Re: Linux 5.15.204

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

diff --git a/Makefile b/Makefile
index 0ca0891b993d..3937e96d463f 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 VERSION = 5
 PATCHLEVEL = 15
-SUBLEVEL = 203
+SUBLEVEL = 204
 EXTRAVERSION =
 NAME = Trick or Treat
 
diff --git a/crypto/Kconfig b/crypto/Kconfig
index db260ccfba51..126d4699f06f 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -195,7 +195,6 @@ config CRYPTO_AUTHENC
 	select CRYPTO_SKCIPHER
 	select CRYPTO_MANAGER
 	select CRYPTO_HASH
-	select CRYPTO_NULL
 	help
 	  Authenc: Combined mode wrapper for IPsec.
 	  This is required for IPSec.
@@ -1872,7 +1871,6 @@ config CRYPTO_USER_API_AEAD
 	depends on NET
 	select CRYPTO_AEAD
 	select CRYPTO_SKCIPHER
-	select CRYPTO_NULL
 	select CRYPTO_USER_API
 	help
 	  This option enables the user-spaces interface for AEAD
diff --git a/crypto/af_alg.c b/crypto/af_alg.c
index 631ee6a220d5..8f7cf57da8f6 100644
--- a/crypto/af_alg.c
+++ b/crypto/af_alg.c
@@ -529,15 +529,13 @@ static int af_alg_alloc_tsgl(struct sock *sk)
 /**
  * af_alg_count_tsgl - Count number of TX SG entries
  *
- * The counting starts from the beginning of the SGL to @bytes. If
- * an @offset is provided, the counting of the SG entries starts at the @offset.
+ * The counting starts from the beginning of the SGL to @bytes.
  *
  * @sk: socket of connection to user space
  * @bytes: Count the number of SG entries holding given number of bytes.
- * @offset: Start the counting of SG entries from the given offset.
  * Return: Number of TX SG entries found given the constraints
  */
-unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
+unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes)
 {
 	const struct alg_sock *ask = alg_sk(sk);
 	const struct af_alg_ctx *ctx = ask->private;
@@ -552,25 +550,11 @@ unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
 		const struct scatterlist *sg = sgl->sg;
 
 		for (i = 0; i < sgl->cur; i++) {
-			size_t bytes_count;
-
-			/* Skip offset */
-			if (offset >= sg[i].length) {
-				offset -= sg[i].length;
-				bytes -= sg[i].length;
-				continue;
-			}
-
-			bytes_count = sg[i].length - offset;
-
-			offset = 0;
 			sgl_count++;
-
-			/* If we have seen requested number of bytes, stop */
-			if (bytes_count >= bytes)
+			if (sg[i].length >= bytes)
 				return sgl_count;
 
-			bytes -= bytes_count;
+			bytes -= sg[i].length;
 		}
 	}
 
@@ -582,19 +566,14 @@ EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
  * af_alg_pull_tsgl - Release the specified buffers from TX SGL
  *
  * If @dst is non-null, reassign the pages to @dst. The caller must release
- * the pages. If @dst_offset is given only reassign the pages to @dst starting
- * at the @dst_offset (byte). The caller must ensure that @dst is large
- * enough (e.g. by using af_alg_count_tsgl with the same offset).
+ * the pages.
  *
  * @sk: socket of connection to user space
  * @used: Number of bytes to pull from TX SGL
  * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
  *	 caller must release the buffers in dst.
- * @dst_offset: Reassign the TX SGL from given offset. All buffers before
- *	        reaching the offset is released.
  */
-void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
-		      size_t dst_offset)
+void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst)
 {
 	struct alg_sock *ask = alg_sk(sk);
 	struct af_alg_ctx *ctx = ask->private;
@@ -618,19 +597,11 @@ void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 			 * Assumption: caller created af_alg_count_tsgl(len)
 			 * SG entries in dst.
 			 */
-			if (dst) {
-				if (dst_offset >= plen) {
-					/* discard page before offset */
-					dst_offset -= plen;
-				} else {
-					/* reassign page to dst after offset */
-					get_page(page);
-					sg_set_page(dst + j, page,
-						    plen - dst_offset,
-						    sg[i].offset + dst_offset);
-					dst_offset = 0;
-					j++;
-				}
+			if (dst && plen) {
+				/* reassign page to dst */
+				get_page(page);
+				sg_set_page(dst + j, page, plen, sg[i].offset);
+				j++;
 			}
 
 			sg[i].length -= plen;
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c
index 42493b4d8ce4..4a285994d106 100644
--- a/crypto/algif_aead.c
+++ b/crypto/algif_aead.c
@@ -26,8 +26,6 @@
 #include <crypto/internal/aead.h>
 #include <crypto/scatterwalk.h>
 #include <crypto/if_alg.h>
-#include <crypto/skcipher.h>
-#include <crypto/null.h>
 #include <linux/init.h>
 #include <linux/list.h>
 #include <linux/kernel.h>
@@ -36,19 +34,13 @@
 #include <linux/net.h>
 #include <net/sock.h>
 
