cifs: we can not use small padding iovs together with encryption

We can not append small padding buffers as separate iovs when encryption is
used. For this case we must flatten the request into a single buffer
containing both the data from all the iovs as well as the padding bytes.

This is at least needed for 4.20 as well due to compounding changes.

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

1 files changed, 46 insertions, 21 deletions

diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 6c99a146fcec..33100ef74d7f 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -884,7 +884,6 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	    struct cifs_sb_info *cifs_sb)
 {
 	struct cifs_ses *ses = tcon->ses;
-	struct TCP_Server_Info *server = ses->server;
 	__le16 *utf16_path = NULL;
 	int ea_name_len = strlen(ea_name);
 	int flags = 0;
@@ -936,7 +935,7 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto sea_exit;
-	smb2_set_next_command(ses->server, &rqst[0], 0);
+	smb2_set_next_command(tcon, &rqst[0]);
 
 
 	/* Set Info */
@@ -963,7 +962,7 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
 				COMPOUND_FID, current->tgid,
 				FILE_FULL_EA_INFORMATION,
 				SMB2_O_INFO_FILE, 0, data, size);
-	smb2_set_next_command(server, &rqst[1], 0);
+	smb2_set_next_command(tcon, &rqst[1]);
 	smb2_set_related(&rqst[1]);
 
 
@@ -1222,7 +1221,7 @@ smb2_ioctl_query_info(const unsigned int xid,
 	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, path);
 	if (rc)
 		goto iqinf_exit;
-	smb2_set_next_command(ses->server, &rqst[0], 0);
+	smb2_set_next_command(tcon, &rqst[0]);
 
 	/* Query */
 	memset(&qi_iov, 0, sizeof(qi_iov));
@@ -1236,7 +1235,7 @@ smb2_ioctl_query_info(const unsigned int xid,
 				  qi.output_buffer_length, buffer);
 	if (rc)
 		goto iqinf_exit;
-	smb2_set_next_command(ses->server, &rqst[1], 0);
+	smb2_set_next_command(tcon, &rqst[1]);
 	smb2_set_related(&rqst[1]);
 
 	/* Close */
@@ -1789,26 +1788,53 @@ smb2_set_related(struct smb_rqst *rqst)
 char smb2_padding[7] = {0, 0, 0, 0, 0, 0, 0};
 
 void
-smb2_set_next_command(struct TCP_Server_Info *server, struct smb_rqst *rqst,
-		      bool has_space_for_padding)
+smb2_set_next_command(struct cifs_tcon *tcon, struct smb_rqst *rqst)
 {
 	struct smb2_sync_hdr *shdr;
+	struct cifs_ses *ses = tcon->ses;
+	struct TCP_Server_Info *server = ses->server;
 	unsigned long len = smb_rqst_len(server, rqst);
+	int i, num_padding;
 
 	/* SMB headers in a compound are 8 byte aligned. */
-	if (len & 7) {
-		if (has_space_for_padding) {
-			len = rqst->rq_iov[rqst->rq_nvec - 1].iov_len;
-			rqst->rq_iov[rqst->rq_nvec - 1].iov_len =
-				(len + 7) & ~7;
-		} else {
-			rqst->rq_iov[rqst->rq_nvec].iov_base = smb2_padding;
-			rqst->rq_iov[rqst->rq_nvec].iov_len = 8 - (len & 7);
-			rqst->rq_nvec++;
+
+	/* No padding needed */
+	if (!(len & 7))
+		goto finished;
+
+	num_padding = 8 - (len & 7);
+	if (!smb3_encryption_required(tcon)) {
+		/*
+		 * If we do not have encryption then we can just add an extra
+		 * iov for the padding.
+		 */
+		rqst->rq_iov[rqst->rq_nvec].iov_base = smb2_padding;
+		rqst->rq_iov[rqst->rq_nvec].iov_len = num_padding;
+		rqst->rq_nvec++;
+		len += num_padding;
+	} else {
+		/*
+		 * We can not add a small padding iov for the encryption case
+		 * because the encryption framework can not handle the padding
+		 * iovs.
+		 * We have to flatten this into a single buffer and add
+		 * the padding to it.
+		 */
+		for (i = 1; i < rqst->rq_nvec; i++) {
+			memcpy(rqst->rq_iov[0].iov_base +
+			       rqst->rq_iov[0].iov_len,
+			       rqst->rq_iov[i].iov_base,
+			       rqst->rq_iov[i].iov_len);
+			rqst->rq_iov[0].iov_len += rqst->rq_iov[i].iov_len;
 		}
-		len = smb_rqst_len(server, rqst);
+		memset(rqst->rq_iov[0].iov_base + rqst->rq_iov[0].iov_len,
+		       0, num_padding);
+		rqst->rq_iov[0].iov_len += num_padding;
+		len += num_padding;
+		rqst->rq_nvec = 1;
 	}
 
+ finished:
 	shdr = (struct smb2_sync_hdr *)(rqst->rq_iov[0].iov_base);
 	shdr->NextCommand = cpu_to_le32(len);
 }
@@ -1825,7 +1851,6 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 			 struct cifs_sb_info *cifs_sb)
 {
 	struct cifs_ses *ses = tcon->ses;
-	struct TCP_Server_Info *server = ses->server;
 	int flags = 0;
 	struct smb_rqst rqst[3];
 	int resp_buftype[3];
@@ -1862,7 +1887,7 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 	rc = SMB2_open_init(tcon, &rqst[0], &oplock, &oparms, utf16_path);
 	if (rc)
 		goto qic_exit;
-	smb2_set_next_command(server, &rqst[0], 0);
+	smb2_set_next_command(tcon, &rqst[0]);
 
 	memset(&qi_iov, 0, sizeof(qi_iov));
 	rqst[1].rq_iov = qi_iov;
@@ -1874,7 +1899,7 @@ smb2_query_info_compound(const unsigned int xid, struct cifs_tcon *tcon,
 				  NULL);
 	if (rc)
 		goto qic_exit;
-	smb2_set_next_command(server, &rqst[1], 0);
+	smb2_set_next_command(tcon, &rqst[1]);
 	smb2_set_related(&rqst[1]);
 
 	memset(&close_iov, 0, sizeof(close_iov));
@@ -2806,7 +2831,7 @@ init_sg(int num_rqst, struct smb_rqst *rqst, u8 *sign)
 			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;