selinux: fix error initialization in inode_doinit_with_dentry()

stable inclusion
from linux-4.19.164
commit bd7223dda090c9246b290a0b901c112d6484466a

--------------------------------

[ Upstream commit 83370b31 ]

Mark the inode security label as invalid if we cannot find
a dentry so that we will retry later rather than marking it
initialized with the unlabeled SID.

Fixes: 9287aed2 ("selinux: Convert isec->lock into a spinlock")
Signed-off-by: NTianyue Ren <rentianyue@kylinos.cn>
[PM: minor comment tweaks]
Signed-off-by: NPaul Moore <paul@paul-moore.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>

security/selinux/hooks.c

@@ -1618,7 +1618,13 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 			 * inode_doinit with a dentry, before these inodes could
 			 * be used again by userspace.
 			 */
-			goto out;
+			isec->initialized = LABEL_INVALID;
+			/*
+			 * There is nothing useful to jump to the "out"
+			 * label, except a needless spin lock/unlock
+			 * cycle.
+			 */
+			return 0;
 		}
 
 		len = INITCONTEXTLEN;
@@ -1733,8 +1739,15 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
 			 * inode_doinit() with a dentry, before these inodes
 			 * could be used again by userspace.
 			 */
-			if (!dentry)
-				goto out;
+			if (!dentry) {
+				isec->initialized = LABEL_INVALID;
+				/*
+				 * There is nothing useful to jump to the "out"
+				 * label, except a needless spin lock/unlock
+				 * cycle.
+				 */
+				return 0;
+			}
 			rc = selinux_genfs_get_sid(dentry, sclass,
 						   sbsec->flags, &sid);
 			dput(dentry);