-struct aead_tfm {
-	struct crypto_aead *aead;
-	struct crypto_sync_skcipher *null_tfm;
-};
-
 static inline bool aead_sufficient_data(struct sock *sk)
 {
 	struct alg_sock *ask = alg_sk(sk);
 	struct sock *psk = ask->parent;
 	struct alg_sock *pask = alg_sk(psk);
 	struct af_alg_ctx *ctx = ask->private;
-	struct aead_tfm *aeadc = pask->private;
-	struct crypto_aead *tfm = aeadc->aead;
+	struct crypto_aead *tfm = pask->private;
 	unsigned int as = crypto_aead_authsize(tfm);
 
 	/*
@@ -64,27 +56,12 @@ static int aead_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
 	struct alg_sock *ask = alg_sk(sk);
 	struct sock *psk = ask->parent;
 	struct alg_sock *pask = alg_sk(psk);
-	struct aead_tfm *aeadc = pask->private;
-	struct crypto_aead *tfm = aeadc->aead;
+	struct crypto_aead *tfm = pask->private;
 	unsigned int ivsize = crypto_aead_ivsize(tfm);
 
 	return af_alg_sendmsg(sock, msg, size, ivsize);
 }
 
-static int crypto_aead_copy_sgl(struct crypto_sync_skcipher *null_tfm,
-				struct scatterlist *src,
-				struct scatterlist *dst, unsigned int len)
-{
-	SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, null_tfm);
-
-	skcipher_request_set_sync_tfm(skreq, null_tfm);
-	skcipher_request_set_callback(skreq, CRYPTO_TFM_REQ_MAY_SLEEP,
-				      NULL, NULL);
-	skcipher_request_set_crypt(skreq, src, dst, len, NULL);
-
-	return crypto_skcipher_encrypt(skreq);
-}
-
 static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 			 size_t ignored, int flags)
 {
@@ -93,13 +70,12 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 	struct sock *psk = ask->parent;
 	struct alg_sock *pask = alg_sk(psk);
 	struct af_alg_ctx *ctx = ask->private;
-	struct aead_tfm *aeadc = pask->private;
-	struct crypto_aead *tfm = aeadc->aead;
-	struct crypto_sync_skcipher *null_tfm = aeadc->null_tfm;
-	unsigned int i, as = crypto_aead_authsize(tfm);
+	struct crypto_aead *tfm = pask->private;
+	unsigned int as = crypto_aead_authsize(tfm);
+	unsigned int ivsize = crypto_aead_ivsize(tfm);
 	struct af_alg_async_req *areq;
-	struct af_alg_tsgl *tsgl, *tmp;
 	struct scatterlist *rsgl_src, *tsgl_src = NULL;
+	void *iv;
 	int err = 0;
 	size_t used = 0;		/* [in]  TX bufs to be en/decrypted */
 	size_t outlen = 0;		/* [out] RX bufs produced by kernel */
@@ -151,10 +127,14 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 
 	/* Allocate cipher request for current operation. */
 	areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) +
-				     crypto_aead_reqsize(tfm));
+				     crypto_aead_reqsize(tfm) + ivsize);
 	if (IS_ERR(areq))
 		return PTR_ERR(areq);
 
+	iv = (u8 *)aead_request_ctx(&areq->cra_u.aead_req) +
+	     crypto_aead_reqsize(tfm);
+	memcpy(iv, ctx->iv, ivsize);
+
 	/* convert iovecs of output buffers into RX SGL */
 	err = af_alg_get_rsgl(sk, msg, flags, areq, outlen, &usedpages);
 	if (err)
@@ -170,7 +150,7 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 	if (usedpages < outlen) {
 		size_t less = outlen - usedpages;
 
-		if (used < less) {
+		if (used < less + (ctx->enc ? 0 : as)) {
 			err = -EINVAL;
 			goto free;
 		}
@@ -178,23 +158,24 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 		outlen -= less;
 	}
 
