From c72b5cbb09bd76634b8d19695db2219964e24128 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Thu, 21 May 2020 13:07:46 -0700 Subject: [PATCH] bpf: Selftests, verifier case for non null pointer check branch taken When we have pointer type that is known to be non-null and comparing against zero we only follow the non-null branch. This adds tests to cover this case for reference tracking. Also add the other case when comparison against a non-zero value and ensure we still fail with unreleased reference. Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/159009166599.6313.1593680633787453767.stgit@john-Precision-5820-Tower --- .../testing/selftests/bpf/verifier/ref_tracking.c | 33 ++++++++++++++++++++++ 1 file changed, 33 insertions(+) diff --git a/tools/testing/selftests/bpf/verifier/ref_tracking.c b/tools/testing/selftests/bpf/verifier/ref_tracking.c index 604b461..056e027 100644 --- a/tools/testing/selftests/bpf/verifier/ref_tracking.c +++ b/tools/testing/selftests/bpf/verifier/ref_tracking.c @@ -821,3 +821,36 @@ .result = REJECT, .errstr = "invalid mem access", }, +{ + "reference tracking: branch tracking valid pointer null comparison", + .insns = { + BPF_SK_LOOKUP(sk_lookup_tcp), + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_3, 1), + BPF_JMP_IMM(BPF_JNE, BPF_REG_6, 0, 1), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 2), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .result = ACCEPT, +}, +{ + "reference tracking: branch tracking valid pointer value comparison", + .insns = { + BPF_SK_LOOKUP(sk_lookup_tcp), + BPF_MOV64_REG(BPF_REG_6, BPF_REG_0), + BPF_MOV64_IMM(BPF_REG_3, 1), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 0, 4), + BPF_MOV64_IMM(BPF_REG_3, 0), + BPF_JMP_IMM(BPF_JEQ, BPF_REG_6, 1234, 2), + BPF_MOV64_REG(BPF_REG_1, BPF_REG_6), + BPF_EMIT_CALL(BPF_FUNC_sk_release), + BPF_EXIT_INSN(), + }, + .prog_type = BPF_PROG_TYPE_SCHED_CLS, + .errstr = "Unreleased reference", + .result = REJECT, +}, -- 2.7.4