Commit 62554d52 authored Nov 03, 2021 by Andrii Nakryiko Committed by Alexei Starovoitov Nov 03, 2021

libbpf: Validate that .BTF and .BTF.ext sections contain data



.BTF and .BTF.ext ELF sections should have SHT_PROGBITS type and contain
data. If they are not, ELF is invalid or corrupted, so bail out.
Otherwise this can lead to data->d_buf being NULL and SIGSEGV later on.
Reported by oss-fuzz project.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20211103173213.1376990-4-andrii@kernel.org

parent 88918dc1

tools/lib/bpf/libbpf.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -3270,8 +3270,12 @@ static int bpf_object__elf_collect(struct bpf_object *obj)
		} else if (strcmp(name, MAPS_ELF_SEC) == 0) {
		obj->efile.btf_maps_shndx = idx;
		} else if (strcmp(name, BTF_ELF_SEC) == 0) {
		if (sh->sh_type != SHT_PROGBITS)
		return -LIBBPF_ERRNO__FORMAT;
		btf_data = data;
		} else if (strcmp(name, BTF_EXT_ELF_SEC) == 0) {
		if (sh->sh_type != SHT_PROGBITS)
		return -LIBBPF_ERRNO__FORMAT;
		btf_ext_data = data;
		} else if (sh->sh_type == SHT_SYMTAB) {
		/* already processed during the first pass above */