From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by sourceware.org (Postfix) with ESMTPS id A18273891C05 for ; Mon, 10 Jan 2022 00:36:01 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org A18273891C05 Received: by mail-pj1-x102d.google.com with SMTP id m13so11880385pji.3 for ; Sun, 09 Jan 2022 16:36:01 -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=a55cklIdyyvslp0qR6/HdzjnXmvbLQBM7Zx9RtYx37A=; b=pgC4Kw8tBo6XJ54Yl6oMrt0pbzmkF5xtQDNE0CUJ2GSI2FY7XFU8KvgzvnALUgeHLm rVM0gcdk30Aj/sFkvwjYO3PH1i7DjsOIsPEJD7o8rimVCYmKZdWCQzTJ3nfxTPu6bGsy RnCdPSY/J28+vEItRCrjdtbOIakhR8GonQOlicAkmeCbwppBsrQSx6kNg0k8MYeDYnfD Mmt5u3SlKu8MNLw7WEyLMLhU2Cm3yfx9URfItxXSfrL/uY/3m4jotKY5egazGQUHAmT0 ZM2Nuc6U9Nh9tNVJgD54kQcaQl5z5WDgPSiDzA2PupDqhwQhnsf4pk5ch/eeXwQZdcQ+ VYlA== X-Gm-Message-State: AOAM532HwPNYad30Eckvc4kMN0L3h/8c/Azt1irFsP7nwsr4ICwtbwvI skpSEVzX0IZalj2phtIiHHZx12Bf+jV1PwiqboQ= X-Google-Smtp-Source: ABdhPJwElHciFUrkYvLACYWK+qOIdNT8bNEGuRzDMPw7ztsmZZ18F3UPSYvYCpLyTny0cU0T46F6wKSir6RzqBhmD/g= X-Received: by 2002:a17:90b:4f86:: with SMTP id qe6mr27453698pjb.120.1641774960799; Sun, 09 Jan 2022 16:36:00 -0800 (PST) MIME-Version: 1.0 References: <20220109122946.2754917-1-goldstein.w.n@gmail.com> <20220110002746.3653516-1-goldstein.w.n@gmail.com> <20220110002746.3653516-2-goldstein.w.n@gmail.com> In-Reply-To: <20220110002746.3653516-2-goldstein.w.n@gmail.com> From: "H.J. Lu" Date: Sun, 9 Jan 2022 16:35:25 -0800 Message-ID: Subject: Re: [PATCH v2 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=-3027.9 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: Mon, 10 Jan 2022 00:36:03 -0000 On Sun, Jan 9, 2022 at 4:28 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.