Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754825AbbGHSys (ORCPT ); Wed, 8 Jul 2015 14:54:48 -0400 Received: from mail-ig0-f178.google.com ([209.85.213.178]:35551 "EHLO mail-ig0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753656AbbGHSyk (ORCPT ); Wed, 8 Jul 2015 14:54:40 -0400 Message-ID: <559D71EA.8080501@gmail.com> Date: Wed, 08 Jul 2015 14:54:34 -0400 From: Austin S Hemmelgarn User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Linus Torvalds , Andy Lutomirski CC: Arjan van de Ven , Andy Lutomirski , the arch/x86 maintainers , Linux Kernel Mailing List , Oleg Nesterov , Kees Cook , Peter Zijlstra , Borislav Petkov Subject: Re: [PATCH] x86/kconfig/32: Mark CONFIG_VM86 as BROKEN References: <23d4709cee2fe92c32d41b99c7a3c1823725925a.1436312944.git.luto@kernel.org> <559C8BFE.6050604@linux.intel.com> In-Reply-To: x-hashcash: 1:21:150708:torvalds@linux-foundation.org::de7cf90bc626b765f5504bd3cb14bdd6:a3332dab3a599fa7 x-hashcash: 1:21:150708:luto@amacapital.net::20e762b7b694ce5defaf7fe74c9966b:3835216b3fc5cb2b x-hashcash: 1:21:150708:arjan@linux.intel.com::3227c51550327bf455d5d69d4aa34453:2519f97c229abf44 x-hashcash: 1:21:150708:luto@kernel.org::6193c4a4fe1e3edd29bf330925fbafd9:92ac740e53168fb7 x-hashcash: 1:21:150708:x86@kernel.org::6ea7d13fb645f27c1cfa64b1609530d9:96f24ed2273766d5 x-hashcash: 1:21:150708:linux-kernel@vger.kernel.org::fe35ee801c130bd7ccc5564e50c492ae:71b037a8e2628f5f x-hashcash: 1:21:150708:oleg@redhat.com::b0aa245c37222521cfc3d069275e3b79:a20da8c00dcd28c3 x-hashcash: 1:21:150708:keescook@chromium.org::ee7e5f90cfeed1fef73fbbe79a70b460:2ab5d2692bb0e8e0 x-hashcash: 1:21:150708:peterz@infradead.org::8b3be634683587fabe0018466ecee7ee:b992c9515e902af2 x-hashcash: 1:21:150708:bp@alien8.de::53d16f4844d6546735d6986d656a5dba:19adf04c098255c7 x-stampprotocols: hashcash:1:17;mbound:0:10:3000:5000 Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha1; boundary="------------ms010100070906020106020900" X-Antivirus: avast! (VPS 150708-1, 2015-07-08), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6214 Lines: 105 This is a cryptographically signed message in MIME format. --------------ms010100070906020106020900 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-07-08 13:55, Linus Torvalds wrote: > On Wed, Jul 8, 2015 at 10:49 AM, Andy Lutomirski = wrote: >> >> I don't know how to tell whether something is trying to use real mode,= >> but I can play this just fine in DOSEMU on my 64-bit laptop: > > So a 64-bit distro obviously will never have used vm86 mode - it > doesn't work there. Never has. There's no sane way to get to vm86 mode > from