Factor out two helpers to check the read access of ctx for BTF
function. bpf_tracing_ctx_access() is used to check the
read access to argument is valid, and bpf_tracing_btf_ctx_access()
checks whether the btf type of argument is valid besides
the checking of argument read. bpf_tracing_btf_ctx_access()
will be used by the following patch.
Signed-off-by: Hou Tao <houtao1@xxxxxxxxxx>
---
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 3d2cf94a72ce..0dd2de9eeed3 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -1649,6 +1649,33 @@ 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_tracing_ctx_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_tracing_btf_ctx_access(int off, int size,
+ enum bpf_access_type type,
+ const struct bpf_prog *prog,
+ struct bpf_insn_access_aux *info)
+{
+ if (!bpf_tracing_ctx_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 cbcd0d6fca7c..7396488793ff 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -1646,13 +1646,7 @@ 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_tracing_ctx_access(off, size, type);
}
static bool tracing_prog_is_valid_access(int off, int size,
@@ -1660,13 +1654,7 @@ 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_tracing_btf_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..2cf02b4d77fb 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_tracing_btf_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
