release/5.2.40/s390-zcrypt-fix-card-and-queue-total-counter-wrap.patch

From 09c1e8dd0c18948fa8cdcee5d7666d99061ee07e Mon Sep 17 00:00:00 2001
From: Harald Freudenberger <freude@linux.ibm.com>
Date: Fri, 20 Dec 2019 16:02:54 +0100
Subject: [PATCH] s390/zcrypt: fix card and queue total counter wrap

commit fcd98d4002539f1e381916fc1b6648938c1eac76 upstream.

The internal statistic counters for the total number of
requests processed per card and per queue used integers. So they do
wrap after a rather huge amount of crypto requests processed. This
patch introduces uint64 counters which should hold much longer but
still may wrap. The sysfs attributes request_count for card and queue
also used only %ld and now display the counter value with %llu.

This is not a security relevant fix. The int overflow which happened
is not in any way exploitable as a security breach.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index 10f8024f03cb..36a3bfada3e4 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -161,7 +161,7 @@ struct ap_card {
 	unsigned int functions;		/* AP device function bitfield. */
 	int queue_depth;		/* AP queue depth.*/
 	int id;				/* AP card number. */
-	atomic_t total_request_count;	/* # requests ever for this AP device.*/
+	atomic64_t total_request_count;	/* # requests ever for this AP device.*/
 };
 
 #define to_ap_card(x) container_of((x), struct ap_card, ap_dev.device)
@@ -178,7 +178,7 @@ struct ap_queue {
 	enum ap_state state;		/* State of the AP device. */
 	int pendingq_count;		/* # requests on pendingq list. */
 	int requestq_count;		/* # requests on requestq list. */
-	int total_request_count;	/* # requests ever for this AP device.*/
+	u64 total_request_count;	/* # requests ever for this AP device.*/
 	int request_timeout;		/* Request timeout in jiffies. */
 	struct timer_list timeout;	/* Timer for request timeouts. */
 	struct list_head pendingq;	/* List of message sent to AP queue. */
diff --git a/drivers/s390/crypto/ap_card.c b/drivers/s390/crypto/ap_card.c
index 63b4cc6cd7e5..e85bfca1ed16 100644
--- a/drivers/s390/crypto/ap_card.c
+++ b/drivers/s390/crypto/ap_card.c
@@ -63,13 +63,13 @@ static ssize_t request_count_show(struct device *dev,
 				  char *buf)
 {
 	struct ap_card *ac = to_ap_card(dev);
-	unsigned int req_cnt;
+	u64 req_cnt;
 
 	req_cnt = 0;
 	spin_lock_bh(&ap_list_lock);
-	req_cnt = atomic_read(&ac->total_request_count);
+	req_cnt = atomic64_read(&ac->total_request_count);
 	spin_unlock_bh(&ap_list_lock);
-	return snprintf(buf, PAGE_SIZE, "%d\n", req_cnt);
+	return snprintf(buf, PAGE_SIZE, "%llu\n", req_cnt);
 }
 
 static ssize_t request_count_store(struct device *dev,
@@ -83,7 +83,7 @@ static ssize_t request_count_store(struct device *dev,
 	for_each_ap_queue(aq, ac)
 		aq->total_request_count = 0;
 	spin_unlock_bh(&ap_list_lock);
-	atomic_set(&ac->total_request_count, 0);
+	atomic64_set(&ac->total_request_count, 0);
 
 	return count;
 }
diff --git a/drivers/s390/crypto/ap_queue.c b/drivers/s390/crypto/ap_queue.c
index a3f8d2512698..4d3a31b9e14d 100644
--- a/drivers/s390/crypto/ap_queue.c
+++ b/drivers/s390/crypto/ap_queue.c
@@ -478,12 +478,12 @@ static ssize_t request_count_show(struct device *dev,
 				  char *buf)
 {
 	struct ap_queue *aq = to_ap_queue(dev);
-	unsigned int req_cnt;
+	u64 req_cnt;
 