+	/*
+	 * Create a per request TX SGL for this request which tracks the
+	 * SG entries from the global TX SGL.
+	 */
 	processed = used + ctx->aead_assoclen;
-	list_for_each_entry_safe(tsgl, tmp, &ctx->tsgl_list, list) {
-		for (i = 0; i < tsgl->cur; i++) {
-			struct scatterlist *process_sg = tsgl->sg + i;
-
-			if (!(process_sg->length) || !sg_page(process_sg))
-				continue;
-			tsgl_src = process_sg;
-			break;
-		}
-		if (tsgl_src)
-			break;
-	}
-	if (processed && !tsgl_src) {
-		err = -EFAULT;
+	areq->tsgl_entries = af_alg_count_tsgl(sk, processed);
+	if (!areq->tsgl_entries)
+		areq->tsgl_entries = 1;
+	areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
+					         areq->tsgl_entries),
+				  GFP_KERNEL);
+	if (!areq->tsgl) {
+		err = -ENOMEM;
 		goto free;
 	}
+	sg_init_table(areq->tsgl, areq->tsgl_entries);
+	af_alg_pull_tsgl(sk, processed, areq->tsgl);
+	tsgl_src = areq->tsgl;
 
 	/*
 	 * Copy of AAD from source to destination
@@ -203,82 +184,16 @@ static int _aead_recvmsg(struct socket *sock, struct msghdr *msg,
 	 * when user space uses an in-place cipher operation, the kernel
 	 * will copy the data as it does not see whether such in-place operation
 	 * is initiated.
-	 *
-	 * To ensure efficiency, the following implementation ensure that the
-	 * ciphers are invoked to perform a crypto operation in-place. This
-	 * is achieved by memory management specified as follows.
 	 */
 
 	/* Use the RX SGL as source (and destination) for crypto op. */
 	rsgl_src = areq->first_rsgl.sgl.sg;
 
-	if (ctx->enc) {
-		/*
-		 * Encryption operation - The in-place cipher operation is
-		 * achieved by the following operation:
-		 *
-		 * TX SGL: AAD || PT
-		 *	    |	   |
-		 *	    | copy |
-		 *	    v	   v
-		 * RX SGL: AAD || PT || Tag
-		 */
-		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
-					   areq->first_rsgl.sgl.sg, processed);
-		if (err)
-			goto free;
-		af_alg_pull_tsgl(sk, processed, NULL, 0);
-	} else {
-		/*
-		 * Decryption operation - To achieve an in-place cipher
-		 * operation, the following  SGL structure is used:
-		 *
-		 * TX SGL: AAD || CT || Tag
-		 *	    |	   |	 ^
-		 *	    | copy |	 | Create SGL link.
-		 *	    v	   v	 |
-		 * RX SGL: AAD || CT ----+
-		 */
-
-		 /* Copy AAD || CT to RX SGL buffer for in-place operation. */
-		err = crypto_aead_copy_sgl(null_tfm, tsgl_src,
-					   areq->first_rsgl.sgl.sg, outlen);
-		if (err)
-			goto free;
-
-		/* Create TX SGL for tag and chain it to RX SGL. */
-		areq->tsgl_entries = af_alg_count_tsgl(sk, processed,
-						       processed - as);
-		if (!areq->tsgl_entries)
-			areq->tsgl_entries = 1;
-		areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
-							 areq->tsgl_entries),
-					  GFP_KERNEL);
-		if (!areq->tsgl) {
-			err = -ENOMEM;
-			goto free;
-		}
-		sg_init_table(areq->tsgl, areq->tsgl_entries);
-
-		/* Release TX SGL, except for tag data and reassign tag data. */
-		af_alg_pull_tsgl(sk, processed, areq->tsgl, processed - as);
-
-		/* chain the areq TX SGL holding the tag with RX SGL */
-		if (usedpages) {
-			/* RX SGL present */
-			struct af_alg_sgl *sgl_prev = &areq->last_rsgl->sgl;
-
-			sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
-			sg_chain(sgl_prev->sg, sgl_prev->npages + 1,
-				 areq->tsgl);
-		} else
-			/* no RX SGL present (e.g. authentication only) */
-			rsgl_src = areq->tsgl;
-	}
+	memcpy_sglist(rsgl_src, tsgl_src, ctx->aead_assoclen);
 
 	/* Initialize the crypto operation */
-	aead_request_set_crypt(&areq->cra_u.aead_req, rsgl_src,
-			       areq->first_rsgl.sgl.sg, used, ctx->iv);
+	aead_request_set_crypt(&areq->cra_u.aead_req, tsgl_src,
+			       areq->first_rsgl.sgl.sg, used, iv);
 	aead_request_set_ad(&areq->cra_u.aead_req, ctx->aead_assoclen);
 	aead_request_set_tfm(&areq->cra_u.aead_req, tfm);
 
@@ -378,7 +293,7 @@ static int aead_check_key(struct socket *sock)
 	int err = 0;
 	struct sock *psk;
 	struct alg_sock *pask;
-	struct aead_tfm *tfm;
+	struct crypto_aead *tfm;
 	struct sock *sk = sock->sk;
 	struct alg_sock *ask = alg_sk(sk);
 
