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=-5.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 A791AC43381 for ; Tue, 19 Feb 2019 03:03:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 77C6B2177E for ; Tue, 19 Feb 2019 03:03:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="EhEG3ZBd" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726152AbfBSDDw (ORCPT ); Mon, 18 Feb 2019 22:03:52 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:46378 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725308AbfBSDDw (ORCPT ); Mon, 18 Feb 2019 22:03:52 -0500 Received: by mail-pf1-f194.google.com with SMTP id g6so9476181pfh.13 for ; Mon, 18 Feb 2019 19:03:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=AUxYkpUOGVLojnBzMownAJmT4JzMv+qBE9F7iqL0iVA=; b=EhEG3ZBdr5KMPHwlgs8yf6x65xyo7j/jwyEiUjomuC3LRBxryAu3H7JUlwydWQ0UWW S3UVaafT5AflEbLmT4Ey8bQ4aBKBRL+yE57z0BvDyIf7/26nDamfkGGRRtSEw3uJ8I9s QzqXzcvEZkmkjZfDViOrjhaRVUhmY6nWRsvWRS3Ajo40X98mACI5DtIR3cCrylhu8lW0 s76omqRGoNgOqhsqFXRP9BVdsQAXvS78nsvb9q86ka3nbO/aIGF9bHRB/+VYcrPn5Nhd Jh0RYJV5n3pdsNtaNItezixpGBHTtV6uBL4JoT0v2UIJJaxTOYmQmH7bLor7IaMp2U6i PYiQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=AUxYkpUOGVLojnBzMownAJmT4JzMv+qBE9F7iqL0iVA=; b=Me2w5jIXsRrSNxSVi6KrPqdSMyhQNeiif+DUmG/rhHPbcz/nBdUM6h8l1Zcy7CInjf dTHgnQseXr3kKqCju7wXloKZI/JvVTg7fwXBgv51dJ0ylOB4p2M8QgbkTtx9mJflQDmy F3EjI984OpH6SCcYrCfxzHuiO3onjxA7C/1IqEuIhaIw9m0rOxVPX95M5Tl7kJDvJ7Bg u5YvDJgQMNZH1H8s0kVI5173Duatee19UrdLWoWRaLP/TBg8T3ZNMOaBO2oTmdMikjSY uoEiP0d3s9RhWxzrc6D6jMTy6AS3WpXuI1OHUtIDc9f/k1X1Cec3Gm89P7SNX0NxyiTG C+PA== X-Gm-Message-State: AHQUAuYzf9deYgncoGSrgOUmZn4OVZDT2Dv/N6/iXhHyGLoAH2GXVBp6 h/VzL7tnq0do+pm7tBJbYHs= X-Google-Smtp-Source: AHgI3IYFEzvQmV2+NSDG8NO+PzEHwvueCAJyYDiz9a4WXoTm+s5pXsI7ZOxGN57Yj1V/BCwzMCP+kg== X-Received: by 2002:a62:bd17:: with SMTP id a23mr26929404pff.233.1550545431216; Mon, 18 Feb 2019 19:03:51 -0800 (PST) Received: from localhost ([175.223.35.193]) by smtp.gmail.com with ESMTPSA id e20sm18309778pgg.62.2019.02.18.19.03.49 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 18 Feb 2019 19:03:50 -0800 (PST) Date: Tue, 19 Feb 2019 12:03:46 +0900 From: Sergey Senozhatsky To: Petr Mladek Cc: Andy Shevchenko , Rasmus Villemoes , Linus Torvalds , "Tobin C . Harding" , Joe Perches , Andrew Morton , Michal Hocko , Sergey Senozhatsky , Steven Rostedt , Sergey Senozhatsky , linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 9/9] vsprintf: Avoid confusion between invalid address and value Message-ID: <20190219030300.GA640@jagdpanzerIV> References: <20190208152310.29531-1-pmladek@suse.com> <20190208152310.29531-10-pmladek@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190208152310.29531-10-pmladek@suse.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (02/08/19 16:23), Petr Mladek wrote: [..] > Plain Pointers > -------------- > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index 3a95b4d1ca2e..e51cbc2be540 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -1510,7 +1510,7 @@ char *ip_addr_string(char *buf, char *end, const void *ptr, > case AF_INET6: > return ip6_addr_string_sa(buf, end, &sa->v6, spec, fmt); > default: > - return string_nocheck(buf, end, "(invalid address)", spec); > + return string_nocheck(buf, end, "(einval)", spec); > }} Hmm... The original code looks "a bit" dangerous. Suppose, in my driver I want to sprintf() IPv4 address. The longest possible address is 3 * 4 (%d%d%d) + 3 bytes (dots) + terminating NULL. E.g. 111.111.111.111 So I can allocate a 16-bytes buffer (stack or slab) and accidentally do an %piS sprintf() on a corrupted in_addr struct: char buf[16]; sprintf(buf, "%piS", in_addr); forcing sprintf() to write "(invalid address)" to a 16-bytes buffer, but the thing is - strlen("(invalid address)") > 16. We might want to take this change out of this series. -ss