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: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/drbg.c b/crypto/drbg.c
index 54cfd4820abc8f321fe1dac7c0212107d16d521d..8c0a742b60f6596b9a367338ff533c9d3b6fc755 100644 (file)
--- a/crypto/drbg.c
+++ b/crypto/drbg.c
@@ -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: