[CRYPTO] seqiv: Add AEAD support

This patch adds support for using seqiv with AEAD algorithms. This is
useful for those AEAD algorithms that performs authentication before
encryption because the IV generated by the underlying encryption algorithm
won't be available for authentication.

Signed-off-by: Herbert Xu <[e-mail]>

crypto/seqiv.c

···
  *
  */
 
+#include <crypto/internal/aead.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/err.h>
 #include <linux/init.h>
···
 	skcipher_givcrypt_complete(req, err);
 }
 
+static void seqiv_aead_complete2(struct aead_givcrypt_request *req, int err)
+{
+	struct aead_request *subreq = aead_givcrypt_reqctx(req);
+	struct crypto_aead *geniv;
+
+	if (err == -EINPROGRESS)
+		return;
+
+	if (err)
+		goto out;
+
+	geniv = aead_givcrypt_reqtfm(req);
+	memcpy(req->areq.iv, subreq->iv, crypto_aead_ivsize(geniv));
+
+out:
+	kfree(subreq->iv);
+}
+
+static void seqiv_aead_complete(struct crypto_async_request *base, int err)
+{
+	struct aead_givcrypt_request *req = base->data;
+
+	seqiv_aead_complete2(req, err);
+	aead_givcrypt_complete(req, err);
+}
+
+static void seqiv_geniv(struct seqiv_ctx *ctx, u8 *info, u64 seq,
+			unsigned int ivsize)
+{
+	unsigned int len = ivsize;
+
+	if (ivsize > sizeof(u64)) {
+		memset(info, 0, ivsize - sizeof(u64));
+		len = sizeof(u64);
+	}
+	seq = cpu_to_be64(seq);
+	memcpy(info + ivsize - len, &seq, len);
+	crypto_xor(info, ctx->salt, ivsize);
+}
+
 static int seqiv_givencrypt(struct skcipher_givcrypt_request *req)
 {
 	struct crypto_ablkcipher *geniv = skcipher_givcrypt_reqtfm(req);
···
 	crypto_completion_t complete;
 	void *data;
 	u8 *info;
-	__be64 seq;
 	unsigned int ivsize;
-	unsigned int len;
 	int err;
 
 	ablkcipher_request_set_tfm(subreq, skcipher_geniv_cipher(geniv));
···
 	ablkcipher_request_set_crypt(subreq, req->creq.src, req->creq.dst,
 				     req->creq.nbytes, info);
 
-	len = ivsize;
-	if (ivsize > sizeof(u64)) {
-		memset(info, 0, ivsize - sizeof(u64));
-		len = sizeof(u64);
-	}
-	seq = cpu_to_be64(req->seq);
-	memcpy(info + ivsize - len, &seq, len);
-	crypto_xor(info, ctx->salt, ivsize);
-
+	seqiv_geniv(ctx, info, req->seq, ivsize);
 	memcpy(req->giv, info, ivsize);
 
 	err = crypto_ablkcipher_encrypt(subreq);
 	if (unlikely(info != req->creq.info))
 		seqiv_complete2(req, err);
+	return err;
+}
+
+static int seqiv_aead_givencrypt(struct aead_givcrypt_request *req)
+{
+	struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
+	struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
+	struct aead_request *areq = &req->areq;
+	struct aead_request *subreq = aead_givcrypt_reqctx(req);
+	crypto_completion_t complete;
+	void *data;
+	u8 *info;
+	unsigned int ivsize;
+	int err;
+
+	aead_request_set_tfm(subreq, aead_geniv_base(geniv));
+
+	complete = areq->base.complete;
+	data = areq->base.data;
+	info = areq->iv;
+
+	ivsize = crypto_aead_ivsize(geniv);
+
+	if (unlikely(!IS_ALIGNED((unsigned long)info,
+				 crypto_aead_alignmask(geniv) + 1))) {
+		info = kmalloc(ivsize, areq->base.flags &
+				       CRYPTO_TFM_REQ_MAY_SLEEP ? GFP_KERNEL:
+								  GFP_ATOMIC);
+		if (!info)
+			return -ENOMEM;
+
+		complete = seqiv_aead_complete;
+		data = req;
+	}
+
+	aead_request_set_callback(subreq, areq->base.flags, complete, data);
+	aead_request_set_crypt(subreq, areq->src, areq->dst, areq->cryptlen,
+			       info);
+	aead_request_set_assoc(subreq, areq->assoc, areq->assoclen);
+
+	seqiv_geniv(ctx, info, req->seq, ivsize);
+	memcpy(req->giv, info, ivsize);
+
+	err = crypto_aead_encrypt(subreq);
+	if (unlikely(info != areq->iv))
+		seqiv_aead_complete2(req, err);
 	return err;
 }
 
