From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Kicinski Subject: [PATCHv7 net-next 07/15] bpf: recognize 64bit immediate loads as consts Date: Wed, 21 Sep 2016 11:43:59 +0100 Message-ID: <1474454647-20137-8-git-send-email-jakub.kicinski@netronome.com> References: <1474454647-20137-1-git-send-email-jakub.kicinski@netronome.com> Cc: ast@kernel.org, daniel@iogearbox.net, Jakub Kicinski To: netdev@vger.kernel.org Return-path: Received: from mail-wm0-f50.google.com ([74.125.82.50]:34942 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754878AbcIUKoz (ORCPT ); Wed, 21 Sep 2016 06:44:55 -0400 Received: by mail-wm0-f50.google.com with SMTP id l132so260338339wmf.0 for ; Wed, 21 Sep 2016 03:44:41 -0700 (PDT) In-Reply-To: <1474454647-20137-1-git-send-email-jakub.kicinski@netronome.com> Sender: netdev-owner@vger.kernel.org List-ID: When running as parser interpret BPF_LD | BPF_IMM | BPF_DW instructions as loading CONST_IMM with the value stored in imm. The verifier will continue not recognizing those due to concerns about search space/program complexity increase. Signed-off-by: Jakub Kicinski Acked-by: Alexei Starovoitov Acked-by: Daniel Borkmann --- v3: - limit to parsers. --- kernel/bpf/verifier.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index ee86a77dc40b..8c3f794c7028 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1769,9 +1769,19 @@ static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn) if (err) return err; - if (insn->src_reg == 0) - /* generic move 64-bit immediate into a register */ + if (insn->src_reg == 0) { + /* generic move 64-bit immediate into a register, + * only analyzer needs to collect the ld_imm value. + */ + u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm; + + if (!env->analyzer_ops) + return 0; + + regs[insn->dst_reg].type = CONST_IMM; + regs[insn->dst_reg].imm = imm; return 0; + } /* replace_map_fd_with_map_ptr() should have caught bad ld_imm64 */ BUG_ON(insn->src_reg != BPF_PSEUDO_MAP_FD); -- 1.9.1