Re: [RFC PATCH 3/7] tun: allow use of BPF_PROG_TYPE_SCHED_CLS program type
From: Alexei Starovoitov <hidden>
Date: 2021-01-05 19:31:45
Also in:
bpf, lkml
On Tue, Jan 05, 2021 at 02:24:12PM +0200, Yuri Benditovich wrote:
quoted hunk ↗ jump to hunk
This program type can set skb hash value. It will be useful when the tun will support hash reporting feature if virtio-net. Signed-off-by: Yuri Benditovich <redacted> --- drivers/net/tun.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 7959b5c2d11f..455f7afc1f36 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c@@ -2981,6 +2981,8 @@ static int tun_set_ebpf(struct tun_struct *tun, struct tun_prog __rcu **prog_p, prog = NULL; } else { prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SOCKET_FILTER); + if (IS_ERR(prog)) + prog = bpf_prog_get_type(fd, BPF_PROG_TYPE_SCHED_CLS);
Patches 1 and 2 are missing for me, so I couldn't review properly, but this diff looks odd. It allows sched_cls prog type to attach to tun. That means everything that sched_cls progs can do will be done from tun hook? sched_cls assumes l2 and can modify the packet. I think crashes are inevitable.