[PATCH v2] drivers/misc/vmw_vmci: restrict too big queue size in

From: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
To: gregkh@linuxfoundation.org
Cc: alex.dewar90@gmail.com, arnd@arndb.de,
	linux-kernel@vger.kernel.org, snovitoll@gmail.com,
	syzbot+15ec7391f3d6a1a7cc7d@syzkaller.appspotmail.com
Subject: [PATCH v2] drivers/misc/vmw_vmci: restrict too big queue size in
Date: Tue,  9 Feb 2021 15:31:01 +0600	[thread overview]
Message-ID: <20210209093101.2097627-1-snovitoll@gmail.com> (raw)
In-Reply-To: <YCJKIVhNS4N4glUa@kroah.com>

syzbot found WARNING in qp_broker_alloc[1] in qp_host_alloc_queue()
when num_pages is 0x100001, giving queue_size + queue_page_size
bigger than KMALLOC_MAX_SIZE for kzalloc(), resulting order >= MAX_ORDER
condition.

queue_size + queue_page_size=0x8000d8, where KMALLOC_MAX_SIZE=0x400000.

Reported-by: syzbot+15ec7391f3d6a1a7cc7d@syzkaller.appspotmail.com
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@gmail.com>
---
>As this is controllable by userspace, you just provided a way to flood
>the kernel logs.
>
>Please make this a dev_dbg() call instead, if you really want to see it.
>Otherwise just return NULL, no need to report anything, right?

Thanks, removed pr_warn().

v2: Removed pr_warn() to avoid flood from user-space
---
 drivers/misc/vmw_vmci/vmci_queue_pair.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index f6af406fda80..ea16df73cde0 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -538,9 +538,7 @@ static struct vmci_queue *qp_host_alloc_queue(u64 size)
 	queue_page_size = num_pages * sizeof(*queue->kernel_if->u.h.page);
 
 	if (queue_size + queue_page_size > KMALLOC_MAX_SIZE) {
-		pr_warn("too big queue to allocate\n");
 		return NULL;
-	}
 
 	queue = kzalloc(queue_size + queue_page_size, GFP_KERNEL);
 	if (queue) {
-- 
2.25.1

