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Commit a07203fb authored by Stephan Mueller's avatar Stephan Mueller Committed by Herbert Xu
Browse files

crypto: drbg - use full CTR AES for update 



The CTR DRBG update function performs a full CTR AES operation including
the XOR with "plaintext" data. Hence, remove the XOR from the code and
use the CTR mode to do the XOR.

Signed-off-by: default avatarStephan Mueller <smueller@chronox.de>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 3cfc3b97

crypto/drbg.c

+13 −17
Original line number Original line Diff line number Diff line
@@ -258,7 +258,10 @@ static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval, 
			  const struct drbg_string *in);

			  const struct drbg_string *in);

static int drbg_init_sym_kernel(struct drbg_state *drbg);

static int drbg_init_sym_kernel(struct drbg_state *drbg);

static int drbg_fini_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, u8 *outbuf, u32 outlen);

static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,

			      u8 *inbuf, u32 inbuflen,

			      u8 *outbuf, u32 outlen);

#define DRBG_CTR_NULL_LEN 128





/* BCC function for CTR DRBG as defined in 10.4.3 */

/* BCC function for CTR DRBG as defined in 10.4.3 */

static int drbg_ctr_bcc(struct drbg_state *drbg,

static int drbg_ctr_bcc(struct drbg_state *drbg,
@@ -481,8 +484,6 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, 
	unsigned char *temp = drbg->scratchpad;

	unsigned char *temp = drbg->scratchpad;

	unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +

	unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +

				 drbg_blocklen(drbg);

				 drbg_blocklen(drbg);

	unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */

	unsigned int len = 0;





	if (3 > reseed)

	if (3 > reseed)

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

		memset(df_data, 0, drbg_statelen(drbg));
@@ -510,18 +511,11 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed, 
			goto out;

			goto out;

	}

	}





	ret = drbg_kcapi_sym_ctr(drbg, temp, drbg_statelen(drbg));

	ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),

				 temp, drbg_statelen(drbg));

	if (ret)

	if (ret)

		return ret;

		return ret;





	/* 10.2.1.2 step 4 */

	temp_p = temp;

	df_data_p = df_data;

	for (len = 0; len < drbg_statelen(drbg); len++) {

		*temp_p ^= *df_data_p;

		df_data_p++; temp_p++;

	}



	/* 10.2.1.2 step 5 */

	/* 10.2.1.2 step 5 */

	memcpy(drbg->C, temp, drbg_keylen(drbg));

	memcpy(drbg->C, temp, drbg_keylen(drbg));

	ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,

	ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
@@ -561,7 +555,8 @@ static int drbg_ctr_generate(struct drbg_state *drbg, 
	}

	}





	/* 10.2.1.5.2 step 4.1 */

	/* 10.2.1.5.2 step 4.1 */

	ret = drbg_kcapi_sym_ctr(drbg, buf, len);

	ret = drbg_kcapi_sym_ctr(drbg, drbg->ctr_null_value, DRBG_CTR_NULL_LEN,

				 buf, len);

	if (ret)

	if (ret)

		return ret;

		return ret;
@@ -1657,7 +1652,6 @@ static void drbg_skcipher_cb(struct crypto_async_request *req, int error) 
	complete(&drbg->ctr_completion);

	complete(&drbg->ctr_completion);

}

}





#define DRBG_CTR_NULL_LEN 128

static int drbg_init_sym_kernel(struct drbg_state *drbg)

static int drbg_init_sym_kernel(struct drbg_state *drbg)

{

{

	struct crypto_cipher *tfm;

	struct crypto_cipher *tfm;
@@ -1733,14 +1727,16 @@ static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval, 
	return 0;

	return 0;

}

}





static int drbg_kcapi_sym_ctr(struct drbg_state *drbg, u8 *outbuf, u32 outlen)

static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,

			      u8 *inbuf, u32 inlen,

			      u8 *outbuf, u32 outlen)

{

{

	struct scatterlist sg_in;

	struct scatterlist sg_in;





	sg_init_one(&sg_in, drbg->ctr_null_value, DRBG_CTR_NULL_LEN);

	sg_init_one(&sg_in, inbuf, inlen);





	while (outlen) {

	while (outlen) {

		u32 cryptlen = min_t(u32, outlen, DRBG_CTR_NULL_LEN);

		u32 cryptlen = min_t(u32, inlen, outlen);

		struct scatterlist sg_out;

		struct scatterlist sg_out;

		int ret;

		int ret;