[PATCH 6.1 0382/1146] selftests/bpf: Make sure zero-len skbs arent redirectable

Greg Kroah-Hartman
2022-12-28T15:53:18Z

From: Stanislav Fomichev <sdf@google.com>

[ Upstream commit 68f8e3d4b916531ea3bb8b83e35138cf78f2fce5 ]

LWT_XMIT to test L3 case, TC to test L2 case.

v2:
- s/veth_ifindex/ipip_ifindex/ in two places (Martin)
- add comment about which condition triggers the rejection (Martin)

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20221121180340.1983627-2-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Stable-dep-of: 8ac88eece800 ("selftests/bpf: Mount debugfs in setns_by_fd")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../selftests/bpf/prog_tests/empty_skb.c | 146 ++++++++++++++++++
tools/testing/selftests/bpf/progs/empty_skb.c | 37 +++++
2 files changed, 183 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/empty_skb.c
create mode 100644 tools/testing/selftests/bpf/progs/empty_skb.c

diff --git a/tools/testing/selftests/bpf/prog_tests/empty_skb.c b/tools/testing/selftests/bpf/prog_tests/empty_skb.c
new file mode 100644
index 000000000000..32dd731e9070
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/empty_skb.c
@@ -0,0 +1,146 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <network_helpers.h>
+#include <net/if.h>
+#include "empty_skb.skel.h"
+
+#define SYS(cmd) ({ \
+ if (!ASSERT_OK(system(cmd), (cmd))) \
+ goto out; \
+})
+
+void test_empty_skb(void)
+{
+ LIBBPF_OPTS(bpf_test_run_opts, tattr);
+ struct empty_skb *bpf_obj = NULL;
+ struct nstoken *tok = NULL;
+ struct bpf_program *prog;
+ char eth_hlen_pp[15];
+ char eth_hlen[14];
+ int veth_ifindex;
+ int ipip_ifindex;
+ int err;
+ int i;
+
+ struct {
+ const char *msg;
+ const void *data_in;
+ __u32 data_size_in;
+ int *ifindex;
+ int err;
+ int ret;
+ bool success_on_tc;
+ } tests[] = {
+ /* Empty packets are always rejected. */
+
+ {
+ /* BPF_PROG_RUN ETH_HLEN size check */
+ .msg = "veth empty ingress packet",
+ .data_in = NULL,
+ .data_size_in = 0,
+ .ifindex = &veth_ifindex,
+ .err = -EINVAL,
+ },
+ {
+ /* BPF_PROG_RUN ETH_HLEN size check */
+ .msg = "ipip empty ingress packet",
+ .data_in = NULL,
+ .data_size_in = 0,
+ .ifindex = &ipip_ifindex,
+ .err = -EINVAL,
+ },
+
+ /* ETH_HLEN-sized packets:
+ * - can not be redirected at LWT_XMIT
+ * - can be redirected at TC to non-tunneling dest
+ */
+
+ {
+ /* __bpf_redirect_common */
+ .msg = "veth ETH_HLEN packet ingress",
+ .data_in = eth_hlen,
+ .data_size_in = sizeof(eth_hlen),
+ .ifindex = &veth_ifindex,
+ .ret = -ERANGE,
+ .success_on_tc = true,
+ },
+ {
+ /* __bpf_redirect_no_mac
+ *
+ * lwt: skb->len=0 <= skb_network_offset=0
+ * tc: skb->len=14 <= skb_network_offset=14
+ */
+ .msg = "ipip ETH_HLEN packet ingress",
+ .data_in = eth_hlen,
+ .data_size_in = sizeof(eth_hlen),
+ .ifindex = &ipip_ifindex,
+ .ret = -ERANGE,
