[S390] zcrypt: initialize ap_messages for cex3 exploitation

AP messages need to be initialized, before they will be used. Values
will be zeroized. This will be needed later when introducing support
for the special commands.

Signed-off-by: Felix Beck <felix.beck@de.ibm.com>
Signed-off-by: Ralph Wuerthner <ralph.wuerthner@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index a35362241805..fcf2497556dd 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -167,6 +167,17 @@ struct ap_message {
         .dev_type=(dt),                                 \
         .match_flags=AP_DEVICE_ID_MATCH_DEVICE_TYPE,
 
+/**
+ * ap_init_message() - Initialize ap_message.
+ * Initialize a message before using. Otherwise this might result in
+ * unexpected behaviour.
+ */
+static inline void ap_init_message(struct ap_message *ap_msg)
+{
+        ap_msg->psmid = 0;
+        ap_msg->length = 0;
+}
+
 /*
  * Note: don't use ap_send/ap_recv after using ap_queue_message
  * for the first time. Otherwise the ap message queue will get