From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="GiY1k/0d" Received: from mail-pf1-x435.google.com (mail-pf1-x435.google.com [IPv6:2607:f8b0:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5276C199A for ; Fri, 8 Dec 2023 09:23:02 -0800 (PST) Received: by mail-pf1-x435.google.com with SMTP id d2e1a72fcca58-6ce33234fd7so1616559b3a.0 for ; Fri, 08 Dec 2023 09:23:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1702056182; x=1702660982; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=WNXDom1pGgFzD7z60+nX5wKE72JYAG4paS5sk2JCKg8=; b=GiY1k/0deCp31KIS/rscp6m71yTNYUEL+kB1zQ9qcDADBj76CBBvx96QLXr4UQf3Nf OYdJGf3XPP7YZoJg1Y2dC9/qVCN1IkX0g2Hy5/Ly98HxRGmVzHiV8Jv+CrND1k4IBlBo +AGAJa6nLkIv8JFMTzIl0elnYLMdooCku0EdA= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702056182; x=1702660982; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=WNXDom1pGgFzD7z60+nX5wKE72JYAG4paS5sk2JCKg8=; b=tfpOaG4EAjwboOwMjenFFFkd4ZX1G2KPsvM8kggTeXmmUkqfTN2qYt1/N+n8GtYvhJ 749ruKb4oRnV3IbAMjb1/KpmnNG11Gn4ZjBnCfj82ybi32xjWz1pD9Q6D87DnrIb8EFB 1KQM22SpNZG/o9oQQZcyAsa/zqOZWtTzsX9HGwUQeG3x+dhe3N2eoUGfjE4piBYMtEPk XceAqtKYEJu6vjIUgZUslPlafp6gmv9WFV0II3968vf+BhEaJs+C7Vdi9IbKOeIoLIOc Ew5lYJIPvWnu5IGrCZ4mG5o+/S4RdbJIG7pE4d9maJjhWF+fxjcQgrH1pMxrSvo+XYkZ +t6w== X-Gm-Message-State: AOJu0YyaRhX+6JxeeCqMqyIjbYh2l+xdFXn3S2+AAOeGNa1dcS1uIk0G QiNPZK3X/gPZ8yDD/CGUfhkexA== X-Google-Smtp-Source: AGHT+IF0odaLvAeilH7K2WI0rkMDi0C9smclmU3oIrDkxldyXyKpbjGkUJWAwcvrZUO929m23SwWqw== X-Received: by 2002:a05:6a00:1a8f:b0:6ce:50b4:a21 with SMTP id e15-20020a056a001a8f00b006ce50b40a21mr321026pfv.27.1702056181771; Fri, 08 Dec 2023 09:23:01 -0800 (PST) Received: from www.outflux.net (198-0-35-241-static.hfc.comcastbusiness.net. [198.0.35.241]) by smtp.gmail.com with ESMTPSA id u3-20020a056a00098300b006ce7fb8f59csm1837731pfg.32.2023.12.08.09.23.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 08 Dec 2023 09:23:00 -0800 (PST) Date: Fri, 8 Dec 2023 09:22:55 -0800 From: Kees Cook To: justinstitt@google.com Cc: Shay Agroskin , Arthur Kiyanovski , David Arinzon , Noam Dagan , Saeed Bishara , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH v2] net: ena: replace deprecated strncpy with strscpy Message-ID: <202312080922.881A1515F3@keescook> References: <20231207-strncpy-drivers-net-ethernet-amazon-ena-ena_netdev-c-v2-1-a1f2893d1b70@google.com> 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-Disposition: inline In-Reply-To: <20231207-strncpy-drivers-net-ethernet-amazon-ena-ena_netdev-c-v2-1-a1f2893d1b70@google.com> On Thu, Dec 07, 2023 at 09:34:42PM +0000, justinstitt@google.com wrote: > `strncpy` is deprecated for use on NUL-terminated destination strings > [1] and as such we should prefer more robust and less ambiguous string > interfaces. > > A suitable replacement is `strscpy` [2] due to the fact that it > guarantees NUL-termination on the destination buffer without > unnecessarily NUL-padding. > > host_info allocation is done in ena_com_allocate_host_info() via > dma_alloc_coherent() and is not zero initialized by alloc_etherdev_mq(). > > However zero initialization of the destination doesn't matter in this case, > because strscpy() guarantees a NULL termination. > > Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] > Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2] > Link: https://github.com/KSPP/linux/issues/90 > Cc: linux-hardening@vger.kernel.org > Signed-off-by: Justin Stitt Yeah, this reads much better. Reviewed-by: Kees Cook -- Kees Cook