From d200cf624c9247ab52b67d34d9e198262a23df31 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 23 Jul 2020 08:08:45 +0200 Subject: [PATCH] bpfilter: reject kernel addresses The bpfilter user mode helper processes the optval address using process_vm_readv. Don't send it kernel addresses fed under set_fs(KERNEL_DS) as that won't work. Signed-off-by: Christoph Hellwig Signed-off-by: David S. Miller --- net/bpfilter/bpfilter_kern.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/bpfilter/bpfilter_kern.c b/net/bpfilter/bpfilter_kern.c index 78d561f2c54da7..00540457e5f4d3 100644 --- a/net/bpfilter/bpfilter_kern.c +++ b/net/bpfilter/bpfilter_kern.c @@ -70,6 +70,10 @@ static int bpfilter_process_sockopt(struct sock *sk, int optname, .addr = (uintptr_t)optval, .len = optlen, }; + if (uaccess_kernel()) { + pr_err("kernel access not supported\n"); + return -EFAULT; + } return bpfilter_send_req(&req); }