@@ -392,7 +307,7 @@ static int aead_check_key(struct socket *sock)
 
 	err = -ENOKEY;
 	lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
-	if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
+	if (crypto_aead_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		goto unlock;
 
 	atomic_dec(&pask->nokey_refcnt);
@@ -466,54 +381,22 @@ static struct proto_ops algif_aead_ops_nokey = {
 
 static void *aead_bind(const char *name, u32 type, u32 mask)
 {
-	struct aead_tfm *tfm;
-	struct crypto_aead *aead;
-	struct crypto_sync_skcipher *null_tfm;
-
-	tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
-	if (!tfm)
-		return ERR_PTR(-ENOMEM);
-
-	aead = crypto_alloc_aead(name, type, mask);
-	if (IS_ERR(aead)) {
-		kfree(tfm);
-		return ERR_CAST(aead);
-	}
-
-	null_tfm = crypto_get_default_null_skcipher();
-	if (IS_ERR(null_tfm)) {
-		crypto_free_aead(aead);
-		kfree(tfm);
-		return ERR_CAST(null_tfm);
-	}
-
-	tfm->aead = aead;
-	tfm->null_tfm = null_tfm;
-
-	return tfm;
+	return crypto_alloc_aead(name, type, mask);
 }
 
 static void aead_release(void *private)
 {
-	struct aead_tfm *tfm = private;
-
-	crypto_free_aead(tfm->aead);
-	crypto_put_default_null_skcipher();
-	kfree(tfm);
+	crypto_free_aead(private);
 }
 
 static int aead_setauthsize(void *private, unsigned int authsize)
 {
-	struct aead_tfm *tfm = private;
-
-	return crypto_aead_setauthsize(tfm->aead, authsize);
+	return crypto_aead_setauthsize(private, authsize);
 }
 
 static int aead_setkey(void *private, const u8 *key, unsigned int keylen)
 {
-	struct aead_tfm *tfm = private;
-
-	return crypto_aead_setkey(tfm->aead, key, keylen);
+	return crypto_aead_setkey(private, key, keylen);
 }
 
 static void aead_sock_destruct(struct sock *sk)
@@ -522,11 +405,10 @@ static void aead_sock_destruct(struct sock *sk)
 	struct af_alg_ctx *ctx = ask->private;
 	struct sock *psk = ask->parent;
 	struct alg_sock *pask = alg_sk(psk);
-	struct aead_tfm *aeadc = pask->private;
-	struct crypto_aead *tfm = aeadc->aead;
+	struct crypto_aead *tfm = pask->private;
 	unsigned int ivlen = crypto_aead_ivsize(tfm);
 
-	af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
+	af_alg_pull_tsgl(sk, ctx->used, NULL);
 	sock_kzfree_s(sk, ctx->iv, ivlen);
 	sock_kfree_s(sk, ctx, ctx->len);
 	af_alg_release_parent(sk);
@@ -536,10 +418,9 @@ static int aead_accept_parent_nokey(void *private, struct sock *sk)
 {
 	struct af_alg_ctx *ctx;
 	struct alg_sock *ask = alg_sk(sk);
-	struct aead_tfm *tfm = private;
-	struct crypto_aead *aead = tfm->aead;
+	struct crypto_aead *tfm = private;
 	unsigned int len = sizeof(*ctx);
-	unsigned int ivlen = crypto_aead_ivsize(aead);
+	unsigned int ivlen = crypto_aead_ivsize(tfm);
 
 	ctx = sock_kmalloc(sk, len, GFP_KERNEL);
 	if (!ctx)
@@ -566,9 +447,9 @@ static int aead_accept_parent_nokey(void *private, struct sock *sk)
 
 static int aead_accept_parent(void *private, struct sock *sk)
 {
-	struct aead_tfm *tfm = private;
+	struct crypto_aead *tfm = private;
 
-	if (crypto_aead_get_flags(tfm->aead) & CRYPTO_TFM_NEED_KEY)
+	if (crypto_aead_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		return -ENOKEY;
 
 	return aead_accept_parent_nokey(private, sk);
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index ee8890ee8f33..8b314260929f 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -89,7 +89,7 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 	 * Create a per request TX SGL for this request which tracks the
 	 * SG entries from the global TX SGL.
 	 */
-	areq->tsgl_entries = af_alg_count_tsgl(sk, len, 0);
+	areq->tsgl_entries = af_alg_count_tsgl(sk, len);
 	if (!areq->tsgl_entries)
 		areq->tsgl_entries = 1;
 	areq->tsgl = sock_kmalloc(sk, array_size(sizeof(*areq->tsgl),
@@ -100,7 +100,7 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
 		goto free;
 	}
 	sg_init_table(areq->tsgl, areq->tsgl_entries);
-	af_alg_pull_tsgl(sk, len, areq->tsgl, 0);
+	af_alg_pull_tsgl(sk, len, areq->tsgl);
 
