+ if (keylen > bs) {
+ struct hash_desc desc;
+ struct scatterlist tmp;
+ int err;
+
+ desc.tfm = tfm;
+ desc.flags = crypto_hash_get_flags(parent);
+ desc.flags &= CRYPTO_TFM_REQ_MAY_SLEEP;
+ sg_set_buf(&tmp, inkey, keylen);
+
+ err = crypto_hash_digest(&desc, &tmp, keylen, digest);
+ if (err)
+ return err;
+
+ inkey = digest;
+ keylen = ds;
+ }
+
+ memcpy(ipad, inkey, keylen);
+ memset(ipad + keylen, 0, bs - keylen);
+ memcpy(opad, ipad, bs);
+
+ for (i = 0; i < bs; i++) {
+ ipad[i] ^= 0x36;
+ opad[i] ^= 0x5c;
+ }
+
+ return 0;
+}
+
+static int hmac_init(struct hash_desc *pdesc)
+{
+ struct crypto_hash *parent = pdesc->tfm;
+ int bs = crypto_hash_blocksize(parent);
+ int ds = crypto_hash_digestsize(parent);
+ char *ipad = crypto_hash_ctx_aligned(parent);
+ struct hmac_ctx *ctx = align_ptr(ipad + bs * 2 + ds, sizeof(void *));
+ struct hash_desc desc;
+ struct scatterlist tmp;
+ int err;
+
+ desc.tfm = ctx->child;
+ desc.flags = pdesc->flags & CRYPTO_TFM_REQ_MAY_SLEEP;
+ sg_set_buf(&tmp, ipad, bs);
+
+ err = crypto_hash_init(&desc);
+ if (unlikely(err))
+ return err;
+
+ return crypto_hash_update(&desc, &tmp, bs);