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Message-Id: <20230418131038.18054-7-fw@strlen.de>
Date: Tue, 18 Apr 2023 15:10:38 +0200
From: Florian Westphal <fw@...len.de>
To: <bpf@...r.kernel.org>
Cc: netdev@...r.kernel.org, netfilter-devel@...r.kernel.org,
dxu@...uu.xyz, qde@...cy.de, Florian Westphal <fw@...len.de>
Subject: [PATCH bpf-next v3 6/6] bpf: add test_run support for netfilter program type
also extend prog_tests with a small retval test: values other
than accept or drop (0, 1) will cause issues.
NF_QUEUE could be implemented later if we can guarantee that attachment
of such programs can be rejected if they get attached to a pf/hook that
doesn't support async reinjection.
NF_STOLEN could be implemented via trusted helpers that can guarantee
that the skb will eventually be free'd.
$ ./test_progs --allow=verifier_netfilter_retcode
#278/1 verifier_netfilter_retcode/bpf_exit with invalid return code. test1:OK
#278/2 verifier_netfilter_retcode/bpf_exit with valid return code. test2:OK
#278/3 verifier_netfilter_retcode/bpf_exit with valid return code. test3:OK
#278/4 verifier_netfilter_retcode/bpf_exit with invalid return code. test4:OK
#278 verifier_netfilter_retcode:OK
Signed-off-by: Florian Westphal <fw@...len.de>
---
include/linux/bpf.h | 3 +
net/bpf/test_run.c | 140 ++++++++++++++++++
net/netfilter/nf_bpf_link.c | 1 +
.../selftests/bpf/prog_tests/verifier.c | 2 +
.../bpf/progs/verifier_netfilter_retcode.c | 49 ++++++
5 files changed, 195 insertions(+)
create mode 100644 tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 18b592fde896..e53ceee1df37 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -2264,6 +2264,9 @@ int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
int bpf_prog_test_run_sk_lookup(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr);
+int bpf_prog_test_run_nf(struct bpf_prog *prog,
+ const union bpf_attr *kattr,
+ union bpf_attr __user *uattr);
bool btf_ctx_access(int off, int size, enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info);
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index f170e8a17974..1f6d785ad028 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -19,7 +19,9 @@
#include <linux/error-injection.h>
#include <linux/smp.h>
#include <linux/sock_diag.h>
+#include <linux/netfilter.h>
#include <net/xdp.h>
+#include <net/netfilter/nf_bpf_link.h>
#define CREATE_TRACE_POINTS
#include <trace/events/bpf_test_run.h>
@@ -1691,6 +1693,144 @@ int bpf_prog_test_run_syscall(struct bpf_prog *prog,
return err;
}
+static int verify_and_copy_hook_state(struct nf_hook_state *state,
+ const struct nf_hook_state *user,
+ struct net_device *dev)
+{
+ if (user->in || user->out)
+ return -EINVAL;
+
+ if (user->net || user->sk || user->okfn)
+ return -EINVAL;
+
+ switch (user->pf) {
+ case NFPROTO_IPV4:
+ case NFPROTO_IPV6:
+ switch (state->hook) {
+ case NF_INET_PRE_ROUTING:
+ state->in = dev;
+ break;
+ case NF_INET_LOCAL_IN:
+ state->in = dev;
+ break;
+ case NF_INET_FORWARD:
+ state->in = dev;
+ state->out = dev;
+ break;
+ case NF_INET_LOCAL_OUT:
+ state->out = dev;
+ break;
+ case NF_INET_POST_ROUTING:
+ state->out = dev;
+ break;
+ }
+
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ state->pf = user->pf;
+ state->hook = user->hook;
+
+ return 0;
+}
+
+int bpf_prog_test_run_nf(struct bpf_prog *prog,
+ const union bpf_attr *kattr,
+ union bpf_attr __user *uattr)
+{
+ struct net *net = current->nsproxy->net_ns;
+ struct net_device *dev = net->loopback_dev;
+ struct nf_hook_state *user_ctx, hook_state = {
+ .pf = NFPROTO_IPV4,
+ .hook = NF_INET_PRE_ROUTING,
+ };
+ u32 size = kattr->test.data_size_in;
+ u32 repeat = kattr->test.repeat;
+ struct bpf_nf_ctx ctx = {
+ .state = &hook_state,
+ };
+ struct sk_buff *skb = NULL;
+ u32 retval, duration;
+ void *data;
+ int ret;
+
+ if (kattr->test.flags || kattr->test.cpu || kattr->test.batch_size)
+ return -EINVAL;
+
+ if (size < ETH_HLEN + sizeof(struct iphdr))
+ return -EINVAL;
+
+ data = bpf_test_init(kattr, kattr->test.data_size_in, size,
+ NET_SKB_PAD + NET_IP_ALIGN,
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ if (!repeat)
