Add security hooks to binder and implement the hooks for SELinux.
Add security hooks to the binder and implement the hooks for SELinux.
The security hooks enable security modules such as SELinux to implement
controls over binder IPC. The security hooks include support for
controlling what process can become the binder context manager
(binder_set_context_mgr), controlling the ability of a process
to invoke a binder transaction/IPC to another process (binder_transaction),
controlling the ability a process to transfer a binder reference to
another process (binder_transfer_binder), and controlling the ability
of a process to transfer an open file to another process (binder_transfer_file).
This support is used by SE Android, http://selinuxproject.org/page/SEAndroid.
Change-Id: I9a64a87825df2e60b9c51400377af4a9cd1c4049
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Satya Durga Srinivasu Prabhala <satyap@codeaurora.org>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index d85b793..b28b7eb 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1818,6 +1818,67 @@
/* Hook functions begin here. */
+static int selinux_binder_set_context_mgr(struct task_struct *mgr)
+{
+ u32 mysid = current_sid();
+ u32 mgrsid = task_sid(mgr);
+
+ return avc_has_perm(mysid, mgrsid, SECCLASS_BINDER, BINDER__SET_CONTEXT_MGR, NULL);
+}
+
+static int selinux_binder_transaction(struct task_struct *from, struct task_struct *to)
+{
+ u32 mysid = current_sid();
+ u32 fromsid = task_sid(from);
+ u32 tosid = task_sid(to);
+ int rc;
+
+ if (mysid != fromsid) {
+ rc = avc_has_perm(mysid, fromsid, SECCLASS_BINDER, BINDER__IMPERSONATE, NULL);
+ if (rc)
+ return rc;
+ }
+
+ return avc_has_perm(fromsid, tosid, SECCLASS_BINDER, BINDER__CALL, NULL);
+}
+
+static int selinux_binder_transfer_binder(struct task_struct *from, struct task_struct *to)
+{
+ u32 fromsid = task_sid(from);
+ u32 tosid = task_sid(to);
+ return avc_has_perm(fromsid, tosid, SECCLASS_BINDER, BINDER__TRANSFER, NULL);
+}
+
+static int selinux_binder_transfer_file(struct task_struct *from, struct task_struct *to, struct file *file)
+{
+ u32 sid = task_sid(to);
+ struct file_security_struct *fsec = file->f_security;
+ struct inode *inode = file->f_path.dentry->d_inode;
+ struct inode_security_struct *isec = inode->i_security;
+ struct common_audit_data ad;
+ struct selinux_audit_data sad = {0,};
+ int rc;
+
+ COMMON_AUDIT_DATA_INIT(&ad, PATH);
+ ad.u.path = file->f_path;
+ ad.selinux_audit_data = &sad;
+
+ if (sid != fsec->sid) {
+ rc = avc_has_perm(sid, fsec->sid,
+ SECCLASS_FD,
+ FD__USE,
+ &ad);
+ if (rc)
+ return rc;
+ }
+
+ if (unlikely(IS_PRIVATE(inode)))
+ return 0;
+
+ return avc_has_perm(sid, isec->sid, isec->sclass, file_to_av(file),
+ &ad);
+}
+
static int selinux_ptrace_access_check(struct task_struct *child,
unsigned int mode)
{
@@ -5523,6 +5584,11 @@
static struct security_operations selinux_ops = {
.name = "selinux",
+ .binder_set_context_mgr = selinux_binder_set_context_mgr,
+ .binder_transaction = selinux_binder_transaction,
+ .binder_transfer_binder = selinux_binder_transfer_binder,
+ .binder_transfer_file = selinux_binder_transfer_file,
+
.ptrace_access_check = selinux_ptrace_access_check,
.ptrace_traceme = selinux_ptrace_traceme,
.capget = selinux_capget,