From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753116AbbJFRer (ORCPT ); Tue, 6 Oct 2015 13:34:47 -0400 Received: from mail-db3on0053.outbound.protection.outlook.com ([157.55.234.53]:24544 "EHLO emea01-db3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752347AbbJFRep (ORCPT ); Tue, 6 Oct 2015 13:34:45 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=cmetcalf@ezchip.com; Subject: Re: [PATCH] strscpy: zero any trailing garbage bytes in the destination To: Linus Torvalds , Ingo Molnar , Alexey Dobriyan , "Linux Kernel Mailing List" References: <1444150034-31729-1-git-send-email-cmetcalf@ezchip.com> From: Chris Metcalf Message-ID: <56140624.80801@ezchip.com> Date: Tue, 6 Oct 2015 13:34:28 -0400 User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1444150034-31729-1-git-send-email-cmetcalf@ezchip.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [12.216.194.146] X-ClientProxiedBy: CY1PR0801CA0039.namprd08.prod.outlook.com (25.163.136.177) To VI1PR02MB0783.eurprd02.prod.outlook.com (25.162.14.145) X-Microsoft-Exchange-Diagnostics: 1;VI1PR02MB0783;2:Xl30c6qaZgsw7mdyTGdqtfPcl7uENzXfESyNpntzKxCxwefTurRvPAmFyI4WxSs1Xy7Ao8ENu90RLgXRCLqginXxJBrXO61yjGxz765vXQc0vaFWnNuDzJ6Xktc53oGvAVn+5hBxU0SPf9GY59dIvciyiaGpUSRjkgDt6hM4pgY=;3:vcbFdLRb/+ErD+/QTaHEr4YH4HHdgWo10Jop0ufE0JD+36jjrxqopOxIF0RgiaSzItkP8xdkh02T4LpLmJLlf5Ctd5cyNaU8zpiwAEnMkrofq44fmzbMtedxlEagwi/QYAz1/NM9Xp7/2dZBJkpinw==;25:cC1J4eL2hrJnt/pdnFGNBF0PQ/Z88cSzBkwqxUsSy8v1nAXWVbFljcAg3gznedjr8X/rQfYp+T2zVldOR5RV20PX9Sd9JFdcz7zhpuzQPRtk3PVDBpgGFS/StHRftOX8IJX+vzgChWEW/pm0CYr4PjBrEDgFy8tpnjdi13kiPYUq9zc3DMXUDZodVlCqOT6CodRWNsu4PXufYkew8JuBYO3xJ7kEZPFQ172UAJ/vZYcsH5eExqDALdvdRH8HPQzXeTLybqzsJfbBqElcud4FVA==;20:rYCDEb0zwt/j5YxbKKAixdKJwEGXfgDS3t0xmgJuQWIdAUN8WQMt/6af7k7Rh8A1EvpX5YX4qOuvmNZLYZSdbX62qjcgwNUpHmDLJb3f/nRJPFA73ML8EnsoIPVe8jwic4mRmwAWeTgpoNKnLsYolwq3C7mAjxwrNFuTYXyVqZ8= X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:VI1PR02MB0783; X-Microsoft-Antispam-PRVS: X-Exchange-Antispam-Report-Test: UriScan:; X-Exchange-Antispam-Report-CFA-Test: BCL:0;PCL:0;RULEID:(601004)(2401047)(5005006)(520078)(8121501046)(3002001);SRVR:VI1PR02MB0783;BCL:0;PCL:0;RULEID:;SRVR:VI1PR02MB0783; X-Microsoft-Exchange-Diagnostics: 