netdev - Re: [PATCH bpf] libbpf: handle BTF parsing and loading properly

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Sat, 9 Mar 2019 07:30:55 +0000
From:   Yonghong Song <yhs@...com>
To:     Andrii Nakryiko <andriin@...com>,
        "andrii.nakryiko@...il.com" <andrii.nakryiko@...il.com>,
        Kernel Team <Kernel-team@...com>,
        "Alexei Starovoitov" <ast@...com>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "bpf@...r.kernel.org" <bpf@...r.kernel.org>,
        "daniel@...earbox.net" <daniel@...earbox.net>,
        Martin Lau <kafai@...com>,
        "tehnerd@...nerd.com" <tehnerd@...nerd.com>
Subject: Re: [PATCH bpf] libbpf: handle BTF parsing and loading properly



On 3/8/19 3:58 PM, Andrii Nakryiko wrote:
> This patch splits and cleans up error handling logic for loading BTF data.
> Previously, if BTF data was parsed successfully, but failed to load into
> kernel, we'd report nonsensical error code, instead of error returned from
> btf__load(). Now btf__new() and btf__load() are handled separately with proper
> cleanup and warning reporting.
> 
> Fixes: d29d87f7e612 ("btf: separate btf creation and loading")
> Reported-by: Martin KaFai Lau <kafai@...com>
> Signed-off-by: Andrii Nakryiko <andriin@...com>

Acked-by: Yonghong Song <yhs@...com>

> ---
>   tools/lib/bpf/libbpf.c | 13 ++++++++++---
>   1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index d5b830d60601..5e977d2688da 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -835,12 +835,19 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags)
>   			obj->efile.maps_shndx = idx;
>   		else if (strcmp(name, BTF_ELF_SEC) == 0) {
>   			obj->btf = btf__new(data->d_buf, data->d_size);
> -			if (IS_ERR(obj->btf) || btf__load(obj->btf)) {
> +			if (IS_ERR(obj->btf)) {
>   				pr_warning("Error loading ELF section %s: %ld. Ignored and continue.\n",
>   					   BTF_ELF_SEC, PTR_ERR(obj->btf));
> -				if (!IS_ERR(obj->btf))
> -					btf__free(obj->btf);
>   				obj->btf = NULL;
> +				continue;
> +			}
> +			err = btf__load(obj->btf);
> +			if (err) {
> +				pr_warning("Error loading %s into kernel: %d. Ignored and continue.\n",
> +					   BTF_ELF_SEC, err);
> +				btf__free(obj->btf);
> +				obj->btf = NULL;
> +				err = 0;
>   			}
>   		} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
>   			btf_ext_data = data;
>