[PATCH v3] drivers/misc/vmw_vmci: restrict too big queue size in

From: Sabyrzhan Tasbolatov
Date: Tue Feb 09 2021 - 04:48:36 EST


> 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@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Sabyrzhan Tasbolatov <snovitoll@xxxxxxxxx>
> ---
>>> 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().

>Looks like you forgot to take out the opening brace.

Cringe moment. Sorry, should've checked it properly first.

v3: Removed opening brace.
---
drivers/misc/vmw_vmci/vmci_queue_pair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index ea16df73cde0..024dcdbd9d01 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -537,7 +537,7 @@ 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) {
+ if (queue_size + queue_page_size > KMALLOC_MAX_SIZE)
return NULL;

queue = kzalloc(queue_size + queue_page_size, GFP_KERNEL);
--
2.25.1