 	/* Initialize the crypto operation */
 	skcipher_request_set_tfm(&areq->cra_u.skcipher_req, tfm);
@@ -313,7 +313,7 @@ static void skcipher_sock_destruct(struct sock *sk)
 	struct alg_sock *pask = alg_sk(psk);
 	struct crypto_skcipher *tfm = pask->private;
 
-	af_alg_pull_tsgl(sk, ctx->used, NULL, 0);
+	af_alg_pull_tsgl(sk, ctx->used, NULL);
 	sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm));
 	sock_kfree_s(sk, ctx, ctx->len);
 	af_alg_release_parent(sk);
diff --git a/crypto/authenc.c b/crypto/authenc.c
index 17f674a7cdff..2b402e764529 100644
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -9,7 +9,6 @@
 #include <crypto/internal/hash.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/authenc.h>
-#include <crypto/null.h>
 #include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -28,7 +27,6 @@ struct authenc_instance_ctx {
 struct crypto_authenc_ctx {
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
-	struct crypto_sync_skcipher *null;
 };
 
 struct authenc_request_ctx {
@@ -174,21 +172,6 @@ static void crypto_authenc_encrypt_done(struct crypto_async_request *req,
 	authenc_request_complete(areq, err);
 }
 
-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);
-	SYNC_SKCIPHER_REQUEST_ON_STACK(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,
-				   NULL);
-
-	return crypto_skcipher_encrypt(skreq);
-}
-
 static int crypto_authenc_encrypt(struct aead_request *req)
 {
 	struct crypto_aead *authenc = crypto_aead_reqtfm(req);
@@ -207,10 +190,7 @@ static int crypto_authenc_encrypt(struct aead_request *req)
 	dst = src;
 
 	if (req->src != req->dst) {
-		err = crypto_authenc_copy_assoc(req);
-		if (err)
-			return err;
-
+		memcpy_sglist(req->dst, req->src, req->assoclen);
 		dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
 	}
 
@@ -311,7 +291,6 @@ 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_sync_skcipher *null;
 	int err;
 
 	auth = crypto_spawn_ahash(&ictx->auth);
@@ -323,14 +302,8 @@ static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
 	if (IS_ERR(enc))
 		goto err_free_ahash;
 
-	null = crypto_get_default_null_skcipher();
-	err = PTR_ERR(null);
-	if (IS_ERR(null))
-		goto err_free_skcipher;
-
 	ctx->auth = auth;
 	ctx->enc = enc;
-	ctx->null = null;
 
 	crypto_aead_set_reqsize(
 		tfm,
@@ -344,8 +317,6 @@ static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
 
 	return 0;
 
-err_free_skcipher:
-	crypto_free_skcipher(enc);
 err_free_ahash:
 	crypto_free_ahash(auth);
 	return err;
@@ -357,7 +328,6 @@ static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
 
 	crypto_free_ahash(ctx->auth);
 	crypto_free_skcipher(ctx->enc);
-	crypto_put_default_null_skcipher();
 }
 
 static void crypto_authenc_free(struct aead_instance *inst)
diff --git a/crypto/authencesn.c b/crypto/authencesn.c
index 6487b35851d5..2154d4ab5c95 100644
--- a/crypto/authencesn.c
+++ b/crypto/authencesn.c
@@ -12,7 +12,6 @@
 #include <crypto/internal/hash.h>
 #include <crypto/internal/skcipher.h>
 #include <crypto/authenc.h>
-#include <crypto/null.h>
 #include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -31,7 +30,6 @@ struct crypto_authenc_esn_ctx {
 	unsigned int reqoff;
 	struct crypto_ahash *auth;
 	struct crypto_skcipher *enc;
-	struct crypto_sync_skcipher *null;
 };
 
 struct authenc_esn_request_ctx {
@@ -164,20 +162,6 @@ static void crypto_authenc_esn_encrypt_done(struct crypto_async_request *req,
 	authenc_esn_request_complete(areq, err);
 }
 
-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);
-	SYNC_SKCIPHER_REQUEST_ON_STACK(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);
-
-	return crypto_skcipher_encrypt(skreq);
-}
-
 static int crypto_authenc_esn_encrypt(struct aead_request *req)
 {
 	struct crypto_aead *authenc_esn = crypto_aead_reqtfm(req);
@@ -199,10 +183,7 @@ static int crypto_authenc_esn_encrypt(struct aead_request *req)
 	dst = src;
 
 	if (req->src != req->dst) {
-		err = crypto_authenc_esn_copy(req, assoclen);
-		if (err)
-			return err;
-
+		memcpy_sglist(req->dst, req->src, assoclen);
 		sg_init_table(areq_ctx->dst, 2);
 		dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, assoclen);
 	}
@@ -233,6 +214,7 @@ static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
 			      crypto_ahash_alignmask(auth) + 1);
 	unsigned int cryptlen = req->cryptlen - authsize;
 	unsigned int assoclen = req->assoclen;
+	struct scatterlist *src = req->src;
 	struct scatterlist *dst = req->dst;
 	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
 	u32 tmp[2];
@@ -240,23 +222,29 @@ static int crypto_authenc_esn_decrypt_tail(struct aead_request *req,
 	if (!authsize)
 		goto decrypt;
 
