Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 41a84982 authored by Stephan Mueller's avatar Stephan Mueller Committed by Herbert Xu
Browse files

crypto: drbg - use crypto_inc 



The DRBG internal buffer addition function is replaced with crypto_inc when
a buffer is to be incremented by one.

The function drbg_add_buf is moved to the CONFIG_CRYPTO_DRBG_HASH ifdef
area as it is now only needed for the Hash DRBG.

Signed-off-by: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 3e8cffd4

crypto/drbg.c

+38 −41
Original line number Diff line number Diff line
@@ -283,38 +283,6 @@ static inline void drbg_cpu_to_be32(__u32 val, unsigned char *buf) 


	conversion->conv = cpu_to_be32(val);

}



/*

 * Increment buffer

 *

 * @dst buffer to increment

 * @add value to add

 */

static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,

				const unsigned char *add, size_t addlen)

{

	/* implied: dstlen > addlen */

	unsigned char *dstptr;

	const unsigned char *addptr;

	unsigned int remainder = 0;

	size_t len = addlen;



	dstptr = dst + (dstlen-1);

	addptr = add + (addlen-1);

	while (len) {

		remainder += *dstptr + *addptr;

		*dstptr = remainder & 0xff;

		remainder >>= 8;

		len--; dstptr--; addptr--;

	}

	len = dstlen - addlen;

	while (len && remainder > 0) {

		remainder = *dstptr + 1;

		*dstptr = remainder & 0xff;

		remainder >>= 8;

		len--; dstptr--;

	}

}

#endif /* defined(CONFIG_CRYPTO_DRBG_HASH) || defined(CONFIG_CRYPTO_DRBG_CTR) */



/******************************************************************
@@ -554,7 +522,6 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, 
	unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */

	unsigned int len = 0;

	struct drbg_string cipherin;

	unsigned char prefix = DRBG_PREFIX1;



	memset(temp, 0, drbg_statelen(drbg) + drbg_blocklen(drbg));

	if (3 > reseed)
@@ -574,7 +541,7 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, 
	 */

	while (len < (drbg_statelen(drbg))) {

		/* 10.2.1.2 step 2.1 */

		drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);

		crypto_inc(drbg->V, drbg_blocklen(drbg));

		/*

		 * 10.2.1.2 step 2.2 */

		ret = drbg_kcapi_sym(drbg, drbg->C, temp + len, &cipherin);
@@ -617,7 +584,6 @@ static int drbg_ctr_generate(struct drbg_state *drbg, 
	int len = 0;

	int ret = 0;

	struct drbg_string data;

	unsigned char prefix = DRBG_PREFIX1;



	memset(drbg->scratchpad, 0, drbg_blocklen(drbg));
@@ -629,7 +595,7 @@ static int drbg_ctr_generate(struct drbg_state *drbg, 
	}



	/* 10.2.1.5.2 step 4.1 */

	drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);

	crypto_inc(drbg->V, drbg_blocklen(drbg));

	drbg_string_fill(&data, drbg->V, drbg_blocklen(drbg));

	while (len < buflen) {

		int outlen = 0;
@@ -643,7 +609,7 @@ static int drbg_ctr_generate(struct drbg_state *drbg, 
			  drbg_blocklen(drbg) : (buflen - len);

		if (!drbg_fips_continuous_test(drbg, drbg->scratchpad)) {

			/* 10.2.1.5.2 step 6 */

			drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);

			crypto_inc(drbg->V, drbg_blocklen(drbg));

			continue;

		}

		/* 10.2.1.5.2 step 4.3 */
@@ -651,7 +617,7 @@ static int drbg_ctr_generate(struct drbg_state *drbg, 
		len += outlen;

		/* 10.2.1.5.2 step 6 */

		if (len < buflen)

			drbg_add_buf(drbg->V, drbg_blocklen(drbg), &prefix, 1);

			crypto_inc(drbg->V, drbg_blocklen(drbg));

	}



	/* 10.2.1.5.2 step 6 */
@@ -796,6 +762,38 @@ static struct drbg_state_ops drbg_hmac_ops = { 


#ifdef CONFIG_CRYPTO_DRBG_HASH

#define CRYPTO_DRBG_HASH_STRING "HASH "

/*

 * Increment buffer

 *

 * @dst buffer to increment

 * @add value to add

 */

static inline void drbg_add_buf(unsigned char *dst, size_t dstlen,

				const unsigned char *add, size_t addlen)

{

	/* implied: dstlen > addlen */

	unsigned char *dstptr;

	const unsigned char *addptr;

	unsigned int remainder = 0;

	size_t len = addlen;



	dstptr = dst + (dstlen-1);

	addptr = add + (addlen-1);

	while (len) {

		remainder += *dstptr + *addptr;

		*dstptr = remainder & 0xff;

		remainder >>= 8;

		len--; dstptr--; addptr--;

	}

	len = dstlen - addlen;

	while (len && remainder > 0) {

		remainder = *dstptr + 1;

		*dstptr = remainder & 0xff;

		remainder >>= 8;

		len--; dstptr--;

	}

}



/*

 * scratchpad usage: as drbg_hash_update and drbg_hash_df are used

 * interlinked, the scratchpad is used as follows:
@@ -942,7 +940,6 @@ static int drbg_hash_hashgen(struct drbg_state *drbg, 
	unsigned char *dst = drbg->scratchpad + drbg_statelen(drbg);

	struct drbg_string data;

	LIST_HEAD(datalist);

	unsigned char prefix = DRBG_PREFIX1;



	memset(src, 0, drbg_statelen(drbg));

	memset(dst, 0, drbg_blocklen(drbg));
@@ -963,7 +960,7 @@ static int drbg_hash_hashgen(struct drbg_state *drbg, 
		outlen = (drbg_blocklen(drbg) < (buflen - len)) ?

			  drbg_blocklen(drbg) : (buflen - len);

		if (!drbg_fips_continuous_test(drbg, dst)) {

			drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);

			crypto_inc(src, drbg_statelen(drbg));

			continue;

		}

		/* 10.1.1.4 step hashgen 4.2 */
@@ -971,7 +968,7 @@ static int drbg_hash_hashgen(struct drbg_state *drbg, 
		len += outlen;

		/* 10.1.1.4 hashgen step 4.3 */

		if (len < buflen)

			drbg_add_buf(src, drbg_statelen(drbg), &prefix, 1);

			crypto_inc(src, drbg_statelen(drbg));

	}



out: