On Sun, May 13, 2018 at 11:59:58AM -0700, Linus Torvalds wrote:
> On Sun, May 13, 2018 at 11:56 AM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> > The whole reason why that thing is getting a dentry is that some
> filesystems
> > really want a *connected* dentry for getxattr. Sure, saner ones will be
> > happy with disconnected dentry, but...
>
> Can we just add a big comment to that effect?
>
> Because I don't mind the complexity, but I do mind having code that _looks_
> complex with no reason, where the natural reaction is "why is it bothering
> being complex, when it could just do X".
Point taken. How about the following variant?
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 4cafe6a19167..398d165f884e 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1568,8 +1568,15 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
/* Called from d_instantiate or d_splice_alias. */
dentry = dget(opt_dentry);
} else {
- /* Called from selinux_complete_init, try to find a dentry. */
+ /*
+ * Called from selinux_complete_init, try to find a dentry.
+ * Some filesystems really want a connected one, so try
+ * that first. We could split SECURITY_FS_USE_XATTR in
+ * two, depending upon that...
+ */
dentry = d_find_alias(inode);
+ if (!dentry)
+ dentry = d_find_any_alias(inode);
}
if (!dentry) {
/*
@@ -1674,14 +1681,19 @@ static int inode_doinit_with_dentry(struct inode *inode, struct dentry *opt_dent
if ((sbsec->flags & SE_SBGENFS) && !S_ISLNK(inode->i_mode)) {
/* We must have a dentry to determine the label on
* procfs inodes */
- if (opt_dentry)
+ if (opt_dentry) {
/* Called from d_instantiate or
* d_splice_alias. */
dentry = dget(opt_dentry);
- else
+ } else {
/* Called from selinux_complete_init, try to
- * find a dentry. */
+ * find a dentry. Some filesystems really want
+ * a connected one, so try that first.
+ */
dentry = d_find_alias(inode);
+ if (!dentry)
+ dentry = d_find_any_alias(inode);
+ }
/*
* This can be hit on boot when a file is accessed
* before the policy is loaded. When we load policy we
