From: Pavel Skripkin <paskripkin@gmail.com> stable inclusion from stable-v5.10.110 commit b267a8118c2b171bf7d67b90ed64154eeab9fae0 bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 2b6dd600dd72573c23ea180b5b0b2f1813405882 ] 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 <paskripkin@gmail.com> Link: http://patchwork.freedesktop.org/patch/msgid/20211230142649.23022-1-paskripk... Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- drivers/dma-buf/udmabuf.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/dma-buf/udmabuf.c b/drivers/dma-buf/udmabuf.c index db732f71e59a..cfbf10128aae 100644 --- a/drivers/dma-buf/udmabuf.c +++ b/drivers/dma-buf/udmabuf.c @@ -181,6 +181,10 @@ 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) { -- 2.20.1