@@ -605,3 +605,76 @@
.prog_type = BPF_PROG_TYPE_SCHED_CLS,
.result = ACCEPT,
},
+{
+ "reference tracking: use ptr from bpf_tcp_sock() after release",
+ .insns = {
+ BPF_SK_LOOKUP,
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_tcp_sock),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_EMIT_CALL(BPF_FUNC_sk_release),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_EMIT_CALL(BPF_FUNC_sk_release),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_tcp_sock, snd_cwnd)),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .result = REJECT,
+ .errstr = "invalid mem access",
+},
+{
+ "reference tracking: use ptr from bpf_sk_fullsock() after release",
+ .insns = {
+ BPF_SK_LOOKUP,
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_EMIT_CALL(BPF_FUNC_sk_release),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_7, BPF_REG_0),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_EMIT_CALL(BPF_FUNC_sk_release),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_7, offsetof(struct bpf_sock, type)),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .result = REJECT,
+ .errstr = "invalid mem access",
+},
+{
+ "reference tracking: use ptr from bpf_sk_fullsock(tp) after release",
+ .insns = {
+ BPF_SK_LOOKUP,
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_tcp_sock),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 3),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_EMIT_CALL(BPF_FUNC_sk_release),
+ BPF_EXIT_INSN(),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_sk_fullsock),
+ BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+ BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+ BPF_EMIT_CALL(BPF_FUNC_sk_release),
+ BPF_JMP_IMM(BPF_JNE, BPF_REG_6, 0, 1),
+ BPF_EXIT_INSN(),
+ BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_6, offsetof(struct bpf_sock, type)),
+ BPF_EXIT_INSN(),
+ },
+ .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+ .result = REJECT,
+ .errstr = "invalid mem access",
+},
Adding verifier tests to ensure the ptr returned from bpf_tcp_sock() and bpf_sk_fullsock() cannot be accessed after bpf_sk_release() is called. It is derived from a reproducer test from Lorenz Bauer. Cc: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Martin KaFai Lau <kafai@fb.com> --- .../selftests/bpf/verifier/ref_tracking.c | 73 +++++++++++++++++++ 1 file changed, 73 insertions(+)