From: Andrii Nakryiko <andrii@kernel.org>
Date: Wed, 3 Nov 2021 10:32:11 -0700
Subject: libbpf: Validate that .BTF and .BTF.ext sections contain data
Patch-mainline: v5.17-rc1
Git-commit: 62554d52e71797eefa3fc15b54008038837bb2d4
References: jsc#PED-1368

.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
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/lib/bpf/libbpf.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3270,8 +3270,12 @@ static int bpf_object__elf_collect(struc
 		} 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 */