From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752749AbbKJNgu (ORCPT ); Tue, 10 Nov 2015 08:36:50 -0500 Received: from mail-io0-f176.google.com ([209.85.223.176]:35000 "EHLO mail-io0-f176.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751284AbbKJNgt (ORCPT ); Tue, 10 Nov 2015 08:36:49 -0500 Subject: Re: [KERNEL] [PATCH] Kernel 4.3 breaks security in systems using capabilities To: "Theodore Ts'o" , Andy Lutomirski , Serge Hallyn , Kees Cook , Christoph Lameter , "Serge E. Hallyn" , Andrew Morton , Richard Weinberger , LKML , Linus Torvalds References: <20151106175619.GA19491@ikki.ethgen.ch> <20151106181820.GB16749@mail.hallyn.com> <20151107110246.GA7230@ikki.ethgen.ch> <5640C999.5050807@gmail.com> <20151109172340.GF3714@ikki.ethgen.ch> <5640EDB4.70407@gmail.com> <20151109212937.GA17624@ikki.ethgen.ch> <20151110115526.GA2958@ikki.ethgen.ch> <20151110124043.GC3717@thunk.org> <20151110131907.GB2958@ikki.ethgen.ch> From: Austin S Hemmelgarn Message-ID: <5641F2B7.9050408@gmail.com> Date: Tue, 10 Nov 2015 08:35:51 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <20151110131907.GB2958@ikki.ethgen.ch> Content-Type: multipart/signed; protocol="application/pkcs7-signature"; micalg=sha-512; boundary="------------ms060805010103030702040309" X-Antivirus: avast! (VPS 151110-0, 2015-11-10), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is a cryptographically signed message in MIME format. --------------ms060805010103030702040309 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable On 2015-11-10 08:19, Klaus Ethgen wrote: > Hi Ted, hy others in this discussion, > > Am Di den 10. Nov 2015 um 13:40 schrieb Theodore Ts'o: >> Whether or not that will be acceptable upstream, I don't know, mainly >> because I think a strong case can be made that such a patch has an >> audience of one, and adding more complexity here for an idea which has= >> been time-tested over decades to be a failure is just not a good idea.= > > I wouldn't tell the implementation until now to be a failure. It helped= > a lot to keep a system sane. It is true that all distributions ignored > capabilities completely but I don't think that is due the design. I think it's mostly due to the fact that there are a lot of potential=20 security issues in using capabilities as implemented in Linux (and other = POSIX systems), and unlike chroot(), it's not as easy to protect against = stuff trying to bypass them while still keeping them useful. If you do a = web search you can relatively easily find info on how to use many of the = defined capabilities to get root-equivalent access (CAP_SYS_ADMIN and=20 CAP_SYS_MODULE are obvious, but many of the