From: Andrii Nakryiko <andrii@xxxxxxxxxx> [ Upstream commit 401891a9debaf0a684502f2aaecf53448cee9414 ] Perform a memory copy before we do the sanity checks of btf_ext_hdr. This prevents misaligned memory access if raw btf_ext data is not 4-byte aligned ([0]). While at it, also add missing const qualifier. [0] Closes: https://github.com/libbpf/libbpf/issues/391 Fixes: 2993e0515bb4 ("tools/bpf: add support to read .BTF.ext sections") Reported-by: Evgeny Vereshchagin <evvers@xxxxx> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx> Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Link: https://lore.kernel.org/bpf/20211124002325.1737739-3-andrii@xxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- tools/lib/bpf/btf.c | 10 +++++----- tools/lib/bpf/btf.h | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 1b9341ef638b0..5fa64a7f0dda8 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -2626,15 +2626,11 @@ void btf_ext__free(struct btf_ext *btf_ext) free(btf_ext); } -struct btf_ext *btf_ext__new(__u8 *data, __u32 size) +struct btf_ext *btf_ext__new(const __u8 *data, __u32 size) { struct btf_ext *btf_ext; int err; - err = btf_ext_parse_hdr(data, size); - if (err) - return libbpf_err_ptr(err); - btf_ext = calloc(1, sizeof(struct btf_ext)); if (!btf_ext) return libbpf_err_ptr(-ENOMEM); @@ -2647,6 +2643,10 @@ struct btf_ext *btf_ext__new(__u8 *data, __u32 size) } memcpy(btf_ext->data, data, size); + err = btf_ext_parse_hdr(btf_ext->data, size); + if (err) + goto done; + if (btf_ext->hdr->hdr_len < offsetofend(struct btf_ext_header, line_info_len)) { err = -EINVAL; goto done; diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index 4a711f990904b..b0ee338a0cc87 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -80,7 +80,7 @@ LIBBPF_API int btf__get_map_kv_tids(const struct btf *btf, const char *map_name, __u32 expected_value_size, __u32 *key_type_id, __u32 *value_type_id); -LIBBPF_API struct btf_ext *btf_ext__new(__u8 *data, __u32 size); +LIBBPF_API struct btf_ext *btf_ext__new(const __u8 *data, __u32 size); LIBBPF_API void btf_ext__free(struct btf_ext *btf_ext); LIBBPF_API const void *btf_ext__get_raw_data(const struct btf_ext *btf_ext, __u32 *size); -- 2.34.1
