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Date: Mon, 27 Apr 2020 16:46:22 -0600 From: David Ahern <dsahern@...nel.org> To: netdev@...r.kernel.org Cc: davem@...emloft.net, kuba@...nel.org, prashantbhole.linux@...il.com, jasowang@...hat.com, brouer@...hat.com, toke@...hat.com, toshiaki.makita1@...il.com, daniel@...earbox.net, john.fastabend@...il.com, ast@...nel.org, kafai@...com, songliubraving@...com, yhs@...com, andriin@...com, dsahern@...il.com, David Ahern <dahern@...italocean.com> Subject: [PATCH v4 bpf-next 04/15] net: Add BPF_XDP_EGRESS as a bpf_attach_type From: David Ahern <dahern@...italocean.com> Add new bpf_attach_type, BPF_XDP_EGRESS, for BPF programs attached at the XDP layer, but the egress path. Since egress path will not have ingress_ifindex and rx_queue_index set, update xdp_is_valid_access to block access to these entries in the xdp context when a program is attached with expected_attach_type set. Update dev_change_xdp_fd to verify expected_attach_type for a program is BPF_XDP_EGRESS if egress argument is set. The next patch adds support for the egress ifindex. Signed-off-by: Prashant Bhole <prashantbhole.linux@...il.com> Co-developed-by: David Ahern <dahern@...italocean.com> Signed-off-by: David Ahern <dahern@...italocean.com> --- include/uapi/linux/bpf.h | 1 + net/core/dev.c | 11 +++++++++++ net/core/filter.c | 11 +++++++++++ tools/include/uapi/linux/bpf.h | 1 + 4 files changed, 24 insertions(+) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 4a6c47f3febe..c89da2c2b1f2 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -215,6 +215,7 @@ enum bpf_attach_type { BPF_TRACE_FEXIT, BPF_MODIFY_RETURN, BPF_LSM_MAC, + BPF_XDP_EGRESS, __MAX_BPF_ATTACH_TYPE }; diff --git a/net/core/dev.c b/net/core/dev.c index c0455e764f97..88672ea4fc80 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -8737,6 +8737,17 @@ int dev_change_xdp_fd(struct net_device *dev, struct netlink_ext_ack *extack, if (IS_ERR(prog)) return PTR_ERR(prog); + if (egress && prog->expected_attach_type != BPF_XDP_EGRESS) { + NL_SET_ERR_MSG(extack, "XDP program in Tx path must use BPF_XDP_EGRESS attach type"); + bpf_prog_put(prog); + return -EINVAL; + } + if (!egress && prog->expected_attach_type == BPF_XDP_EGRESS) { + NL_SET_ERR_MSG(extack, "XDP program in Rx path can not use BPF_XDP_EGRESS attach type"); + bpf_prog_put(prog); + return -EINVAL; + } + if (!offload && bpf_prog_is_dev_bound(prog->aux)) { NL_SET_ERR_MSG(extack, "using device-bound program without HW_MODE flag is not supported"); bpf_prog_put(prog); diff --git a/net/core/filter.c b/net/core/filter.c index da3b7a72c37c..00e1941137ab 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -6861,6 +6861,17 @@ static bool xdp_is_valid_access(int off, int size, const struct bpf_prog *prog, struct bpf_insn_access_aux *info) { + /* Rx data is only accessible from original XDP where + * expected_attach_type is not set + */ + if (prog->expected_attach_type) { + switch (off) { + case offsetof(struct xdp_md, ingress_ifindex): + case offsetof(struct xdp_md, rx_queue_index): + return false; + } + } + if (type == BPF_WRITE) { if (bpf_prog_is_dev_bound(prog->aux)) { switch (off) { diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 4a6c47f3febe..c89da2c2b1f2 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -215,6 +215,7 @@ enum bpf_attach_type { BPF_TRACE_FEXIT, BPF_MODIFY_RETURN, BPF_LSM_MAC, + BPF_XDP_EGRESS, __MAX_BPF_ATTACH_TYPE }; -- 2.21.1 (Apple Git-122.3)
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