long mode, that's just how the 64-bit extensions worked. > > (64-bit hardware obviously does support vm86 mode, but you have to > play games with mixing long mode and CPL0 32-bit protected mode to get > there, and we never did that). > > It's the 32-bit distros I would worry about. The ones that may have > well disabled emulation, because they have vm86 mode enabled. > Other than the enterprise distros (which _probably_ don't even have=20 dosemu packages, and I'm 99% certain would have VM86 enabled only for=20 'backwards compatibility'), I highly doubt that there are any modern=20 ones that have real-mode emulation disabled in dosemu, there's just too=20 high of a chance of a security minded user building their own kernel=20 with VM86 disabled (or they just have it disabled anyway in the distro=20 kernel, Ubuntu does this, and I'm pretty sure that Debian and Fedora do=20 also). FWIW, there's no easy way to disable such emulation on Gentoo=20 (it is possible, it just requires some significant configuration file=20 hacking for portage). --------------ms010100070906020106020900 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExCzAJBgUrDgMCGgUAMIAGCSqGSIb3DQEHAQAAoIIGuDCC BrQwggScoAMCAQICAxBuVTANBgkqhkiG9w0BAQ0FADB5MRAwDgYDVQQKEwdSb290IENBMR4w HAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmlu ZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZzAeFw0xNTAz MjUxOTM0MzhaFw0xNTA5MjExOTM0MzhaMGMxGDAWBgNVBAMTD0NBY2VydCBXb1QgVXNlcjEj MCEGCSqGSIb3DQEJARYUYWhmZXJyb2luN0BnbWFpbC5jb20xIjAgBgkqhkiG9w0BCQEWE2Fo ZW1tZWxnQG9oaW9ndC5jb20wggIiMA0GCSqGSIb3DQEBAQUAA4ICDwAwggIKAoICAQCdD/zW 2rRAFCLnDfXpWxU1+ODqRVUgzHvrRO7ADUxRo1CBDc3JSX5TIW2OGmQ3DAKGOACp8Z0sgxMc B05tzAZ/M7m4jajVrwwdVCdrwVGxTdAai7Kwg4ZCVfyMVhcwo8R2eW3QahBx34G0RKumK9sZ ZQSQ+zULAzpY6uz7T1sAk/erMoivRXF6u8WvOsLkOD1F/Xyv1ZccSUG5YeDgZgc0nZUBvyIp zXSHjgWerFkrxEM3y2z/Ff3eL1sgGYecV/I1F+I5S01V7Kclt/qRW10c/4JEGRcI1FmrJBPu BtMYPbg/3Y9LZROYN+mVIFxZxOfrmjfFZ96xt/TaMXo8vcEKtWcNEjhGBjEbfMUEm4aq8ygQ 4MuEcpJc8DJCHBkg2KBk13DkbU2qNepTD6Uip1C+g+KMr0nd6KOJqSH27ZuNY4xqV4hIxFHp ex0zY7mq6fV2o6sKBGQzRdI20FDYmNjsLJwjH6qJ8laxFphZnPRpBThmu0AjuBWE72GnI1oA aO+bs92MQGJernt7hByCnDO82W/ykbVz+Ge3Sax8NY0m2Xdvp6WFDY/PjD9CdaJ9nwQGsUSa N54lrZ2qMTeCI9Vauwf6U69BA42xgk65VvxvTNqji+tZ4aZbarZ7el2/QDHOb/rRwlCFplS/ z4l1f1nOrE6bnDl5RBJyW3zi74P6GwIDAQABo4IBWTCCAVUwDAYDVR0TAQH/BAIwADBWBglg hkgBhvhCAQ0ESRZHVG8gZ2V0IHlvdXIgb3duIGNlcnRpZmljYXRlIGZvciBGUkVFIGhlYWQg b3ZlciB0byBodHRwOi8vd3d3LkNBY2VydC5vcmcwDgYDVR0PAQH/BAQDAgOoMEAGA1UdJQQ5 MDcGCCsGAQUFBwMEBggrBgEFBQcDAgYKKwYBBAGCNwoDBAYKKwYBBAGCNwoDAwYJYIZIAYb4 QgQBMDIGCCsGAQUFBwEBBCYwJDAiBggrBgEFBQcwAYYWaHR0cDovL29jc3AuY2FjZXJ0Lm9y