cifs: update init_sg, crypt_message to take an array of rqst

These are used for SMB3 encryption and compounded requests.
Update these functions and the other functions related to SMB3 encryption to
take an array of requests.

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>

3 files changed, 131 insertions, 109 deletions

diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 4a3a737134ea..0553929e8339 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -454,10 +454,8 @@ struct smb_version_operations {
 	long (*fallocate)(struct file *, struct cifs_tcon *, int, loff_t,
 			  loff_t);
 	/* init transform request - used for encryption for now */
-	int (*init_transform_rq)(struct TCP_Server_Info *, struct smb_rqst *,
-				 struct smb_rqst *);
-	/* free transform request */
-	void (*free_transform_rq)(struct smb_rqst *);
+	int (*init_transform_rq)(struct TCP_Server_Info *, int num_rqst,
+				 struct smb_rqst *, struct smb_rqst *);
 	int (*is_transform_hdr)(void *buf);
 	int (*receive_transform)(struct TCP_Server_Info *,
 				 struct mid_q_entry **);
@@ -1023,6 +1021,7 @@ struct tcon_link {
 };
 
 extern struct tcon_link *cifs_sb_tlink(struct cifs_sb_info *cifs_sb);
+extern void smb3_free_compound_rqst(int num_rqst, struct smb_rqst *rqst);
 
 static inline struct cifs_tcon *
 tlink_tcon(struct tcon_link *tlink)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 85e848007f91..ebc13ebebddf 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -2378,35 +2378,51 @@ static inline void smb2_sg_set_buf(struct scatterlist *sg, const void *buf,
 	sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
 }
 
-/* Assumes:
- * rqst->rq_iov[0]  is transform header
- * rqst->rq_iov[1+] data to be encrypted/decrypted
+/* Assumes the first rqst has a transform header as the first iov.
+ * I.e.
+ * rqst[0].rq_iov[0]  is transform header
+ * rqst[0].rq_iov[1+] data to be encrypted/decrypted
+ * rqst[1+].rq_iov[0+] data to be encrypted/decrypted
  */
 static struct scatterlist *
-init_sg(struct smb_rqst *rqst, u8 *sign)
+init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign)
 {
-	unsigned int sg_len = rqst->rq_nvec + rqst->rq_npages + 1;
-	unsigned int assoc_data_len = sizeof(struct smb2_transform_hdr) - 20;
+	unsigned int sg_len;
 	struct scatterlist *sg;
 	unsigned int i;
 	unsigned int j;
+	unsigned int idx = 0;
+	int skip;
+
+	sg_len = 1;
+	for (i = 0; i < num_rqst; i++)
+		sg_len += rqst[i].rq_nvec + rqst[i].rq_npages;
 
 	sg = kmalloc_array(sg_len, sizeof(struct scatterlist), GFP_KERNEL);
 	if (!sg)
 		return NULL;
 
 	sg_init_table(sg, sg_len);
-	smb2_sg_set_buf(&sg[0], rqst->rq_iov[0].iov_base + 20, assoc_data_len);
-	for (i = 1; i < rqst->rq_nvec; i++)
-		smb2_sg_set_buf(&sg[i], rqst->rq_iov[i].iov_base,
-						rqst->rq_iov[i].iov_len);
-	for (j = 0; i < sg_len - 1; i++, j++) {
-		unsigned int len, offset;
+	for (i = 0; i < num_rqst; i++) {
+		for (j = 0; j < rqst[i].rq_nvec; j++) {
+			/*
+			 * The first rqst has a transform header where the
+			 * first 20 bytes are not part of the encrypted blob
+			 */
+			skip = (i == 0) && (j == 0) ? 20 : 0;
+			smb2_sg_set_buf(&sg[idx++],
+					rqst[i].rq_iov[j].iov_base + skip,
+					rqst[i].rq_iov[j].iov_len - skip);
+		}
+
+		for (j = 0; j < rqst[i].rq_npages; j++) {
+			unsigned int len, offset;
 
