From: Daniel Borkmann <daniel@iogearbox.net>
To: ast@kernel.org
Cc: netdev@vger.kernel.org, Daniel Borkmann <daniel@iogearbox.net>,
Roman Gushchin <guro@fb.com>
Subject: [PATCH bpf 2/4] bpf: don't set id on after map lookup with ptr_to_map_val return
Date: Thu, 1 Nov 2018 00:05:53 +0100 [thread overview]
Message-ID: <20181031230555.3371-3-daniel@iogearbox.net> (raw)
In-Reply-To: <20181031230555.3371-1-daniel@iogearbox.net>
In the verifier there is no such semantics where registers with
PTR_TO_MAP_VALUE type have an id assigned to them. This is only
used in PTR_TO_MAP_VALUE_OR_NULL and later on nullified once the
test against NULL has been pattern matched and type transformed
into PTR_TO_MAP_VALUE.
Fixes: 3e6a4b3e0289 ("bpf/verifier: introduce BPF_PTR_TO_MAP_VALUE")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Roman Gushchin <guro@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/bpf/verifier.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 774fa40..1971ca32 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2852,10 +2852,6 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
regs[BPF_REG_0].type = NOT_INIT;
} else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL ||
fn->ret_type == RET_PTR_TO_MAP_VALUE) {
- if (fn->ret_type == RET_PTR_TO_MAP_VALUE)
- regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
- else
- regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
/* There is no offset yet applied, variable or fixed */
mark_reg_known_zero(env, regs, BPF_REG_0);
/* remember map_ptr, so that check_map_access()
@@ -2868,7 +2864,12 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
return -EINVAL;
}
regs[BPF_REG_0].map_ptr = meta.map_ptr;
- regs[BPF_REG_0].id = ++env->id_gen;
+ if (fn->ret_type == RET_PTR_TO_MAP_VALUE) {
+ regs[BPF_REG_0].type = PTR_TO_MAP_VALUE;
+ } else {
+ regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
+ regs[BPF_REG_0].id = ++env->id_gen;
+ }
} else if (fn->ret_type == RET_PTR_TO_SOCKET_OR_NULL) {
int id = acquire_reference_state(env, insn_idx);
if (id < 0)
--
2.9.5
next prev parent reply other threads:[~2018-11-01 8:06 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-31 23:05 [PATCH bpf 0/4] BPF fixes and tests Daniel Borkmann
2018-10-31 23:05 ` [PATCH bpf 1/4] bpf: fix partial copy of map_ptr when dst is scalar Daniel Borkmann
2018-11-01 19:17 ` Edward Cree
2018-11-01 19:18 ` Arnaldo Carvalho de Melo
2018-10-31 23:05 ` Daniel Borkmann [this message]
2018-11-01 1:11 ` [PATCH bpf 2/4] bpf: don't set id on after map lookup with ptr_to_map_val return Roman Gushchin
2018-10-31 23:05 ` [PATCH bpf 3/4] bpf: add various test cases to test_verifier Daniel Borkmann
2018-10-31 23:05 ` [PATCH bpf 4/4] bpf: test make sure to run unpriv test cases in test_verifier Daniel Borkmann
2018-11-01 0:08 ` [PATCH bpf 0/4] BPF fixes and tests Alexei Starovoitov
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