[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>

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

drivers/s390/crypto/zcrypt_cex2a.c

@@ -298,6 +298,7 @@ static long zcrypt_cex2a_modexpo(struct zcrypt_device *zdev,
 	struct completion work;
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;
@@ -335,6 +336,7 @@ static long zcrypt_cex2a_modexpo_crt(struct zcrypt_device *zdev,
 	struct completion work;
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = kmalloc(CEX2A_MAX_MESSAGE_SIZE, GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;

drivers/s390/crypto/zcrypt_pcica.c

@@ -281,6 +281,7 @@ static long zcrypt_pcica_modexpo(struct zcrypt_device *zdev,
 	struct completion work;
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = kmalloc(PCICA_MAX_MESSAGE_SIZE, GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;
@@ -318,6 +319,7 @@ static long zcrypt_pcica_modexpo_crt(struct zcrypt_device *zdev,
 	struct completion work;
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = kmalloc(PCICA_MAX_MESSAGE_SIZE, GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;

drivers/s390/crypto/zcrypt_pcicc.c

@@ -483,6 +483,7 @@ static long zcrypt_pcicc_modexpo(struct zcrypt_device *zdev,
 	struct completion work;
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;
@@ -521,6 +522,7 @@ static long zcrypt_pcicc_modexpo_crt(struct zcrypt_device *zdev,
 	struct completion work;
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;

drivers/s390/crypto/zcrypt_pcixcc.c

@@ -688,6 +688,7 @@ static long zcrypt_pcixcc_modexpo(struct zcrypt_device *zdev,
 	};
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;
@@ -727,6 +728,7 @@ static long zcrypt_pcixcc_modexpo_crt(struct zcrypt_device *zdev,
 	};
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;
@@ -766,6 +768,7 @@ static long zcrypt_pcixcc_send_cprb(struct zcrypt_device *zdev,
 	};
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = kmalloc(PCIXCC_MAX_XCRB_MESSAGE_SIZE, GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;
@@ -805,6 +808,7 @@ static long zcrypt_pcixcc_rng(struct zcrypt_device *zdev,
 	};
 	int rc;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = kmalloc(PCIXCC_MAX_XCRB_MESSAGE_SIZE, GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;
@@ -972,6 +976,7 @@ static int zcrypt_pcixcc_rng_supported(struct ap_device *ap_dev)
 	} __attribute__((packed)) *reply;
 	int rc, i;
 
+	ap_init_message(&ap_msg);
 	ap_msg.message = (void *) get_zeroed_page(GFP_KERNEL);
 	if (!ap_msg.message)
 		return -ENOMEM;