On Mon, Oct 2, 2023 at 12:04 AM Dan Carpenter dan.carpenter@linaro.org wrote:
The buffer->pages[] has "buffer->pagecount" elements so this > comparison has to be changed to >= to avoid reading beyond the end of the array. The buffer->pages[] array is allocated in cma_heap_allocate().
Fixes: a5d2d29e24be ("dma-buf: heaps: Move heap-helper logic into the cma_heap implementation") Signed-off-by: Dan Carpenter dan.carpenter@linaro.org
drivers/dma-buf/heaps/cma_heap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index ee899f8e6721..bea7e574f916 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -165,7 +165,7 @@ static vm_fault_t cma_heap_vm_fault(struct vm_fault *vmf) struct vm_area_struct *vma = vmf->vma; struct cma_heap_buffer *buffer = vma->vm_private_data;
if (vmf->pgoff > buffer->pagecount)
if (vmf->pgoff >= buffer->pagecount) return VM_FAULT_SIGBUS;
Hi Dan,
Your fix looks correct to me, but I'm curious if you observed this problem on a device? The mmap in dma-buf.c looks like it prevents creating a mapping that is too large, and I think an access beyond the VMA should segfault before reaching here.
Thanks, T.J.