Merge tag 'apparmor-pr-2021-11-10' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor

Pull apparmor updates from John Johansen:
 "Features
   - use per file locks for transactional queries
   - update policy management capability checks to work with LSM stacking

  Bug Fixes:
   - check/put label on apparmor_sk_clone_security()
   - fix error check on update of label hname
   - fix introspection of of task mode for unconfined tasks

  Cleanups:
   - avoid -Wempty-body warning
   - remove duplicated 'Returns:' comments
   - fix doc warning
   - remove unneeded one-line hook wrappers
   - use struct_size() helper in kzalloc()
   - fix zero-length compiler warning in AA_BUG()
   - file.h: delete duplicated word
   - delete repeated words in comments
   - remove repeated declaration"

* tag 'apparmor-pr-2021-11-10' of git://git.kernel.org/pub/scm/linux/kernel/git/jj/linux-apparmor:
  apparmor: remove duplicated 'Returns:' comments
  apparmor: remove unneeded one-line hook wrappers
  apparmor: Use struct_size() helper in kzalloc()
  apparmor: fix zero-length compiler warning in AA_BUG()
  apparmor: use per file locks for transactional queries
  apparmor: fix doc warning
  apparmor: Remove the repeated declaration
  apparmor: avoid -Wempty-body warning
  apparmor: Fix internal policy capable check for policy management
  apparmor: fix error check
  security: apparmor: delete repeated words in comments
  security: apparmor: file.h: delete duplicated word
  apparmor: switch to apparmor to internal capable check for policy management
  apparmor: update policy capable checks to use a label
  apparmor: fix introspection of of task mode for unconfined tasks
  apparmor: check/put label on apparmor_sk_clone_security()

1 files changed, 51 insertions, 11 deletions

diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index 4c010c9a6af1..b0cbc4906cb3 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -260,8 +260,7 @@ struct aa_profile *aa_alloc_profile(const char *hname, struct aa_proxy *proxy,
 	struct aa_profile *profile;
 
 	/* freed by free_profile - usually through aa_put_profile */
-	profile = kzalloc(sizeof(*profile) + sizeof(struct aa_profile *) * 2,
-			  gfp);
+	profile = kzalloc(struct_size(profile, label.vec, 2), gfp);
 	if (!profile)
 		return NULL;
 
@@ -632,18 +631,35 @@ static int audit_policy(struct aa_label *label, const char *op,
 	return error;
 }
 
+/* don't call out to other LSMs in the stack for apparmor policy admin
+ * permissions
+ */
+static int policy_ns_capable(struct aa_label *label,
+			     struct user_namespace *userns, int cap)
+{
+	int err;
+
+	/* check for MAC_ADMIN cap in cred */
+	err = cap_capable(current_cred(), userns, cap, CAP_OPT_NONE);
+	if (!err)
+		err = aa_capable(label, cap, CAP_OPT_NONE);
+
+	return err;
+}
+
 /**
- * policy_view_capable - check if viewing policy in at @ns is allowed
- * ns: namespace being viewed by current task (may be NULL)
+ * aa_policy_view_capable - check if viewing policy in at @ns is allowed
+ * label: label that is trying to view policy in ns
+ * ns: namespace being viewed by @label (may be NULL if @label's ns)
  * Returns: true if viewing policy is allowed
  *
  * If @ns is NULL then the namespace being viewed is assumed to be the
  * tasks current namespace.
  */
-bool policy_view_capable(struct aa_ns *ns)
+bool aa_policy_view_capable(struct aa_label *label, struct aa_ns *ns)
 {
 	struct user_namespace *user_ns = current_user_ns();
-	struct aa_ns *view_ns = aa_get_current_ns();
+	struct aa_ns *view_ns = labels_view(label);
 	bool root_in_user_ns = uid_eq(current_euid(), make_kuid(user_ns, 0)) ||
 			       in_egroup_p(make_kgid(user_ns, 0));
 	bool response = false;
@@ -655,20 +671,44 @@ bool policy_view_capable(struct aa_ns *ns)
 	     (unprivileged_userns_apparmor_policy != 0 &&
 	      user_ns->level == view_ns->level)))
 		response = true;
-	aa_put_ns(view_ns);
 
 	return response;
 }
 
-bool policy_admin_capable(struct aa_ns *ns)
+bool aa_policy_admin_capable(struct aa_label *label, struct aa_ns *ns)
 {
 	struct user_namespace *user_ns = current_user_ns();
-	bool capable = ns_capable(user_ns, CAP_MAC_ADMIN);
+	bool capable = policy_ns_capable(label, user_ns, CAP_MAC_ADMIN) == 0;
 
 	AA_DEBUG("cap_mac_admin? %d\n", capable);
 	AA_DEBUG("policy locked? %d\n", aa_g_lock_policy);
 
-	return policy_view_capable(ns) && capable && !aa_g_lock_policy;
+	return aa_policy_view_capable(label, ns) && capable &&
+		!aa_g_lock_policy;
+}
+
+bool aa_current_policy_view_capable(struct aa_ns *ns)
+{
+	struct aa_label *label;
+	bool res;
+
+	label = __begin_current_label_crit_section();
+	res = aa_policy_view_capable(label, ns);
+	__end_current_label_crit_section(label);
+
+	return res;
+}
+
+bool aa_current_policy_admin_capable(struct aa_ns *ns)
+{
+	struct aa_label *label;
+	bool res;
+
+	label = __begin_current_label_crit_section();
+	res = aa_policy_admin_capable(label, ns);
+	__end_current_label_crit_section(label);
+
+	return res;
 }
 
 /**
@@ -694,7 +734,7 @@ int aa_may_manage_policy(struct aa_label *label, struct aa_ns *ns, u32 mask)
 		return audit_policy(label, op, NULL, NULL, "policy_locked",
 				    -EACCES);
 
-	if (!policy_admin_capable(ns))
+	if (!aa_policy_admin_capable(label, ns))
 		return audit_policy(label, op, NULL, NULL, "not policy admin",
 				    -EACCES);