[PATCH v39 03/42] LSM: Add the lsmblob data structure.

[Casey Schaufler <casey@schaufler-ca.com>]

When more than one security module is exporting data to audit and
networking sub-systems a single 32 bit integer is no longer
sufficient to represent the data. Add a structure to be used instead.

The lsmblob structure definition is intended to keep the LSM
specific information private to the individual security modules.
The module specific information is included in a new set of
header files under include/lsm. Each security module is allowed
to define the information included for its use in the lsmblob.
SELinux includes a u32 secid. Smack includes a pointer into its
global label list. The conditional compilation based on feature
inclusion is contained in the include/lsm files.

Suggested-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
---
 include/linux/lsm/apparmor.h | 17 +++++++++++++++++
 include/linux/lsm/bpf.h      | 16 ++++++++++++++++
 include/linux/lsm/selinux.h  | 16 ++++++++++++++++
 include/linux/lsm/smack.h    | 17 +++++++++++++++++
 include/linux/security.h     | 20 ++++++++++++++++++++
 5 files changed, 86 insertions(+)
 create mode 100644 include/linux/lsm/apparmor.h
 create mode 100644 include/linux/lsm/bpf.h
 create mode 100644 include/linux/lsm/selinux.h
 create mode 100644 include/linux/lsm/smack.h

diff --git a/include/linux/lsm/apparmor.h b/include/linux/lsm/apparmor.h
new file mode 100644
index 000000000000..8ff1cd899a20
--- /dev/null
+++ b/include/linux/lsm/apparmor.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Linux Security Module interface to other subsystems.
+ * AppArmor presents a single u32 value which is known as a secid.
+ */
+#ifndef __LINUX_LSM_APPARMOR_H
+#define __LINUX_LSM_APPARMOR_H
+
+struct aa_label;
+
+struct lsmblob_apparmor {
+#ifdef CONFIG_SECURITY_APPARMOR
+	struct aa_label *label;
+#endif
+};
+
+#endif /* ! __LINUX_LSM_APPARMOR_H */
diff --git a/include/linux/lsm/bpf.h b/include/linux/lsm/bpf.h
new file mode 100644
index 000000000000..48abdcd82ded
--- /dev/null
+++ b/include/linux/lsm/bpf.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Linux Security Module interface to other subsystems.
+ * BPF may present a single u32 value.
+ */
+#ifndef __LINUX_LSM_BPF_H
+#define __LINUX_LSM_BPF_H
+#include <linux/types.h>
+
+struct lsmblob_bpf {
+#ifdef CONFIG_BPF_LSM
+	u32 secid;
+#endif
+};
+
+#endif /* ! __LINUX_LSM_BPF_H */
diff --git a/include/linux/lsm/selinux.h b/include/linux/lsm/selinux.h
new file mode 100644
index 000000000000..fd16456b36ac
--- /dev/null
+++ b/include/linux/lsm/selinux.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Linux Security Module interface to other subsystems.
+ * SELinux presents a single u32 value which is known as a secid.
+ */
+#ifndef __LINUX_LSM_SELINUX_H
+#define __LINUX_LSM_SELINUX_H
+#include <linux/types.h>
+
+struct lsmblob_selinux {
+#ifdef CONFIG_SECURITY_SELINUX
+	u32 secid;
+#endif
+};
+
+#endif /* ! __LINUX_LSM_SELINUX_H */
diff --git a/include/linux/lsm/smack.h b/include/linux/lsm/smack.h
new file mode 100644
index 000000000000..2018f288302f
--- /dev/null
+++ b/include/linux/lsm/smack.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Linux Security Module interface to other subsystems.
+ * Smack presents a pointer into the global Smack label list.
+ */
+#ifndef __LINUX_LSM_SMACK_H
+#define __LINUX_LSM_SMACK_H
+
+struct smack_known;
+
+struct lsmblob_smack {
+#ifdef CONFIG_SECURITY_SMACK
+	struct smack_known *skp;
+#endif
+};
+
+#endif /* ! __LINUX_LSM_SMACK_H */
diff --git a/include/linux/security.h b/include/linux/security.h
index 4790508818ee..d4103b6cd3fc 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -33,6 +33,10 @@
 #include <linux/mm.h>
 #include <linux/sockptr.h>
 #include <uapi/linux/lsm.h>
+#include <linux/lsm/selinux.h>
+#include <linux/lsm/smack.h>
+#include <linux/lsm/apparmor.h>
+#include <linux/lsm/bpf.h>
 
 struct linux_binprm;
 struct cred;
@@ -139,6 +143,22 @@ enum lockdown_reason {
 	LOCKDOWN_CONFIDENTIALITY_MAX,
 };
 
+/* stacking scaffolding */
+struct lsmblob_scaffold {
+	u32 secid;
+};
+
+/*
+ * Data exported by the security modules
+ */
+struct lsmblob {
+	struct lsmblob_selinux selinux;
+	struct lsmblob_smack smack;
+	struct lsmblob_apparmor apparmor;
+	struct lsmblob_bpf bpf;
+	struct lsmblob_scaffold scaffold;
+};
+
 extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
 extern u32 lsm_active_cnt;
 extern const struct lsm_id *lsm_idlist[];
-- 
2.41.0