-	/* Move high-order bits of sequence number back. */
-	scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
-	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
-	scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
+	if (src == dst) {
+		/* Move high-order bits of sequence number back. */
+		scatterwalk_map_and_copy(tmp, dst, 4, 4, 0);
+		scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 0);
+		scatterwalk_map_and_copy(tmp, dst, 0, 8, 1);
+	} else
+		memcpy_sglist(dst, src, assoclen);
 
 	if (crypto_memneq(ihash, ohash, authsize))
 		return -EBADMSG;
 
 decrypt:
 
-	sg_init_table(areq_ctx->dst, 2);
 	dst = scatterwalk_ffwd(areq_ctx->dst, dst, assoclen);
+	if (req->src == req->dst)
+		src = dst;
+	else
+		src = scatterwalk_ffwd(areq_ctx->src, src, assoclen);
 
 	skcipher_request_set_tfm(skreq, ctx->enc);
 	skcipher_request_set_callback(skreq, flags,
 				      req->base.complete, req->base.data);
-	skcipher_request_set_crypt(skreq, dst, dst, cryptlen, req->iv);
+	skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
 
 	return crypto_skcipher_decrypt(skreq);
 }
@@ -283,6 +271,7 @@ static int crypto_authenc_esn_decrypt(struct aead_request *req)
 	unsigned int assoclen = req->assoclen;
 	unsigned int cryptlen = req->cryptlen;
 	u8 *ihash = ohash + crypto_ahash_digestsize(auth);
+	struct scatterlist *src = req->src;
 	struct scatterlist *dst = req->dst;
 	u32 tmp[2];
 	int err;
@@ -290,27 +279,28 @@ static int crypto_authenc_esn_decrypt(struct aead_request *req)
 	if (assoclen < 8)
 		return -EINVAL;
 
-	cryptlen -= authsize;
-
-	if (req->src != dst) {
-		err = crypto_authenc_esn_copy(req, assoclen + cryptlen);
-		if (err)
-			return err;
-	}
+	if (!authsize)
+		goto tail;
 
+	cryptlen -= authsize;
 	scatterwalk_map_and_copy(ihash, req->src, assoclen + cryptlen,
 				 authsize, 0);
 
-	if (!authsize)
-		goto tail;
-
 	/* Move high-order bits of sequence number to the end. */
-	scatterwalk_map_and_copy(tmp, dst, 0, 8, 0);
-	scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
-	scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
-
-	sg_init_table(areq_ctx->dst, 2);
-	dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
+	scatterwalk_map_and_copy(tmp, src, 0, 8, 0);
+	if (src == dst) {
+		scatterwalk_map_and_copy(tmp, dst, 4, 4, 1);
+		scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen, 4, 1);
+		dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
+	} else {
+		scatterwalk_map_and_copy(tmp, dst, 0, 4, 1);
+		scatterwalk_map_and_copy(tmp + 1, dst, assoclen + cryptlen - 4, 4, 1);
+
+		src = scatterwalk_ffwd(areq_ctx->src, src, 8);
+		dst = scatterwalk_ffwd(areq_ctx->dst, dst, 4);
+		memcpy_sglist(dst, src, assoclen + cryptlen - 8);
+		dst = req->dst;
+	}
 
 	ahash_request_set_tfm(ahreq, auth);
 	ahash_request_set_crypt(ahreq, dst, ohash, assoclen + cryptlen);
@@ -332,7 +322,6 @@ 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_sync_skcipher *null;
 	int err;
 
 	auth = crypto_spawn_ahash(&ictx->auth);
@@ -344,14 +333,8 @@ static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
 	if (IS_ERR(enc))
 		goto err_free_ahash;
 
-	null = crypto_get_default_null_skcipher();
-	err = PTR_ERR(null);
-	if (IS_ERR(null))
-		goto err_free_skcipher;
-
 	ctx->auth = auth;
 	ctx->enc = enc;
-	ctx->null = null;
 
 	ctx->reqoff = ALIGN(2 * crypto_ahash_digestsize(auth),
 			    crypto_ahash_alignmask(auth) + 1);
@@ -368,8 +351,6 @@ static int crypto_authenc_esn_init_tfm(struct crypto_aead *tfm)
 
 	return 0;
 
