AppArmor: mediation of non file objects

ipc:
AppArmor ipc is currently limited to mediation done by file mediation
and basic ptrace tests.  Improved mediation is a wip.

rlimits:
AppArmor provides basic abilities to set and control rlimits at
a per profile level.  Only resources specified in a profile are controled
or set.  AppArmor rules set the hard limit to a value <= to the current
hard limit (ie. they can not currently raise hard limits), and if
necessary will lower the soft limit to the new hard limit value.

AppArmor does not track resource limits to reset them when a profile
is left so that children processes inherit the limits set by the
parent even if they are not confined by the same profile.

Capabilities:  AppArmor provides a per profile mask of capabilities,
that will further restrict.

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 141 insertions, 0 deletions

diff --git a/security/apparmor/capability.c b/security/apparmor/capability.c
new file mode 100644
index 000000000000..9982c48def4e
--- /dev/null
+++ b/security/apparmor/capability.c
@@ -0,0 +1,141 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor capability mediation functions
+ *
+ * Copyright (C) 1998-2008 Novell/SUSE
+ * Copyright 2009-2010 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ */
+
+#include <linux/capability.h>
+#include <linux/errno.h>
+#include <linux/gfp.h>
+
+#include "include/apparmor.h"
+#include "include/capability.h"
+#include "include/context.h"
+#include "include/policy.h"
+#include "include/audit.h"
+
+/*
+ * Table of capability names: we generate it from capabilities.h.
+ */
+#include "capability_names.h"
+
+struct audit_cache {
+        struct aa_profile *profile;
+        kernel_cap_t caps;
+};
+
+static DEFINE_PER_CPU(struct audit_cache, audit_cache);
+
+/**
+ * audit_cb - call back for capability components of audit struct
+ * @ab - audit buffer   (NOT NULL)
+ * @va - audit struct to audit data from  (NOT NULL)
+ */
+static void audit_cb(struct audit_buffer *ab, void *va)
+{
+        struct common_audit_data *sa = va;
+        audit_log_format(ab, " capname=");
+        audit_log_untrustedstring(ab, capability_names[sa->u.cap]);
+}
+
+/**
+ * audit_caps - audit a capability
+ * @profile: profile confining task (NOT NULL)
+ * @task: task capability test was performed against (NOT NULL)
+ * @cap: capability tested
+ * @error: error code returned by test
+ *
+ * Do auditing of capability and handle, audit/complain/kill modes switching
+ * and duplicate message elimination.
+ *
+ * Returns: 0 or sa->error on success,  error code on failure
+ */
+static int audit_caps(struct aa_profile *profile, struct task_struct *task,
+                      int cap, int error)
+{
+        struct audit_cache *ent;
+        int type = AUDIT_APPARMOR_AUTO;
+        struct common_audit_data sa;
+        COMMON_AUDIT_DATA_INIT(&sa, CAP);
+        sa.tsk = task;
+        sa.u.cap = cap;
+        sa.aad.op = OP_CAPABLE;
+        sa.aad.error = error;
+
+        if (likely(!error)) {
+                /* test if auditing is being forced */
+                if (likely((AUDIT_MODE(profile) != AUDIT_ALL) &&
+                           !cap_raised(profile->caps.audit, cap)))
+                        return 0;
+                type = AUDIT_APPARMOR_AUDIT;
+        } else if (KILL_MODE(profile) ||
+                   cap_raised(profile->caps.kill, cap)) {
+                type = AUDIT_APPARMOR_KILL;
+        } else if (cap_raised(profile->caps.quiet, cap) &&
+                   AUDIT_MODE(profile) != AUDIT_NOQUIET &&
+                   AUDIT_MODE(profile) != AUDIT_ALL) {
+                /* quiet auditing */
+                return error;
+        }
+
+        /* Do simple duplicate message elimination */
+        ent = &get_cpu_var(audit_cache);
+        if (profile == ent->profile && cap_raised(ent->caps, cap)) {
+                put_cpu_var(audit_cache);
+                if (COMPLAIN_MODE(profile))
+                        return complain_error(error);
+                return error;
+        } else {
+                aa_put_profile(ent->profile);
+                ent->profile = aa_get_profile(profile);
+                cap_raise(ent->caps, cap);
+        }
+        put_cpu_var(audit_cache);
+
+        return aa_audit(type, profile, GFP_ATOMIC, &sa, audit_cb);
+}
+
+/**
+ * profile_capable - test if profile allows use of capability @cap
+ * @profile: profile being enforced    (NOT NULL, NOT unconfined)
+ * @cap: capability to test if allowed
+ *
+ * Returns: 0 if allowed else -EPERM
+ */
+static int profile_capable(struct aa_profile *profile, int cap)
+{
+        return cap_raised(profile->caps.allow, cap) ? 0 : -EPERM;
+}
+
+/**
+ * aa_capable - test permission to use capability
+ * @task: task doing capability test against (NOT NULL)
+ * @profile: profile confining @task (NOT NULL)
+ * @cap: capability to be tested
+ * @audit: whether an audit record should be generated
+ *
+ * Look up capability in profile capability set.
+ *
+ * Returns: 0 on success, or else an error code.
+ */
+int aa_capable(struct task_struct *task, struct aa_profile *profile, int cap,
+               int audit)
+{
+        int error = profile_capable(profile, cap);
+
+        if (!audit) {
+                if (COMPLAIN_MODE(profile))
+                        return complain_error(error);
+                return error;
+        }
+
+        return audit_caps(profile, task, cap, error);
+}