWARE || COMPILE_TEST + select CRYPTO_DF80090A select CRYPTO_RNG select HW_RANDOM help diff --git a/include/crypto/df_sp80090a.h b/include/crypto/df_sp80090a.h new file mode 100644 index 0000000000000..182865538662d --- /dev/null +++ b/include/crypto/df_sp80090a.h @@ -0,0 +1,27 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright Stephan Mueller , 2014 + */ + +#ifndef _CRYPTO_DF80090A_H +#define _CRYPTO_DF80090A_H + +#include + +static inline int crypto_drbg_ctr_df_datalen(u8 statelen, u8 blocklen) +{ + return statelen + /* df_data */ + blocklen + /* pad */ + blocklen + /* iv */ + statelen + blocklen; /* temp */ +} + +int crypto_drbg_ctr_df(struct crypto_cipher *tfm, + unsigned char *df_data, + size_t bytes_to_return, + struct list_head *seedlist, + u8 blocklen_bytes, + u8 statelen); + +#endif /* _CRYPTO_DF80090A_H */ diff --git a/include/crypto/drbg.h b/include/crypto/drbg.h index af5ad51d3eef8..2d42518cbdce8 100644 --- a/include/crypto/drbg.h +++ b/include/crypto/drbg.h @@ -47,6 +47,7 @@ #include #include #include +#include #include #include #include @@ -54,30 +55,6 @@ #include #include -/* - * Concatenation Helper and string operation helper - * - * SP800-90A requires the concatenation of different data. To avoid copying - * buffers around or allocate additional memory, the following data structure - * is used to point to the original memory with its size. In addition, it - * is used to build a linked list. The linked list defines the concatenation - * of individual buffers. The order of memory block referenced in that - * linked list determines the order of concatenation. - */ -struct drbg_string { - const unsigned char *buf; - size_t len; - struct list_head list; -}; - -static inline void drbg_string_fill(struct drbg_string *string, - const unsigned char *buf, size_t len) -{ - string->buf = buf; - string->len = len; - INIT_LIST_HEAD(&string->list); -} - struct drbg_state; typedef uint32_t drbg_flag_t; diff --git a/include/crypto/internal/drbg.h b/include/crypto/internal/drbg.h new file mode 100644 index 0000000000000..371e52dcee6c5 --- /dev/null +++ b/include/crypto/internal/drbg.h @@ -0,0 +1,54 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * NIST SP800-90A DRBG derivation function + * + * Copyright (C) 2014, Stephan Mueller + */ + +#ifndef _INTERNAL_DRBG_H +#define _INTERNAL_DRBG_H + +/* + * Convert an integer into a byte representation of this integer. + * The byte representation is big-endian + * + * @val value to be converted + * @buf buffer holding the converted integer -- caller must ensure that + * buffer size is at least 32 bit + */ +static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf) +{ + struct s { + __be32 conv; + }; + struct s *conversion = (struct s *)buf; + + conversion->conv = cpu_to_be32(val); +} + +/* + * Concatenation Helper and string operation helper + * + * SP800-90A requires the concatenation of different data. To avoid copying + * buffers around or allocate additional memory, the following data structure + * is used to point to the original memory with its size. In addition, it + * is used to build a linked list. The linked list defines the concatenation + * of individual buffers. The order of memory block referenced in that + * linked list determines the order of concatenation. + */ +struct drbg_string { + const unsigned char *buf; + size_t len; + struct list_head list; +}; + +static inline void drbg_string_fill(struct drbg_string *string, + const unsigned char *buf, size_t len) +{ + string->buf = buf; + string->len = len; + INIT_LIST_HEAD(&string->list); +} + +#endif //_INTERNAL_DRBG_H