* [PATCH bpf-next] bpf: explicitly size compatible_reg_types
@ 2020-09-23 16:01 Lorenz Bauer
2020-09-23 16:05 ` Andrii Nakryiko
0 siblings, 1 reply; 3+ messages in thread
From: Lorenz Bauer @ 2020-09-23 16:01 UTC (permalink / raw)
To: Alexei Starovoitov, Daniel Borkmann
Cc: kernel-team, Lorenz Bauer, netdev, bpf, linux-kernel
Arrays with designated initializers have an implicit length of the highest
initialized value plus one. I used this to ensure that newly added entries
in enum bpf_reg_type get a NULL entry in compatible_reg_types.
This is difficult to understand since it requires knowledge of the
peculiarities of designated initializers. Use __BPF_ARG_TYPE_MAX to size
the array instead.
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Suggested-by: Alexei Starovoitov <ast@kernel.org>
---
kernel/bpf/verifier.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 15ab889b0a3f..d7c993ded26a 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -4002,7 +4002,7 @@ static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_T
static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
-static const struct bpf_reg_types *compatible_reg_types[] = {
+static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
[ARG_PTR_TO_MAP_KEY] = &map_key_value_types,
[ARG_PTR_TO_MAP_VALUE] = &map_key_value_types,
[ARG_PTR_TO_UNINIT_MAP_VALUE] = &map_key_value_types,
@@ -4025,7 +4025,6 @@ static const struct bpf_reg_types *compatible_reg_types[] = {
[ARG_PTR_TO_ALLOC_MEM_OR_NULL] = &alloc_mem_types,
[ARG_PTR_TO_INT] = &int_ptr_types,
[ARG_PTR_TO_LONG] = &int_ptr_types,
- [__BPF_ARG_TYPE_MAX] = NULL,
};
static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH bpf-next] bpf: explicitly size compatible_reg_types
2020-09-23 16:01 [PATCH bpf-next] bpf: explicitly size compatible_reg_types Lorenz Bauer
@ 2020-09-23 16:05 ` Andrii Nakryiko
2020-09-23 18:49 ` Alexei Starovoitov
0 siblings, 1 reply; 3+ messages in thread
From: Andrii Nakryiko @ 2020-09-23 16:05 UTC (permalink / raw)
To: Lorenz Bauer
Cc: Alexei Starovoitov, Daniel Borkmann, kernel-team, Networking,
bpf, open list
On Wed, Sep 23, 2020 at 9:03 AM Lorenz Bauer <lmb@cloudflare.com> wrote:
>
> Arrays with designated initializers have an implicit length of the highest
> initialized value plus one. I used this to ensure that newly added entries
> in enum bpf_reg_type get a NULL entry in compatible_reg_types.
>
> This is difficult to understand since it requires knowledge of the
> peculiarities of designated initializers. Use __BPF_ARG_TYPE_MAX to size
> the array instead.
>
> Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
> Suggested-by: Alexei Starovoitov <ast@kernel.org>
> ---
I like this more as well.
Acked-by: Andrii Nakryiko <andriin@fb.com>
> kernel/bpf/verifier.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 15ab889b0a3f..d7c993ded26a 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -4002,7 +4002,7 @@ static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_T
> static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
> static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
>
> -static const struct bpf_reg_types *compatible_reg_types[] = {
> +static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
> [ARG_PTR_TO_MAP_KEY] = &map_key_value_types,
> [ARG_PTR_TO_MAP_VALUE] = &map_key_value_types,
> [ARG_PTR_TO_UNINIT_MAP_VALUE] = &map_key_value_types,
> @@ -4025,7 +4025,6 @@ static const struct bpf_reg_types *compatible_reg_types[] = {
> [ARG_PTR_TO_ALLOC_MEM_OR_NULL] = &alloc_mem_types,
> [ARG_PTR_TO_INT] = &int_ptr_types,
> [ARG_PTR_TO_LONG] = &int_ptr_types,
> - [__BPF_ARG_TYPE_MAX] = NULL,
> };
>
> static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
> --
> 2.25.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH bpf-next] bpf: explicitly size compatible_reg_types
2020-09-23 16:05 ` Andrii Nakryiko
@ 2020-09-23 18:49 ` Alexei Starovoitov
0 siblings, 0 replies; 3+ messages in thread
From: Alexei Starovoitov @ 2020-09-23 18:49 UTC (permalink / raw)
To: Andrii Nakryiko
Cc: Lorenz Bauer, Alexei Starovoitov, Daniel Borkmann, kernel-team,
Networking, bpf, open list
On Wed, Sep 23, 2020 at 9:05 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Sep 23, 2020 at 9:03 AM Lorenz Bauer <lmb@cloudflare.com> wrote:
> >
> > Arrays with designated initializers have an implicit length of the highest
> > initialized value plus one. I used this to ensure that newly added entries
> > in enum bpf_reg_type get a NULL entry in compatible_reg_types.
> >
> > This is difficult to understand since it requires knowledge of the
> > peculiarities of designated initializers. Use __BPF_ARG_TYPE_MAX to size
> > the array instead.
> >
> > Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
> > Suggested-by: Alexei Starovoitov <ast@kernel.org>
> > ---
>
> I like this more as well.
>
> Acked-by: Andrii Nakryiko <andriin@fb.com>
Applied. Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-09-23 16:05 ` Andrii Nakryiko
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