SELinux: Enable setting security contexts on rootfs inodes.

rootfs (ramfs) can support setting of security contexts
by userspace due to the vfs fallback behavior of calling
the security module to set the in-core inode state
for security.* attributes when the filesystem does not
provide an xattr handler.  No xattr handler required
as the inodes are pinned in memory and have no backing
store.

This is useful in allowing early userspace to label individual
files within a rootfs while still providing a policy-defined
default via genfs.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Paul Moore <pmoore@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d0cfaa9f19d08034a3c3600d8381ed166a369388..0ff911a947576cb32a1a80c7f5f471f1adf64091 100644 (file)
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -464,6 +464,13 @@ static int sb_finish_set_opts(struct super_block *sb)
        if (selinux_is_sblabel_mnt(sb))
                sbsec->flags |= SBLABEL_MNT;
 
+       /*
+        * Special handling for rootfs. Is genfs but supports
+        * setting SELinux context on in-core inodes.
+        */
+       if (strncmp(sb->s_type->name, "rootfs", sizeof("rootfs")) == 0)
+               sbsec->flags |= SE_SBLABELSUPP;
+
        /* Initialize the root inode. */
        rc = inode_doinit_with_dentry(root_inode, root);