From: Andrii Nakryiko andrii@kernel.org
[ Upstream commit 62554d52e71797eefa3fc15b54008038837bb2d4 ]
.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 Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index b337d6f29098b..e8ad53d31044a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2870,8 +2870,12 @@ 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 */