From: David Ahern <dah...@digitalocean.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.li...@gmail.com>
Co-developed-by: David Ahern <dah...@digitalocean.com>
Signed-off-by: David Ahern <dah...@digitalocean.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 bfb31c1be219..05accb95bb4a 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -220,6 +220,7 @@ enum bpf_attach_type {
BPF_MODIFY_RETURN,
BPF_LSM_MAC,
BPF_TRACE_ITER,
+ 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 da0634979f53..19272eb7bb8f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -6931,6 +6931,17 @@ 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 bfb31c1be219..05accb95bb4a 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -220,6 +220,7 @@ enum bpf_attach_type {
BPF_MODIFY_RETURN,
BPF_LSM_MAC,
BPF_TRACE_ITER,
+ BPF_XDP_EGRESS,
__MAX_BPF_ATTACH_TYPE
};
--
2.21.1 (Apple Git-122.3)
