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 <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/159009166599.6313.1593680633787453767.stgit@john-Precision-5820-Tower
This commit is contained in:
John Fastabend 2020-05-21 13:07:46 -07:00 committed by Alexei Starovoitov
parent cac616db39
commit c72b5cbb09

View File

@ -821,3 +821,36 @@
.result = REJECT, .result = REJECT,
.errstr = "invalid mem access", .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,
},