modsign: use all trusted keys to verify module signature

commit e84cd7ee630e44a2cc8ae49e85920a271b214cb3 upstream

Make mod_verify_sig to use all trusted keys. This allows keys in
secondary_trusted_keys to be used to verify PKCS#7 signature on a
kernel module.
Signed-off-by: NKe Wu <mikewu@google.com>
Signed-off-by: NJessica Yu <jeyu@kernel.org>
Signed-off-by: NTianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Jia Zhang <zhang.jia@linux.alibaba.com>

kernel/module_signing.c

@@ -83,6 +83,7 @@ int mod_verify_sig(const void *mod, struct load_info *info)
 	}
 
 	return verify_pkcs7_signature(mod, modlen, mod + modlen, sig_len,
-				      NULL, VERIFYING_MODULE_SIGNATURE,
+				      VERIFY_USE_SECONDARY_KEYRING,
+				      VERIFYING_MODULE_SIGNATURE,
 				      NULL, NULL);
 }