From: Matthew Cover <werekraken@gmail.com>
To: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Martin KaFai Lau <kafai@fb.com>, Song Liu <songliubraving@fb.com>,
Yonghong Song <yhs@fb.com>, Andrii Nakryiko <andriin@fb.com>,
"David S. Miller" <davem@davemloft.net>,
Shuah Khan <shuah@kernel.org>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
Jakub Sitnicki <jakub@cloudflare.com>,
Quentin Monnet <quentin.monnet@netronome.com>,
Matthew Cover <matthew.cover@stackpath.com>,
Stanislav Fomichev <sdf@google.com>, Andrey Ignatov <rdna@fb.com>,
Lorenz Bauer <lmb@cloudflare.com>,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: [PATCH bpf-next v2 2/2] selftests/bpf: test references to nf_conn
Date: Tue, 21 Jan 2020 13:22:33 -0700 [thread overview]
Message-ID: <20200121202233.26583-1-matthew.cover@stackpath.com> (raw)
In-Reply-To: <20200121202038.26490-1-matthew.cover@stackpath.com>
Make sure that returning a struct nf_conn * reference invokes
the reference tracking machinery in the verifier.
Signed-off-by: Matthew Cover <matthew.cover@stackpath.com>
---
tools/testing/selftests/bpf/test_verifier.c | 18 ++++++++
.../testing/selftests/bpf/verifier/ref_tracking.c | 48 ++++++++++++++++++++++
2 files changed, 66 insertions(+)
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 87eaa49..7569db2 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -294,6 +294,24 @@ static void bpf_fill_scale(struct bpf_test *self)
}
}
+/* BPF_CT_LOOKUP contains 13 instructions, if you need to fix up maps */
+#define BPF_CT_LOOKUP(func) \
+ /* struct bpf_nf_conntrack_tuple tuple = {} */ \
+ BPF_MOV64_IMM(BPF_REG_2, 0), \
+ BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -8), \
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -16), \
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -24), \
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -32), \
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -40), \
+ BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -48), \
+ /* ct = func(ctx, &tuple, sizeof tuple, 0, 0) */ \
+ BPF_MOV64_REG(BPF_REG_2, BPF_REG_10), \
+ BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -48), \
+ BPF_MOV64_IMM(BPF_REG_3, sizeof(struct bpf_nf_conntrack_tuple)),\
+ BPF_MOV64_IMM(BPF_REG_4, 0), \
+ BPF_MOV64_IMM(BPF_REG_5, 0), \
+ BPF_EMIT_CALL(BPF_FUNC_ ## func)
+
/* BPF_SK_LOOKUP contains 13 instructions, if you need to fix up maps */
#define BPF_SK_LOOKUP(func) \
/* struct bpf_sock_tuple tuple = {} */ \
diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c b/tools/testing/selftests/bpf/verifier/ref_tracking.c
index 604b461..de5c550a 100644
--- a/tools/testing/selftests/bpf/verifier/ref_tracking.c
+++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c
@@ -21,6 +21,17 @@
.result = REJECT,
},
{
+ "reference tracking: leak potential reference to nf_conn",
+ .insns = {
+ BPF_CT_LOOKUP(ct_lookup_tcp),
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), /* leak reference */
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .errstr = "Unreleased reference",
+ .result = REJECT,
+},
+{
"reference tracking: leak potential reference on stack",
.insns = {
BPF_SK_LOOKUP(sk_lookup_tcp),
@@ -72,6 +83,17 @@
.result = REJECT,
},
{
+ "reference tracking: zero potential reference to nf_conn",
+ .insns = {
+ BPF_CT_LOOKUP(ct_lookup_tcp),
+ BPF_MOV64_IMM(BPF_REG_0, 0), /* leak reference */
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .errstr = "Unreleased reference",
+ .result = REJECT,
+},
+{
"reference tracking: copy and zero potential references",
.insns = {
BPF_SK_LOOKUP(sk_lookup_tcp),
@@ -113,6 +135,20 @@
.result = REJECT,
},
{
+ "reference tracking: release reference to nf_conn without check",
+ .insns = {
+ BPF_CT_LOOKUP(ct_lookup_tcp),
+ /* reference in r0 may be NULL */
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_MOV64_IMM(BPF_REG_2, 0),
+ BPF_EMIT_CALL(BPF_FUNC_ct_release),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .errstr = "type=nf_conn_or_null expected=nf_conn",
+ .result = REJECT,
+},
+{
"reference tracking: release reference",
.insns = {
BPF_SK_LOOKUP(sk_lookup_tcp),
@@ -137,6 +173,18 @@
.result = ACCEPT,
},
{
+ "reference tracking: release reference to nf_conn",
+ .insns = {
+ BPF_CT_LOOKUP(ct_lookup_tcp),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
+ BPF_EMIT_CALL(BPF_FUNC_ct_release),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .result = ACCEPT,
+},
+{
"reference tracking: release reference 2",
.insns = {
BPF_SK_LOOKUP(sk_lookup_tcp),
--
1.8.3.1
next prev parent reply other threads:[~2020-01-21 20:22 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-18 0:01 [PATCH bpf-next] bpf: add bpf_ct_lookup_{tcp,udp}() helpers Matthew Cover
2020-01-18 11:37 ` kbuild test robot
2020-01-18 11:58 ` kbuild test robot
2020-01-19 3:05 ` John Fastabend
2020-01-20 18:11 ` Matt Cover
2020-01-20 20:10 ` Matt Cover
2020-01-20 21:11 ` Daniel Borkmann
2020-01-20 21:21 ` Matt Cover
2020-01-23 21:28 ` Matt Cover
2020-01-21 20:20 ` [PATCH bpf-next v2 1/2] " Matthew Cover
2020-01-21 20:22 ` Matthew Cover [this message]
2020-01-21 20:35 ` Matt Cover
2020-01-21 21:31 ` Matt Cover
2020-01-24 19:11 ` Joe Stringer
2020-01-24 21:46 ` Matt Cover
2020-01-30 21:53 ` unstable bpf helpers proposal. Was: " Alexei Starovoitov
2020-02-06 6:13 ` Matt Cover
2020-02-20 4:45 ` Alexei Starovoitov
2020-04-03 23:56 ` Matt Cover
2020-04-07 3:03 ` Alexei Starovoitov
2020-04-07 5:28 ` Matt Cover
2020-04-07 17:34 ` Alexei Starovoitov
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