-		rqst_page_get_length(rqst, j, &len, &offset);
-		sg_set_page(&sg[i], rqst->rq_pages[j], len, offset);
+			rqst_page_get_length(&rqst[i], j, &len, &offset);
+			sg_set_page(&sg[idx++], rqst[i].rq_pages[j], len, offset);
+		}
 	}
-	smb2_sg_set_buf(&sg[sg_len - 1], sign, SMB2_SIGNATURE_SIZE);
+	smb2_sg_set_buf(&sg[idx], sign, SMB2_SIGNATURE_SIZE);
 	return sg;
 }
 
@@ -2438,10 +2454,11 @@ smb2_get_enc_key(struct TCP_Server_Info *server, __u64 ses_id, int enc, u8 *key)
  * untouched.
  */
 static int
-crypt_message(struct TCP_Server_Info *server, struct smb_rqst *rqst, int enc)
+crypt_message(struct TCP_Server_Info *server, int num_rqst,
+	      struct smb_rqst *rqst, int enc)
 {
 	struct smb2_transform_hdr *tr_hdr =
-			(struct smb2_transform_hdr *)rqst->rq_iov[0].iov_base;
+		(struct smb2_transform_hdr *)rqst[0].rq_iov[0].iov_base;
 	unsigned int assoc_data_len = sizeof(struct smb2_transform_hdr) - 20;
 	int rc = 0;
 	struct scatterlist *sg;
@@ -2492,7 +2509,7 @@ crypt_message(struct TCP_Server_Info *server, struct smb_rqst *rqst, int enc)
 		crypt_len += SMB2_SIGNATURE_SIZE;
 	}
 
-	sg = init_sg(rqst, sign);
+	sg = init_sg(num_rqst, rqst, sign);
 	if (!sg) {
 		cifs_dbg(VFS, "%s: Failed to init sg", __func__);
 		rc = -ENOMEM;
@@ -2529,103 +2546,98 @@ free_req:
 	return rc;
 }
 
+void
+smb3_free_compound_rqst(int num_rqst, struct smb_rqst *rqst)
+{
+	int i, j;
+
+	for (i = 0; i < num_rqst; i++) {
+		if (rqst[i].rq_pages) {
+			for (j = rqst[i].rq_npages - 1; j >= 0; j--)
+				put_page(rqst[i].rq_pages[j]);
+			kfree(rqst[i].rq_pages);
+		}
+	}
+}
+
+/*
+ * This function will initialize new_rq and encrypt the content.
+ * The first entry, new_rq[0], only contains a single iov which contains
+ * a smb2_transform_hdr and is pre-allocated by the caller.
+ * This function then populates new_rq[1+] with the content from olq_rq[0+].
+ *
+ * The end result is an array of smb_rqst structures where the first structure
+ * only contains a single iov for the transform header which we then can pass
+ * to crypt_message().
+ *
+ * new_rq[0].rq_iov[0] :  smb2_transform_hdr pre-allocated by the caller
+ * new_rq[1+].rq_iov[*] == old_rq[0+].rq_iov[*] : SMB2/3 requests
+ */
 static int
-smb3_init_transform_rq(struct TCP_Server_Info *server, struct smb_rqst *new_rq,
-		       struct smb_rqst *old_rq)
+smb3_init_transform_rq(struct TCP_Server_Info *server, int num_rqst,
+		       struct smb_rqst *new_rq, struct smb_rqst *old_rq)
 {
-	struct kvec *iov;
 	struct page **pages;
-	struct smb2_transform_hdr *tr_hdr;
-	unsigned int npages = old_rq->rq_npages;
-	unsigned int orig_len;
-	int i;
+	struct smb2_transform_hdr *tr_hdr = new_rq[0].rq_iov[0].iov_base;
+	unsigned int npages;
+	unsigned int orig_len = 0;
+	int i, j;
 	int rc = -ENOMEM;
 
