Linux-Crypto Archive on lore.kernel.org
 help / color / Atom feed
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-crypto@vger.kernel.org
Cc: Ard Biesheuvel <ardb@kernel.org>,
	Corentin Labbe <clabbe.montjoie@gmail.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	"David S. Miller" <davem@davemloft.net>,
	Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Ayush Sawal <ayush.sawal@chelsio.com>,
	Vinay Kumar Yadav <vinay.yadav@chelsio.com>,
	Rohit Maheshwari <rohitm@chelsio.com>,
	Shawn Guo <shawnguo@kernel.org>,
	Sascha Hauer <s.hauer@pengutronix.de>,
	Pengutronix Kernel Team <kernel@pengutronix.de>,
	Fabio Estevam <festevam@gmail.com>,
	NXP Linux Team <linux-imx@nxp.com>,
	Jamie Iles <jamie@jamieiles.com>,
	Eric Biggers <ebiggers@google.com>, Tero Kristo <t-kristo@ti.com>,
	Matthias Brugger <matthias.bgg@gmail.com>
Subject: [PATCH v3 11/13] crypto: qce - permit asynchronous skcipher as fallback
Date: Tue, 30 Jun 2020 14:19:05 +0200
Message-ID: <20200630121907.24274-12-ardb@kernel.org> (raw)
In-Reply-To: <20200630121907.24274-1-ardb@kernel.org>

Even though the qce driver implements asynchronous versions of ecb(aes),
cbc(aes)and xts(aes), the fallbacks it allocates are required to be
synchronous. Given that SIMD based software implementations are usually
asynchronous as well, even though they rarely complete asynchronously
(this typically only happens in cases where the request was made from
softirq context, while SIMD was already in use in the task context that
it interrupted), these implementations are disregarded, and either the
generic C version or another table based version implemented in assembler
is selected instead.

Since falling back to synchronous AES is not only a performance issue, but
potentially a security issue as well (due to the fact that table based AES
is not time invariant), let's fix this, by allocating an ordinary skcipher
as the fallback, and invoke it with the completion routine that was given
to the outer request.

While at it, remove the pointless memset() from qce_skcipher_init(), and
remove the unnecessary call to it from qce_skcipher_init_fallback().

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 drivers/crypto/qce/cipher.h   |  3 +-
 drivers/crypto/qce/skcipher.c | 42 ++++++++++----------
 2 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/drivers/crypto/qce/cipher.h b/drivers/crypto/qce/cipher.h
index 7770660bc853..cffa9fc628ff 100644
--- a/drivers/crypto/qce/cipher.h
+++ b/drivers/crypto/qce/cipher.h
@@ -14,7 +14,7 @@
 struct qce_cipher_ctx {
 	u8 enc_key[QCE_MAX_KEY_SIZE];
 	unsigned int enc_keylen;
-	struct crypto_sync_skcipher *fallback;
+	struct crypto_skcipher *fallback;
 };
 
 /**
@@ -43,6 +43,7 @@ struct qce_cipher_reqctx {
 	struct sg_table src_tbl;
 	struct scatterlist *src_sg;
 	unsigned int cryptlen;
+	struct skcipher_request fallback_req;	// keep at the end
 };
 
 static inline struct qce_alg_template *to_cipher_tmpl(struct crypto_skcipher *tfm)
diff --git a/drivers/crypto/qce/skcipher.c b/drivers/crypto/qce/skcipher.c
index 9412433f3b21..a8147381b774 100644
--- a/drivers/crypto/qce/skcipher.c
+++ b/drivers/crypto/qce/skcipher.c
@@ -178,7 +178,7 @@ static int qce_skcipher_setkey(struct crypto_skcipher *ablk, const u8 *key,
 		break;
 	}
 
-	ret = crypto_sync_skcipher_setkey(ctx->fallback, key, keylen);
+	ret = crypto_skcipher_setkey(ctx->fallback, key, keylen);
 	if (!ret)
 		ctx->enc_keylen = keylen;
 	return ret;
@@ -235,16 +235,15 @@ static int qce_skcipher_crypt(struct skcipher_request *req, int encrypt)
 	      req->cryptlen <= aes_sw_max_len) ||
 	     (IS_XTS(rctx->flags) && req->cryptlen > QCE_SECTOR_SIZE &&
 	      req->cryptlen % QCE_SECTOR_SIZE))) {
-		SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, ctx->fallback);
-
-		skcipher_request_set_sync_tfm(subreq, ctx->fallback);
-		skcipher_request_set_callback(subreq, req->base.flags,
-					      NULL, NULL);
-		skcipher_request_set_crypt(subreq, req->src, req->dst,
-					   req->cryptlen, req->iv);
-		ret = encrypt ? crypto_skcipher_encrypt(subreq) :
-				crypto_skcipher_decrypt(subreq);
-		skcipher_request_zero(subreq);
+		skcipher_request_set_tfm(&rctx->fallback_req, ctx->fallback);
+		skcipher_request_set_callback(&rctx->fallback_req,
+					      req->base.flags,
+					      req->base.complete,
+					      req->base.data);
+		skcipher_request_set_crypt(&rctx->fallback_req, req->src,
+					   req->dst, req->cryptlen, req->iv);
+		ret = encrypt ? crypto_skcipher_encrypt(&rctx->fallback_req) :
+				crypto_skcipher_decrypt(&rctx->fallback_req);
 		return ret;
 	}
 
