[PATCH] apparmor: fix SECURITY_APPARMOR_HASH_DEFAULT parameter handling

[Loic <hackurx@opensec.fr>]

Hello,

Tested without any problem so please picked up this for 4.4 to fix the 
problem.
The patch below is slightly modified to adapt to this version.

[ Upstream commit 7616ac70d1bb4f2e9d25c1a82d283f3368a7b632 ]

The newly added Kconfig option could never work and just causes a build 
error
when disabled:

security/apparmor/lsm.c:675:25: error: 
'CONFIG_SECURITY_APPARMOR_HASH_DEFAULT' undeclared here (not in a 
function)
  bool aa_g_hash_policy = CONFIG_SECURITY_APPARMOR_HASH_DEFAULT;

The problem is that the macro undefined in this case, and we need to use 
the IS_ENABLED()
helper to turn it into a boolean constant.

Another minor problem with the original patch is that the option is even 
offered
in sysfs when SECURITY_APPARMOR_HASH is not enabled, so this also hides 
the option
in that case.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 6059f71f1e94 ("apparmor: add parameter to control whether policy 
hashing is used")
Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
---
diff -Nurp a/security/apparmor/crypto.c b/security/apparmor/crypto.c
--- a/security/apparmor/crypto.c
+++ b/security/apparmor/crypto.c
@@ -39,6 +39,9 @@ int aa_calc_profile_hash(struct aa_profi
  	int error = -ENOMEM;
  	u32 le32_version = cpu_to_le32(version);

+	if (!aa_g_hash_policy)
+		return 0;
+
  	if (!apparmor_tfm)
  		return 0;

diff -Nurp a/security/apparmor/lsm.c b/security/apparmor/lsm.c
--- a/security/apparmor/lsm.c
+++ b/security/apparmor/lsm.c
@@ -692,6 +692,12 @@ enum profile_mode aa_g_profile_mode = AP
  module_param_call(mode, param_set_mode, param_get_mode,
  		  &aa_g_profile_mode, S_IRUSR | S_IWUSR);

+#ifdef CONFIG_SECURITY_APPARMOR_HASH
+/* whether policy verification hashing is enabled */
+bool aa_g_hash_policy = 
IS_ENABLED(CONFIG_SECURITY_APPARMOR_HASH_DEFAULT);
+module_param_named(hash_policy, aa_g_hash_policy, aabool, S_IRUSR | 
S_IWUSR);
+#endif
+
  /* Debug mode */
  bool aa_g_debug;
  module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);
---