apparmor: move capability checks to using labels

Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/capability.c

@@ -48,15 +48,16 @@ static DEFINE_PER_CPU(struct audit_cache, audit_cache);
 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
+ * @sa: audit data
  * @profile: profile being tested for confinement (NOT NULL)
  * @cap: capability tested
- @audit: whether an audit record should be generated
  * @error: error code returned by test
  *
  * Do auditing of capability and handle, audit/complain/kill modes switching
@@ -64,16 +65,13 @@ static void audit_cb(struct audit_buffer *ab, void *va)
  *
  * Returns: 0 or sa->error on success,  error code on failure
  */
-static int audit_caps(struct aa_profile *profile, int cap, int audit,
-		      int error)
+static int audit_caps(struct common_audit_data *sa, struct aa_profile *profile,
+		      int cap, int error)
 {
 	struct audit_cache *ent;
 	int type = AUDIT_APPARMOR_AUTO;
-	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_CAP, OP_CAPABLE);
-	sa.u.cap = cap;
-	aad(&sa)->error = error;
-	if (audit == SECURITY_CAP_NOAUDIT)
-		aad(&sa)->info = "optional: no audit";
+
+	aad(sa)->error = error;
 
 	if (likely(!error)) {
 		/* test if auditing is being forced */
@@ -105,24 +103,44 @@ static int audit_caps(struct aa_profile *profile, int cap, int audit,
 	}
 	put_cpu_var(audit_cache);
 
-	return aa_audit(type, profile, &sa, audit_cb);
+	return aa_audit(type, profile, 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
+ * @audit: whether an audit record should be generated
+ * @sa: audit data (MAY BE NULL indicating no auditing)
  *
  * Returns: 0 if allowed else -EPERM
  */
-static int profile_capable(struct aa_profile *profile, int cap)
+static int profile_capable(struct aa_profile *profile, int cap, int audit,
+			   struct common_audit_data *sa)
 {
-	return cap_raised(profile->caps.allow, cap) ? 0 : -EPERM;
+	int error;
+
+	if (cap_raised(profile->caps.allow, cap) &&
+	    !cap_raised(profile->caps.denied, cap))
+		error = 0;
+	else
+		error = -EPERM;
+
+	if (audit == SECURITY_CAP_NOAUDIT) {
+		if (!COMPLAIN_MODE(profile))
+			return error;
+		/* audit the cap request in complain mode but note that it
+		 * should be optional.
+		 */
+		aad(sa)->info = "optional: no audit";
+	}
+
+	return audit_caps(sa, profile, cap, error);
 }
 
 /**
  * aa_capable - test permission to use capability
- * @profile: profile being tested against (NOT NULL)
+ * @label: label being tested for capability (NOT NULL)
  * @cap: capability to be tested
  * @audit: whether an audit record should be generated
  *
@@ -130,14 +148,15 @@ static int profile_capable(struct aa_profile *profile, int cap)
  *
  * Returns: 0 on success, or else an error code.
  */
-int aa_capable(struct aa_profile *profile, int cap, int audit)
+int aa_capable(struct aa_label *label, int cap, int audit)
 {
-	int error = profile_capable(profile, cap);
+	struct aa_profile *profile;
+	int error = 0;
+	DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_CAP, OP_CAPABLE);
 
-	if (audit == SECURITY_CAP_NOAUDIT) {
-		if (!COMPLAIN_MODE(profile))
-			return error;
-	}
+	sa.u.cap = cap;
+	error = fn_for_each_confined(label, profile,
+			profile_capable(profile, cap, audit, &sa));
 
-	return audit_caps(profile, cap, audit, error);
+	return error;
 }

security/apparmor/include/capability.h

@@ -19,11 +19,12 @@
 
 #include "apparmorfs.h"
 
-struct aa_profile;
+struct aa_label;
 
 /* aa_caps - confinement data for capabilities
  * @allowed: capabilities mask
  * @audit: caps that are to be audited
+ * @denied: caps that are explicitly denied
  * @quiet: caps that should not be audited
  * @kill: caps that when requested will result in the task being killed
  * @extended: caps that are subject finer grained mediation
@@ -31,6 +32,7 @@ struct aa_profile;
 struct aa_caps {
 	kernel_cap_t allow;
 	kernel_cap_t audit;
+	kernel_cap_t denied;
 	kernel_cap_t quiet;
 	kernel_cap_t kill;
 	kernel_cap_t extended;
@@ -38,7 +40,7 @@ struct aa_caps {
 
 extern struct aa_sfs_entry aa_sfs_entry_caps[];
 
-int aa_capable(struct aa_profile *profile, int cap, int audit);
+int aa_capable(struct aa_label *label, int cap, int audit);
 
 static inline void aa_free_cap_rules(struct aa_caps *caps)
 {

security/apparmor/ipc.c

@@ -68,7 +68,7 @@ int aa_may_ptrace(struct aa_profile *tracer, struct aa_profile *tracee,
 	if (profile_unconfined(tracer) || tracer == tracee)
 		return 0;
 	/* log this capability request */
-	return aa_capable(tracer, CAP_SYS_PTRACE, 1);
+	return aa_capable(&tracer->label, CAP_SYS_PTRACE, 1);
 }
 
 /**

security/apparmor/lsm.c

@@ -117,20 +117,28 @@ static int apparmor_capget(struct task_struct *target, kernel_cap_t *effective,
 			   kernel_cap_t *inheritable, kernel_cap_t *permitted)
 {
 	struct aa_label *label;
-	struct aa_profile *profile;
 	const struct cred *cred;
 
 	rcu_read_lock();
 	cred = __task_cred(target);
 	label = aa_get_newest_cred_label(cred);
-	profile = labels_profile(label);
+
 	/*
 	 * cap_capget is stacked ahead of this and will
 	 * initialize effective and permitted.
 	 */
-	if (!profile_unconfined(profile) && !COMPLAIN_MODE(profile)) {
-		*effective = cap_intersect(*effective, profile->caps.allow);
-		*permitted = cap_intersect(*permitted, profile->caps.allow);
+	if (!unconfined(label)) {
+		struct aa_profile *profile;
+		struct label_it i;
+
+		label_for_each_confined(i, label, profile) {
+			if (COMPLAIN_MODE(profile))
+				continue;
+			*effective = cap_intersect(*effective,
+						   profile->caps.allow);
+			*permitted = cap_intersect(*permitted,
+						   profile->caps.allow);
+		}
 	}
 	rcu_read_unlock();
 	aa_put_label(label);
@@ -146,7 +154,7 @@ static int apparmor_capable(const struct cred *cred, struct user_namespace *ns,
 
 	label = aa_get_newest_cred_label(cred);
 	if (!unconfined(label))
-		error = aa_capable(labels_profile(label), cap, audit);
+		error = aa_capable(label, cap, audit);
 	aa_put_label(label);
 
 	return error;

security/apparmor/resource.c

@@ -100,7 +100,7 @@ int aa_task_setrlimit(struct aa_profile *profile, struct task_struct *task,
 	 * task has CAP_SYS_RESOURCE.
 	 */
 	if ((profile != labels_profile(task_label) &&
-	     aa_capable(profile, CAP_SYS_RESOURCE, 1)) ||
+	     aa_capable(&profile->label, CAP_SYS_RESOURCE, 1)) ||
 	    (profile->rlimits.mask & (1 << resource) &&
 	     new_rlim->rlim_max > profile->rlimits.limits[resource].rlim_max))
 		error = -EACCES;