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: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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@ -258,7 +258,10 @@ static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
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const struct drbg_string *in);
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static int drbg_init_sym_kernel(struct drbg_state *drbg);
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static int drbg_fini_sym_kernel(struct drbg_state *drbg);
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static int drbg_kcapi_sym_ctr(struct drbg_state *drbg, u8 *outbuf, u32 outlen);
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static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
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u8 *inbuf, u32 inbuflen,
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u8 *outbuf, u32 outlen);
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#define DRBG_CTR_NULL_LEN 128
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/* BCC function for CTR DRBG as defined in 10.4.3 */
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static int drbg_ctr_bcc(struct drbg_state *drbg,
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@ -481,8 +484,6 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
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unsigned char *temp = drbg->scratchpad;
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unsigned char *df_data = drbg->scratchpad + drbg_statelen(drbg) +
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drbg_blocklen(drbg);
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unsigned char *temp_p, *df_data_p; /* pointer to iterate over buffers */
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unsigned int len = 0;
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if (3 > reseed)
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memset(df_data, 0, drbg_statelen(drbg));
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@ -510,18 +511,11 @@ static int drbg_ctr_update(struct drbg_state *drbg, struct list_head *seed,
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goto out;
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}
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ret = drbg_kcapi_sym_ctr(drbg, temp, drbg_statelen(drbg));
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ret = drbg_kcapi_sym_ctr(drbg, df_data, drbg_statelen(drbg),
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temp, drbg_statelen(drbg));
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if (ret)
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return ret;
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/* 10.2.1.2 step 4 */
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temp_p = temp;
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df_data_p = df_data;
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for (len = 0; len < drbg_statelen(drbg); len++) {
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*temp_p ^= *df_data_p;
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df_data_p++; temp_p++;
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}
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/* 10.2.1.2 step 5 */
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memcpy(drbg->C, temp, drbg_keylen(drbg));
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ret = crypto_skcipher_setkey(drbg->ctr_handle, drbg->C,
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@ -561,7 +555,8 @@ static int drbg_ctr_generate(struct drbg_state *drbg,
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}
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/* 10.2.1.5.2 step 4.1 */
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ret = drbg_kcapi_sym_ctr(drbg, buf, len);
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ret = drbg_kcapi_sym_ctr(drbg, drbg->ctr_null_value, DRBG_CTR_NULL_LEN,
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buf, len);
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if (ret)
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return ret;
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@ -1657,7 +1652,6 @@ static void drbg_skcipher_cb(struct crypto_async_request *req, int error)
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complete(&drbg->ctr_completion);
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}
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#define DRBG_CTR_NULL_LEN 128
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static int drbg_init_sym_kernel(struct drbg_state *drbg)
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{
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struct crypto_cipher *tfm;
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@ -1733,14 +1727,16 @@ static int drbg_kcapi_sym(struct drbg_state *drbg, unsigned char *outval,
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return 0;
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}
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static int drbg_kcapi_sym_ctr(struct drbg_state *drbg, u8 *outbuf, u32 outlen)
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static int drbg_kcapi_sym_ctr(struct drbg_state *drbg,
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u8 *inbuf, u32 inlen,
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u8 *outbuf, u32 outlen)
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{
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struct scatterlist sg_in;
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sg_init_one(&sg_in, drbg->ctr_null_value, DRBG_CTR_NULL_LEN);
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sg_init_one(&sg_in, inbuf, inlen);
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while (outlen) {
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u32 cryptlen = min_t(u32, outlen, DRBG_CTR_NULL_LEN);
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u32 cryptlen = min_t(u32, inlen, outlen);
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struct scatterlist sg_out;
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int ret;
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