On Thu, Nov 25, 2021 at 06:18:22PM +0300, Dan Carpenter wrote:
> I had thought that ->kmap_cnt was a regular int and not an unsigned
> int, but I would have to pull a stable tree to see where I misread the
> code.
I was looking at (struct ion_buffer)->kmap_cnt but this is
(struct ion_handle)->kmap_cnt. I'm not sure how those are related but
it makes me nervous that one can go higher than the other. Also both
probably need overflow protection.
So I guess I would just do something like:
diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c
index 806e9b30b9dc8..e8846279b33b5 100644
--- a/drivers/staging/android/ion/ion.c
+++ b/drivers/staging/android/ion/ion.c
@@ -489,6 +489,8 @@ static void *ion_buffer_kmap_get(struct ion_buffer *buffer)
void *vaddr;
if (buffer->kmap_cnt) {
+ if (buffer->kmap_cnt == INT_MAX)
+ return ERR_PTR(-EOVERFLOW);
buffer->kmap_cnt++;
return buffer->vaddr;
}
@@ -509,6 +511,8 @@ static void *ion_handle_kmap_get(struct ion_handle *handle)
void *vaddr;
if (handle->kmap_cnt) {
+ if (handle->kmap_cnt == INT_MAX)
+ return ERR_PTR(-EOVERFLOW);
handle->kmap_cnt++;
return buffer->vaddr;
}
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