| Message ID | 20220320001911.3640917-1-andrii@kernel.org (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | a8fee96202e279441d0e52d83eb100bd4a6d6272 |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] libbpf: avoid NULL deref when initializing map BTF info | expand |
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.
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!
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.
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.
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(+)