From 2b6dd600dd72573c23ea180b5b0b2f1813405882 Mon Sep 17 00:00:00 2001 From: Pavel Skripkin Date: Thu, 30 Dec 2021 17:26:49 +0300 Subject: udmabuf: validate ubuf->pagecount Syzbot has reported GPF in sg_alloc_append_table_from_pages(). The problem was in ubuf->pages == ZERO_PTR. ubuf->pagecount is calculated from arguments passed from user-space. If user creates udmabuf with list.size == 0 then ubuf->pagecount will be also equal to zero; it causes kmalloc_array() to return ZERO_PTR. Fix it by validating ubuf->pagecount before passing it to kmalloc_array(). Fixes: fbb0de795078 ("Add udmabuf misc device") Reported-and-tested-by: syzbot+2c56b725ec547fa9cb29@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin Link: http://patchwork.freedesktop.org/patch/msgid/20211230142649.23022-1-paskripkin@gmail.com Signed-off-by: Gerd Hoffmann --- drivers/dma-buf/udmabuf.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'drivers/dma-buf') diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index c57a609db75b..e7330684d3b8 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -190,6 +190,10 @@ static long udmabuf_create(struct miscdevice *device, if (ubuf->pagecount > pglimit) goto err; } + + if (!ubuf->pagecount) + goto err; + ubuf->pages = kmalloc_array(ubuf->pagecount, sizeof(*ubuf->pages), GFP_KERNEL); if (!ubuf->pages) { -- cgit v1.2.3