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

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
...@@ -258,7 +258,10 @@ static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval, ...@@ -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, ...@@ -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, ...@@ -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, ...@@ -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) ...@@ -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, ...@@ -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;
......
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