From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-x634.google.com (mail-pl1-x634.google.com [IPv6:2607:f8b0:4864:20::634]) by sourceware.org (Postfix) with ESMTPS id 858B33891C09 for ; Tue, 11 Jan 2022 02:16:11 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 858B33891C09 Received: by mail-pl1-x634.google.com with SMTP id q14so14949329plx.4 for ; Mon, 10 Jan 2022 18:16:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lwzOYjLS8DPZZBzSgDolL+OsAZsm1pJnrxJ68maB1VE=; b=H0JotJD0u8QjRaxEzMoXen6KUf2Ifo+99eyaxCgoALPBSKEnyNoiu+D9UMyNZArOf1 /8FThhIzP0ozvFZ6WMd0rcSQbefIEcKyvNt9bjFSlpT1KQ2TI+PxESmlLvbqTYt//FDk n73k6vQ6qLWiylPiM4g9r9lXoC8JxO/tm3282CPyqcKeIxjQ/9AhdzRBVQRqJIOVImLL nwFovBt8LVOWX5mFYBZVkGrSVbHj+1U+IbxshmjoALQzk6zX0XioCZMK6ugVqfZcRFu6 xE7K6TwvOaaGI1hu/fHGD5AAWBLldVtF0POje6JtnfrEfn6fEX8bdqqxVGsq8s3EWKUB cTxA== X-Gm-Message-State: AOAM530FX5H4+MpF/coAVzelHsYfeVZZAeG992zA9zbdDR8w6DwOfUYT mk7CeFBlenTie1DfLomI73L/i6R4hnrVEOGMLKBEfldJbms= X-Google-Smtp-Source: ABdhPJwt/3jB3zZqdIpOoty7rl/xTBiP8LwqQUAOA0pyKTPtN2NukIlKzqFR2dFzMiJKaAgNXGo2OdNBChJNQXmx5ro= X-Received: by 2002:a17:90a:4e81:: with SMTP id o1mr784667pjh.28.1641867370622; Mon, 10 Jan 2022 18:16:10 -0800 (PST) MIME-Version: 1.0 References: <20220109122946.2754917-1-goldstein.w.n@gmail.com> <20220110213540.1258344-1-goldstein.w.n@gmail.com> <20220110213540.1258344-2-goldstein.w.n@gmail.com> In-Reply-To: <20220110213540.1258344-2-goldstein.w.n@gmail.com> From: "H.J. Lu" Date: Mon, 10 Jan 2022 18:15:34 -0800 Message-ID: Subject: Re: [PATCH v3 2/7] x86: Fix __wcsncmp_evex in strcmp-evex.S [BZ# 28755] To: Noah Goldstein Cc: GNU C Library Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-3027.8 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 11 Jan 2022 02:16:12 -0000 On Mon, Jan 10, 2022 at 1:36 PM Noah Goldstein via Libc-alpha wrote: > > Fixes [BZ# 28755] for wcsncmp by redirecting length >= 2^56 to > __wcscmp_evex. For x86_64 this covers the entire address range so any > length larger could not possibly be used to bound `s1` or `s2`. > > test-strcmp, test-strncmp, test-wcscmp, and test-wcsncmp all pass. > > Signed-off-by: Noah Goldstein > --- > sysdeps/x86_64/multiarch/strcmp-evex.S | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/sysdeps/x86_64/multiarch/strcmp-evex.S b/sysdeps/x86_64/multiarch/strcmp-evex.S > index 1d971f3889..0cd939d5af 100644 > --- a/sysdeps/x86_64/multiarch/strcmp-evex.S > +++ b/sysdeps/x86_64/multiarch/strcmp-evex.S > @@ -104,6 +104,16 @@ ENTRY (STRCMP) > je L(char0) > jb L(zero) > # ifdef USE_AS_WCSCMP > +# ifndef __ILP32__ > + movq %rdx, %rcx > + /* Check if length could overflow when multiplied by > + sizeof(wchar_t). Checking top 8 bits will cover all potential > + overflow cases as well as redirect cases where its impossible to > + length to bound a valid memory region. In these cases just use > + 'wcscmp'. */ > + shrq $56, %rcx > + jnz __wcscmp_evex > +# endif > /* Convert units: from wide to byte char. */ > shl $2, %RDX_LP > # endif > -- > 2.25.1 > LGTM. Reviewed-by: H.J. Lu Thanks. -- H.J.