diff options
| author | Quentin Monnet <qmo@kernel.org> | 2024-03-14 18:04:38 +0300 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2024-03-14 23:41:17 +0300 |
| commit | 9bf48fa19a4b1d186e08b20bf7e5de26a15644fb (patch) | |
| tree | 1fcbb6ba740bcc479893149a2ad3f1dc2f83db8d | |
| parent | fe879bb42f8a6513ed18e9d22efb99cb35590201 (diff) | |
| download | linux-9bf48fa19a4b1d186e08b20bf7e5de26a15644fb.tar.xz | |
libbpf: Prevent null-pointer dereference when prog to load has no BTF
In bpf_objec_load_prog(), there's no guarantee that obj->btf is non-NULL
when passing it to btf__fd(), and this function does not perform any
check before dereferencing its argument (as bpf_object__btf_fd() used to
do). As a consequence, we get segmentation fault errors in bpftool (for
example) when trying to load programs that come without BTF information.
v2: Keep btf__fd() in the fix instead of reverting to bpf_object__btf_fd().
Fixes: df7c3f7d3a3d ("libbpf: make uniform use of btf__fd() accessor inside libbpf")
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240314150438.232462-1-qmo@kernel.org
| -rw-r--r-- | tools/lib/bpf/libbpf.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index efab29b8935b..124883eaa0cf 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7317,9 +7317,9 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog char *cp, errmsg[STRERR_BUFSIZE]; size_t log_buf_size = 0; char *log_buf = NULL, *tmp; - int btf_fd, ret, err; bool own_log_buf = true; __u32 log_level = prog->log_level; + int ret, err; if (prog->type == BPF_PROG_TYPE_UNSPEC) { /* @@ -7343,9 +7343,8 @@ static int bpf_object_load_prog(struct bpf_object *obj, struct bpf_program *prog load_attr.prog_ifindex = prog->prog_ifindex; /* specify func_info/line_info only if kernel supports them */ - btf_fd = btf__fd(obj->btf); - if (btf_fd >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) { - load_attr.prog_btf_fd = btf_fd; + if (obj->btf && btf__fd(obj->btf) >= 0 && kernel_supports(obj, FEAT_BTF_FUNC)) { + load_attr.prog_btf_fd = btf__fd(obj->btf); load_attr.func_info = prog->func_info; load_attr.func_info_rec_size = prog->func_info_rec_size; load_attr.func_info_cnt = prog->func_info_cnt; |