+ repeat = 1;
+
+ user_ctx = bpf_ctx_init(kattr, sizeof(struct nf_hook_state));
+ if (IS_ERR(user_ctx)) {
+ kfree(data);
+ return PTR_ERR(user_ctx);
+ }
+
+ if (user_ctx) {
+ ret = verify_and_copy_hook_state(&hook_state, user_ctx, dev);
+ if (ret)
+ goto out;
+ }
+
+ skb = slab_build_skb(data);
+ if (!skb) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ data = NULL; /* data released via kfree_skb */
+
+ skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
+ __skb_put(skb, size);
+
+ skb->protocol = eth_type_trans(skb, dev);
+
+ skb_reset_network_header(skb);
+
+ ret = -EINVAL;
+
+ switch (skb->protocol) {
+ case htons(ETH_P_IP):
+ if (hook_state.pf == NFPROTO_IPV4)
+ break;
+ goto out;
+ case htons(ETH_P_IPV6):
+ if (size < ETH_HLEN + sizeof(struct ipv6hdr))
+ goto out;
+ if (hook_state.pf == NFPROTO_IPV6)
+ break;
+ goto out;
+ default:
+ ret = -EPROTO;
+ goto out;
+ }
+
+ ctx.skb = skb;
+
+ ret = bpf_test_run(prog, &ctx, repeat, &retval, &duration, false);
+ if (ret)
+ goto out;
+
+ ret = bpf_test_finish(kattr, uattr, NULL, NULL, 0, retval, duration);
+
+out:
+ kfree(user_ctx);
+ kfree_skb(skb);
+ kfree(data);
+ return ret;
+}
+
static const struct btf_kfunc_id_set bpf_prog_test_kfunc_set = {
.owner = THIS_MODULE,
.set = &test_sk_check_kfunc_ids,
diff --git a/net/netfilter/nf_bpf_link.c b/net/netfilter/nf_bpf_link.c
index 2d12c978e4e7..01292e654b6a 100644
--- a/net/netfilter/nf_bpf_link.c
+++ b/net/netfilter/nf_bpf_link.c
@@ -167,6 +167,7 @@ int bpf_nf_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
}
const struct bpf_prog_ops netfilter_prog_ops = {
+ .test_run = bpf_prog_test_run_nf,
};
static bool nf_ptr_to_btf_id(struct bpf_insn_access_aux *info, const char *name)
diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c
index 25bc8958dbfe..491efd5f22ff 100644
--- a/tools/testing/selftests/bpf/prog_tests/verifier.c
+++ b/tools/testing/selftests/bpf/prog_tests/verifier.c
@@ -29,6 +29,7 @@
#include "verifier_map_ret_val.skel.h"
#include "verifier_masking.skel.h"
#include "verifier_meta_access.skel.h"
+#include "verifier_netfilter_retcode.skel.h"
#include "verifier_raw_stack.skel.h"
#include "verifier_raw_tp_writable.skel.h"
#include "verifier_reg_equal.skel.h"
@@ -94,6 +95,7 @@ void test_verifier_map_ptr(void) { RUN(verifier_map_ptr); }
void test_verifier_map_ret_val(void) { RUN(verifier_map_ret_val); }
void test_verifier_masking(void) { RUN(verifier_masking); }
void test_verifier_meta_access(void) { RUN(verifier_meta_access); }
+void test_verifier_netfilter_retcode(void) { RUN(verifier_netfilter_retcode); }
void test_verifier_raw_stack(void) { RUN(verifier_raw_stack); }
void test_verifier_raw_tp_writable(void) { RUN(verifier_raw_tp_writable); }
void test_verifier_reg_equal(void) { RUN(verifier_reg_equal); }
diff --git a/tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c b/tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c
new file mode 100644
index 000000000000..353ae6da00e1
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/verifier_netfilter_retcode.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+SEC("netfilter")
+__description("bpf_exit with invalid return code. test1")
+__failure __msg("R0 is not a known value")
+__naked void with_invalid_return_code_test1(void)
+{
+ asm volatile (" \
+ r0 = *(u64*)(r1 + 0); \
+ exit; \
+" ::: __clobber_all);
+}
+
+SEC("netfilter")
+__description("bpf_exit with valid return code. test2")
+__success
+__naked void with_valid_return_code_test2(void)
+{
+ asm volatile (" \
+ r0 = 0; \
+ exit; \
+" ::: __clobber_all);
+}
+
+SEC("netfilter")
+__description("bpf_exit with valid return code. test3")
+__success
+__naked void with_valid_return_code_test3(void)
+{
+ asm volatile (" \
+ r0 = 1; \
+ exit; \
+" ::: __clobber_all);
+}
+
+SEC("netfilter")
+__description("bpf_exit with invalid return code. test4")
+__failure __msg("R0 has value (0x2; 0x0)")
+__naked void with_invalid_return_code_test4(void)
+{
+ asm volatile (" \
+ r0 = 2; \
+ exit; \
+" ::: __clobber_all);
+}
--
2.39.2
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