+ },
+
+ /* ETH_HLEN+1-sized packet should be redirected. */
+
+ {
+ .msg = "veth ETH_HLEN+1 packet ingress",
+ .data_in = eth_hlen_pp,
+ .data_size_in = sizeof(eth_hlen_pp),
+ .ifindex = &veth_ifindex,
+ },
+ {
+ .msg = "ipip ETH_HLEN+1 packet ingress",
+ .data_in = eth_hlen_pp,
+ .data_size_in = sizeof(eth_hlen_pp),
+ .ifindex = &ipip_ifindex,
+ },
+ };
+
+ SYS("ip netns add empty_skb");
+ tok = open_netns("empty_skb");
+ SYS("ip link add veth0 type veth peer veth1");
+ SYS("ip link set dev veth0 up");
+ SYS("ip link set dev veth1 up");
+ SYS("ip addr add 10.0.0.1/8 dev veth0");
+ SYS("ip addr add 10.0.0.2/8 dev veth1");
+ veth_ifindex = if_nametoindex("veth0");
+
+ SYS("ip link add ipip0 type ipip local 10.0.0.1 remote 10.0.0.2");
+ SYS("ip link set ipip0 up");
+ SYS("ip addr add 192.168.1.1/16 dev ipip0");
+ ipip_ifindex = if_nametoindex("ipip0");
+
+ bpf_obj = empty_skb__open_and_load();
+ if (!ASSERT_OK_PTR(bpf_obj, "open skeleton"))
+ goto out;
+
+ for (i = 0; i < ARRAY_SIZE(tests); i++) {
+ bpf_object__for_each_program(prog, bpf_obj->obj) {
+ char buf[128];
+ bool at_tc = !strncmp(bpf_program__section_name(prog), "tc", 2);
+
+ tattr.data_in = tests[i].data_in;
+ tattr.data_size_in = tests[i].data_size_in;
+
+ tattr.data_size_out = 0;
+ bpf_obj->bss->ifindex = *tests[i].ifindex;
+ bpf_obj->bss->ret = 0;
+ err = bpf_prog_test_run_opts(bpf_program__fd(prog), &tattr);
+ sprintf(buf, "err: %s [%s]", tests[i].msg, bpf_program__name(prog));
+
+ if (at_tc && tests[i].success_on_tc)
+ ASSERT_GE(err, 0, buf);
+ else
+ ASSERT_EQ(err, tests[i].err, buf);
+ sprintf(buf, "ret: %s [%s]", tests[i].msg, bpf_program__name(prog));
+ if (at_tc && tests[i].success_on_tc)
+ ASSERT_GE(bpf_obj->bss->ret, 0, buf);
+ else
+ ASSERT_EQ(bpf_obj->bss->ret, tests[i].ret, buf);
+ }
+ }
+
+out:
+ if (bpf_obj)
+ empty_skb__destroy(bpf_obj);
+ if (tok)
+ close_netns(tok);
+ system("ip netns del empty_skb");
+}
diff --git a/tools/testing/selftests/bpf/progs/empty_skb.c b/tools/testing/selftests/bpf/progs/empty_skb.c
new file mode 100644
index 000000000000..4b0cd6753251
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/empty_skb.c
@@ -0,0 +1,37 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+
+char _license[] SEC("license") = "GPL";
+
+int ifindex;
+int ret;
+
+SEC("lwt_xmit")
+int redirect_ingress(struct __sk_buff *skb)
+{
+ ret = bpf_clone_redirect(skb, ifindex, BPF_F_INGRESS);
+ return 0;
+}
+
+SEC("lwt_xmit")
+int redirect_egress(struct __sk_buff *skb)
+{
+ ret = bpf_clone_redirect(skb, ifindex, 0);
+ return 0;
+}
+
+SEC("tc")
+int tc_redirect_ingress(struct __sk_buff *skb)
+{
+ ret = bpf_clone_redirect(skb, ifindex, BPF_F_INGRESS);
+ return 0;
+}
+
+SEC("tc")
+int tc_redirect_egress(struct __sk_buff *skb)
+{
+ ret = bpf_clone_redirect(skb, ifindex, 0);
+ return 0;
+}
--
2.35.1