struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *prog)
{
	struct bpf_insn insn_buff[16], aux[2];
	struct bpf_prog *clone, *tmp;
	int insn_delta, insn_cnt;
	struct bpf_insn *insn;
	int i, rewritten;

	if (!bpf_jit_blinding_enabled(prog) || prog->blinded)
		return prog;

	clone = bpf_prog_clone_create(prog, GFP_USER);
	if (!clone)
		return ERR_PTR(-ENOMEM);

	insn_cnt = clone->len;
	insn = clone->insnsi;

	for (i = 0; i < insn_cnt; i++, insn++) {
		/* We temporarily need to hold the original ld64 insn
		 * so that we can still access the first part in the
		 * second blinding run.
		 */
		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW) &&
		    insn[1].code == 0)
			memcpy(aux, insn, sizeof(aux));

		rewritten = bpf_jit_blind_insn(insn, aux, insn_buff);
		if (!rewritten)
			continue;

		tmp = bpf_patch_insn_single(clone, i, insn_buff, rewritten);
		if (!tmp) {
			/* Patching may have repointed aux->prog during
			 * realloc from the original one, so we need to
			 * fix it up here on error.
			 */
			bpf_jit_prog_release_other(prog, clone);
			return ERR_PTR(-ENOMEM);
		}

		clone = tmp;
		insn_delta = rewritten - 1;

		/* Walk new program and skip insns we just inserted. */
		insn = clone->insnsi + i + insn_delta;
		insn_cnt += insn_delta;
		i        += insn_delta;
	}

	clone->blinded = 1;
	return clone;
}
Unknown