From: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Date: Tue, 5 Jun 2018 08:27:30 +0000 (+0100)
Subject: um: Fix initialization of vector queues
X-Git-Tag: microblaze-v4.19-rc1~96^2~1
X-Git-Url: http://git.monstr.eu/?a=commitdiff_plain;h=4579a1ba692af81da7ea6ce197f8169ddc0c327f;p=linux-2.6-microblaze.git

um: Fix initialization of vector queues

UML vector drivers could derefence uninitialized memory
when cleaning up after a queue allocation failure.

Fixes: 49da7e64f33e ("High Performance UML Vector Network Driver")
Cc: <stable@vger.kernel.org>
Reported-by: Dan Capenter <dan.carpenter@oracle.com>
Signed-off-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---

diff --git a/arch/um/drivers/vector_kern.c b/arch/um/drivers/vector_kern.c
index 02168fe25105..8b852928959b 100644
--- a/arch/um/drivers/vector_kern.c
+++ b/arch/um/drivers/vector_kern.c
@@ -504,15 +504,19 @@ static struct vector_queue *create_queue(
 
 	result = kmalloc(sizeof(struct vector_queue), GFP_KERNEL);
 	if (result == NULL)
-		goto out_fail;
+		return NULL;
 	result->max_depth = max_size;
 	result->dev = vp->dev;
 	result->mmsg_vector = kmalloc(
 		(sizeof(struct mmsghdr) * max_size), GFP_KERNEL);
+	if (result->mmsg_vector == NULL)
+		goto out_mmsg_fail;
 	result->skbuff_vector = kmalloc(
 		(sizeof(void *) * max_size), GFP_KERNEL);
-	if (result->mmsg_vector == NULL || result->skbuff_vector == NULL)
-		goto out_fail;
+	if (result->skbuff_vector == NULL)
+		goto out_skb_fail;
+
+	/* further failures can be handled safely by destroy_queue*/
 
 	mmsg_vector = result->mmsg_vector;
 	for (i = 0; i < max_size; i++) {
@@ -563,6 +567,11 @@ static struct vector_queue *create_queue(
 	result->head = 0;
 	result->tail = 0;
 	return result;
+out_skb_fail:
+	kfree(result->mmsg_vector);
+out_mmsg_fail:
+	kfree(result);
+	return NULL;
 out_fail:
 	destroy_queue(result);
 	return NULL;