From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 48349 invoked by alias); 16 Nov 2016 15:06:36 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 47216 invoked by uid 89); 16 Nov 2016 15:06:35 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=AWL,BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,RCVD_IN_SORBS_SPAM,SPF_PASS autolearn=no version=3.3.2 spammy=measures, defensive, Hx-languages-length:1777, concerns X-HELO: mail-qk0-f193.google.com X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:to:references:cc:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=H1sDG4p1Xf386RT59H7UlpYdr22hMni7v/qV9yZ/FaI=; b=Co17I6esBhnvTyfvGdLSHLTWDy7684++slYp/Vba/9me8PzA+XOCJfRiegbFWwh+jt UlmJuqPCxYFtGcquyy8+zbufBrqMAHfxBYJr0kuUPX8wzr4yjSn5BxJOjODzJqRpAO1B lzvxDfZg9CBWNLp0EWoqm+HdTrXgAv/fepZ2QvsGUcdks0aC+HRlTrKykHKMOw+JzGUD wOXPK6RTGwU39XhWer9HxizK8oFmed+JiJGFUfg+WfYGulgGSMaz8IrXx/mPfgh271Yp nIn7HAC6yetLJGiUoPQ2jkTQqUeyTHt/xQQVgRTTmpIaQC0u55odWibUpguTtmnuvMM5 Z9sw== X-Gm-Message-State: AKaTC03UQ0lERxVrEPTD/HX6aqU8gekWWGqiv8MbLAVup5F0945rG24VKzirqYhj+PmesQ== X-Received: by 10.55.109.199 with SMTP id i190mr3604639qkc.287.1479308787500; Wed, 16 Nov 2016 07:06:27 -0800 (PST) Subject: Re: [PATCH 0/3] explicit_bzero v5 To: Joseph Myers References: <20161115155509.12692-1-zackw@panix.com> Cc: libc-alpha@sourceware.org, carlos@redhat.com, fweimer@redhat.com From: Zack Weinberg Message-ID: Date: Wed, 16 Nov 2016 15:06:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-SW-Source: 2016-11/txt/msg00559.txt.bz2 On 11/15/2016 09:03 PM, Joseph Myers wrote: > On Tue, 15 Nov 2016, Zack Weinberg wrote: > >> * libc.so now exports __explicit_bzero as well as explicit_bzero; the >> implementation-namespace symbol is used by libcrypt.so, and the >> user-namespace symbol is weak. (Requested by Joseph, iirc.) > > Requested by Florian (together with header pieces to cause normal calls to > explicit_bzero to end up calling the implementation-namespace version) > because of concerns about interposition. Oh, right, that. I think I should reply directly to Florian's proposal for impl-namespace names for all new symbols; I'm not convinced it's a good idea. I'd feel better about it if __REDIRECT could be implemented using only ISO C facilities, but I'd still be somewhat dubious. >> The impl-namespace symbol is versioned GLIBC_2.25 instead of >> GLIBC_PRIVATE, because that seems to be what was done for other >> impl-namespace aliases for string functions. I wasn't able to find >> anything definitive about when GLIBC_PRIVATE should be used. > > We need an implementation-namespace export for libcrypt use for namespace > reasons [*]. That's what I thought. > If it's only for libcrypt use, GLIBC_PRIVATE would suffice. If we want to > support it for other libraries limiting the namespace they use, with or > without header pieces to protect against accidental interposition, a > GLIBC_2.25 export is needed. It does seem to me that e.g. libssl might want to take defensive measures against a broken explicit_bzero in the main executable. > I'd expect a NEWS entry to be included somewhere in the patch series. I have been holding off on writing one until it was clear that the _feature_ was going to be accepted. Have we reached that point? zw