ZzAxBgNVHR8EKjAoMCagJKAihiBodHRwOi8vY3JsLmNhY2VydC5vcmcvcmV2b2tlLmNybDA0 BgNVHREELTArgRRhaGZlcnJvaW43QGdtYWlsLmNvbYETYWhlbW1lbGdAb2hpb2d0LmNvbTAN BgkqhkiG9w0BAQ0FAAOCAgEAGvl7xb42JMRH5D/vCIDYvFY3dR2FPd5kmOqpKU/fvQ8ovmJa p5N/FDrsCL+YdslxPY+AAn78PYmL5pFHTdRadT++07DPIMtQyy2qd+XRmz6zP8Il7vGcEDmO WmMLYMq4xV9s/N7t7JJp6ftdIYUcoTVChUgilDaRWMLidtslCdRsBVfUjPb1bF5Ua31diKDP e0M9/e2CU36rbcTtiNCXhptMigzuL3zJXUf2B9jyUV8pnqNEQH36fqJ7YTBLcpq3aYa2XbAH Hgx9GehJBIqwspDmhPCFZ/QmqUXCkt+XfvinQ2NzKR6P3+OdYbwqzVX8BdMeojh7Ig8x/nIx mQ+/ufstL1ZYp0bg13fyK/hPYSIBpayaC76vzWovkIm70DIDRIFLi20p/qTd7rfDYy831Hjm +lDdCECF9bIXEWFk33kA97dgQIMbf5chEmlFg8S0e4iw7LMjvRqMX3eCD8GJ2+oqyZUwzZxy S0Mx+rBld5rrN7LsXwZ671HsGqNeYbYeU25e7t7/Gcc6Bd/kPfA+adEuUGFcvUKH3trDYqNq 6mOkAd8WO/mQadlc3ztS++XDMhmIpfBre9MPAr6usqf+wc+R8Nk9KLK39kEgrqVfzc/fgf8L MaD4rHnusdg4gca6Yi+kNrm99anw7SwaBrBvULYBp7ixNRUhaYiNW4YjTrYxggShMIIEnQIB ATCBgDB5MRAwDgYDVQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5v cmcxIjAgBgNVBAMTGUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEW EnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5VMAkGBSsOAwIaBQCgggH1MBgGCSqGSIb3DQEJAzEL BgkqhkiG9w0BBwEwHAYJKoZIhvcNAQkFMQ8XDTE1MDcwODE4NTQzNFowIwYJKoZIhvcNAQkE MRYEFPk9fdBaWc8sQUEaLGx9RAdjr/70MGwGCSqGSIb3DQEJDzFfMF0wCwYJYIZIAWUDBAEq MAsGCWCGSAFlAwQBAjAKBggqhkiG9w0DBzAOBggqhkiG9w0DAgICAIAwDQYIKoZIhvcNAwIC AUAwBwYFKw4DAgcwDQYIKoZIhvcNAwICASgwgZEGCSsGAQQBgjcQBDGBgzCBgDB5MRAwDgYD VQQKEwdSb290IENBMR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMT GUNBIENlcnQgU2lnbmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2Fj ZXJ0Lm9yZwIDEG5VMIGTBgsqhkiG9w0BCRACCzGBg6CBgDB5MRAwDgYDVQQKEwdSb290IENB MR4wHAYDVQQLExVodHRwOi8vd3d3LmNhY2VydC5vcmcxIjAgBgNVBAMTGUNBIENlcnQgU2ln bmluZyBBdXRob3JpdHkxITAfBgkqhkiG9w0BCQEWEnN1cHBvcnRAY2FjZXJ0Lm9yZwIDEG5V MA0GCSqGSIb3DQEBAQUABIICAIoEb58//1ruOivcQ0fKEVOKjo4YwJj0D1kAlytKqaUBCusv 2UvFd54MIvaPeXXU2DwRVpHcoqf6dJ6JRLbqh0rYEDQN9+sTvb7luVZyS/EzHETR3l1dzhld QSOy9u5u6B9JVbUGoY2LJlHg0jusq3yyiMlQHgCtkdWb3/e+XDHnj0DLkqcrZHEm4tefTRZ1 me6otlPCF7dqG1TKPf1IaRb/7j+4WKJX4jLoIudka1xB++8J41az9M/XElDFJYUsM3Uqaz/q 4VeC7G5BOtDeVjdGW09z59cnwlDHAoi/ydgGcO11GJQZV9gEkfIlPnyJYEcOrbZ9Ea09Sbd5 ByJvs8HqYgksfKUnsZu3VGUUvFT8mgfq/uEepS+VF13zkNPRRvOtMGiYHNJ5hwWKzd3VLcje pRu3eWqtSWhjpK6AewGbSGykEzr+QHsfAM5vmXMeYcwNtZYtx94rcvXrT3T/iDaEo4MeHtxc dmZFGPl10uTsOiL16x9GmFWX53WfXRevggp04wovlanG6wtyQlkggScE0Qe6J3Wb2VBU9tzD mQWU4YGAVfDX/Qkgl5xIuQPKMd/UfAXgLsXwxtiCNHb0ssqkSHWibc+DcnhwNiHll6uXpvcN pn2/htSN9joCtuJMpbwmqmx+rdykve2FSLAxoOjPU3UfH0SyMOl7/Y5Qu2hcAAAAAAAA --------------ms010100070906020106020900-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/