apparmor: fix module parameters can be changed after policy is locked
the policy_lock parameter is a one way switch that prevents policy
from being further modified. Unfortunately some of the module parameters
can effectively modify policy by turning off enforcement.
split policy_admin_capable into a view check and a full admin check,
and update the admin check to test the policy_lock parameter.
Signed-off-by: John Johansen <john.johansen@canonical.com>
diff --git a/security/apparmor/include/policy.h b/security/apparmor/include/policy.h
index c28b0f2..52275f0 100644
--- a/security/apparmor/include/policy.h
+++ b/security/apparmor/include/policy.h
@@ -403,6 +403,8 @@
return profile->audit;
}
+bool policy_view_capable(void);
+bool policy_admin_capable(void);
bool aa_may_manage_policy(int op);
#endif /* __AA_POLICY_H */
diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 656b97c..300f833 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -730,51 +730,49 @@
/* set global flag turning off the ability to load policy */
static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_admin_capable())
return -EPERM;
- if (aa_g_lock_policy)
- return -EACCES;
return param_set_bool(val, kp);
}
static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_view_capable())
return -EPERM;
return param_get_bool(buffer, kp);
}
static int param_set_aabool(const char *val, const struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_admin_capable())
return -EPERM;
return param_set_bool(val, kp);
}
static int param_get_aabool(char *buffer, const struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_view_capable())
return -EPERM;
return param_get_bool(buffer, kp);
}
static int param_set_aauint(const char *val, const struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_admin_capable())
return -EPERM;
return param_set_uint(val, kp);
}
static int param_get_aauint(char *buffer, const struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_view_capable())
return -EPERM;
return param_get_uint(buffer, kp);
}
static int param_get_audit(char *buffer, struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_view_capable())
return -EPERM;
if (!apparmor_enabled)
@@ -786,7 +784,7 @@
static int param_set_audit(const char *val, struct kernel_param *kp)
{
int i;
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_admin_capable())
return -EPERM;
if (!apparmor_enabled)
@@ -807,7 +805,7 @@
static int param_get_mode(char *buffer, struct kernel_param *kp)
{
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_admin_capable())
return -EPERM;
if (!apparmor_enabled)
@@ -819,7 +817,7 @@
static int param_set_mode(const char *val, struct kernel_param *kp)
{
int i;
- if (!capable(CAP_MAC_ADMIN))
+ if (!policy_admin_capable())
return -EPERM;
if (!apparmor_enabled)
diff --git a/security/apparmor/policy.c b/security/apparmor/policy.c
index 7807125..179e68d 100644
--- a/security/apparmor/policy.c
+++ b/security/apparmor/policy.c
@@ -918,6 +918,22 @@
&sa, NULL);
}
+bool policy_view_capable(void)
+{
+ struct user_namespace *user_ns = current_user_ns();
+ bool response = false;
+
+ if (ns_capable(user_ns, CAP_MAC_ADMIN))
+ response = true;
+
+ return response;
+}
+
+bool policy_admin_capable(void)
+{
+ return policy_view_capable() && !aa_g_lock_policy;
+}
+
/**
* aa_may_manage_policy - can the current task manage policy
* @op: the policy manipulation operation being done
@@ -932,7 +948,7 @@
return 0;
}
- if (!capable(CAP_MAC_ADMIN)) {
+ if (!policy_admin_capable()) {
audit_policy(op, GFP_KERNEL, NULL, "not policy admin", -EACCES);
return 0;
}