-	pages = kmalloc_array(npages, sizeof(struct page *), GFP_KERNEL);
-	if (!pages)
-		return rc;
-
-	new_rq->rq_pages = pages;
-	new_rq->rq_offset = old_rq->rq_offset;
-	new_rq->rq_npages = old_rq->rq_npages;
-	new_rq->rq_pagesz = old_rq->rq_pagesz;
-	new_rq->rq_tailsz = old_rq->rq_tailsz;
-
-	for (i = 0; i < npages; i++) {
-		pages[i] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
-		if (!pages[i])
-			goto err_free_pages;
-	}
-
-	iov = kmalloc_array(old_rq->rq_nvec + 1, sizeof(struct kvec),
-			    GFP_KERNEL);
-	if (!iov)
-		goto err_free_pages;
+	for (i = 1; i < num_rqst; i++) {
+		npages = old_rq[i - 1].rq_npages;
+		pages = kmalloc_array(npages, sizeof(struct page *),
+				      GFP_KERNEL);
+		if (!pages)
+			goto err_free;
+
+		new_rq[i].rq_pages = pages;
+		new_rq[i].rq_npages = npages;
+		new_rq[i].rq_offset = old_rq[i - 1].rq_offset;
+		new_rq[i].rq_pagesz = old_rq[i - 1].rq_pagesz;
+		new_rq[i].rq_tailsz = old_rq[i - 1].rq_tailsz;
+		new_rq[i].rq_iov = old_rq[i - 1].rq_iov;
+		new_rq[i].rq_nvec = old_rq[i - 1].rq_nvec;
+
+		orig_len += smb_rqst_len(server, &old_rq[i - 1]);
+
+		for (j = 0; j < npages; j++) {
+			pages[j] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
+			if (!pages[j])
+				goto err_free;
+		}
 
-	/* copy all iovs from the old */
-	memcpy(&iov[1], &old_rq->rq_iov[0],
-				sizeof(struct kvec) * old_rq->rq_nvec);
+		/* copy pages form the old */
+		for (j = 0; j < npages; j++) {
+			char *dst, *src;
+			unsigned int offset, len;
 
-	new_rq->rq_iov = iov;
-	new_rq->rq_nvec = old_rq->rq_nvec + 1;
+			rqst_page_get_length(&new_rq[i], j, &len, &offset);
 
-	tr_hdr = kmalloc(sizeof(struct smb2_transform_hdr), GFP_KERNEL);
-	if (!tr_hdr)
-		goto err_free_iov;
+			dst = (char *) kmap(new_rq[i].rq_pages[j]) + offset;
+			src = (char *) kmap(old_rq[i - 1].rq_pages[j]) + offset;
 
-	orig_len = smb_rqst_len(server, old_rq);
+			memcpy(dst, src, len);
+			kunmap(new_rq[i].rq_pages[j]);
+			kunmap(old_rq[i - 1].rq_pages[j]);
+		}
+	}
 
-	/* fill the 2nd iov with a transform header */
+	/* fill the 1st iov with a transform header */
 	fill_transform_hdr(tr_hdr, orig_len, old_rq);
-	new_rq->rq_iov[0].iov_base = tr_hdr;
-	new_rq->rq_iov[0].iov_len = sizeof(struct smb2_transform_hdr);
-
-	/* copy pages form the old */
-	for (i = 0; i < npages; i++) {
-		char *dst, *src;
-		unsigned int offset, len;
-
-		rqst_page_get_length(new_rq, i, &len, &offset);
 
-		dst = (char *) kmap(new_rq->rq_pages[i]) + offset;
-		src = (char *) kmap(old_rq->rq_pages[i]) + offset;
-
-		memcpy(dst, src, len);
-		kunmap(new_rq->rq_pages[i]);
-		kunmap(old_rq->rq_pages[i]);
-	}
-
-	rc = crypt_message(server, new_rq, 1);
+	rc = crypt_message(server, num_rqst, new_rq, 1);
 	cifs_dbg(FYI, "encrypt message returned %d", rc);
 	if (rc)
-		goto err_free_tr_hdr;
+		goto err_free;
 
 	return rc;
 
-err_free_tr_hdr:
-	kfree(tr_hdr);
-err_free_iov:
-	kfree(iov);
-err_free_pages:
-	for (i = i - 1; i >= 0; i--)
-		put_page(pages[i]);
-	kfree(pages);
+err_free:
+	smb3_free_compound_rqst(num_rqst - 1, &new_rq[1]);
 	return rc;
 }
 
