From nobody Sat Feb 7 09:39:57 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1E24C6FA82 for ; Tue, 13 Sep 2022 15:41:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232450AbiIMPln (ORCPT ); Tue, 13 Sep 2022 11:41:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52536 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236724AbiIMPlF (ORCPT ); Tue, 13 Sep 2022 11:41:05 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E39FD8287F; Tue, 13 Sep 2022 07:45:44 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 3C547B80ECE; Tue, 13 Sep 2022 14:33:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A85FEC433D6; Tue, 13 Sep 2022 14:33:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1663079619; bh=PZSImN124wNr3us3+Y8nvBFBloECDt4+TqCOelhU4Wk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B2Lcm99PvAZBFTWu4F7Zqk0G7iniiU4zeMu+aXJxi+5vFO4oT2gvzbpN7wZcbCfaX Dph7J3yOKu1ggRvyYrF/cuZE4R1P/9KydLrtuEHM8dm0yiQtXdYDd0lRmcMTJw0BXh Rnetd4dO6GxkE/YK6leRd6W9cfAY9Cmc6MLhNvuM= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , John Fastabend , Alexei Starovoitov , Ovidiu Panait Subject: [PATCH 4.14 01/61] bpf: Verifer, adjust_scalar_min_max_vals to always call update_reg_bounds() Date: Tue, 13 Sep 2022 16:07:03 +0200 Message-Id: <20220913140346.518913754@linuxfoundation.org> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20220913140346.422813036@linuxfoundation.org> References: <20220913140346.422813036@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: John Fastabend commit 294f2fc6da27620a506e6c050241655459ccd6bd upstream. Currently, for all op verification we call __red_deduce_bounds() and __red_bound_offset() but we only call __update_reg_bounds() in bitwise ops. However, we could benefit from calling __update_reg_bounds() in BPF_ADD, BPF_SUB, and BPF_MUL cases as well. For example, a register with state 'R1_w=3DinvP0' when we subtract from it, w1 -=3D 2 Before coerce we will now have an smin_value=3DS64_MIN, smax_value=3DU64_MAX and unsigned bounds umin_value=3D0, umax_value=3DU64_MAX. These will then be clamped to S32_MIN, U32_MAX values by coerce in the case of alu32 op as done in above example. However tnum will be a constant because the ALU op is done on a constant. Without update_reg_bounds() we have a scenario where tnum is a const but our unsigned bounds do not reflect this. By calling update_reg_bounds after coerce to 32bit we further refine the umin_value to U64_MAX in the alu64 case or U32_MAX in the alu32 case above. Signed-off-by: John Fastabend Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/158507151689.15666.566796274289413203.stg= it@john-Precision-5820-Tower Signed-off-by: Ovidiu Panait Signed-off-by: Greg Kroah-Hartman --- kernel/bpf/verifier.c | 1 + 1 file changed, 1 insertion(+) --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -2739,6 +2739,7 @@ static int adjust_scalar_min_max_vals(st coerce_reg_to_size(dst_reg, 4); } =20 + __update_reg_bounds(dst_reg); __reg_deduce_bounds(dst_reg); __reg_bound_offset(dst_reg); return 0;