s390/zcrypt: Fix CCA and EP11 CPRB processing failure memory leak.

Tests showed, that the zcrypt device driver produces memory
leaks when a valid CCA or EP11 CPRB can't get delivered or has
a failure during processing within the zcrypt device driver.

This happens when a invalid domain or adapter number is used
or the lower level software or hardware layers produce any
kind of failure during processing of the request.

Only CPRBs send to CCA or EP11 cards can produce this memory
leak. The accelerator and the CPRBs processed by this type
of crypto card is not affected.

The two fields message and private within the ap_message struct
are allocated with pulling the function code for the CPRB but
only freed when processing of the CPRB succeeds. So for example
an invalid domain or adapter field causes the processing to
fail, leaving these two memory areas allocated forever.

Signed-off-by: Harald Freudenberger <freude@de.ibm.com>
Reviewed-by: Ingo Franzki <ifranzki@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 43 insertions, 40 deletions

diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index 02184cf35834..6a273c5ebca5 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -198,11 +198,18 @@ struct ap_message {
  */
 static inline void ap_init_message(struct ap_message *ap_msg)
 {
-	ap_msg->psmid = 0;
-	ap_msg->length = 0;
-	ap_msg->rc = 0;
-	ap_msg->special = 0;
-	ap_msg->receive = NULL;
+	memset(ap_msg, 0, sizeof(*ap_msg));
+}
+
+/**
+ * ap_release_message() - Release ap_message.
+ * Releases all memory used internal within the ap_message struct
+ * Currently this is the message and private field.
+ */
+static inline void ap_release_message(struct ap_message *ap_msg)
+{
+	kzfree(ap_msg->message);
+	kzfree(ap_msg->private);
 }
 
 #define for_each_ap_card(_ac) \
diff --git a/drivers/s390/crypto/zcrypt_api.c b/drivers/s390/crypto/zcrypt_api.c
index 5efd84862ccb..febcdb5135bf 100644
--- a/drivers/s390/crypto/zcrypt_api.c
+++ b/drivers/s390/crypto/zcrypt_api.c
@@ -371,6 +371,7 @@ long zcrypt_send_cprb(struct ica_xcRB *xcRB)
 
 	trace_s390_zcrypt_req(xcRB, TB_ZSECSENDCPRB);
 
+	ap_init_message(&ap_msg);
 	rc = get_cprb_fc(xcRB, &ap_msg, &func_code, &domain);
 	if (rc)
 		goto out;
@@ -425,6 +426,7 @@ long zcrypt_send_cprb(struct ica_xcRB *xcRB)
 	spin_unlock(&zcrypt_list_lock);
 
 out:
+	ap_release_message(&ap_msg);
 	trace_s390_zcrypt_rep(xcRB, func_code, rc,
 			      AP_QID_CARD(qid), AP_QID_QUEUE(qid));
 	return rc;
@@ -468,6 +470,8 @@ static long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
 
 	trace_s390_zcrypt_req(xcrb, TP_ZSENDEP11CPRB);
 
+	ap_init_message(&ap_msg);
+
 	target_num = (unsigned short) xcrb->targets_num;
 
 	/* empty list indicates autoselect (all available targets) */
@@ -485,7 +489,7 @@ static long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
 		if (copy_from_user(targets, uptr,
 				   target_num * sizeof(*targets))) {
 			rc = -EFAULT;
-			goto out;
+			goto out_free;
 		}
 	}
 
@@ -542,6 +546,7 @@ static long zcrypt_send_ep11_cprb(struct ep11_urb *xcrb)
 out_free:
 	kfree(targets);
 out:
+	ap_release_message(&ap_msg);
 	trace_s390_zcrypt_rep(xcrb, func_code, rc,
 			      AP_QID_CARD(qid), AP_QID_QUEUE(qid));
 	return rc;
@@ -559,6 +564,7 @@ static long zcrypt_rng(char *buffer)
 
 	trace_s390_zcrypt_req(buffer, TP_HWRNGCPRB);
 
+	ap_init_message(&ap_msg);
 	rc = get_rng_fc(&ap_msg, &func_code, &domain);
 	if (rc)
 		goto out;
@@ -589,8 +595,10 @@ static long zcrypt_rng(char *buffer)
 	pref_zq = zcrypt_pick_queue(pref_zc, pref_zq, weight);
 	spin_unlock(&zcrypt_list_lock);
 
-	if (!pref_zq)
-		return -ENODEV;
+	if (!pref_zq) {
+		rc = -ENODEV;
+		goto out;
+	}
 
 	qid = pref_zq->queue->qid;
 	rc = pref_zq->ops->rng(pref_zq, buffer, &ap_msg);
@@ -600,6 +608,7 @@ static long zcrypt_rng(char *buffer)
 	spin_unlock(&zcrypt_list_lock);
 
 out:
+	ap_release_message(&ap_msg);
 	trace_s390_zcrypt_rep(buffer, func_code, rc,
 			      AP_QID_CARD(qid), AP_QID_QUEUE(qid));
 	return rc;
diff --git a/drivers/s390/crypto/zcrypt_msgtype6.c b/drivers/s390/crypto/zcrypt_msgtype6.c
index f54bef4a928e..97d4bacbc442 100644
--- a/drivers/s390/crypto/zcrypt_msgtype6.c
+++ b/drivers/s390/crypto/zcrypt_msgtype6.c
@@ -1084,6 +1084,13 @@ out_free:
 	return rc;
 }
 
