SipHash: add separate setter for the hash size

[openssl.git] / crypto / siphash / siphash.c

diff --git a/crypto/siphash/siphash.c b/crypto/siphash/siphash.c
index 72fd5198b8993c7971ed92743c2969499e98e96b..e2352fc73043ec34ae51e0c49d577b73a2635a36 100644 (file)
--- a/crypto/siphash/siphash.c
+++ b/crypto/siphash/siphash.c
@@ -80,17 +80,32 @@ size_t SipHash_hash_size(SIPHASH *ctx)
     return ctx->hash_size;
 }
 
+static size_t siphash_adjust_hash_size(size_t hash_size)
+{
+    if (hash_size == 0)
+        hash_size = SIPHASH_MAX_DIGEST_SIZE;
+    return hash_size;
+}
+
+int SipHash_set_hash_size(SIPHASH *ctx, size_t hash_size)
+{
+    hash_size = siphash_adjust_hash_size(hash_size);
+    if (hash_size != SIPHASH_MIN_DIGEST_SIZE
+        && hash_size != SIPHASH_MAX_DIGEST_SIZE)
+        return 0;
+
+    ctx->hash_size = hash_size;
+    return 1;
+}
+
 /* hash_size = crounds = drounds = 0 means SipHash24 with 16-byte output */
-int SipHash_Init(SIPHASH *ctx, const unsigned char *k, int hash_size, int crounds, int drounds)
+int SipHash_Init(SIPHASH *ctx, const unsigned char *k, int crounds, int drounds)
 {
     uint64_t k0 = U8TO64_LE(k);
     uint64_t k1 = U8TO64_LE(k + 8);
 
-    if (hash_size == 0)
-        hash_size = SIPHASH_MAX_DIGEST_SIZE;
-    else if (hash_size != SIPHASH_MIN_DIGEST_SIZE &&
-             hash_size != SIPHASH_MAX_DIGEST_SIZE)
-        return 0;
+    /* If the hash size wasn't set, i.e. is zero */
+    ctx->hash_size = siphash_adjust_hash_size(ctx->hash_size);
 
     if (drounds == 0)
         drounds = SIPHASH_D_ROUNDS;
@@ -99,7 +114,6 @@ int SipHash_Init(SIPHASH *ctx, const unsigned char *k, int hash_size, int cround
 
     ctx->crounds = crounds;
     ctx->drounds = drounds;
-    ctx->hash_size = hash_size;
 
     ctx->len = 0;
     ctx->total_inlen = 0;