From 7595078c8686ef7d0ce160848144f3884f0e3b54 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Mon, 20 Jun 2022 09:15:47 +0200 Subject: [PATCH] udmabuf: add back sanity check Check vm_fault->pgoff before using it. When we removed the warning, we also removed the check. Fixes: b4f2e096eaa6 ("udmabuf: drop WARN_ON() check.") Reported-by: zdi-disclosures@trendmicro.com Suggested-by: Linus Torvalds Signed-off-by: Gerd Hoffmann Signed-off-by: Linus Torvalds --- drivers/dma-buf/udmabuf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index e7330684d3b82..9631f2fd2faf7 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -32,8 +32,11 @@ static vm_fault_t udmabuf_vm_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; struct udmabuf *ubuf = vma->vm_private_data; + pgoff_t pgoff = vmf->pgoff; - vmf->page = ubuf->pages[vmf->pgoff]; + if (pgoff >= ubuf->pagecount) + return VM_FAULT_SIGBUS; + vmf->page = ubuf->pages[pgoff]; get_page(vmf->page); return 0; } -- 2.39.5