apparmor: update policy capable checks to use a label

Previously the policy capable checks assumed they were using the
current task. Make them take the task label so the query can be
made against an arbitrary task.
Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/apparmorfs.c

@@ -1357,7 +1357,7 @@ static int rawdata_open(struct inode *inode, struct file *file)
 	struct aa_loaddata *loaddata;
 	struct rawdata_f_data *private;
 
-	if (!policy_view_capable(NULL))
+	if (!aa_current_policy_view_capable(NULL))
 		return -EACCES;
 
 	loaddata = __aa_get_loaddata(inode->i_private);
@@ -2266,7 +2266,7 @@ static const struct seq_operations aa_sfs_profiles_op = {
 
 static int profiles_open(struct inode *inode, struct file *file)
 {
-	if (!policy_view_capable(NULL))
+	if (!aa_current_policy_view_capable(NULL))
 		return -EACCES;
 
 	return seq_open(file, &aa_sfs_profiles_op);

security/apparmor/include/label.h

@@ -148,6 +148,7 @@ do {							\
 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
 #define labels_set(X) (&labels_ns(X)->labels)
+#define labels_view(X) labels_ns(X)
 #define labels_profile(X) ((X)->vec[(X)->size - 1])
 
 

security/apparmor/include/policy.h

@@ -301,9 +301,11 @@ static inline int AUDIT_MODE(struct aa_profile *profile)
 	return profile->audit;
 }
 
-bool policy_view_capable(struct aa_ns *ns);
-bool policy_admin_capable(struct aa_ns *ns);
+bool aa_policy_view_capable(struct aa_label *label, struct aa_ns *ns);
+bool aa_policy_admin_capable(struct aa_label *label, struct aa_ns *ns);
 int aa_may_manage_policy(struct aa_label *label, struct aa_ns *ns,
 			 u32 mask);
+bool aa_current_policy_view_capable(struct aa_ns *ns);
+bool aa_current_policy_admin_capable(struct aa_ns *ns);
 
 #endif /* __AA_POLICY_H */

security/apparmor/lsm.c

@@ -1392,7 +1392,7 @@ static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_admin_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_admin_capable(NULL))
 		return -EPERM;
 	return param_set_bool(val, kp);
 }
@@ -1401,7 +1401,7 @@ static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_view_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_view_capable(NULL))
 		return -EPERM;
 	return param_get_bool(buffer, kp);
 }
@@ -1410,7 +1410,7 @@ static int param_set_aabool(const char *val, const struct kernel_param *kp)
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_admin_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_admin_capable(NULL))
 		return -EPERM;
 	return param_set_bool(val, kp);
 }
@@ -1419,7 +1419,7 @@ static int param_get_aabool(char *buffer, const struct kernel_param *kp)
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_view_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_view_capable(NULL))
 		return -EPERM;
 	return param_get_bool(buffer, kp);
 }
@@ -1445,7 +1445,7 @@ static int param_get_aauint(char *buffer, const struct kernel_param *kp)
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_view_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_view_capable(NULL))
 		return -EPERM;
 	return param_get_uint(buffer, kp);
 }
@@ -1516,7 +1516,7 @@ static int param_get_aacompressionlevel(char *buffer,
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_view_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_view_capable(NULL))
 		return -EPERM;
 	return param_get_int(buffer, kp);
 }
@@ -1525,7 +1525,7 @@ static int param_get_audit(char *buffer, const struct kernel_param *kp)
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_view_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_view_capable(NULL))
 		return -EPERM;
 	return sprintf(buffer, "%s", audit_mode_names[aa_g_audit]);
 }
@@ -1538,7 +1538,7 @@ static int param_set_audit(const char *val, const struct kernel_param *kp)
 		return -EINVAL;
 	if (!val)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_admin_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_admin_capable(NULL))
 		return -EPERM;
 
 	i = match_string(audit_mode_names, AUDIT_MAX_INDEX, val);
@@ -1553,7 +1553,7 @@ static int param_get_mode(char *buffer, const struct kernel_param *kp)
 {
 	if (!apparmor_enabled)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_view_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_view_capable(NULL))
 		return -EPERM;
 
 	return sprintf(buffer, "%s", aa_profile_mode_names[aa_g_profile_mode]);
@@ -1567,7 +1567,7 @@ static int param_set_mode(const char *val, const struct kernel_param *kp)
 		return -EINVAL;
 	if (!val)
 		return -EINVAL;
-	if (apparmor_initialized && !policy_admin_capable(NULL))
+	if (apparmor_initialized && !aa_current_policy_admin_capable(NULL))
 		return -EPERM;
 
 	i = match_string(aa_profile_mode_names, APPARMOR_MODE_NAMES_MAX_INDEX,
@@ -1703,7 +1703,7 @@ static int __init alloc_buffers(void)
 static int apparmor_dointvec(struct ctl_table *table, int write,
 			     void __user *buffer, size_t *lenp, loff_t *ppos)
 {
-	if (!policy_admin_capable(NULL))
+	if (!aa_current_policy_admin_capable(NULL))
 		return -EPERM;
 	if (!apparmor_enabled)
 		return -EINVAL;

security/apparmor/policy.c

@@ -632,17 +632,18 @@ static int audit_policy(struct aa_label *label, const char *op,
 }
 
 /**
- * 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;
@@ -654,12 +655,11 @@ 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);
@@ -667,7 +667,32 @@ bool policy_admin_capable(struct aa_ns *ns)
 	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;
 }
 
 /**
@@ -693,7 +718,7 @@ 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);