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Groups > linux.kernel > #1311654 > unrolled thread
| Started by | Insu Yun <wuninsu@gmail.com> |
|---|---|
| First post | 2016-01-18 17:30 +0100 |
| Last post | 2016-01-18 17:50 +0100 |
| Articles | 3 — 2 participants |
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[PATCH] xen: fix potential integer overflow in queue_reply Insu Yun <wuninsu@gmail.com> - 2016-01-18 17:30 +0100
Re: [PATCH] xen: fix potential integer overflow in queue_reply David Vrabel <david.vrabel@citrix.com> - 2016-01-18 17:40 +0100
Re: [Xen-devel] [PATCH] xen: fix potential integer overflow in queue_reply David Vrabel <david.vrabel@citrix.com> - 2016-01-18 17:50 +0100
| From | Insu Yun <wuninsu@gmail.com> |
|---|---|
| Date | 2016-01-18 17:30 +0100 |
| Subject | [PATCH] xen: fix potential integer overflow in queue_reply |
| Message-ID | <qSkQO-38H-1@gated-at.bofh.it> |
When len is greater than UINT_MAX - sizeof(*rb), in next allocation,
it can overflow integer range and allocates small size of heap.
After that, memcpy will overflow the allocated heap.
Therefore, it needs to check the size of given length.
Signed-off-by: Insu Yun <wuninsu@gmail.com>
---
drivers/xen/xenbus/xenbus_dev_frontend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c
index 9433e46..b45ed69 100644
--- a/drivers/xen/xenbus/xenbus_dev_frontend.c
+++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
@@ -186,7 +186,7 @@ static int queue_reply(struct list_head *queue, const void *data, size_t len)
{
struct read_buffer *rb;
- if (len == 0)
+ if (len == 0 || len >= UINT_MAX - sizeof(*rb))
return 0;
rb = kmalloc(sizeof(*rb) + len, GFP_KERNEL);
--
1.9.1
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| From | David Vrabel <david.vrabel@citrix.com> |
|---|---|
| Date | 2016-01-18 17:40 +0100 |
| Message-ID | <qSl0t-3eo-3@gated-at.bofh.it> |
| In reply to | #1311654 |
On 18/01/16 16:29, Insu Yun wrote:
> When len is greater than UINT_MAX - sizeof(*rb), in next allocation,
> it can overflow integer range and allocates small size of heap.
> After that, memcpy will overflow the allocated heap.
> Therefore, it needs to check the size of given length.
[...]
> --- a/drivers/xen/xenbus/xenbus_dev_frontend.c
> +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
> @@ -186,7 +186,7 @@ static int queue_reply(struct list_head *queue, const void *data, size_t len)
> {
> struct read_buffer *rb;
>
> - if (len == 0)
> + if (len == 0 || len >= UINT_MAX - sizeof(*rb))
^^^^^^^^^^^^^^^^^^^^^^
Please check
len > XENSTORE_PAYLOAD_MAX
instead.
David
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| From | David Vrabel <david.vrabel@citrix.com> |
|---|---|
| Date | 2016-01-18 17:50 +0100 |
| Subject | Re: [Xen-devel] [PATCH] xen: fix potential integer overflow in queue_reply |
| Message-ID | <qSlaa-3jC-19@gated-at.bofh.it> |
| In reply to | #1311660 |
On 18/01/16 16:38, David Vrabel wrote:
> On 18/01/16 16:29, Insu Yun wrote:
>> When len is greater than UINT_MAX - sizeof(*rb), in next allocation,
>> it can overflow integer range and allocates small size of heap.
>> After that, memcpy will overflow the allocated heap.
>> Therefore, it needs to check the size of given length.
> [...]
>> --- a/drivers/xen/xenbus/xenbus_dev_frontend.c
>> +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c
>> @@ -186,7 +186,7 @@ static int queue_reply(struct list_head *queue, const void *data, size_t len)
>> {
>> struct read_buffer *rb;
>>
>> - if (len == 0)
>> + if (len == 0 || len >= UINT_MAX - sizeof(*rb))
> ^^^^^^^^^^^^^^^^^^^^^^
> Please check
>
> len > XENSTORE_PAYLOAD_MAX
>
> instead.
And return -EINVAL in this case (not zero).
David
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