On Mon, Nov 30, 2015 at 07:32:01AM +0000, Wang Nan wrote:
> Commit 561bbccac72d08babafaa33fd7fa9100ec4c9fb6 ("tools lib bpf:
> Extract and collect map names from BPF object file") forgets checking
> return value of strdup(). This patch fixes it. It also checks names
> pointer before strcmp() for safty.
>
> Reported-by: Namhyung Kim <namhy...@kernel.org>
> Signed-off-by: Wang Nan <wangn...@huawei.com>
> Cc: Arnaldo Carvalho de Melo <a...@redhat.com>
Acked-by: Namhyung Kim <namhy...@kernel.org>
Thanks,
Namhyung
> ---
> tools/lib/bpf/libbpf.c | 13 +++++++++----
> 1 file changed, 9 insertions(+), 4 deletions(-)
>
> diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
> index a298614..16485ab 100644
> --- a/tools/lib/bpf/libbpf.c
> +++ b/tools/lib/bpf/libbpf.c
> @@ -527,14 +527,14 @@ bpf_object__init_maps(struct bpf_object *obj, void
> *data,
> return 0;
> }
>
> -static void
> +static int
> bpf_object__init_maps_name(struct bpf_object *obj, int maps_shndx)
> {
> int i;
> Elf_Data *symbols = obj->efile.symbols;
>
> if (!symbols || maps_shndx < 0)
> - return;
> + return -EINVAL;
>
> for (i = 0; i < symbols->d_size / sizeof(GElf_Sym); i++) {
> GElf_Sym sym;
> @@ -556,9 +556,14 @@ bpf_object__init_maps_name(struct bpf_object *obj, int
> maps_shndx)
> continue;
> }
> obj->maps[map_idx].name = strdup(map_name);
> + if (!obj->maps[map_idx].name) {
> + pr_warning("failed to alloc map name\n");
> + return -ENOMEM;
> + }
> pr_debug("map %zu is \"%s\"\n", map_idx,
> obj->maps[map_idx].name);
> }
> + return 0;
> }
>
> static int bpf_object__elf_collect(struct bpf_object *obj)
> @@ -663,7 +668,7 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
> }
>
> if (maps_shndx >= 0)
> - bpf_object__init_maps_name(obj, maps_shndx);
> + err = bpf_object__init_maps_name(obj, maps_shndx);
> out:
> return err;
> }
> @@ -1372,7 +1377,7 @@ bpf_object__get_map_by_name(struct bpf_object *obj,
> const char *name)
> struct bpf_map *pos;
>
> bpf_map__for_each(pos, obj) {
> - if (strcmp(pos->name, name) == 0)
> + if (pos->name && !strcmp(pos->name, name))
> return pos;
> }
> return NULL;
> --
> 1.8.3.4
>
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