* [PATCH bpf-next] libbpf: avoid NULL deref when initializing map BTF info
@ 2022-03-20 0:19 Andrii Nakryiko
2022-03-20 3:37 ` Yonghong Song
2022-03-21 2:00 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 4+ messages in thread
From: Andrii Nakryiko @ 2022-03-20 0:19 UTC (permalink / raw)
To: bpf, ast, daniel; +Cc: andrii, kernel-team
If BPF object doesn't have an BTF info, don't attempt to search for BTF
types describing BPF map key or value layout.
Fixes: 262cfb74ffda ("libbpf: Init btf_{key,value}_type_id on internal map open")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
tools/lib/bpf/libbpf.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 7526419e59e0..2efe9431c1ba 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4197,6 +4197,9 @@ static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
__u32 key_type_id = 0, value_type_id = 0;
int ret;
+ if (!obj->btf)
+ return -ENOENT;
+
/* if it's BTF-defined map, we don't need to search for type IDs.
* For struct_ops map, it does not need btf_key_type_id and
* btf_value_type_id.
--
2.30.2
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] libbpf: avoid NULL deref when initializing map BTF info
2022-03-20 0:19 [PATCH bpf-next] libbpf: avoid NULL deref when initializing map BTF info Andrii Nakryiko
@ 2022-03-20 3:37 ` Yonghong Song
2022-03-21 16:58 ` Andrii Nakryiko
2022-03-21 2:00 ` patchwork-bot+netdevbpf
1 sibling, 1 reply; 4+ messages in thread
From: Yonghong Song @ 2022-03-20 3:37 UTC (permalink / raw)
To: Andrii Nakryiko, bpf, ast, daniel; +Cc: kernel-team
On 3/19/22 5:19 PM, Andrii Nakryiko wrote:
> If BPF object doesn't have an BTF info, don't attempt to search for BTF
> types describing BPF map key or value layout.
>
> Fixes: 262cfb74ffda ("libbpf: Init btf_{key,value}_type_id on internal map open")
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
So without this patch, we may have segfault or other errors, right?
It would be good to specify that in the commit message.
The code change looks good to me.
Acked-by: Yonghong Song <yhs@fb.com>
> ---
> tools/lib/bpf/libbpf.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 7526419e59e0..2efe9431c1ba 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -4197,6 +4197,9 @@ static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
> __u32 key_type_id = 0, value_type_id = 0;
> int ret;
>
> + if (!obj->btf)
> + return -ENOENT;
> +
> /* if it's BTF-defined map, we don't need to search for type IDs.
> * For struct_ops map, it does not need btf_key_type_id and
> * btf_value_type_id.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] libbpf: avoid NULL deref when initializing map BTF info
2022-03-20 0:19 [PATCH bpf-next] libbpf: avoid NULL deref when initializing map BTF info Andrii Nakryiko
2022-03-20 3:37 ` Yonghong Song
@ 2022-03-21 2:00 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 4+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-03-21 2:00 UTC (permalink / raw)
To: Andrii Nakryiko; +Cc: bpf, ast, daniel, kernel-team
Hello:
This patch was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:
On Sat, 19 Mar 2022 17:19:11 -0700 you wrote:
> If BPF object doesn't have an BTF info, don't attempt to search for BTF
> types describing BPF map key or value layout.
>
> Fixes: 262cfb74ffda ("libbpf: Init btf_{key,value}_type_id on internal map open")
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---
> tools/lib/bpf/libbpf.c | 3 +++
> 1 file changed, 3 insertions(+)
Here is the summary with links:
- [bpf-next] libbpf: avoid NULL deref when initializing map BTF info
https://git.kernel.org/bpf/bpf-next/c/a8fee96202e2
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] libbpf: avoid NULL deref when initializing map BTF info
2022-03-20 3:37 ` Yonghong Song
@ 2022-03-21 16:58 ` Andrii Nakryiko
0 siblings, 0 replies; 4+ messages in thread
From: Andrii Nakryiko @ 2022-03-21 16:58 UTC (permalink / raw)
To: Yonghong Song
Cc: Andrii Nakryiko, bpf, Alexei Starovoitov, Daniel Borkmann, Kernel Team
On Sat, Mar 19, 2022 at 8:37 PM Yonghong Song <yhs@fb.com> wrote:
>
>
>
> On 3/19/22 5:19 PM, Andrii Nakryiko wrote:
> > If BPF object doesn't have an BTF info, don't attempt to search for BTF
> > types describing BPF map key or value layout.
> >
> > Fixes: 262cfb74ffda ("libbpf: Init btf_{key,value}_type_id on internal map open")
> > Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
>
> So without this patch, we may have segfault or other errors, right?
> It would be good to specify that in the commit message.
>
> The code change looks good to me.
>
> Acked-by: Yonghong Song <yhs@fb.com>
>
> > ---
> > tools/lib/bpf/libbpf.c | 3 +++
> > 1 file changed, 3 insertions(+)
> >
> > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> > index 7526419e59e0..2efe9431c1ba 100644
> > --- a/tools/lib/bpf/libbpf.c
> > +++ b/tools/lib/bpf/libbpf.c
> > @@ -4197,6 +4197,9 @@ static int bpf_map_find_btf_info(struct bpf_object *obj, struct bpf_map *map)
> > __u32 key_type_id = 0, value_type_id = 0;
> > int ret;
> >
> > + if (!obj->btf)
> > + return -ENOENT;
> > +
yeah, it was SIGSEGV, which I only saw in libbpf CI on old 5.5 kernel.
I'll include a bit more specifics for future fixes, sorry.
> > /* if it's BTF-defined map, we don't need to search for type IDs.
> > * For struct_ops map, it does not need btf_key_type_id and
> > * btf_value_type_id.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-03-21 16:58 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-03-20 0:19 [PATCH bpf-next] libbpf: avoid NULL deref when initializing map BTF info Andrii Nakryiko
2022-03-20 3:37 ` Yonghong Song
2022-03-21 16:58 ` Andrii Nakryiko
2022-03-21 2:00 ` patchwork-bot+netdevbpf
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.