1;VI1PR02MB0783;4:HtRnwA/UCpiTut8y93oWPwXyTZawUgdmd2SNph8B4VYW/amYWDNVcyYWWYV078WotYGtgO90U3BLqXYZ0Mvb9PG5U9koKANkXtAZFJ82sj+T7p5teul/SkYN9xyjBONxCw2I85qJjyjFiwMELf83Km5sQ/148Qd28kyCowr3geI3DN1+tvu2N3KUUH4+rw4NJkhe0+gdbL2oHuX1d0G4TbHgZvlogZpoEn2GR/YWw1ufVCr0HiXREWvShzUwCNFuA0TadtIDuKxMI4MudhyXhQ4kTTKie7UMdVXXZbdm8aY8ARP9CQFEu1MlCdwcyymF2Ghdt4ARIWt7twXZHQaRP8Gzw32vcEUeV+mXPcuqdAo= X-Forefront-PRVS: 07215D0470 X-Forefront-Antispam-Report: SFV:NSPM;SFS:(10009020)(6049001)(6009001)(189002)(377454003)(479174004)(199003)(24454002)(54356999)(65816999)(76176999)(23746002)(86362001)(101416001)(83506001)(50986999)(46102003)(5008740100001)(50466002)(97736004)(5001770100001)(5007970100001)(81156007)(87976001)(15975445007)(65956001)(2950100001)(64706001)(105586002)(66066001)(106356001)(4001350100001)(77096005)(92566002)(65806001)(47776003)(5001960100002)(5004730100002)(117636001)(122386002)(36756003)(40100003)(42186005)(64126003)(19580395003)(107886002)(189998001)(62816006)(18886065003);DIR:OUT;SFP:1101;SCL:1;SRVR:VI1PR02MB0783;H:[10.7.0.41];FPR:;SPF:None;PTR:InfoNoRecords;MX:1;A:1;LANG:en; X-Microsoft-Exchange-Diagnostics: =?Windows-1252?Q?1;VI1PR02MB0783;23:KsWDXDgPjSqyM1kD2JkMmV3TA5LBYLNbMbB+b?= =?Windows-1252?Q?V1ZS7xsJuUm/plPDqC128quaQ+kYGofOh8/3Kn6x7NLzWGlAeIZUadbb?= =?Windows-1252?Q?Dl5VIUtZBcTqD30HJKi/o48Ml5TboQ5CaHgeXxuOVfOX764MJWYdniMM?= =?Windows-1252?Q?CDwdd2y3/nvmJ/nqgJmWdmG98QZ5j8pAPW9O8RI0sDGve+wkcorU1vZH?= =?Windows-1252?Q?WM760HytpL2Rwp47P/udzeeoa+/t0W5ozQ5pWyBK18fZfQMPAU0V0+Is?= =?Windows-1252?Q?jKL7Nns2LPlXIWw7b8Nu8CRZS+Ilm8Dxl4JAtJccGwPOybtSHJX1Oq1D?= =?Windows-1252?Q?y4HrONjKfFRlVfuJBdD706LucdWpX1f4u+xGGk7uE+dnpPwO4x1050aI?= =?Windows-1252?Q?8hGBRS41Bx9E8xdEVJ7XyGQy4sR4BK2mjglG+ZAU2k0hD1+3vO62q+j+?= =?Windows-1252?Q?Y193b0UJ8ILe1LqivVGnUyzWd3AShAKEqUrIpijn5RZMaFbbdpGCt36l?= =?Windows-1252?Q?zYih0f21r4DrBwV5QfpSiL4K1PPiFAYj8XzQQ7kybf1+qXkdhDzW2Un7?= =?Windows-1252?Q?UbXqM511uC2g1zGFwaPEcK1tGLz6ZTIlaf59Y/RdyCouVgfu7Qj+VpAA?= =?Windows-1252?Q?XkcejGVeXjZo6efO8iJL41QlyRbaWobHQkRGvQgUfYT5FJn7pEUclt5D?= =?Windows-1252?Q?rOjsPBsiCjJ6cpVnCohJPjrPSgwc83g+BtAWezLBNvTU6zqMcGJsgoEV?= =?Windows-1252?Q?vy37UNZf7aejW+u+IcxpCzq/kGqzoLUlqekEHS+SaGSbP52qi16cdI3B?= =?Windows-1252?Q?Xp0m65IEipWmiMfINhlWBB2F1K1+Hc/ac2/5a6lJgh0oOSWnXMsRgiDr?= =?Windows-1252?Q?HVbgcXwbucUBvbP8Ty7ZkDtGc9xbb/jZ43KUEws08dHqEeSjjvkWvpNQ?= =?Windows-1252?Q?k7t7a1FyjZACIztH8PuwqMkuRRU9uqH/Bl3RDDdXwFbGpWT7ZmKMPayS?= =?Windows-1252?Q?2HosdoTQ6lKxy0Pfx4S7wolpGyHv1Gl/5MMNfiEfe6V48dk9z9g3NEGG?