From 19fa77522e45e384be0f0f93b10c928763460ae3 Mon Sep 17 00:00:00 2001
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Wed, 27 May 2015 17:24:41 +0800
Subject: [PATCH] crypto: algif_aead - Switch to new AEAD interface

This patch makes use of the new AEAD interface which uses a single
SG list instead of separate lists for the AD and plain text.

Note that the user-space interface now requires both input and
output to be of the same length, and both must include space for
the AD as well as the authentication tag.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
---
 crypto/algif_aead.c | 66 ++++++---------------------------------------
 1 file changed, 8 insertions(+), 58 deletions(-)

diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index a55e4e6fa3d8..38a6cab7aeca 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -72,7 +72,7 @@ static inline bool aead_sufficient_data(struct aead_ctx *ctx)
 {
 	unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
 
-	return (ctx->used >= (ctx->aead_assoclen + (ctx->enc ? 0 : as)));
+	return ctx->used >= ctx->aead_assoclen + as;
 }
 
 static void aead_put_sgl(struct sock *sk)
@@ -353,12 +353,8 @@ static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);
 	struct aead_ctx *ctx = ask->private;
-	unsigned bs = crypto_aead_blocksize(crypto_aead_reqtfm(&ctx->aead_req));
 	unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req));
 	struct aead_sg_list *sgl = &ctx->tsgl;
-	struct scatterlist *sg = NULL;
-	struct scatterlist assoc[ALG_MAX_PAGES];
-	size_t assoclen = 0;
 	unsigned int i = 0;
 	int err = -EINVAL;
 	unsigned long used = 0;
@@ -407,23 +403,13 @@ static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
 	if (!aead_sufficient_data(ctx))
 		goto unlock;
 
+	outlen = used;
+
 	/*
 	 * The cipher operation input data is reduced by the associated data
 	 * length as this data is processed separately later on.
 	 */
-	used -= ctx->aead_assoclen;
-
-	if (ctx->enc) {
-		/* round up output buffer to multiple of block size */
-		outlen = ((used + bs - 1) / bs * bs);
-		/* add the size needed for the auth tag to be created */
-		outlen += as;
-	} else {
-		/* output data size is input without the authentication tag */
-		outlen = used - as;
-		/* round up output buffer to multiple of block size */
-		outlen = ((outlen + bs - 1) / bs * bs);
-	}
+	used -= ctx->aead_assoclen + (ctx->enc ? as : 0);
 
 	/* convert iovecs of output buffers into scatterlists */
 	while (iov_iter_count(&msg->msg_iter)) {
@@ -452,47 +438,11 @@ static int aead_recvmsg(struct socket *sock, struct msghdr *msg, size_t ignored,
 	if (usedpages < outlen)
 		goto unlock;
 
-	sg_init_table(assoc, ALG_MAX_PAGES);
-	assoclen = ctx->aead_assoclen;
-	/*
-	 * Split scatterlist into two: first part becomes AD, second part
-	 * is plaintext / ciphertext. The first part is assigned to assoc
-	 * scatterlist. When this loop finishes, sg points to the start of the
-	 * plaintext / ciphertext.
-	 */
-	for (i = 0; i < ctx->tsgl.cur; i++) {
-		sg = sgl->sg + i;
-		if (sg->length <= assoclen) {
-			/* AD is larger than one page */
-			sg_set_page(assoc + i, sg_page(sg),
-				    sg->length, sg->offset);
-			assoclen -= sg->length;
-			if (i >= ctx->tsgl.cur)
-				goto unlock;
-		} else if (!assoclen) {
-			/* current page is to start of plaintext / ciphertext */
-			if (i)
-				/* AD terminates at page boundary */
-				sg_mark_end(assoc + i - 1);
-			else
-				/* AD size is zero */
-				sg_mark_end(assoc);
-			break;
-		} else {
-			/* AD does not terminate at page boundary */
-			sg_set_page(assoc + i, sg_page(sg),
-				    assoclen, sg->offset);
-			sg_mark_end(assoc + i);
-			/* plaintext / ciphertext starts after AD */
-			sg->length -= assoclen;
-			sg->offset += assoclen;
-			break;
-		}
-	}
+	sg_mark_end(sgl->sg + sgl->cur - 1);
 
-	aead_request_set_assoc(&ctx->aead_req, assoc, ctx->aead_assoclen);
-	aead_request_set_crypt(&ctx->aead_req, sg, ctx->rsgl[0].sg, used,
-			       ctx->iv);
+	aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->rsgl[0].sg,
+			       used, ctx->iv);
+	aead_request_set_ad(&ctx->aead_req, ctx->aead_assoclen);
 
 	err = af_alg_wait_for_completion(ctx->enc ?
 					 crypto_aead_encrypt(&ctx->aead_req) :
-- 
2.20.1