-err_free_skcipher:
-	crypto_free_skcipher(enc);
 err_free_ahash:
 	crypto_free_ahash(auth);
 	return err;
@@ -381,7 +362,6 @@ static void crypto_authenc_esn_exit_tfm(struct crypto_aead *tfm)
 
 	crypto_free_ahash(ctx->auth);
 	crypto_free_skcipher(ctx->enc);
-	crypto_put_default_null_skcipher();
 }
 
 static void crypto_authenc_esn_free(struct aead_instance *inst)
diff --git a/crypto/scatterwalk.c b/crypto/scatterwalk.c
index 16f6ba896fb6..9f0b27005166 100644
--- a/crypto/scatterwalk.c
+++ b/crypto/scatterwalk.c
@@ -69,6 +69,100 @@ void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
 }
 EXPORT_SYMBOL_GPL(scatterwalk_map_and_copy);
 
+/**
+ * memcpy_sglist() - Copy data from one scatterlist to another
+ * @dst: The destination scatterlist.  Can be NULL if @nbytes == 0.
+ * @src: The source scatterlist.  Can be NULL if @nbytes == 0.
+ * @nbytes: Number of bytes to copy
+ *
+ * The scatterlists can describe exactly the same memory, in which case this
+ * function is a no-op.  No other overlaps are supported.
+ *
+ * Context: Any context
+ */
+void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
+		   unsigned int nbytes)
+{
+	unsigned int src_offset, dst_offset;
+
+	if (unlikely(nbytes == 0)) /* in case src and/or dst is NULL */
+		return;
+
+	src_offset = src->offset;
+	dst_offset = dst->offset;
+	for (;;) {
+		/* Compute the length to copy this step. */
+		unsigned int len = min3(src->offset + src->length - src_offset,
+					dst->offset + dst->length - dst_offset,
+					nbytes);
+		struct page *src_page = sg_page(src);
+		struct page *dst_page = sg_page(dst);
+		const void *src_virt;
+		void *dst_virt;
+
+		if (IS_ENABLED(CONFIG_HIGHMEM)) {
+			/* HIGHMEM: we may have to actually map the pages. */
+			const unsigned int src_oip = offset_in_page(src_offset);
+			const unsigned int dst_oip = offset_in_page(dst_offset);
+			const unsigned int limit = PAGE_SIZE;
+
+			/* Further limit len to not cross a page boundary. */
+			len = min3(len, limit - src_oip, limit - dst_oip);
+
+			/* Compute the source and destination pages. */
+			src_page += src_offset / PAGE_SIZE;
+			dst_page += dst_offset / PAGE_SIZE;
+
+			if (src_page != dst_page) {
+				/* Copy between different pages. */
+				memcpy_page(dst_page, dst_oip,
+					    src_page, src_oip, len);
+				flush_dcache_page(dst_page);
+			} else if (src_oip != dst_oip) {
+				/* Copy between different parts of same page. */
+				dst_virt = kmap_local_page(dst_page);
+				memcpy(dst_virt + dst_oip, dst_virt + src_oip,
+				       len);
+				kunmap_local(dst_virt);
+				flush_dcache_page(dst_page);
+			} /* Else, it's the same memory.  No action needed. */
+		} else {
+			/*
+			 * !HIGHMEM: no mapping needed.  Just work in the linear
+			 * buffer of each sg entry.  Note that we can cross page
+			 * boundaries, as they are not significant in this case.
+			 */
+			src_virt = page_address(src_page) + src_offset;
+			dst_virt = page_address(dst_page) + dst_offset;
+			if (src_virt != dst_virt) {
+				memcpy(dst_virt, src_virt, len);
+				if (ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE)
+					__scatterwalk_flush_dcache_pages(
+						dst_page, dst_offset, len);
+			} /* Else, it's the same memory.  No action needed. */
+		}
+		nbytes -= len;
+		if (nbytes == 0) /* No more to copy? */
+			break;
+
+		/*
+		 * There's more to copy.  Advance the offsets by the length
+		 * copied this step, and advance the sg entries as needed.
+		 */
+		src_offset += len;
+		if (src_offset >= src->offset + src->length) {
+			src = sg_next(src);
+			src_offset = src->offset;
+		}
+		dst_offset += len;
+		if (dst_offset >= dst->offset + dst->length) {
+			dst = sg_next(dst);
+			dst_offset = dst->offset;
+		}
+	}
+}
+EXPORT_SYMBOL_GPL(memcpy_sglist);
+
 struct scatterlist *scatterwalk_ffwd(struct scatterlist dst[2],
 				     struct scatterlist *src,
 				     unsigned int len)
diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c
index abcca5526111..af5a0495e62d 100644
--- a/drivers/xen/privcmd.c
+++ b/drivers/xen/privcmd.c
@@ -934,6 +934,12 @@ static void privcmd_close(struct vm_area_struct *vma)
 	kvfree(pages);
 }
 
