[PATCH][Xenial][Zesty] UBUNTU: SAUCE: fix oops when disabled and module parameters, are accessed

[John Johansen]

The virtualization of apparmor module parameters failed to take into
account the parameters being accessed when apparmor is not enabled
in some cases.

It also failed to take into account that policy_admin_capable checks
should not be applied to parameters specified at kernel boot as this
is the callback is used before apparmor is initialized.

BugLink: http://bugs.launchpad.net/bugs/1626984
Signed-off-by: John Johansen <john.johansen at canonical.com>
---
 security/apparmor/lsm.c | 52 +++++++++++++++++++++++++++++--------------------
 1 file changed, 31 insertions(+), 21 deletions(-)

diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
index 70617e50a0d4..7951c3dc9393 100644
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -41,7 +41,7 @@
 #include "include/mount.h"
 
 /* Flag indicating whether initialization completed */
-int apparmor_initialized __initdata;
+int apparmor_initialized;
 
 DEFINE_PER_CPU(struct aa_buffers, aa_buffers);
 
@@ -1409,74 +1409,83 @@ __setup("apparmor=", apparmor_enabled_setup);
 /* set global flag turning off the ability to load policy */
 static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp)
 {
-	if (!policy_admin_capable(NULL))
+	if (!apparmor_enabled)
+		return -EINVAL;
+	if (apparmor_initialized && !policy_admin_capable(NULL))
 		return -EPERM;
 	return param_set_bool(val, kp);
 }
 
 static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
 {
-	if (!policy_view_capable(NULL))
-		return -EPERM;
 	if (!apparmor_enabled)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_view_capable(NULL))
+		return -EPERM;
 	return param_get_bool(buffer, kp);
 }
 
 static int param_set_aabool(const char *val, const struct kernel_param *kp)
 {
-	if (!policy_admin_capable(NULL))
-		return -EPERM;
 	if (!apparmor_enabled)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_admin_capable(NULL))
+		return -EPERM;
 	return param_set_bool(val, kp);
 }
 
 static int param_get_aabool(char *buffer, const struct kernel_param *kp)
 {
-	if (!policy_view_capable(NULL))
-		return -EPERM;
 	if (!apparmor_enabled)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_view_capable(NULL))
+		return -EPERM;
 	return param_get_bool(buffer, kp);
 }
 
 static int param_set_aauint(const char *val, const struct kernel_param *kp)
 {
-	if (!policy_admin_capable(NULL))
-		return -EPERM;
+	int error;
+
 	if (!apparmor_enabled)
 		return -EINVAL;
-	return param_set_uint(val, kp);
+	if (apparmor_initialized && !policy_admin_capable(NULL))
+		return -EPERM;
+
+	error = param_set_uint(val, kp);
+	pr_info("AppArmor: buffer size set to %d bytes\n", aa_g_path_max);
+
+	return error;
 }
 
 static int param_get_aauint(char *buffer, const struct kernel_param *kp)
 {
-	if (!policy_view_capable(NULL))
-		return -EPERM;
 	if (!apparmor_enabled)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_view_capable(NULL))
+		return -EPERM;
 	return param_get_uint(buffer, kp);
 }
 
 static int param_get_audit(char *buffer, struct kernel_param *kp)
 {
-	if (!policy_view_capable(NULL))
-		return -EPERM;
 	if (!apparmor_enabled)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_view_capable(NULL))
+		return -EPERM;
 	return sprintf(buffer, "%s", audit_mode_names[aa_g_audit]);
 }
 
 static int param_set_audit(const char *val, struct kernel_param *kp)
 {
 	int i;
-	if (!policy_admin_capable(NULL))
-		return -EPERM;
+
 	if (!apparmor_enabled)
 		return -EINVAL;
 	if (!val)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_admin_capable(NULL))
+		return -EPERM;
 
 	for (i = 0; i < AUDIT_MAX_INDEX; i++) {
 		if (strcmp(val, audit_mode_names[i]) == 0) {
@@ -1490,10 +1499,10 @@ static int param_set_audit(const char *val, struct kernel_param *kp)
 
 static int param_get_mode(char *buffer, struct kernel_param *kp)
 {
-	if (!policy_view_capable(NULL))
-		return -EPERM;
 	if (!apparmor_enabled)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_view_capable(NULL))
+		return -EPERM;
 
 	return sprintf(buffer, "%s", aa_profile_mode_names[aa_g_profile_mode]);
 }
@@ -1501,12 +1510,13 @@ static int param_get_mode(char *buffer, struct kernel_param *kp)
 static int param_set_mode(const char *val, struct kernel_param *kp)
 {
 	int i;
-	if (!policy_admin_capable(NULL))
-		return -EPERM;
+
 	if (!apparmor_enabled)
 		return -EINVAL;
 	if (!val)
 		return -EINVAL;
+	if (apparmor_initialized && !policy_admin_capable(NULL))
+		return -EPERM;
 
 	for (i = 0; i < APPARMOR_MODE_NAMES_MAX_INDEX; i++) {
 		if (strcmp(val, aa_profile_mode_names[i]) == 0) {
-- 
2.11.0