From: Hou Tao <houtao1@huawei.com>
To: Alexei Starovoitov <ast@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>, Yonghong Song <yhs@fb.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, <netdev@vger.kernel.org>,
<bpf@vger.kernel.org>, <houtao1@huawei.com>
Subject: [PATCH bpf-next v2 2/5] bpf: factor out helpers to check ctx access for BTF function
Date: Sat, 16 Oct 2021 20:48:03 +0800 [thread overview]
Message-ID: <20211016124806.1547989-3-houtao1@huawei.com> (raw)
In-Reply-To: <20211016124806.1547989-1-houtao1@huawei.com>
Factor out two helpers to check the read access of ctx for BTF
function. bpf_check_btf_func_arg_access() is used to check the
read access to argument is valid, and bpf_check_btf_func_ctx_access()
also checks whether the btf type of argument is valid besides
the checking of arguments read. bpf_check_btf_func_ctx_access()
will be used by the following patch.
Signed-off-by: Hou Tao <houtao1@huawei.com>
---
include/linux/bpf.h | 27 +++++++++++++++++++++++++++
kernel/trace/bpf_trace.c | 16 ++--------------
net/ipv4/bpf_tcp_ca.c | 9 +--------
3 files changed, 30 insertions(+), 22 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index b7c1e2bc93f7..b503306da2ab 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1648,6 +1648,33 @@ bool bpf_prog_test_check_kfunc_call(u32 kfunc_id, struct module *owner);
bool btf_ctx_access(int off, int size, enum bpf_access_type type,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info);
+
+/*
+ * The maximum number of BTF function arguments is MAX_BPF_FUNC_ARGS.
+ * And only aligned read is allowed.
+ */
+static inline bool bpf_check_btf_func_arg_access(int off, int size,
+ enum bpf_access_type type)
+{
+ if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
+ return false;
+ if (type != BPF_READ)
+ return false;
+ if (off % size != 0)
+ return false;
+ return true;
+}
+
+static inline bool bpf_check_btf_func_ctx_access(int off, int size,
+ enum bpf_access_type type,
+ const struct bpf_prog *prog,
+ struct bpf_insn_access_aux *info)
+{
+ if (!bpf_check_btf_func_arg_access(off, size, type))
+ return false;
+ return btf_ctx_access(off, size, type, prog, info);
+}
+
int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
const struct btf_type *t, int off, int size,
enum bpf_access_type atype,
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 6b3153841a33..f2858ef32e16 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1644,13 +1644,7 @@ static bool raw_tp_prog_is_valid_access(int off, int size,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info)
{
- if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
- return false;
- if (type != BPF_READ)
- return false;
- if (off % size != 0)
- return false;
- return true;
+ return bpf_check_btf_func_arg_access(off, size, type);
}
static bool tracing_prog_is_valid_access(int off, int size,
@@ -1658,13 +1652,7 @@ static bool tracing_prog_is_valid_access(int off, int size,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info)
{
- if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
- return false;
- if (type != BPF_READ)
- return false;
- if (off % size != 0)
- return false;
- return btf_ctx_access(off, size, type, prog, info);
+ return bpf_check_btf_func_ctx_access(off, size, type, prog, info);
}
int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog,
diff --git a/net/ipv4/bpf_tcp_ca.c b/net/ipv4/bpf_tcp_ca.c
index 57709ac09fb2..1eccc4974382 100644
--- a/net/ipv4/bpf_tcp_ca.c
+++ b/net/ipv4/bpf_tcp_ca.c
@@ -81,14 +81,7 @@ static bool bpf_tcp_ca_is_valid_access(int off, int size,
const struct bpf_prog *prog,
struct bpf_insn_access_aux *info)
{
- if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS)
- return false;
- if (type != BPF_READ)
- return false;
- if (off % size != 0)
- return false;
-
- if (!btf_ctx_access(off, size, type, prog, info))
+ if (!bpf_check_btf_func_ctx_access(off, size, type, prog, info))
return false;
if (info->reg_type == PTR_TO_BTF_ID && info->btf_id == sock_id)
--
2.29.2
next prev parent reply other threads:[~2021-10-16 12:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-16 12:48 [PATCH bpf-next v2 0/5] introduce dummy BPF STRUCT_OPS Hou Tao
2021-10-16 12:48 ` [PATCH bpf-next v2 1/5] bpf: factor out a helper to prepare trampoline for struct_ops prog Hou Tao
2021-10-16 12:48 ` Hou Tao [this message]
2021-10-20 5:00 ` [PATCH bpf-next v2 2/5] bpf: factor out helpers to check ctx access for BTF function Martin KaFai Lau
2021-10-16 12:48 ` [PATCH bpf-next v2 3/5] bpf: add dummy BPF STRUCT_OPS for test purpose Hou Tao
2021-10-20 1:22 ` Martin KaFai Lau
2021-10-16 12:48 ` [PATCH bpf-next v2 4/5] bpf: hook .test_run for struct_ops program Hou Tao
2021-10-20 1:25 ` Martin KaFai Lau
2021-10-20 5:24 ` Martin KaFai Lau
2021-10-16 12:48 ` [PATCH bpf-next v2 5/5] selftests/bpf: add test cases for struct_ops prog Hou Tao
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