[PATCH bpf-next v3 7/8] selftests/bpf: test references to sock_common

[Lorenz Bauer]

Make sure that returning a struct sock_common * reference invokes
the reference tracking machinery in the verifier.

Signed-off-by: Lorenz Bauer <l...@cloudflare.com>
---
 .../selftests/bpf/verifier/ref_tracking.c     | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c 
b/tools/testing/selftests/bpf/verifier/ref_tracking.c
index a6905e5017dc..ebcbf154c460 100644
--- a/tools/testing/selftests/bpf/verifier/ref_tracking.c
+++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c
@@ -9,6 +9,17 @@
        .errstr = "Unreleased reference",
        .result = REJECT,
 },
+{
+       "reference tracking: leak potential reference to sock_common",
+       .insns = {
+       BPF_SK_LOOKUP(skc_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 = {
@@ -49,6 +60,17 @@
        .errstr = "Unreleased reference",
        .result = REJECT,
 },
+{
+       "reference tracking: zero potential reference to sock_common",
+       .insns = {
+       BPF_SK_LOOKUP(skc_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 = {
@@ -76,6 +98,20 @@
        .errstr = "type=sock_or_null expected=sock",
        .result = REJECT,
 },
+{
+       "reference tracking: release reference to sock_common without check",
+       .insns = {
+       BPF_SK_LOOKUP(skc_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_sk_release),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       .errstr = "type=sock_common_or_null expected=sock",
+       .result = REJECT,
+},
 {
        "reference tracking: release reference",
        .insns = {
@@ -88,6 +124,18 @@
        .prog_type = BPF_PROG_TYPE_SCHED_CLS,
        .result = ACCEPT,
 },
+{
+       "reference tracking: release reference to sock_common",
+       .insns = {
+       BPF_SK_LOOKUP(skc_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_sk_release),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+       .result = ACCEPT,
+},
 {
        "reference tracking: release reference 2",
        .insns = {
-- 
2.19.1