From: Al Viro <viro@zeniv.linux.org.uk>
Date: Thu, 11 Feb 2021 15:04:35 -0500
Subject: [PATCH] do_cifs_create(): don't set ->i_mode of something we had not
 created
Git-commit: 4ab5260dab28109979a1b47a8996c9922219927f
References: bsc#1190317
Patch-mainline: v5.12-rc3

If the file had existed before we'd called ->atomic_open() (without
O_EXCL, that is), we have no more business setting ->i_mode than
we would setting ->i_uid or ->i_gid.  We also have no business
doing either if another client has managed to get unlink+mkdir
between ->open() and cifs_inode_get_info().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Enzo Matsumiya <ematsumiya@suse.de>
---
 fs/cifs/dir.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/fs/cifs/dir.c b/fs/cifs/dir.c
index a3fb81e0ba17..9d7ae93c8af7 100644
--- a/fs/cifs/dir.c
+++ b/fs/cifs/dir.c
@@ -418,15 +418,16 @@ cifs_do_create(struct inode *inode, struct dentry *direntry, unsigned int xid,
 		if (newinode) {
 			if (server->ops->set_lease_key)
 				server->ops->set_lease_key(newinode, fid);
-			if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM)
-				newinode->i_mode = mode;
-			if ((*oplock & CIFS_CREATE_ACTION) &&
-			    (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID)) {
-				newinode->i_uid = current_fsuid();
-				if (inode->i_mode & S_ISGID)
-					newinode->i_gid = inode->i_gid;
-				else
-					newinode->i_gid = current_fsgid();
+			if ((*oplock & CIFS_CREATE_ACTION) && S_ISREG(newinode->i_mode)) {
+				if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_DYNPERM)
+					newinode->i_mode = mode;
+				if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
+					newinode->i_uid = current_fsuid();
+					if (inode->i_mode & S_ISGID)
+						newinode->i_gid = inode->i_gid;
+					else
+						newinode->i_gid = current_fsgid();
+				}
 			}
 		}
 	}
-- 
2.33.0