From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f42.google.com (mail-wm1-f42.google.com [209.85.128.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4947B3803F8 for ; Wed, 15 Apr 2026 18:38:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776278337; cv=none; b=FuBRUb1sMz+93ZeNOgrDsoQW5+HhNqqnGBwnvAdovS2RyeVElNA6Bzd5Acw5pECohF84gh9K4uTVtS7KM+dwiplRqSFufsTBbyXAPIahO51F/qxuomxPYDb1zGj7hTG5p7Nx1UHDFGRt0rI/r/2ufJrNycjeBrAGWhCqbxATe4g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776278337; c=relaxed/simple; bh=6VzPvjn6SlsaPNHRPPpez6ncx8IwPQo3kOQ6NYhJvSo=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=jSk+4kSWFUfNLM16xN0AlqHs81N1horLj+uI1RawQIOcFgV5+EfQQ1n6On8sffEnND2vg1ci7hXhryHYXnitJWukE1O30iWJG6BDwZPINNGVcvizjfEYjmq5Z1nAj42RRulpXTBnO3xSmLOKgRAGa+PtPfjKS/tMiiF7zzIHkVw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=maUZSdRP; arc=none smtp.client-ip=209.85.128.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="maUZSdRP" Received: by mail-wm1-f42.google.com with SMTP id 5b1f17b1804b1-488ab2db91aso110030545e9.3 for ; Wed, 15 Apr 2026 11:38:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776278335; x=1776883135; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=dqlBBTCIOKsamPbXZbMcmO0lTLqgGDxSRYX2crrZHzI=; b=maUZSdRPQI4B/DkFX9jS9TtUByS5aC607qgDMON1JCScHu1nmMe43f3n4nJKpUgQx3 TElN7DNpuRrl38wpKFXGmype9VqHXKe8kGNRMy6XGRU3I/qSbxUCXthZJybit03O2sYE MTU+f7KoUqKPCT3ebiSFeYyH2W3xbx8KsctaJ9I1OxMnH55S5E6be0NH3kBnphq1wQkY r3o1DC24YydEx9oDwkOR6YpBmDzdSbCj7LMElt4DT0jflD2j7JLVwCu9mATke9ioOQ4l BoDZnd02iX93cLg0l7I3+qb1L8m0bhGx+hsaMNnDFXA2oNIIJcdh9rgVwCuOFGwUT8yM Ci0Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776278335; x=1776883135; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=dqlBBTCIOKsamPbXZbMcmO0lTLqgGDxSRYX2crrZHzI=; b=b808ZD2NMmIyPLkW23zTSYYfsWKO/HWHL+QTMSgHdjbpS3E+6xURegDUbugAhFLV3C YqHbNi6YSUei0r5RJDzWnTbYaK7AEYRLwmqUx7C8OGMERc/FKG2hiPK6Bzpc0eQ5/vXu hAR9Gbp9tul6Qx602xvQmaIHOIw8HUFXzLPryZSLfAxXQ3QCDYZC0Ux2RJmSGzaF+vPD WoWWlIODRE4um55Rl/R63eirlfKyFaHpmP9Bnj7hX9S08aF1fygz52cH+vjBrx8oUdAG PyPEiTgQZp0hzjj4xMfA7WHy8M9hvgeBZMjNl8eUvcmbLr813/dIxTqxaXe/X3ic2qAF ESPw== X-Forwarded-Encrypted: i=1; AFNElJ/S/5es2ZERNy4mESt2JfJ0WRXqtTlrTUq/XDfaB1zsbG6vOPaSVxbV6qCPE5M3EXOuQ9RTA30dEGMfxHJBxho=@vger.kernel.org X-Gm-Message-State: AOJu0YwV7ZQcFlX0/xN49cboCHHU8yj0VWgBRV63vbhkLvUV8hbjW3N/ 9sjosNt+Oreq9EGWCvUMGG5/Herlui4ypZEwVpfgRKOs4VvbGzJLpREze1tkGowG X-Gm-Gg: AeBDiesx/aclpJeCf+FdEmFT8/+qxdwsoPpk+vKWUlPPga4d+vD1ubnAINjaxRGb/qH 9TM3XB977EXAmNMo21+pXJzPknUBd/QzsvzHQNSLLGjq27nVDnRkwEjUwFo0TvG8/obCTEURGmB 4c3K5XO1FMD9Hk8HioR1GOA2FICqh2bDQA1TMRtPSSiLEtBZ6B4GGOVEMp3iRL7ep+0k4n4+NhN scHvePbkI1xpbuyiwmo39rmd/YLpi10wPkkKjHs5A1oofbTnmmwhJKBlARa+zVUI+vscr0yh1BT ExBbonHh3yJNL5CqjW/DJ23emJMmQqMgTTbv3I69xzmvYBP/JhycGVzD+ElYKr+nHZE99IVqr2w MmKaaDJQVnvDUurjMyjTirdJ6/NVQFqT1XM6qqZKDQ4Kyn8yITnYvbekiRjaUBcE9FjBwvDsoYW 9VfCyC+KhZo/xYqq4hBbp2KlrASYuLgpSYlp5xTYnAVSse4fJoT+2YoFUh3lCnYmOA X-Received: by 2002:a05:6000:186a:b0:43d:77c6:be78 with SMTP id ffacd0b85a97d-43d77c6c462mr21260031f8f.39.1776278334509; Wed, 15 Apr 2026 11:38:54 -0700 (PDT) Received: from pumpkin (82-69-66-36.dsl.in-addr.zen.co.uk. [82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-43ead401ca0sm6144220f8f.36.2026.04.15.11.38.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 15 Apr 2026 11:38:54 -0700 (PDT) Date: Wed, 15 Apr 2026 19:38:52 +0100 From: David Laight To: Andy Shevchenko Cc: Thorsten Blum , Andrew Morton , Kees Cook , Andy Shevchenko , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] lib/string_helpers: drop redundant allocation in kasprintf_strarray Message-ID: <20260415193852.3171301b@pumpkin> In-Reply-To: References: <20260415122542.370926-4-thorsten.blum@linux.dev> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Wed, 15 Apr 2026 17:42:41 +0300 Andy Shevchenko wrote: > On Wed, Apr 15, 2026 at 02:25:43PM +0200, Thorsten Blum wrote: > > kasprintf_strarray() returns an array of N strings and kfree_strarray() > > also frees N entries. However, kasprintf_strarray() currently allocates > > N+1 char pointers. Allocate exactly N pointers instead of N+1. > > > > Also update the kernel-doc for @n. > > Have you checked all current users that they do not rely on the NULL terminated > array? > > Note, that was done on purpose that once allocated it can allow user > to drop the track of the number of strings and rely on NULL terminator. > I.o.w. the number of strings may be just a local variable somewhere > where kasprintf_strarray() is called. > > I tend to NAK this change, rather you can update kernel-doc to explain > why it's done this way (see above). > It isn't as though it is going to make much difference to the memory footprint. Allocating an extra trailing NULL is just a bit safer. David