crypto: null - Remove VLA usage of skcipher

In the quest to remove all stack VLA usage from the kernel[1], this
replaces struct crypto_skcipher and SKCIPHER_REQUEST_ON_STACK() usage
with struct crypto_sync_skcipher and SYNC_SKCIPHER_REQUEST_ON_STACK(),
which uses a fixed stack size.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto/algif_aead.c

@@ -42,7 +42,7 @@
 
 struct aead_tfm {
 	struct crypto_aead *aead;
-	struct crypto_skcipher *null_tfm;
+	struct crypto_sync_skcipher *null_tfm;
 };
 
 static inline bool aead_sufficient_data(struct sock *sk)
@@ -75,13 +75,13 @@ static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	return af_alg_sendmsg(sock, msg, size, ivsize);
 }
 
-static int crypto_aead_copy_sgl(struct crypto_skcipher *null_tfm,
+static int crypto_aead_copy_sgl(struct crypto_sync_skcipher *null_tfm,
 				struct scatterlist *src,
 				struct scatterlist *dst, unsigned int len)
 {
-	SKCIPHER_REQUEST_ON_STACK(skreq, null_tfm);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, null_tfm);
 
-	skcipher_request_set_tfm(skreq, null_tfm);
+	skcipher_request_set_sync_tfm(skreq, null_tfm);
 	skcipher_request_set_callback(skreq, CRYPTO_TFM_REQ_MAY_BACKLOG,
 				      NULL, NULL);
 	skcipher_request_set_crypt(skreq, src, dst, len, NULL);
@@ -99,7 +99,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 	struct af_alg_ctx *ctx = ask->private;
 	struct aead_tfm *aeadc = pask->private;
 	struct crypto_aead *tfm = aeadc->aead;
-	struct crypto_skcipher *null_tfm = aeadc->null_tfm;
+	struct crypto_sync_skcipher *null_tfm = aeadc->null_tfm;
 	unsigned int i, as = crypto_aead_authsize(tfm);
 	struct af_alg_async_req *areq;
 	struct af_alg_tsgl *tsgl, *tmp;
@@ -478,7 +478,7 @@ static void *aead_bind(const char *name, u32 type, u32 mask)
 {
 	struct aead_tfm *tfm;
 	struct crypto_aead *aead;
-	struct crypto_skcipher *null_tfm;
+	struct crypto_sync_skcipher *null_tfm;
 
 	tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
 	if (!tfm)

crypto/authenc.c

@@ -33,7 +33,7 @@ struct authenc_instance_ctx {
 struct crypto_authenc_ctx {
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
-	struct crypto_skcipher *null;
+	struct crypto_sync_skcipher *null;
 };
 
 struct authenc_request_ctx {
@@ -185,9 +185,9 @@ static int crypto_authenc_copy_assoc(struct aead_request *req)
 {
 	struct crypto_aead *authenc = crypto_aead_reqtfm(req);
 	struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
-	SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
 
-	skcipher_request_set_tfm(skreq, ctx->null);
+	skcipher_request_set_sync_tfm(skreq, ctx->null);
 	skcipher_request_set_callback(skreq, aead_request_flags(req),
 				      NULL, NULL);
 	skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen,
@@ -318,7 +318,7 @@ static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
 	struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
-	struct crypto_skcipher *null;
+	struct crypto_sync_skcipher *null;
 	int err;
 
 	auth = crypto_spawn_ahash(&ictx->auth);

crypto/authencesn.c

@@ -36,7 +36,7 @@ struct crypto_authenc_esn_ctx {
 	unsigned int reqoff;
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
-	struct crypto_skcipher *null;
+	struct crypto_sync_skcipher *null;
 };
 
 struct authenc_esn_request_ctx {
@@ -183,9 +183,9 @@ static int crypto_authenc_esn_copy(struct aead_request *req, unsigned int len)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(authenc_esn);
-	SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
 
-	skcipher_request_set_tfm(skreq, ctx->null);
+	skcipher_request_set_sync_tfm(skreq, ctx->null);
 	skcipher_request_set_callback(skreq, aead_request_flags(req),
 				      NULL, NULL);
 	skcipher_request_set_crypt(skreq, req->src, req->dst, len, NULL);
@@ -341,7 +341,7 @@ static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
 	struct crypto_authenc_esn_ctx *ctx = crypto_aead_ctx(tfm);
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
-	struct crypto_skcipher *null;
+	struct crypto_sync_skcipher *null;
 	int err;
 
 	auth = crypto_spawn_ahash(&ictx->auth);

crypto/crypto_null.c

@@ -26,7 +26,7 @@
 #include <linux/string.h>
 
 static DEFINE_MUTEX(crypto_default_null_skcipher_lock);
-static struct crypto_skcipher *crypto_default_null_skcipher;
+static struct crypto_sync_skcipher *crypto_default_null_skcipher;
 static int crypto_default_null_skcipher_refcnt;
 
 static int null_compress(struct crypto_tfm *tfm, const u8 *src,
@@ -152,16 +152,15 @@ MODULE_ALIAS_CRYPTO("compress_null");
 MODULE_ALIAS_CRYPTO("digest_null");
 MODULE_ALIAS_CRYPTO("cipher_null");
 
