tools lib bpf: Check return value of strdup when reading map names

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 safety.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Fixes: 561bbccac72d ("tools lib bpf: Extract and collect map names from BPF object file")
Link: http://lkml.kernel.org/r/1449541544-67621-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index a298614..16485ab 100644 (file)
--- 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;