···
 	return seqiv_givencrypt(req);
 }
 
+static int seqiv_aead_givencrypt_first(struct aead_givcrypt_request *req)
+{
+	struct crypto_aead *geniv = aead_givcrypt_reqtfm(req);
+	struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
+
+	spin_lock_bh(&ctx->lock);
+	if (crypto_aead_crt(geniv)->givencrypt != seqiv_aead_givencrypt_first)
+		goto unlock;
+
+	crypto_aead_crt(geniv)->givencrypt = seqiv_aead_givencrypt;
+	get_random_bytes(ctx->salt, crypto_aead_ivsize(geniv));
+
+unlock:
+	spin_unlock_bh(&ctx->lock);
+
+	return seqiv_aead_givencrypt(req);
+}
+
 static int seqiv_init(struct crypto_tfm *tfm)
 {
 	struct crypto_ablkcipher *geniv = __crypto_ablkcipher_cast(tfm);
···
 	return skcipher_geniv_init(tfm);
 }
 
+static int seqiv_aead_init(struct crypto_tfm *tfm)
+{
+	struct crypto_aead *geniv = __crypto_aead_cast(tfm);
+	struct seqiv_ctx *ctx = crypto_aead_ctx(geniv);
+
+	spin_lock_init(&ctx->lock);
+
+	tfm->crt_aead.reqsize = sizeof(struct aead_request);
+
+	return aead_geniv_init(tfm);
+}
+
 static struct crypto_template seqiv_tmpl;
 
-static struct crypto_instance *seqiv_alloc(struct rtattr **tb)
+static struct crypto_instance *seqiv_ablkcipher_alloc(struct rtattr **tb)
 {
 	struct crypto_instance *inst;
 
 	inst = skcipher_geniv_alloc(&seqiv_tmpl, tb, 0, 0);
+
 	if (IS_ERR(inst))
 		goto out;
 
···
 	inst->alg.cra_init = seqiv_init;
 	inst->alg.cra_exit = skcipher_geniv_exit;
 
-	inst->alg.cra_alignmask |= __alignof__(u32) - 1;
-
-	inst->alg.cra_ctxsize = sizeof(struct seqiv_ctx);
 	inst->alg.cra_ctxsize += inst->alg.cra_ablkcipher.ivsize;
 
 out:
 	return inst;
 }
 
+static struct crypto_instance *seqiv_aead_alloc(struct rtattr **tb)
+{
+	struct crypto_instance *inst;
+
+	inst = aead_geniv_alloc(&seqiv_tmpl, tb, 0, 0);
+
+	if (IS_ERR(inst))
+		goto out;
+
+	inst->alg.cra_aead.givencrypt = seqiv_aead_givencrypt_first;
+
+	inst->alg.cra_init = seqiv_aead_init;
+	inst->alg.cra_exit = aead_geniv_exit;
+
+	inst->alg.cra_ctxsize = inst->alg.cra_aead.ivsize;
+
+out:
+	return inst;
+}
+
+static struct crypto_instance *seqiv_alloc(struct rtattr **tb)
+{
+	struct crypto_attr_type *algt;
+	struct crypto_instance *inst;
+	int err;
+
+	algt = crypto_get_attr_type(tb);
+	err = PTR_ERR(algt);
+	if (IS_ERR(algt))
+		return ERR_PTR(err);
+
+	if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
+		inst = seqiv_ablkcipher_alloc(tb);
+	else
+		inst = seqiv_aead_alloc(tb);
+
+	if (IS_ERR(inst))
+		goto out;
+
+	inst->alg.cra_alignmask |= __alignof__(u32) - 1;
+	inst->alg.cra_ctxsize += sizeof(struct seqiv_ctx);
+
+out:
+	return inst;
+}
+
+static void seqiv_free(struct crypto_instance *inst)
+{
+	if ((inst->alg.cra_flags ^ CRYPTO_ALG_TYPE_AEAD) & CRYPTO_ALG_TYPE_MASK)
+		skcipher_geniv_free(inst);
+	else
+		aead_geniv_free(inst);
+}
+
 static struct crypto_template seqiv_tmpl = {
 	.name = "seqiv",
 	.alloc = seqiv_alloc,
-	.free = skcipher_geniv_free,
+	.free = seqiv_free,
 	.module = THIS_MODULE,
 };