* [PATCH bpf-next v2] libbpf: Fix strncat bounds error in libbpf_prog_type_by_name
@ 2019-10-23 15:40 KP Singh
2019-10-23 17:18 ` Alexei Starovoitov
2019-10-24 4:37 ` Andrii Nakryiko
0 siblings, 2 replies; 3+ messages in thread
From: KP Singh @ 2019-10-23 15:40 UTC (permalink / raw)
To: linux-kernel, bpf
Cc: Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
Yonghong Song, Florent Revest
From: KP Singh <kpsingh@google.com>
On compiling samples with this change, one gets an error:
error: ‘strncat’ specified bound 118 equals destination size
[-Werror=stringop-truncation]
strncat(dst, name + section_names[i].len,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
sizeof(raw_tp_btf_name) - (dst - raw_tp_btf_name));
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
strncat requires the destination to have enough space for the
terminating null byte.
Fixes: f75a697e09137 ("libbpf: Auto-detect btf_id of BTF-based raw_tracepoint")
Signed-off-by: KP Singh <kpsingh@google.com>
---
tools/lib/bpf/libbpf.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 290684b504b7..dc7d493a7d3d 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -4693,7 +4693,7 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
}
/* prepend "btf_trace_" prefix per kernel convention */
strncat(dst, name + section_names[i].len,
- sizeof(raw_tp_btf_name) - (dst - raw_tp_btf_name));
+ sizeof(raw_tp_btf_name) - sizeof("btf_trace_"));
ret = btf__find_by_name(btf, raw_tp_btf_name);
btf__free(btf);
if (ret <= 0) {
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v2] libbpf: Fix strncat bounds error in libbpf_prog_type_by_name
2019-10-23 15:40 [PATCH bpf-next v2] libbpf: Fix strncat bounds error in libbpf_prog_type_by_name KP Singh
@ 2019-10-23 17:18 ` Alexei Starovoitov
2019-10-24 4:37 ` Andrii Nakryiko
1 sibling, 0 replies; 3+ messages in thread
From: Alexei Starovoitov @ 2019-10-23 17:18 UTC (permalink / raw)
To: KP Singh
Cc: LKML, bpf, Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau,
Song Liu, Yonghong Song, Florent Revest
On Wed, Oct 23, 2019 at 8:40 AM KP Singh <kpsingh@chromium.org> wrote:
>
> From: KP Singh <kpsingh@google.com>
>
> On compiling samples with this change, one gets an error:
>
> error: ‘strncat’ specified bound 118 equals destination size
> [-Werror=stringop-truncation]
>
> strncat(dst, name + section_names[i].len,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> sizeof(raw_tp_btf_name) - (dst - raw_tp_btf_name));
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> strncat requires the destination to have enough space for the
> terminating null byte.
>
> Fixes: f75a697e09137 ("libbpf: Auto-detect btf_id of BTF-based raw_tracepoint")
> Signed-off-by: KP Singh <kpsingh@google.com>
Applied. Thanks
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf-next v2] libbpf: Fix strncat bounds error in libbpf_prog_type_by_name
2019-10-23 15:40 [PATCH bpf-next v2] libbpf: Fix strncat bounds error in libbpf_prog_type_by_name KP Singh
2019-10-23 17:18 ` Alexei Starovoitov
@ 2019-10-24 4:37 ` Andrii Nakryiko
1 sibling, 0 replies; 3+ messages in thread
From: Andrii Nakryiko @ 2019-10-24 4:37 UTC (permalink / raw)
To: KP Singh
Cc: open list, bpf, Alexei Starovoitov, Daniel Borkmann,
Martin KaFai Lau, Song Liu, Yonghong Song, Florent Revest
On Wed, Oct 23, 2019 at 9:06 PM KP Singh <kpsingh@chromium.org> wrote:
>
> From: KP Singh <kpsingh@google.com>
>
> On compiling samples with this change, one gets an error:
>
> error: ‘strncat’ specified bound 118 equals destination size
> [-Werror=stringop-truncation]
>
> strncat(dst, name + section_names[i].len,
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> sizeof(raw_tp_btf_name) - (dst - raw_tp_btf_name));
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> strncat requires the destination to have enough space for the
> terminating null byte.
>
> Fixes: f75a697e09137 ("libbpf: Auto-detect btf_id of BTF-based raw_tracepoint")
> Signed-off-by: KP Singh <kpsingh@google.com>
> ---
Acked-by: Andrii Nakryiko <andriin@fb.com>
> tools/lib/bpf/libbpf.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index 290684b504b7..dc7d493a7d3d 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -4693,7 +4693,7 @@ int libbpf_prog_type_by_name(const char *name, enum bpf_prog_type *prog_type,
> }
> /* prepend "btf_trace_" prefix per kernel convention */
> strncat(dst, name + section_names[i].len,
> - sizeof(raw_tp_btf_name) - (dst - raw_tp_btf_name));
> + sizeof(raw_tp_btf_name) - sizeof("btf_trace_"));
> ret = btf__find_by_name(btf, raw_tp_btf_name);
> btf__free(btf);
> if (ret <= 0) {
> --
> 2.20.1
>
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-10-23 15:40 [PATCH bpf-next v2] libbpf: Fix strncat bounds error in libbpf_prog_type_by_name KP Singh
2019-10-23 17:18 ` Alexei Starovoitov
2019-10-24 4:37 ` Andrii Nakryiko
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