Replace magic for trusting the secondary keyring with #define

commit 817aef260037f33ee0f44c17fe341323d3aebd6d upstream.

Replace the use of a magic number that indicates that verify_*_signature()
should use the secondary keyring with a symbol.

Signed-off-by: Yannik Sembritzki <yannik@sembritzki.me>
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: keyrings@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index 50979d6..2476650 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -14,6 +14,7 @@
 #include <linux/sched.h>
 #include <linux/cred.h>
 #include <linux/err.h>
+#include <linux/verification.h>
 #include <keys/asymmetric-type.h>
 #include <keys/system_keyring.h>
 #include <crypto/pkcs7.h>
@@ -207,7 +208,7 @@ int verify_pkcs7_signature(const void *data, size_t len,
 
 	if (!trusted_keys) {
 		trusted_keys = builtin_trusted_keys;
-	} else if (trusted_keys == (void *)1UL) {
+	} else if (trusted_keys == VERIFY_USE_SECONDARY_KEYRING) {
 #ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
 		trusted_keys = secondary_trusted_keys;
 #else