This is a note to let you know that I've just added the patch titled
selinux: fix inode_doinit_with_dentry() LABEL_INVALID error handling
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
selinux-fix-inode_doinit_with_dentry-label_invalid-error-handling.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 200ea5a2292dc444a818b096ae6a32ba3caa51b9 Mon Sep 17 00:00:00 2001
From: Paul Moore <paul@xxxxxxxxxxxxxx>
Date: Tue, 3 Nov 2020 11:49:38 -0500
Subject: selinux: fix inode_doinit_with_dentry() LABEL_INVALID error handling
From: Paul Moore <paul@xxxxxxxxxxxxxx>
commit 200ea5a2292dc444a818b096ae6a32ba3caa51b9 upstream.
A previous fix, commit 83370b31a915 ("selinux: fix error initialization
in inode_doinit_with_dentry()"), changed how failures were handled
before a SELinux policy was loaded. Unfortunately that patch was
potentially problematic for two reasons: it set the isec->initialized
state without holding a lock, and it didn't set the inode's SELinux
label to the "default" for the particular filesystem. The later can
be a problem if/when a later attempt to revalidate the inode fails
and SELinux reverts to the existing inode label.
This patch should restore the default inode labeling that existed
before the original fix, without affecting the LABEL_INVALID marking
such that revalidation will still be attempted in the future.
Fixes: 83370b31a915 ("selinux: fix error initialization in inode_doinit_with_dentry()")
Reported-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
Tested-by: Sven Schnelle <svens@xxxxxxxxxxxxx>
Reviewed-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
Signed-off-by: Paul Moore <paul@xxxxxxxxxxxxxx>
Signed-off-by: Alexander Grund <theflamefire89@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
security/selinux/hooks.c | 31 +++++++++++++------------------
1 file changed, 13 insertions(+), 18 deletions(-)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1450,13 +1450,7 @@ static int inode_doinit_with_dentry(stru
* inode_doinit with a dentry, before these inodes could
* be used again by userspace.
*/
- isec->initialized = LABEL_INVALID;
- /*
- * There is nothing useful to jump to the "out"
- * label, except a needless spin lock/unlock
- * cycle.
- */
- return 0;
+ goto out_invalid;
}
len = INITCONTEXTLEN;
@@ -1564,15 +1558,8 @@ static int inode_doinit_with_dentry(stru
* inode_doinit() with a dentry, before these inodes
* could be used again by userspace.
*/
- 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;
- }
+ if (!dentry)
+ goto out_invalid;
rc = selinux_genfs_get_sid(dentry, sclass,
sbsec->flags, &sid);
dput(dentry);
@@ -1585,11 +1572,10 @@ static int inode_doinit_with_dentry(stru
out:
spin_lock(&isec->lock);
if (isec->initialized == LABEL_PENDING) {
- if (!sid || rc) {
+ if (rc) {
isec->initialized = LABEL_INVALID;
goto out_unlock;
}
-
isec->initialized = LABEL_INITIALIZED;
isec->sid = sid;
}
@@ -1597,6 +1583,15 @@ out:
out_unlock:
spin_unlock(&isec->lock);
return rc;
+
+out_invalid:
+ spin_lock(&isec->lock);
+ if (isec->initialized == LABEL_PENDING) {
+ isec->initialized = LABEL_INVALID;
+ isec->sid = sid;
+ }
+ spin_unlock(&isec->lock);
+ return 0;
}
/* Convert a Linux signal to an access vector. */
Patches currently in stable-queue which might be from paul@xxxxxxxxxxxxxx are
queue-4.9/selinux-clean-up-initialization-of-isec-sclass.patch
queue-4.9/selinux-fix-inode_doinit_with_dentry-label_invalid-error-handling.patch
queue-4.9/proc-pass-file-mode-to-proc_pid_make_inode.patch
queue-4.9/selinux-convert-isec-lock-into-a-spinlock.patch
queue-4.9/selinux-fix-error-initialization-in-inode_doinit_with_dentry.patch
queue-4.9/selinux-minor-cleanups.patch