 	spin_lock_bh(&aq->lock);
 	req_cnt = aq->total_request_count;
 	spin_unlock_bh(&aq->lock);
-	return snprintf(buf, PAGE_SIZE, "%d\n", req_cnt);
+	return snprintf(buf, PAGE_SIZE, "%llu\n", req_cnt);
 }
 
 static ssize_t request_count_store(struct device *dev,
@@ -675,7 +675,7 @@ void ap_queue_message(struct ap_queue *aq, struct ap_message *ap_msg)
 	list_add_tail(&ap_msg->list, &aq->requestq);
 	aq->requestq_count++;
 	aq->total_request_count++;
-	atomic_inc(&aq->card->total_request_count);
+	atomic64_inc(&aq->card->total_request_count);
 	/* Send/receive as many request from the queue as possible. */
 	ap_wait(ap_sm_event_loop(aq, AP_EVENT_POLL));
 	spin_unlock_bh(&aq->lock);
diff --git a/drivers/s390/crypto/zcrypt_api.c b/drivers/s390/crypto/zcrypt_api.c
index 35a0e9569239..71e20fb6a1af 100644
--- a/drivers/s390/crypto/zcrypt_api.c
+++ b/drivers/s390/crypto/zcrypt_api.c
@@ -622,8 +622,8 @@ static inline bool zcrypt_card_compare(struct zcrypt_card *zc,
 	weight += atomic_read(&zc->load);
 	pref_weight += atomic_read(&pref_zc->load);
 	if (weight == pref_weight)
-		return atomic_read(&zc->card->total_request_count) >
-			atomic_read(&pref_zc->card->total_request_count);
+		return atomic64_read(&zc->card->total_request_count) >
+			atomic64_read(&pref_zc->card->total_request_count);
 	return weight > pref_weight;
 }
 
@@ -1205,11 +1205,12 @@ static void zcrypt_qdepth_mask(char qdepth[], size_t max_adapters)
 	spin_unlock(&zcrypt_list_lock);
 }
 
-static void zcrypt_perdev_reqcnt(int reqcnt[], size_t max_adapters)
+static void zcrypt_perdev_reqcnt(u32 reqcnt[], size_t max_adapters)
 {
 	struct zcrypt_card *zc;
 	struct zcrypt_queue *zq;
 	int card;
+	u64 cnt;
 
 	memset(reqcnt, 0, sizeof(int) * max_adapters);
 	spin_lock(&zcrypt_list_lock);
@@ -1221,8 +1222,9 @@ static void zcrypt_perdev_reqcnt(int reqcnt[], size_t max_adapters)
 			    || card >= max_adapters)
 				continue;
 			spin_lock(&zq->queue->lock);
-			reqcnt[card] = zq->queue->total_request_count;
+			cnt = zq->queue->total_request_count;
 			spin_unlock(&zq->queue->lock);
+			reqcnt[card] = (cnt < UINT_MAX) ? (u32) cnt : UINT_MAX;
 		}
 	}
 	local_bh_enable();
@@ -1400,9 +1402,9 @@ static long zcrypt_unlocked_ioctl(struct file *filp, unsigned int cmd,
 		return 0;
 	}
 	case ZCRYPT_PERDEV_REQCNT: {
-		int *reqcnt;
+		u32 *reqcnt;
 
-		reqcnt = kcalloc(AP_DEVICES, sizeof(int), GFP_KERNEL);
+		reqcnt = kcalloc(AP_DEVICES, sizeof(u32), GFP_KERNEL);
 		if (!reqcnt)
 			return -ENOMEM;
 		zcrypt_perdev_reqcnt(reqcnt, AP_DEVICES);
@@ -1459,7 +1461,7 @@ static long zcrypt_unlocked_ioctl(struct file *filp, unsigned int cmd,
 	}
 	case Z90STAT_PERDEV_REQCNT: {
 		/* the old ioctl supports only 64 adapters */
-		int reqcnt[MAX_ZDEV_CARDIDS];
+		u32 reqcnt[MAX_ZDEV_CARDIDS];
 
 		zcrypt_perdev_reqcnt(reqcnt, MAX_ZDEV_CARDIDS);
 		if (copy_to_user((int __user *) arg, reqcnt, sizeof(reqcnt)))
-- 
2.7.4