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    Subject[PATCH 5.16 0548/1039] libbpf: Validate that .BTF and .BTF.ext sections contain data
    Date
    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 c7ba5e6ed9cfe..96cee9cd8c03c 100644
    --- a/tools/lib/bpf/libbpf.c
    +++ b/tools/lib/bpf/libbpf.c
    @@ -3271,8 +3271,12 @@ 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


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