On 3/26/20 2:14 PM, Daniel Colascione wrote:
This change uses the anon_inodes and LSM infrastructure introduced in
the previous patch to give SELinux the ability to control
anonymous-inode files that are created using the new _secure()
anon_inodes functions.
A SELinux policy author detects and controls these anonymous inodes by
adding a name-based type_transition rule that assigns a new security
type to anonymous-inode files created in some domain. The name used
for the name-based transition is the name associated with the
anonymous inode for file listings --- e.g., "[userfaultfd]" or
"[perf_event]".
Example:
type uffd_t;
type_transition sysadm_t sysadm_t : anon_inode uffd_t "[userfaultfd]";
allow sysadm_t uffd_t:anon_inode { create };
(The next patch in this series is necessary for making userfaultfd
support this new interface. The example above is just
for exposition.)
Signed-off-by: Daniel Colascione <dancol@xxxxxxxxxx>
---
security/selinux/hooks.c | 54 +++++++++++++++++++++++++++++
security/selinux/include/classmap.h | 2 ++
2 files changed, 56 insertions(+)
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 1659b59fb5d7..b9eb45c2e4e5 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -2915,6 +2915,59 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
return 0;
}
+static int selinux_inode_init_security_anon(struct inode *inode,
+ const struct qstr *name,
+ const struct file_operations *fops,
+ const struct inode *context_inode)
+{
+ const struct task_security_struct *tsec = selinux_cred(current_cred());
+ struct common_audit_data ad;
+ struct inode_security_struct *isec;
+ int rc;
+
+ if (unlikely(!selinux_state.initialized))
+ return 0;
+
+ isec = selinux_inode(inode);
+
+ /*
+ * We only get here once per ephemeral inode. The inode has
+ * been initialized via inode_alloc_security but is otherwise
+ * untouched.
+ */
+
+ if (context_inode) {
+ struct inode_security_struct *context_isec =
+ selinux_inode(context_inode);
+ isec->sclass = context_isec->sclass;
+ isec->sid = context_isec->sid;
+ } else {
+ isec->sclass = SECCLASS_ANON_INODE;
+ rc = security_transition_sid(
+ &selinux_state, tsec->sid, tsec->sid,
+ SECCLASS_FILE, name, &isec->sid);
I guess you missed the 2nd comment in my reply to v2 of this patch:
You should use isec->sclass aka SECCLASS_ANON_INODE instead of
SECCLASS_FILE here.