-struct crypto_skcipher *crypto_get_default_null_skcipher(void)
+struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void)
 {
-	struct crypto_skcipher *tfm;
+	struct crypto_sync_skcipher *tfm;
 
 	mutex_lock(&crypto_default_null_skcipher_lock);
 	tfm = crypto_default_null_skcipher;
 
 	if (!tfm) {
-		tfm = crypto_alloc_skcipher("ecb(cipher_null)",
-					    0, CRYPTO_ALG_ASYNC);
+		tfm = crypto_alloc_sync_skcipher("ecb(cipher_null)", 0, 0);
 		if (IS_ERR(tfm))
 			goto unlock;
 
@@ -181,7 +180,7 @@ void crypto_put_default_null_skcipher(void)
 {
 	mutex_lock(&crypto_default_null_skcipher_lock);
 	if (!--crypto_default_null_skcipher_refcnt) {
-		crypto_free_skcipher(crypto_default_null_skcipher);
+		crypto_free_sync_skcipher(crypto_default_null_skcipher);
 		crypto_default_null_skcipher = NULL;
 	}
 	mutex_unlock(&crypto_default_null_skcipher_lock);

crypto/echainiv.c

@@ -47,9 +47,9 @@ static int echainiv_encrypt(struct aead_request *req)
 	info = req->iv;
 
 	if (req->src != req->dst) {
-		SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
+		SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
 
-		skcipher_request_set_tfm(nreq, ctx->sknull);
+		skcipher_request_set_sync_tfm(nreq, ctx->sknull);
 		skcipher_request_set_callback(nreq, req->base.flags,
 					      NULL, NULL);
 		skcipher_request_set_crypt(nreq, req->src, req->dst,

crypto/gcm.c

@@ -50,7 +50,7 @@ struct crypto_rfc4543_instance_ctx {
 
 struct crypto_rfc4543_ctx {
 	struct crypto_aead *child;
-	struct crypto_skcipher *null;
+	struct crypto_sync_skcipher *null;
 	u8 nonce[4];
 };
 
@@ -1067,9 +1067,9 @@ static int crypto_rfc4543_copy_src_to_dst(struct aead_request *req, bool enc)
 	unsigned int authsize = crypto_aead_authsize(aead);
 	unsigned int nbytes = req->assoclen + req->cryptlen -
 			      (enc ? 0 : authsize);
-	SKCIPHER_REQUEST_ON_STACK(nreq, ctx->null);
+	SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->null);
 
-	skcipher_request_set_tfm(nreq, ctx->null);
+	skcipher_request_set_sync_tfm(nreq, ctx->null);
 	skcipher_request_set_callback(nreq, req->base.flags, NULL, NULL);
 	skcipher_request_set_crypt(nreq, req->src, req->dst, nbytes, NULL);
 
@@ -1093,7 +1093,7 @@ static int crypto_rfc4543_init_tfm(struct crypto_aead *tfm)
 	struct crypto_aead_spawn *spawn = &ictx->aead;
 	struct crypto_rfc4543_ctx *ctx = crypto_aead_ctx(tfm);
 	struct crypto_aead *aead;
-	struct crypto_skcipher *null;
+	struct crypto_sync_skcipher *null;
 	unsigned long align;
 	int err = 0;
 

crypto/seqiv.c

@@ -73,9 +73,9 @@ static int seqiv_aead_encrypt(struct aead_request *req)
 	info = req->iv;
 
 	if (req->src != req->dst) {
-		SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
+		SYNC_SKCIPHER_REQUEST_ON_STACK(nreq, ctx->sknull);
 
-		skcipher_request_set_tfm(nreq, ctx->sknull);
+		skcipher_request_set_sync_tfm(nreq, ctx->sknull);
 		skcipher_request_set_callback(nreq, req->base.flags,
 					      NULL, NULL);
 		skcipher_request_set_crypt(nreq, req->src, req->dst,

include/crypto/internal/geniv.h

@@ -20,7 +20,7 @@
 struct aead_geniv_ctx {
 	spinlock_t lock;
 	struct crypto_aead *child;
-	struct crypto_skcipher *sknull;
+	struct crypto_sync_skcipher *sknull;
 	u8 salt[] __attribute__ ((aligned(__alignof__(u32))));
 };
 

include/crypto/null.h

@@ -9,7 +9,7 @@
 #define NULL_DIGEST_SIZE	0
 #define NULL_IV_SIZE		0
 
-struct crypto_skcipher *crypto_get_default_null_skcipher(void);
+struct crypto_sync_skcipher *crypto_get_default_null_skcipher(void);
 void crypto_put_default_null_skcipher(void);
 
 #endif