-static void
-smb3_free_transform_rq(struct smb_rqst *rqst)
-{
-	int i = rqst->rq_npages - 1;
-
-	for (; i >= 0; i--)
-		put_page(rqst->rq_pages[i]);
-	kfree(rqst->rq_pages);
-	/* free transform header */
-	kfree(rqst->rq_iov[0].iov_base);
-	kfree(rqst->rq_iov);
-}
-
 static int
 smb3_is_transform_hdr(void *buf)
 {
@@ -2655,7 +2667,7 @@ decrypt_raw_data(struct TCP_Server_Info *server, char *buf,
 	rqst.rq_pagesz = PAGE_SIZE;
 	rqst.rq_tailsz = (page_data_size % PAGE_SIZE) ? : PAGE_SIZE;
 
-	rc = crypt_message(server, &rqst, 0);
+	rc = crypt_message(server, 1, &rqst, 0);
 	cifs_dbg(FYI, "decrypt message returned %d\n", rc);
 
 	if (rc)
@@ -3302,7 +3314,6 @@ struct smb_version_operations smb30_operations = {
 	.fallocate = smb3_fallocate,
 	.enum_snapshots = smb3_enum_snapshots,
 	.init_transform_rq = smb3_init_transform_rq,
-	.free_transform_rq = smb3_free_transform_rq,
 	.is_transform_hdr = smb3_is_transform_hdr,
 	.receive_transform = smb3_receive_transform,
 	.get_dfs_refer = smb2_get_dfs_refer,
@@ -3408,7 +3419,6 @@ struct smb_version_operations smb311_operations = {
 	.fallocate = smb3_fallocate,
 	.enum_snapshots = smb3_enum_snapshots,
 	.init_transform_rq = smb3_init_transform_rq,
-	.free_transform_rq = smb3_free_transform_rq,
 	.is_transform_hdr = smb3_is_transform_hdr,
 	.receive_transform = smb3_receive_transform,
 	.get_dfs_refer = smb2_get_dfs_refer,
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index 357d25351ffa..8039c93ba57a 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -374,27 +374,40 @@ smbd_done:
 	return rc;
 }
 
+#define MAX_COMPOUND 2
+
 static int
 smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst, int flags)
 {
-	struct smb_rqst cur_rqst;
+	struct kvec iov;
+	struct smb2_transform_hdr tr_hdr;
+	struct smb_rqst cur_rqst[MAX_COMPOUND];
 	int rc;
 
 	if (!(flags & CIFS_TRANSFORM_REQ))
 		return __smb_send_rqst(server, 1, rqst);
 
-	if (!server->ops->init_transform_rq ||
-	    !server->ops->free_transform_rq) {
-		cifs_dbg(VFS, "Encryption requested but transform callbacks are missed\n");
+	memset(&cur_rqst[0], 0, sizeof(cur_rqst));
+	memset(&iov, 0, sizeof(iov));
+	memset(&tr_hdr, 0, sizeof(tr_hdr));
+
+	iov.iov_base = &tr_hdr;
+	iov.iov_len = sizeof(tr_hdr);
+	cur_rqst[0].rq_iov = &iov;
+	cur_rqst[0].rq_nvec = 1;
+
+	if (!server->ops->init_transform_rq) {
+		cifs_dbg(VFS, "Encryption requested but transform callback "
+			 "is missing\n");
 		return -EIO;
 	}
 
-	rc = server->ops->init_transform_rq(server, &cur_rqst, rqst);
+	rc = server->ops->init_transform_rq(server, 2, &cur_rqst[0], rqst);
 	if (rc)
 		return rc;
 
-	rc = __smb_send_rqst(server, 1, &cur_rqst);
-	server->ops->free_transform_rq(&cur_rqst);
+	rc = __smb_send_rqst(server, 2, &cur_rqst[0]);
+	smb3_free_compound_rqst(1, &cur_rqst[1]);
 	return rc;
 }