From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4AFB4C433DF for ; Mon, 17 Aug 2020 19:19:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D3C920578 for ; Mon, 17 Aug 2020 19:19:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597691941; bh=w/2g3aLvQltOZyeGMCGkAoO5Cozq7K1AwA0txE6qThI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=QyTtNWDIMQxuL2ViiDanYFFjBTfl4ecAwj2laneJEey/u254DhsjdSAQqIZYV5I8Z QkWF6KXiKdWcdC7hgY9H6JUZhDpJBxlnc/qK88CGbN6kp9pS6Gvedq2XAV2/vDID/n NmEt8ks2fMcNeEume2ILHvIb0yePZeEptRKbWnBI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2392283AbgHQTS6 (ORCPT ); Mon, 17 Aug 2020 15:18:58 -0400 Received: from mail.kernel.org ([198.145.29.99]:45786 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730572AbgHQPh7 (ORCPT ); Mon, 17 Aug 2020 11:37:59 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1C7A223120; Mon, 17 Aug 2020 15:37:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597678677; bh=w/2g3aLvQltOZyeGMCGkAoO5Cozq7K1AwA0txE6qThI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2Yxai9FRdD79CP/X/SAewOIHIJDZysFH9Mfp654rW2AVyklTP2rlGhcttcTPLdRzf 7qwMaMZlWBh/gumNW1WpCTDGbz37HgKrpoK5Z19+hvrNK1Z6Btyma9BP04hquuhYao PMOQivPBuK/vZU5sH2X4jNSpHFAMYBUMdIZnNTlw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masahiro Yamada , Jakub Kicinski , Nick Desaulniers , "David S. Miller" , Sami Tolvanen Subject: [PATCH 5.8 415/464] bitfield.h: dont compile-time validate _val in FIELD_FIT Date: Mon, 17 Aug 2020 17:16:08 +0200 Message-Id: <20200817143853.658940008@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200817143833.737102804@linuxfoundation.org> References: <20200817143833.737102804@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jakub Kicinski commit 444da3f52407d74c9aa12187ac6b01f76ee47d62 upstream. When ur_load_imm_any() is inlined into jeq_imm(), it's possible for the compiler to deduce a case where _val can only have the value of -1 at compile time. Specifically, /* struct bpf_insn: _s32 imm */ u64 imm = insn->imm; /* sign extend */ if (imm >> 32) { /* non-zero only if insn->imm is negative */ /* inlined from ur_load_imm_any */ u32 __imm = imm >> 32; /* therefore, always 0xffffffff */ if (__builtin_constant_p(__imm) && __imm > 255) compiletime_assert_XXX() This can result in tripping a BUILD_BUG_ON() in __BF_FIELD_CHECK() that checks that a given value is representable in one byte (interpreted as unsigned). FIELD_FIT() should return true or false at runtime for whether a value can fit for not. Don't break the build over a value that's too large for the mask. We'd prefer to keep the inlining and compiler optimizations though we know this case will always return false. Cc: stable@vger.kernel.org Fixes: 1697599ee301a ("bitfield.h: add FIELD_FIT() helper") Link: https://lore.kernel.org/kernel-hardening/CAK7LNASvb0UDJ0U5wkYYRzTAdnEs64HjXpEUL7d=V0CXiAXcNw@mail.gmail.com/ Reported-by: Masahiro Yamada Debugged-by: Sami Tolvanen Signed-off-by: Jakub Kicinski Signed-off-by: Nick Desaulniers Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- include/linux/bitfield.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/bitfield.h +++ b/include/linux/bitfield.h @@ -77,7 +77,7 @@ */ #define FIELD_FIT(_mask, _val) \ ({ \ - __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_FIT: "); \ + __BF_FIELD_CHECK(_mask, 0ULL, 0ULL, "FIELD_FIT: "); \ !((((typeof(_mask))_val) << __bf_shf(_mask)) & ~(_mask)); \ })