Commit 700e6f85 authored by Jiri Olsa's avatar Jiri Olsa Committed by Alexei Starovoitov
Browse files

bpf: Do not allow to load sleepable BPF_TRACE_RAW_TP program 



Currently we allow to load any tracing program as sleepable,
but BPF_TRACE_RAW_TP can't sleep. Making the check explicit
for tracing programs attach types, so sleepable BPF_TRACE_RAW_TP
will fail to load.

Updating the verifier error to mention iter programs as well.

Acked-by: default avatarSong Liu <song@kernel.org>
Acked-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230117223705.440975-1-jolsa@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent c1177979

kernel/bpf/verifier.c

+19 −3
Original line number Diff line number Diff line
@@ -16743,6 +16743,23 @@ BTF_ID(func, rcu_read_unlock_strict) 
#endif

BTF_SET_END(btf_id_deny)



static bool can_be_sleepable(struct bpf_prog *prog)

{

	if (prog->type == BPF_PROG_TYPE_TRACING) {

		switch (prog->expected_attach_type) {

		case BPF_TRACE_FENTRY:

		case BPF_TRACE_FEXIT:

		case BPF_MODIFY_RETURN:

		case BPF_TRACE_ITER:

			return true;

		default:

			return false;

		}

	}

	return prog->type == BPF_PROG_TYPE_LSM ||

	       prog->type == BPF_PROG_TYPE_KPROBE; /* only for uprobes */

}



static int check_attach_btf_id(struct bpf_verifier_env *env)

{

	struct bpf_prog *prog = env->prog;
@@ -16761,9 +16778,8 @@ static int check_attach_btf_id(struct bpf_verifier_env *env) 
		return -EINVAL;

	}



	if (prog->aux->sleepable && prog->type != BPF_PROG_TYPE_TRACING &&

	    prog->type != BPF_PROG_TYPE_LSM && prog->type != BPF_PROG_TYPE_KPROBE) {

		verbose(env, "Only fentry/fexit/fmod_ret, lsm, and kprobe/uprobe programs can be sleepable\n");

	if (prog->aux->sleepable && !can_be_sleepable(prog)) {

		verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter and uprobe programs can be sleepable\n");

		return -EINVAL;

	}