[PATCH 4.9 5/6] selinux: fix error initialization in inode_doinit_with_dentry()

[Alexander Grund <theflamefire89@gmail.com>]

From: Tianyue Ren <rentianyue@kylinos.cn>

commit 83370b31a915493231e5b9addc72e4bef69f8d31 upstream.

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: 9287aed2ad1f ("selinux: Convert isec->lock into a spinlock")
Signed-off-by: Tianyue Ren <rentianyue@kylinos.cn>
[PM: minor comment tweaks]
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Alexander Grund <theflamefire89@gmail.com>
---
 security/selinux/hooks.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d252890debf7..b9c7e089906c 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1450,7 +1450,13 @@ 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;
@@ -1558,8 +1564,15 @@ 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);
-- 
2.25.1