linux-kernel - [PATCH 03/19] crypto: sun4i-ss: do not allocate backup IV on requests

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Date:   Thu, 17 Mar 2022 20:55:49 +0000
From:   Corentin Labbe <clabbe@...libre.com>
To:     herbert@...dor.apana.org.au, jernej.skrabec@...il.com,
        samuel@...lland.org, wens@...e.org
Cc:     linux-arm-kernel@...ts.infradead.org, linux-crypto@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-sunxi@...ts.linux.dev,
        Corentin Labbe <clabbe@...libre.com>
Subject: [PATCH 03/19] crypto: sun4i-ss: do not allocate backup IV on requests

Instead of allocate memory on each requests, it is easier to
pre-allocate buffer for backup IV.
This made error path easier.
Signed-off-by: Corentin Labbe <clabbe@...libre.com>
---
 .../allwinner/sun4i-ss/sun4i-ss-cipher.c      | 22 +++++++------------
 drivers/crypto/allwinner/sun4i-ss/sun4i-ss.h  |  1 +
 2 files changed, 9 insertions(+), 14 deletions(-)

diff --git a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
index 8dc2a475c601..a8c784acce13 100644
--- a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
+++ b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss-cipher.c
@@ -20,7 +20,6 @@ static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
 	unsigned int ivsize = crypto_skcipher_ivsize(tfm);
 	struct sun4i_cipher_req_ctx *ctx = skcipher_request_ctx(areq);
 	u32 mode = ctx->mode;
-	void *backup_iv = NULL;
 	/* when activating SS, the default FIFO space is SS_RX_DEFAULT(32) */
 	u32 rx_cnt = SS_RX_DEFAULT;
 	u32 tx_cnt = 0;
@@ -47,10 +46,8 @@ static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
 	}
 
 	if (areq->iv && ivsize > 0 && mode & SS_DECRYPTION) {
-		backup_iv = kzalloc(ivsize, GFP_KERNEL);
-		if (!backup_iv)
-			return -ENOMEM;
-		scatterwalk_map_and_copy(backup_iv, areq->src, areq->cryptlen - ivsize, ivsize, 0);
+		scatterwalk_map_and_copy(ctx->backup_iv, areq->src,
+					 areq->cryptlen - ivsize, ivsize, 0);
 	}
 
 	if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN4I_SS_DEBUG)) {
@@ -133,8 +130,8 @@ static int noinline_for_stack sun4i_ss_opti_poll(struct skcipher_request *areq)
 
 	if (areq->iv) {
 		if (mode & SS_DECRYPTION) {
-			memcpy(areq->iv, backup_iv, ivsize);
-			kfree_sensitive(backup_iv);
+			memcpy(areq->iv, ctx->backup_iv, ivsize);
+			memzero_explicit(ctx->backup_iv, ivsize);
 		} else {
 			scatterwalk_map_and_copy(areq->iv, areq->dst, areq->cryptlen - ivsize,
 						 ivsize, 0);
@@ -198,7 +195,6 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
 	unsigned int ileft = areq->cryptlen;
 	unsigned int oleft = areq->cryptlen;
 	unsigned int todo;
-	void *backup_iv = NULL;
 	struct sg_mapping_iter mi, mo;
 	unsigned long pi = 0, po = 0; /* progress for in and out */
 	bool miter_err;
@@ -242,10 +238,8 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
 		return sun4i_ss_cipher_poll_fallback(areq);
 
 	if (areq->iv && ivsize > 0 && mode & SS_DECRYPTION) {
-		backup_iv = kzalloc(ivsize, GFP_KERNEL);
-		if (!backup_iv)
-			return -ENOMEM;
-		scatterwalk_map_and_copy(backup_iv, areq->src, areq->cryptlen - ivsize, ivsize, 0);
+		scatterwalk_map_and_copy(ctx->backup_iv, areq->src,
+					 areq->cryptlen - ivsize, ivsize, 0);
 	}
 
 	if (IS_ENABLED(CONFIG_CRYPTO_DEV_SUN4I_SS_DEBUG)) {
@@ -382,8 +376,8 @@ static int sun4i_ss_cipher_poll(struct skcipher_request *areq)
 	}
 	if (areq->iv) {
 		if (mode & SS_DECRYPTION) {
-			memcpy(areq->iv, backup_iv, ivsize);
-			kfree_sensitive(backup_iv);
+			memcpy(areq->iv, ctx->backup_iv, ivsize);
+			memzero_explicit(ctx->backup_iv, ivsize);
 		} else {
 			scatterwalk_map_and_copy(areq->iv, areq->dst, areq->cryptlen - ivsize,
 						 ivsize, 0);
diff --git a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss.h b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss.h
index 0fee6f4e2d90..ba59c7a48825 100644
--- a/drivers/crypto/allwinner/sun4i-ss/sun4i-ss.h
+++ b/drivers/crypto/allwinner/sun4i-ss/sun4i-ss.h
@@ -183,6 +183,7 @@ struct sun4i_tfm_ctx {
 
 struct sun4i_cipher_req_ctx {
 	u32 mode;
+	u8 backup_iv[AES_BLOCK_SIZE];
 	struct skcipher_request fallback_req;   // keep at the end
 };
 
-- 
2.34.1