From: Roman Gushchin <guro@fb.com>
To: <netdev@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>, <kernel-team@fb.com>,
Roman Gushchin <guro@fb.com>, Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>
Subject: [PATCH v3 bpf-next 06/14] bpf/verifier: introduce BPF_PTR_TO_MAP_VALUE
Date: Fri, 20 Jul 2018 10:45:50 -0700 [thread overview]
Message-ID: <20180720174558.5829-7-guro@fb.com> (raw)
In-Reply-To: <20180720174558.5829-1-guro@fb.com>
BPF_MAP_TYPE_CGROUP_STORAGE maps are special in a way
that the access from the bpf program side is lookup-free.
That means the result is guaranteed to be a valid
pointer to the cgroup storage; no NULL-check is required.
This patch introduces BPF_PTR_TO_MAP_VALUE return type,
which is required to cause the verifier accept programs,
which are not checking the map value pointer for being NULL.
Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
---
include/linux/bpf.h | 1 +
kernel/bpf/verifier.c | 8 ++++++--
2 files changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 16be67888c30..ca4ac2a39def 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -155,6 +155,7 @@ enum bpf_arg_type {
enum bpf_return_type {
RET_INTEGER, /* function returns integer */
RET_VOID, /* function doesn't return anything */
+ RET_PTR_TO_MAP_VALUE, /* returns a pointer to map elem value */
RET_PTR_TO_MAP_VALUE_OR_NULL, /* returns a pointer to map elem value or NULL */
};
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 0b089ba4595d..8098e39f825e 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2545,8 +2545,12 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
mark_reg_unknown(env, regs, BPF_REG_0);
} else if (fn->ret_type == RET_VOID) {
regs[BPF_REG_0].type = NOT_INIT;
- } else if (fn->ret_type == RET_PTR_TO_MAP_VALUE_OR_NULL) {
- regs[BPF_REG_0].type = PTR_TO_MAP_VALUE_OR_NULL;
+ } 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);
regs[BPF_REG_0].off = 0;
--
2.14.4
next prev parent reply other threads:[~2018-07-20 17:47 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-20 17:45 [PATCH v3 bpf-next 00/14] bpf: cgroup local storage Roman Gushchin
2018-07-20 17:45 ` Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 01/14] bpf: add ability to charge bpf maps memory dynamically Roman Gushchin
2018-07-27 18:01 ` Daniel Borkmann
2018-07-20 17:45 ` [PATCH v3 bpf-next 02/14] bpf: introduce cgroup storage maps Roman Gushchin
2018-07-20 17:45 ` Roman Gushchin
2018-07-27 4:11 ` Daniel Borkmann
2018-07-27 17:12 ` Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 03/14] bpf: pass a pointer to a cgroup storage using pcpu variable Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 04/14] bpf: allocate cgroup storage entries on attaching bpf programs Roman Gushchin
2018-07-27 4:21 ` Daniel Borkmann
2018-07-20 17:45 ` [PATCH v3 bpf-next 05/14] bpf: extend bpf_prog_array to store pointers to the cgroup storage Roman Gushchin
2018-07-20 17:45 ` Roman Gushchin [this message]
2018-07-20 17:45 ` [PATCH v3 bpf-next 07/14] bpf: don't allow create maps of cgroup local storages Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 08/14] bpf: introduce the bpf_get_local_storage() helper function Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 09/14] bpf: sync bpf.h to tools/ Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 10/14] bpftool: add support for CGROUP_STORAGE maps Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 11/14] bpf/test_run: support cgroup local storage Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 12/14] selftests/bpf: add verifier cgroup storage tests Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 13/14] selftests/bpf: add a cgroup storage test Roman Gushchin
2018-07-20 17:45 ` [PATCH v3 bpf-next 14/14] samples/bpf: extend test_cgrp2_attach2 test to use cgroup storage Roman Gushchin
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