+/**
+ * Fetch function code from cprb.
+ * Extracting the fc requires to copy the cprb from userspace.
+ * So this function allocates memory and needs an ap_msg prepared
+ * by the caller with ap_init_message(). Also the caller has to
+ * make sure ap_release_message() is always called even on failure.
+ */
 unsigned int get_cprb_fc(struct ica_xcRB *xcRB,
 				struct ap_message *ap_msg,
 				unsigned int *func_code, unsigned short **dom)
@@ -1091,9 +1098,7 @@ unsigned int get_cprb_fc(struct ica_xcRB *xcRB,
 	struct response_type resp_type = {
 		.type = PCIXCC_RESPONSE_TYPE_XCRB,
 	};
-	int rc;
 
-	ap_init_message(ap_msg);
 	ap_msg->message = kmalloc(MSGTYPE06_MAX_MSG_SIZE, GFP_KERNEL);
 	if (!ap_msg->message)
 		return -ENOMEM;
@@ -1101,17 +1106,10 @@ unsigned int get_cprb_fc(struct ica_xcRB *xcRB,
 	ap_msg->psmid = (((unsigned long long) current->pid) << 32) +
 				atomic_inc_return(&zcrypt_step);
 	ap_msg->private = kmalloc(sizeof(resp_type), GFP_KERNEL);
-	if (!ap_msg->private) {
-		kzfree(ap_msg->message);
+	if (!ap_msg->private)
 		return -ENOMEM;
-	}
 	memcpy(ap_msg->private, &resp_type, sizeof(resp_type));
-	rc = XCRB_msg_to_type6CPRB_msgX(ap_msg, xcRB, func_code, dom);
-	if (rc) {
-		kzfree(ap_msg->message);
-		kzfree(ap_msg->private);
-	}
-	return rc;
+	return XCRB_msg_to_type6CPRB_msgX(ap_msg, xcRB, func_code, dom);
 }
 
 /**
@@ -1139,11 +1137,16 @@ static long zcrypt_msgtype6_send_cprb(struct zcrypt_queue *zq,
 		/* Signal pending. */
 		ap_cancel_message(zq->queue, ap_msg);
 
-	kzfree(ap_msg->message);
-	kzfree(ap_msg->private);
 	return rc;
 }
 
+/**
+ * Fetch function code from ep11 cprb.
+ * Extracting the fc requires to copy the ep11 cprb from userspace.
+ * So this function allocates memory and needs an ap_msg prepared
+ * by the caller with ap_init_message(). Also the caller has to
+ * make sure ap_release_message() is always called even on failure.
+ */
 unsigned int get_ep11cprb_fc(struct ep11_urb *xcrb,
 				    struct ap_message *ap_msg,
 				    unsigned int *func_code)
@@ -1151,9 +1154,7 @@ unsigned int get_ep11cprb_fc(struct ep11_urb *xcrb,
 	struct response_type resp_type = {
 		.type = PCIXCC_RESPONSE_TYPE_EP11,
 	};
-	int rc;
 
-	ap_init_message(ap_msg);
 	ap_msg->message = kmalloc(MSGTYPE06_MAX_MSG_SIZE, GFP_KERNEL);
 	if (!ap_msg->message)
 		return -ENOMEM;
@@ -1161,17 +1162,10 @@ unsigned int get_ep11cprb_fc(struct ep11_urb *xcrb,
 	ap_msg->psmid = (((unsigned long long) current->pid) << 32) +
 				atomic_inc_return(&zcrypt_step);
 	ap_msg->private = kmalloc(sizeof(resp_type), GFP_KERNEL);
-	if (!ap_msg->private) {
-		kzfree(ap_msg->message);
+	if (!ap_msg->private)
 		return -ENOMEM;
-	}
 	memcpy(ap_msg->private, &resp_type, sizeof(resp_type));
-	rc = xcrb_msg_to_type6_ep11cprb_msgx(ap_msg, xcrb, func_code);
-	if (rc) {
-		kzfree(ap_msg->message);
-		kzfree(ap_msg->private);
-	}
-	return rc;
+	return xcrb_msg_to_type6_ep11cprb_msgx(ap_msg, xcrb, func_code);
 }
 
 /**
@@ -1246,8 +1240,6 @@ static long zcrypt_msgtype6_send_ep11_cprb(struct zcrypt_queue *zq,
 		/* Signal pending. */
 		ap_cancel_message(zq->queue, ap_msg);
 
-	kzfree(ap_msg->message);
-	kzfree(ap_msg->private);
 	return rc;
 }
 
@@ -1258,7 +1250,6 @@ unsigned int get_rng_fc(struct ap_message *ap_msg, int *func_code,
 		.type = PCIXCC_RESPONSE_TYPE_XCRB,
 	};
 
-	ap_init_message(ap_msg);
 	ap_msg->message = kmalloc(MSGTYPE06_MAX_MSG_SIZE, GFP_KERNEL);
 	if (!ap_msg->message)
 		return -ENOMEM;
@@ -1266,10 +1257,8 @@ unsigned int get_rng_fc(struct ap_message *ap_msg, int *func_code,
 	ap_msg->psmid = (((unsigned long long) current->pid) << 32) +
 				atomic_inc_return(&zcrypt_step);
 	ap_msg->private = kmalloc(sizeof(resp_type), GFP_KERNEL);
-	if (!ap_msg->private) {
-		kzfree(ap_msg->message);
+	if (!ap_msg->private)
 		return -ENOMEM;
-	}
 	memcpy(ap_msg->private, &resp_type, sizeof(resp_type));
 
 	rng_type6CPRB_msgX(ap_msg, ZCRYPT_RNG_BUFFER_SIZE, domain);
@@ -1313,8 +1302,6 @@ static long zcrypt_msgtype6_rng(struct zcrypt_queue *zq,
 		/* Signal pending. */
 		ap_cancel_message(zq->queue, ap_msg);
 
-	kzfree(ap_msg->message);
-	kzfree(ap_msg->private);
 	return rc;
 }