selinux: avoid dereference of garbage after mount failure

commit 37801a36b4 upstream.

In case kern_mount() fails and returns an error pointer return in the
error branch instead of continuing and dereferencing the error pointer.

While on it drop the never read static variable selinuxfs_mount.

Cc: stable@vger.kernel.org
Fixes: 0619f0f5e3 ("selinux: wrap selinuxfs state")
Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Christian Göttsche 2024-03-28 20:16:58 +01:00 committed by Greg Kroah-Hartman
parent 9e2af26c29
commit 477ed6789e

View File

@ -2135,7 +2135,6 @@ static struct file_system_type sel_fs_type = {
.kill_sb = sel_kill_sb,
};
static struct vfsmount *selinuxfs_mount __ro_after_init;
struct path selinux_null __ro_after_init;
static int __init init_sel_fs(void)
@ -2157,18 +2156,21 @@ static int __init init_sel_fs(void)
return err;
}
selinux_null.mnt = selinuxfs_mount = kern_mount(&sel_fs_type);
if (IS_ERR(selinuxfs_mount)) {
selinux_null.mnt = kern_mount(&sel_fs_type);
if (IS_ERR(selinux_null.mnt)) {
pr_err("selinuxfs: could not mount!\n");
err = PTR_ERR(selinuxfs_mount);
selinuxfs_mount = NULL;
err = PTR_ERR(selinux_null.mnt);
selinux_null.mnt = NULL;
return err;
}
selinux_null.dentry = d_hash_and_lookup(selinux_null.mnt->mnt_root,
&null_name);
if (IS_ERR(selinux_null.dentry)) {
pr_err("selinuxfs: could not lookup null!\n");
err = PTR_ERR(selinux_null.dentry);
selinux_null.dentry = NULL;
return err;
}
return err;