+static int privcmd_may_split(struct vm_area_struct *area, unsigned long addr)
+{
+	/* Forbid splitting, avoids double free via privcmd_close(). */
+	return -EINVAL;
+}
+
 static vm_fault_t privcmd_fault(struct vm_fault *vmf)
 {
 	printk(KERN_DEBUG "privcmd_fault: vma=%p %lx-%lx, pgoff=%lx, uv=%p\n",
@@ -945,6 +951,7 @@ static vm_fault_t privcmd_fault(struct vm_fault *vmf)
 
 static const struct vm_operations_struct privcmd_vm_ops = {
 	.close = privcmd_close,
+	.may_split = privcmd_may_split,
 	.fault = privcmd_fault
 };
 
diff --git a/drivers/xen/sys-hypervisor.c b/drivers/xen/sys-hypervisor.c
index feb1d16252e7..989c9a6e1d18 100644
--- a/drivers/xen/sys-hypervisor.c
+++ b/drivers/xen/sys-hypervisor.c
@@ -364,6 +364,8 @@ static ssize_t buildid_show(struct hyp_sysfs_attr *attr, char *buffer)
 			ret = sprintf(buffer, "<denied>");
 		return ret;
 	}
+	if (ret > PAGE_SIZE)
+		return -ENOSPC;
 
 	buildid = kmalloc(sizeof(*buildid) + ret, GFP_KERNEL);
 	if (!buildid)
@@ -371,8 +373,10 @@ static ssize_t buildid_show(struct hyp_sysfs_attr *attr, char *buffer)
 
 	buildid->len = ret;
 	ret = HYPERVISOR_xen_version(XENVER_build_id, buildid);
-	if (ret > 0)
-		ret = sprintf(buffer, "%s", buildid->buf);
+	if (ret > 0) {
+		/* Build id is binary, not a string. */
+		memcpy(buffer, buildid->buf, ret);
+	}
 	kfree(buildid);
 
 	return ret;
diff --git a/include/crypto/if_alg.h b/include/crypto/if_alg.h
index 9af84cad92e9..bc23cd65879b 100644
--- a/include/crypto/if_alg.h
+++ b/include/crypto/if_alg.h
@@ -230,9 +230,8 @@ static inline bool af_alg_readable(struct sock *sk)
 	return PAGE_SIZE <= af_alg_rcvbuf(sk);
 }
 
-unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset);
-void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
-		      size_t dst_offset);
+unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes);
+void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst);
 void af_alg_wmem_wakeup(struct sock *sk);
 int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min);
 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
diff --git a/include/crypto/scatterwalk.h b/include/crypto/scatterwalk.h
index 7af08174a721..df9c1ba3bd5c 100644
--- a/include/crypto/scatterwalk.h
+++ b/include/crypto/scatterwalk.h
@@ -88,6 +88,35 @@ static inline void scatterwalk_pagedone(struct scatter_walk *walk, int out,
 		scatterwalk_start(walk, sg_next(walk->sg));
 }
 
+/*
+ * Flush the dcache of any pages that overlap the region
+ * [offset, offset + nbytes) relative to base_page.
+ *
+ * This should be called only when ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, to ensure
+ * that all relevant code (including the call to sg_page() in the caller, if
+ * applicable) gets fully optimized out when !ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE.
+ */
+static inline void __scatterwalk_flush_dcache_pages(struct page *base_page,
+						    unsigned int offset,
+						    unsigned int nbytes)
+{
+	unsigned int num_pages;
+	unsigned int i;
+
+	base_page += offset / PAGE_SIZE;
+	offset %= PAGE_SIZE;
+
+	/*
+	 * This is an overflow-safe version of
+	 * num_pages = DIV_ROUND_UP(offset + nbytes, PAGE_SIZE).
+	 */
+	num_pages = nbytes / PAGE_SIZE;
+	num_pages += DIV_ROUND_UP(offset + (nbytes % PAGE_SIZE), PAGE_SIZE);
+
+	for (i = 0; i < num_pages; i++)
+		flush_dcache_page(base_page + i);
+}
+
 static inline void scatterwalk_done(struct scatter_walk *walk, int out,
 				    int more)
 {
@@ -100,6 +129,9 @@ void scatterwalk_copychunks(void *buf, struct scatter_walk *walk,
 			    size_t nbytes, int out);
 void *scatterwalk_map(struct scatter_walk *walk);
 
+void memcpy_sglist(struct scatterlist *dst, struct scatterlist *src,
+		   unsigned int nbytes);
+
 void scatterwalk_map_and_copy(void *buf, struct scatterlist *sg,
 			      unsigned int start, unsigned int nbytes, int out);