[PATCH v4 01/16] tools lib bpf: Check return value of strdup when reading map names

Wang Nan
2015-12-08T02:26:37Z

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.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
---
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