[PATCH AUTOSEL 5.16 010/217] libbpf: Validate that .BTF and .BTF.ext sections contain data
From: Sasha Levin <sashal@kernel.org>
Date: 2022-01-18 02:20:25
Also in:
bpf, lkml, stable
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [library] (libbpf), the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Linus Torvalds
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 <redacted> Link: https://lore.kernel.org/bpf/20211103173213.1376990-4-andrii@kernel.org (local) 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 18651e11b9ba3..7d27152dfb3a6 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c@@ -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 */
--
2.34.1