= =?Windows-1252?Q?8bSwqWU9qfavmohgFffyULiNQBx6VbS2qUxyG1ghfP29wpuuTzr46AyT?= =?Windows-1252?Q?64FzFEVIlMMuyMeizdaEXIkpE9Zx6iQFktJn8xaAWI9EmaoptxBo4ocE?= =?Windows-1252?Q?3UnrFlNrI8pQ4VHiInVNTTB8CUhzh791csX3MPJuJehNzsU8VVM9WA3C?= =?Windows-1252?Q?kYBbY0L72sKlvwCyCfPvlODQvBjhmVXTZtqPu32z/dxwGuVXP9w4BBQb?= =?Windows-1252?Q?KoYIANIebVj6L7/4p3qLP5Fc99cC/YVxy7t+tZl17OhdpabLH9JzMGdr?= =?Windows-1252?Q?4HNK2nqqaOk1avf5HsTFO9+tAQc9i7kGg=3D=3D?= X-Microsoft-Exchange-Diagnostics: 1;VI1PR02MB0783;5:KOPigO+w6bWXKbs3cVCXW56+yiWalkKKuElvqSH/c3j+o35NJ/8YEOSPm8ZmKnxx5YjBdYrL/QnyCX9FVYvT1PEHGEvbHwKHnaqHvoLpCPxjAddnF3eeSiP5YW8hxT439d7MJ7mzpnMY1eku3M/VFg==;24:Kug4G2zKa6tKLloXevv92qd5dHDISMSuFxWrBnXY/sMcHMYDWzocmIhnmHtb7TIeaVWC0cZLaTRKfBiAV4His2GGK8ersR0KjqsK3agJUIA=;20:GNDEDWgQFZ//9/gfZToH+oczM/5QNHTeDPISRfza10kDDv7WP7nnJ0sYDQpN4MkS2BmZrR5UoWrWk70aHHBdJg== SpamDiagnosticOutput: 1:23 SpamDiagnosticMetadata: NSPM X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Oct 2015 17:34:39.9033 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-Transport-CrossTenantHeadersStamped: VI1PR02MB0783 X-Microsoft-Exchange-Diagnostics: 1;VI1PR02MB0653;2:C41P+1L0rKA0dcHOa0KA57Ja0INyk7lx4KJ9j5DeRhjdTKrppJWBpInke6lSZT7DUWx9+IhWDBcLTR4P3Ulioyv5Xv1XflELa1pzBRbXQ0LYTWHBPRcg6q3fLm6idPIFQfCfOfGQJM5VAdQc2exVmxZVlyIY31snfaPTSYnc8lU=;23:nM0qhD1oud+5/pOLM1ifpjoFo+Wn9FqNm0FqdcmuLjRcjlqbgAw7aRlYgGBDfHb+DLw+6OPC5M3XX5FD1/O5sZDeEYko3AYV8xvKgE6PlAH/qw+Q0Sl70S584P508vE1UQva46eV7GYT7PzBsBpOwzZfTzuBEfUbc9WM89MpinO/y1by8PqxT1P6PBRJnZzh X-OriginatorOrg: ezchip.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/06/2015 12:47 PM, Chris Metcalf wrote: > It's possible that the destination can be shadowed in userspace > (as, for example, the perf buffers are now). So we should take > care not to leak data that could be inspected by userspace. Oops, we need to ensure platforms all have zero_bytemask() before we can do this. It's pretty trivial in general, but not all platforms have it now. I'll post a patch to fix this as needed, which should be taken before this patch to avoid git bisect failures. I'll also see about fixing some skew in platforms that are either newer than the patch (h8300) or added word-at-a-time.h since the original patch (powerpc, tile). -- Chris Metcalf, EZChip Semiconductor http://www.ezchip.com