cifs: fix file info setting in cifs_open_file()

In cifs_open_file(), @buf must hold a pointer to a cifs_open_info_data
structure which is passed by cifs_nt_open(), so assigning @buf
directly to @fi was obviously wrong.

Fix this by passing a valid FILE_ALL_INFO structure to SMBLegacyOpen()
and CIFS_open(), and then copy the set structure to the corresponding
cifs_open_info_data::fi field with move_cifs_info_to_smb2() helper.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=216889
Fixes: 76894f3 ("cifs: improve symlink handling for smb2+")
Signed-off-by: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>

fs/cifs/smb1ops.c

@@ -719,17 +719,25 @@ cifs_mkdir_setinfo(struct inode *inode, const char *full_path,
 static int cifs_open_file(const unsigned int xid, struct cifs_open_parms *oparms, __u32 *oplock,
 			  void *buf)
 {
-	FILE_ALL_INFO *fi = buf;
+	struct cifs_open_info_data *data = buf;
+	FILE_ALL_INFO fi = {};
+	int rc;
 
 	if (!(oparms->tcon->ses->capabilities & CAP_NT_SMBS))
-		return SMBLegacyOpen(xid, oparms->tcon, oparms->path,
-				     oparms->disposition,
-				     oparms->desired_access,
-				     oparms->create_options,
-				     &oparms->fid->netfid, oplock, fi,
-				     oparms->cifs_sb->local_nls,
-				     cifs_remap(oparms->cifs_sb));
-	return CIFS_open(xid, oparms, oplock, fi);
+		rc = SMBLegacyOpen(xid, oparms->tcon, oparms->path,
+				   oparms->disposition,
+				   oparms->desired_access,
+				   oparms->create_options,
+				   &oparms->fid->netfid, oplock, &fi,
+				   oparms->cifs_sb->local_nls,
+				   cifs_remap(oparms->cifs_sb));
+	else
+		rc = CIFS_open(xid, oparms, oplock, &fi);
+
+	if (!rc && data)
+		move_cifs_info_to_smb2(&data->fi, &fi);
+
+	return rc;
 }
 
 static void
@@ -1053,7 +1061,7 @@ cifs_make_node(unsigned int xid, struct inode *inode,
 	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
 	struct inode *newinode = NULL;
 	int rc = -EPERM;
-	FILE_ALL_INFO *buf = NULL;
+	struct cifs_open_info_data buf = {};
 	struct cifs_io_parms io_parms;
 	__u32 oplock = 0;
 	struct cifs_fid fid;
@@ -1085,34 +1093,28 @@ cifs_make_node(unsigned int xid, struct inode *inode,
 					    cifs_sb->local_nls,
 					    cifs_remap(cifs_sb));
 		if (rc)
-			goto out;
+			return rc;
 
 		rc = cifs_get_inode_info_unix(&newinode, full_path,
 					      inode->i_sb, xid);
 
 		if (rc == 0)
 			d_instantiate(dentry, newinode);
-		goto out;
+		return rc;
 	}
 
 	/*
 	 * SMB1 SFU emulation: should work with all servers, but only
 	 * support block and char device (no socket & fifo)
 	 */
 	if (!(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL))
-		goto out;
+		return rc;
 
 	if (!S_ISCHR(mode) && !S_ISBLK(mode))
-		goto out;
+		return rc;
 
 	cifs_dbg(FYI, "sfu compat create special file\n");
 
-	buf = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
-	if (buf == NULL) {
-		rc = -ENOMEM;
-		goto out;
-	}
-
 	oparms.tcon = tcon;
 	oparms.cifs_sb = cifs_sb;
 	oparms.desired_access = GENERIC_WRITE;
@@ -1127,21 +1129,21 @@ cifs_make_node(unsigned int xid, struct inode *inode,
 		oplock = REQ_OPLOCK;
 	else
 		oplock = 0;
-	rc = tcon->ses->server->ops->open(xid, &oparms, &oplock, buf);
+	rc = tcon->ses->server->ops->open(xid, &oparms, &oplock, &buf);
 	if (rc)
-		goto out;
+		return rc;
 
 	/*
 	 * BB Do not bother to decode buf since no local inode yet to put
 	 * timestamps in, but we can reuse it safely.
 	 */
 
-	pdev = (struct win_dev *)buf;
+	pdev = (struct win_dev *)&buf.fi;
 	io_parms.pid = current->tgid;
 	io_parms.tcon = tcon;
 	io_parms.offset = 0;
 	io_parms.length = sizeof(struct win_dev);
-	iov[1].iov_base = buf;
+	iov[1].iov_base = &buf.fi;
 	iov[1].iov_len = sizeof(struct win_dev);
 	if (S_ISCHR(mode)) {
 		memcpy(pdev->type, "IntxCHR", 8);
@@ -1160,8 +1162,8 @@ cifs_make_node(unsigned int xid, struct inode *inode,
 	d_drop(dentry);
 
 	/* FIXME: add code here to set EAs */
-out:
-	kfree(buf);
+
+	cifs_free_open_info(&buf);
 	return rc;
 }