From: Pavel Skripkin <paskripkin@gmail.com> stable inclusion from linux-4.19.196 commit f8111c0d7ed42ede41a3d0d393b104de0730a8a6 category: bugfix issue: #I4CC5E CVE: CVE-2021-3743 -------------------------------- [ Upstream commit ad9d24c9429e2159d1e279dc3a83191ccb4daf1d ] Syzbot reported slab-out-of-bounds Read in qrtr_endpoint_post. The problem was in wrong _size_ type: if (len != ALIGN(size, 4) + hdrlen) goto err; If size from qrtr_hdr is 4294967293 (0xfffffffd), the result of ALIGN(size, 4) will be 0. In case of len == hdrlen and size == 4294967293 in header this check won't fail and skb_put_data(skb, data + hdrlen, size); will read out of bound from data, which is hdrlen allocated block. Fixes: 194ccc88297a ("net: qrtr: Support decoding incoming v2 packets") Reported-and-tested-by: syzbot+1917d778024161609247@syzkaller.appspotmail.com Signed-off-by: Pavel Skripkin <paskripkin@gmail.com> Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Reviewed-by: Yue Haibing <yuehaibing@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Signed-off-by: Yu Changchun <yuchangchun1@huawei.com> --- net/qrtr/qrtr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c index 5d152de50dff..4c7ae7155078 100644 --- a/net/qrtr/qrtr.c +++ b/net/qrtr/qrtr.c @@ -264,7 +264,7 @@ int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len) const struct qrtr_hdr_v2 *v2; struct sk_buff *skb; struct qrtr_cb *cb; - unsigned int size; + size_t size; unsigned int ver; size_t hdrlen; -- 2.22.0