From 464f0a710d4677b0e83d160a41e8c69a7f4a614f Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Fri, 17 Jul 2020 23:05:20 +0200
Subject: [KERNEL] Fix leaks, check return codes in module init

---
 src/kernel/core.c | 48 +++++++++++++++++++++++++++++-------------------
 1 file changed, 29 insertions(+), 19 deletions(-)

diff --git a/src/kernel/core.c b/src/kernel/core.c
index 8da2b39..a0854dd 100644
--- a/src/kernel/core.c
+++ b/src/kernel/core.c
@@ -55,12 +55,12 @@
 
 
 
-struct workqueue_struct *dnbd3_wq;
+struct workqueue_struct *dnbd3_wq = NULL;
 DEFINE_IDR(dnbd3_index_idr);
 DEFINE_MUTEX(dnbd3_index_mutex);
 
 static unsigned int max_devs = NUMBER_DEVICES;
-static struct dnbd3_device *device;
+static struct dnbd3_device *device = NULL;
 int major;
 
 /**
@@ -350,8 +350,20 @@ out_free_dnbd3:
  */
 static int __init dnbd3_init(void)
 {
-	int i;
-	debug("starting kernel module");
+	int i, retval;
+	debug("initializing dnbd3 kernel module");
+
+	if (max_devs <= 0 || max_devs >= 256) {
+		error("max_devs must be between 1 and 255");
+		return -EINVAL;
+	}
+
+	device = kcalloc(max_devs, sizeof(*device), GFP_KERNEL);
+	if (!device) {
+		error("failed to allocate memory for dnbd3 device structs");
+		retval = -ENOMEM;
+		goto error;
+	}
 
 	/*
 	 * allocate a workqueue/thread for this modul
@@ -361,28 +373,20 @@ static int __init dnbd3_init(void)
 	 */
 	dnbd3_wq = alloc_workqueue("kdnbd3",
 			WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND, 0);
-
-	if (max_devs < 0) {
-		error("max_devs must be >= 0");
-		return -EINVAL;
-	}
-
-
-	device = kcalloc(max_devs, sizeof(*device), GFP_KERNEL);
-	if (!device) {
-		error("failed to create dnbd3 device");
-		return -ENOMEM;
+	if (!dnbd3_wq) {
+		error("error allocating workqueue");
+		retval = -ENOMEM;
+		goto error;
 	}
 
 	// initialize block device
 	major = register_blkdev(0, "dnbd3");
 	if (major == 0) {
 		error("register_blkdev failed");
-		return -EIO;
+		retval = -EIO;
+		goto error;
 	}
 
-	debug("kernel module loaded. Machine type: " ENDIAN_MODE);
-
 	// add MAX_NUMBER_DEVICES devices
 	mutex_lock(&dnbd3_index_mutex);
 	for (i = 0; i < max_devs; i++) {
@@ -393,6 +397,13 @@ static int __init dnbd3_init(void)
 	info("init successful (%i devices)", max_devs);
 
 	return 0;
+error:
+	if (device) {
+		kfree(device);
+	}
+	if (dnbd3_wq) {
+		destroy_workqueue(dnbd3_wq);
+	}
 }
 
 /**
@@ -465,7 +476,6 @@ static void __exit dnbd3_exit(void)
 	unregister_blkdev(major, "dnbd3");
 
 	kfree(device);
-
 	destroy_workqueue(dnbd3_wq);
 
 	info("stopped kernel module");
-- 
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