| Message ID | 20211022075511.1682588-3-houtao1@huawei.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | introduce dummy BPF STRUCT_OPS | expand |
On Fri, Oct 22, 2021 at 03:55:09PM +0800, Hou Tao wrote: > 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@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 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. It is not always 'BTF' function arguments. Lets remove this comment. The function is short and its intention is clear. Others lgtm. Acked-by: Martin KaFai Lau <kafai@fb.com> > + */ > +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); > +}
Hi Martin, On 10/23/2021 8:18 AM, Martin KaFai Lau wrote: > On Fri, Oct 22, 2021 at 03:55:09PM +0800, Hou Tao wrote: >> @@ -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. > It is not always 'BTF' function arguments. Lets remove this comment. > The function is short and its intention is clear. Yes, you are right, BTF is not necessary for BPF_PROG_TYPE_RAW_TRACEPOINT program. I will remove the inaccurate comments and update commit message accordingly. > Others lgtm. > > Acked-by: Martin KaFai Lau <kafai@fb.com> Thanks for your detailed suggestions and careful review. Regards, Tao
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)
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@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(-)