Re: [PATCH] xen/grants: prevent integer overflow in gnttab_dma_alloc_pages()

[Juergen Gross]

On 01.09.22 17:35, Dan Carpenter wrote:

The change from kcalloc() to kvmalloc() means that arg->nr_pages
might now be large enough that the "args->nr_pages << PAGE_SHIFT" can
result in an integer overflow.

Fixes: b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()")
Signed-off-by: Dan Carpenter 


Reviewed-by: Juergen Gross 


Juergen


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[PATCH] xen/grants: prevent integer overflow in gnttab_dma_alloc_pages()

[Dan Carpenter]

The change from kcalloc() to kvmalloc() means that arg->nr_pages
might now be large enough that the "args->nr_pages << PAGE_SHIFT" can
result in an integer overflow.

Fixes: b3f7931f5c61 ("xen/gntdev: switch from kcalloc() to kvcalloc()")
Signed-off-by: Dan Carpenter 
---
 drivers/xen/grant-table.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 738029de3c67..e1ec725c2819 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -1047,6 +1047,9 @@ int gnttab_dma_alloc_pages(struct gnttab_dma_alloc_args 
*args)
size_t size;
int i, ret;
 
+   if (args->nr_pages < 0 || args->nr_pages > (INT_MAX >> PAGE_SHIFT))
+   return -ENOMEM;
+
size = args->nr_pages << PAGE_SHIFT;
if (args->coherent)
args->vaddr = dma_alloc_coherent(args->dev, size,
-- 
2.35.1