Received: by 2002:a05:7412:f690:b0:e2:908c:2ebd with SMTP id ej16csp525539rdb; Thu, 19 Oct 2023 10:57:33 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEfJ5CiFg3np3oyZcpLVHilkDzFmai6zD4lHAJJpQXZGTDWJw7dQJJbKVql/FbPC2mdOIeL X-Received: by 2002:a05:6a00:1488:b0:6be:b744:c468 with SMTP id v8-20020a056a00148800b006beb744c468mr2886618pfu.29.1697738252800; Thu, 19 Oct 2023 10:57:32 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1697738252; cv=none; d=google.com; s=arc-20160816; b=rWf0vBcS5/mMuva7L0Vb/xVvPeryoK1vN9mnMZvp5sb2KqGUajfcE4p1BvjfPBYTKT 2LCsR583xvZs5yedwNF8OA4NFpWNvQqX/ElW1cDGmCWw4ynQtNxsKc60NPfKvzP9JMWN XCEX8hBLi0IdgOU1LMda3b7QQIQAxWuDhupDQMzE3xsnjY/uWQmRydJhIewZ1pCYGEhA vLVizqs1lPzBsPCDLGH2AzK4erJeD63joPuaRfoTVfC0uOH24UDU1/SvBvgSw/+ppqJE 0ilO4lLYLfB5aWkANc333EM85R1NbRNyvBQdyA98cwS9aNxWksYjpSbgn+a4vtrjAyEv 211Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:cc:to:subject:message-id:date:from:in-reply-to :references:mime-version:dkim-signature; bh=rD0auMna/G8UtkxOnP1VpkXXubqCDzIy0ubtyJSg/vM=; fh=UMAxhxhJSCrNaJEgEImPx2wBQbyVnHguvqGaCt24juk=; b=PYqJi6c4i6WLcwV8/frk48vou1A0mi5X7/5FF84gCzTC8mCGBsY5QZUXFW7UqCRP4P ny27pcb+wppQWDbj/kIE5g9rcYC4vqjINvlCuS+m5wr//6MLxpTWIviPA7N1OciXFSjf l6mU3jSwoaVhfzq+3DVJ8favvJESBNAfXD6KiGrmo7GoAPkMxo7PAHgvFk6HUWhOh9gL yfdCb2R/aLLwW7o6YZJQFxBAEiAZHlSm5sX17wRM6jKe05oja5ypSoCN8IZncCZ2sRTc ovf+1+uN7j8oRrJmmAO0NhMxLpZ6/WBGXxMWwU5w6O8R71RhtTZgtNH+1buUtYOLd8Lh aH3Q== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=H8B575Ba; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Return-Path: Received: from agentk.vger.email (agentk.vger.email. [2620:137:e000::3:2]) by mx.google.com with ESMTPS id z126-20020a633384000000b005ac34859de8si78777pgz.587.2023.10.19.10.57.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Oct 2023 10:57:32 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) client-ip=2620:137:e000::3:2; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=H8B575Ba; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:2 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by agentk.vger.email (Postfix) with ESMTP id BC7BE81B4AE4; Thu, 19 Oct 2023 10:57:30 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at agentk.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345405AbjJSR50 (ORCPT + 99 others); Thu, 19 Oct 2023 13:57:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235502AbjJSR5Z (ORCPT ); Thu, 19 Oct 2023 13:57:25 -0400 Received: from mail-ed1-x52d.google.com (mail-ed1-x52d.google.com [IPv6:2a00:1450:4864:20::52d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3CAD9136 for ; Thu, 19 Oct 2023 10:57:23 -0700 (PDT) Received: by mail-ed1-x52d.google.com with SMTP id 4fb4d7f45d1cf-53df747cfe5so14428116a12.2 for ; Thu, 19 Oct 2023 10:57:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1697738242; x=1698343042; darn=vger.kernel.org; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=rD0auMna/G8UtkxOnP1VpkXXubqCDzIy0ubtyJSg/vM=; b=H8B575Ba75TdEA7Ll5fW87YgPLRBGkc1ikCqxYIUeKZqmQvLd/Y5lvilg/hBAlVvSk cR0WnkjqXULKDYbnRQdx8IBpKE9Ik9bBp36NwWWbgN4mOP2ek+UIj99I6eMXPvDrAdYF isuxNCmpZGijRokW4mFYnIyr0vQOyyhRAh0kbG6KKdQvoMkBadLns564Lr8OeHI58SBC YV7LAQUTRzc3eV9+lH6z92K6+kLFvHIHYqJR+xRBTHjyVR7YcVLCYr67/slH+Ofz/pZW EMLzYDAl6MFRZ9xxD69h49PTROI56AJ7G2t1ayocTfGRrfetMsoj2nU+VorlsFLTRGsO 08tw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697738242; x=1698343042; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=rD0auMna/G8UtkxOnP1VpkXXubqCDzIy0ubtyJSg/vM=; b=vr+R1RC1fj6HhB+/eBcXa03cCUGSFmohIGExR7IyJb5mF/Z5Qlul3a0To/I1/uV3Z2 dmexWcpopy8hHPiECx/GMkKVNshcnJN20x7VRbhi9094uDjVYLKXaGPuLhoMs7Ggjm8L hn1J2S3hbQvLX6Rlk0bYVMJfcAfny+TFOybdVZSCjIm478EUj0snbTHAGLb+YzyGufk9 8wo42OXtkxW4SGzJ3Kni3RqJQIw4Keg81SD6RmfAmo30iZfHGc+KxEN2cL6z0J8HBnCt pqyfi0pXuaZrB2IQnW5c/RVQPfz6sn2EhR1Ky5LF0wfpo+E2jHo1IC/PF5zO5KU+T2kX 6zww== X-Gm-Message-State: AOJu0YyciCOaRZG+YriV24E5//2g8/0zFQMIRFB+hO4NpO56No3t/DaI Z80ByVoXrzGL53gyG0t1542ICTw3KGKR9N96MDE= X-Received: by 2002:a17:907:930a:b0:9c5:64b5:45cc with SMTP id bu10-20020a170907930a00b009c564b545ccmr2183910ejc.14.1697738241303; Thu, 19 Oct 2023 10:57:21 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: James Dutton Date: Thu, 19 Oct 2023 19:13:38 +0100 Message-ID: Subject: Re: Is strncpy really less secure than strscpy ? To: Bagas Sanjaya , Linux Kernel Mailing List Cc: Justin Stitt , Randy Dunlap , Calvince Otieno , Azeem Shaikh , Kees Cook , Andy Shevchenko Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on agentk.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (agentk.vger.email [0.0.0.0]); Thu, 19 Oct 2023 10:57:30 -0700 (PDT) On Thu, 19 Oct 2023 at 02:49, Bagas Sanjaya wrote: > [snip] > > What if printf("a is %.*s\n", a);? Um, it fails to compile. > > > > > > > So, why isn't the printk format specifier "%.*s" used more instead of > > "%s" in the kernel? > > Since basically strings are pointers. Um, I was trying to draw people's attention to the fact that "%.*s" is much safer than "%s". "%s" is like strcpy() but for print statements. "%.*s" is like strncpy() but for print statements. Why wasn't "%.*s" also included in the string discussions previously?