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bpf: Factor out helpers for ctx access checking

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Factor out two helpers to check the read access of ctx for raw tp
and 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@huawei.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20211025064025.2567443-3-houtao1@huawei.com
This commit is contained in:
Hou Tao 2021-10-25 14:40:23 +08:00 committed by Alexei Starovoitov
parent 31a645aea4
commit 35346ab641
3 changed files with 26 additions and 22 deletions
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23
include/linux/bpf.h
View File

@ -1650,6 +1650,29 @@ 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, bool btf_ctx_access(int off, int size, enum bpf_access_type type,
const struct bpf_prog *prog, const struct bpf_prog *prog,
struct bpf_insn_access_aux *info); struct bpf_insn_access_aux *info);
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, int btf_struct_access(struct bpf_verifier_log *log, const struct btf *btf,
const struct btf_type *t, int off, int size, const struct btf_type *t, int off, int size,
enum bpf_access_type atype, enum bpf_access_type atype,

16
kernel/trace/bpf_trace.c
View File

@ -1646,13 +1646,7 @@ static bool raw_tp_prog_is_valid_access(int off, int size,
const struct bpf_prog *prog, const struct bpf_prog *prog,
struct bpf_insn_access_aux *info) struct bpf_insn_access_aux *info)
{ {
if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) return bpf_tracing_ctx_access(off, size, type);
return false;
if (type != BPF_READ)
return false;
if (off % size != 0)
return false;
return true;
} }
static bool tracing_prog_is_valid_access(int off, int size, 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, const struct bpf_prog *prog,
struct bpf_insn_access_aux *info) struct bpf_insn_access_aux *info)
{ {
if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) return bpf_tracing_btf_ctx_access(off, size, type, prog, info);
return false;
if (type != BPF_READ)
return false;
if (off % size != 0)
return false;
return btf_ctx_access(off, size, type, prog, info);
} }
int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog, int __weak bpf_prog_test_run_tracing(struct bpf_prog *prog,

9
net/ipv4/bpf_tcp_ca.c
View File

@ -81,14 +81,7 @@ static bool bpf_tcp_ca_is_valid_access(int off, int size,
const struct bpf_prog *prog, const struct bpf_prog *prog,
struct bpf_insn_access_aux *info) struct bpf_insn_access_aux *info)
{ {
if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) if (!bpf_tracing_btf_ctx_access(off, size, type, prog, info))
return false;
if (type != BPF_READ)
return false;
if (off % size != 0)
return false;
if (!btf_ctx_access(off, size, type, prog, info))
return false; return false;
if (info->reg_type == PTR_TO_BTF_ID && info->btf_id == sock_id) if (info->reg_type == PTR_TO_BTF_ID && info->btf_id == sock_id)