@@ -263,10 +262,9 @@ static int qce_skcipher_decrypt(struct skcipher_request *req)
 
 static int qce_skcipher_init(struct crypto_skcipher *tfm)
 {
-	struct qce_cipher_ctx *ctx = crypto_skcipher_ctx(tfm);
-
-	memset(ctx, 0, sizeof(*ctx));
-	crypto_skcipher_set_reqsize(tfm, sizeof(struct qce_cipher_reqctx));
+	/* take the size without the fallback skcipher_request at the end */
+	crypto_skcipher_set_reqsize(tfm, offsetof(struct qce_cipher_reqctx,
+						  fallback_req));
 	return 0;
 }
 
@@ -274,17 +272,21 @@ static int qce_skcipher_init_fallback(struct crypto_skcipher *tfm)
 {
 	struct qce_cipher_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	qce_skcipher_init(tfm);
-	ctx->fallback = crypto_alloc_sync_skcipher(crypto_tfm_alg_name(&tfm->base),
-						   0, CRYPTO_ALG_NEED_FALLBACK);
-	return PTR_ERR_OR_ZERO(ctx->fallback);
+	ctx->fallback = crypto_alloc_skcipher(crypto_tfm_alg_name(&tfm->base),
+					      0, CRYPTO_ALG_NEED_FALLBACK);
+	if (IS_ERR(ctx->fallback))
+		return PTR_ERR(ctx->fallback);
+
+	crypto_skcipher_set_reqsize(tfm, sizeof(struct qce_cipher_reqctx) +
+					 crypto_skcipher_reqsize(ctx->fallback));
+	return 0;
 }
 
 static void qce_skcipher_exit(struct crypto_skcipher *tfm)
 {
 	struct qce_cipher_ctx *ctx = crypto_skcipher_ctx(tfm);
 
-	crypto_free_sync_skcipher(ctx->fallback);
+	crypto_free_skcipher(ctx->fallback);
 }
 
 struct qce_skcipher_def {
-- 
2.17.1


  parent reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30 12:18 [PATCH v3 00/13] crypto: permit asynchronous skciphers as driver fallbacks Ard Biesheuvel
2020-06-30 12:18 ` [PATCH v3 01/13] crypto: amlogic-gxl - default to build as module Ard Biesheuvel
2020-07-06 17:41   ` Corentin Labbe
2020-06-30 12:18 ` [PATCH v3 02/13] crypto: amlogic-gxl - permit async skcipher as fallback Ard Biesheuvel
2020-07-06 17:42   ` Corentin Labbe
2020-06-30 12:18 ` [PATCH v3 03/13] crypto: omap-aes - permit asynchronous " Ard Biesheuvel
2020-06-30 12:18 ` [PATCH v3 04/13] crypto: sun4i " Ard Biesheuvel
2020-07-06 17:32   ` Corentin Labbe
2020-06-30 12:18 ` [PATCH v3 05/13] crypto: sun8i-ce " Ard Biesheuvel
2020-07-06 20:42   ` Corentin Labbe
2020-06-30 12:19 ` [PATCH v3 06/13] crypto: sun8i-ss " Ard Biesheuvel
2020-07-06 20:40   ` Corentin Labbe
2020-06-30 12:19 ` [PATCH v3 07/13] crypto: ccp " Ard Biesheuvel
2020-06-30 12:19 ` [PATCH v3 08/13] crypto: chelsio " Ard Biesheuvel
2020-06-30 12:19 ` [PATCH v3 09/13] crypto: mxs-dcp " Ard Biesheuvel
2020-07-05 18:28   ` Horia Geantă
2020-06-30 12:19 ` [PATCH v3 10/13] crypto: picoxcell " Ard Biesheuvel
2020-07-06 16:05   ` Jamie Iles
2020-06-30 12:19 ` Ard Biesheuvel [this message]
2020-06-30 12:19 ` [PATCH v3 12/13] crypto: sahara " Ard Biesheuvel
2020-07-05 18:34   ` Horia Geantă
2020-06-30 12:19 ` [PATCH v3 13/13] crypto: mediatek - use AES library for GCM key derivation Ard Biesheuvel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200630121907.24274-12-ardb@kernel.org \
    --to=ardb@kernel.org \
    --cc=ayush.sawal@chelsio.com \
    --cc=clabbe.montjoie@gmail.com \
    --cc=davem@davemloft.net \
    --cc=ebiggers@google.com \
    --cc=festevam@gmail.com \
    --cc=herbert@gondor.apana.org.au \
    --cc=jamie@jamieiles.com \
    --cc=kernel@pengutronix.de \
    --cc=linux-crypto@vger.kernel.org \
    --cc=linux-imx@nxp.com \
    --cc=matthias.bgg@gmail.com \
    --cc=mripard@kernel.org \
    --cc=rohitm@chelsio.com \
    --cc=s.hauer@pengutronix.de \
    --cc=shawnguo@kernel.org \
    --cc=t-kristo@ti.com \
    --cc=thomas.lendacky@amd.com \
    --cc=vinay.yadav@chelsio.com \
    --cc=wens@csie.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Crypto Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-crypto/0 linux-crypto/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-crypto linux-crypto/ https://lore.kernel.org/linux-crypto \
		linux-crypto@vger.kernel.org
	public-inbox-index linux-crypto

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-crypto


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git