libbpf: Improve handling of corrupted ELF during map initialization (98e527af) · Commits · 戴 / test

If we get ELF file with "maps" section, but no symbols pointing to it, we'll end up with division by zero. Add check against this situation and exit early with error. Found by Coverity scan against Github libbpf sources. Fixes: ("libbpf: refactor map initialization") Signed-off-by:

Andrii Nakryiko <andriin@fb.com> Signed-off-by:

Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20191107020855.3834758-6-andriin@fb.com

tools/lib/bpf/libbpf.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -956,13 +956,13 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict)
		pr_debug("maps in %s: %d maps in %zd bytes\n",
		obj->path, nr_maps, data->d_size);

		map_def_sz = data->d_size / nr_maps;
		if (!data->d_size \|\| (data->d_size % nr_maps) != 0) {
		if (!data->d_size \|\| nr_maps == 0 \|\| (data->d_size % nr_maps) != 0) {
		pr_warn("unable to determine map definition size "
		"section %s, %d maps in %zd bytes\n",
		obj->path, nr_maps, data->d_size);
		return -EINVAL;
		}
		map_def_sz = data->d_size / nr_maps;

		/* Fill obj->maps using data in "maps" section. */
		for (i = 0; i < nr_syms; i++) {

Admin message