others can be used also if=20 you know what you are doing, for example CAP_DAC_OVERRIDE+CAP_SYS_BOOT=20 can be used on non-SecureBoot systems to force the system to reboot into = an arbitrary kernel). --------------ms060805010103030702040309 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="smime.p7s" Content-Description: S/MIME Cryptographic Signature MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgMFADCABgkqhkiG9w0BBwEAAKCC Brgwgga0MIIEnKADAgECAgMRLfgwDQYJKoZIhvcNAQENBQAweTEQMA4GA1UEChMHUm9vdCBD QTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNp Z25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcwHhcN MTUwOTIxMTEzNTEzWhcNMTYwMzE5MTEzNTEzWjBjMRgwFgYDVQQDEw9DQWNlcnQgV29UIFVz ZXIxIzAhBgkqhkiG9w0BCQEWFGFoZmVycm9pbjdAZ21haWwuY29tMSIwIAYJKoZIhvcNAQkB FhNhaGVtbWVsZ0BvaGlvZ3QuY29tMIICIjANBgkqhkiG9w0BAQEFAAOCAg8AMIICCgKCAgEA nQ/81tq0QBQi5w316VsVNfjg6kVVIMx760TuwA1MUaNQgQ3NyUl+UyFtjhpkNwwChjgAqfGd LIMTHAdObcwGfzO5uI2o1a8MHVQna8FRsU3QGouysIOGQlX8jFYXMKPEdnlt0GoQcd+BtESr pivbGWUEkPs1CwM6WOrs+09bAJP3qzKIr0VxervFrzrC5Dg9Rf18r9WXHElBuWHg4GYHNJ2V Ab8iKc10h44FnqxZK8RDN8ts/xX93i9bIBmHnFfyNRfiOUtNVeynJbf6kVtdHP+CRBkXCNRZ qyQT7gbTGD24P92PS2UTmDfplSBcWcTn65o3xWfesbf02jF6PL3BCrVnDRI4RgYxG3zFBJuG qvMoEODLhHKSXPAyQhwZINigZNdw5G1NqjXqUw+lIqdQvoPijK9J3eijiakh9u2bjWOMaleI SMRR6XsdM2O5qun1dqOrCgRkM0XSNtBQ2JjY7CycIx+qifJWsRaYWZz0aQU4ZrtAI7gVhO9h pyNaAGjvm7PdjEBiXq57e4QcgpwzvNlv8pG1c/hnt0msfDWNJtl3b6elhQ2Pz4w/QnWifZ8E BrFEmjeeJa2dqjE3giPVWrsH+lOvQQONsYJOuVb8b0zao4vrWeGmW2q2e3pdv0Axzm/60cJQ haZUv8+JdX9ZzqxOm5w5eUQSclt84u+D+hsCAwEAAaOCAVkwggFVMAwGA1UdEwEB/wQCMAAw VgYJYIZIAYb4QgENBEkWR1RvIGdldCB5b3VyIG93biBjZXJ0aWZpY2F0ZSBmb3IgRlJFRSBo ZWFkIG92ZXIgdG8gaHR0cDovL3d3dy5DQWNlcnQub3JnMA4GA1UdDwEB/wQEAwIDqDBABgNV HSUEOTA3BggrBgEFBQcDBAYIKwYBBQUHAwIGCisGAQQBgjcKAwQGCisGAQQBgjcKAwMGCWCG SAGG+EIEATAyBggrBgEFBQcBAQQmMCQwIgYIKwYBBQUHMAGGFmh0dHA6Ly9vY3NwLmNhY2Vy dC5vcmcwMQYDVR0fBCowKDAmoCSgIoYgaHR0cDovL2NybC5jYWNlcnQub3JnL3Jldm9rZS5j cmwwNAYDVR0RBC0wK4EUYWhmZXJyb2luN0BnbWFpbC5jb22BE2FoZW1tZWxnQG9oaW9ndC5j b20wDQYJKoZIhvcNAQENBQADggIBADMnxtSLiIunh/TQcjnRdf63yf2D8jMtYUm4yDoCF++J jCXbPQBGrpCEHztlNSGIkF3PH7ohKZvlqF4XePWxpY9dkr/pNyCF1PRkwxUURqvuHXbu8Lwn 8D3U2HeOEU3KmrfEo65DcbanJCMTTW7+mU9lZICPP7ZA9/zB+L0Gm1UNFZ6AU50N/86vjQfY WgkCd6dZD4rQ5y8L+d/lRbJW7ZGEQw1bSFVTRpkxxDTOwXH4/GpQfnfqTAtQuJ1CsKT12e+H NSD/RUWGTr289dA3P4nunBlz7qfvKamxPymHeBEUcuICKkL9/OZrnuYnGROFwcdvfjGE5iLB kjp/ttrY4aaVW5EsLASNgiRmA6mbgEAMlw3RwVx0sVelbiIAJg9Twzk4Ct6U9uBKiJ8S0sS2 8RCSyTmCRhJs0vvva5W9QUFGmp5kyFQEoSfBRJlbZfGX2ehI2Hi3U2/PMUm2ONuQG1E+a0AP u7I0NJc/Xil7rqR0gdbfkbWp0a+8dAvaM6J00aIcNo+HkcQkUgtfrw+C2Oyl3q8IjivGXZqT 5UdGUb2KujLjqjG91Dun3/RJ/qgQlotH7WkVBs7YJVTCxfkdN36rToPcnMYOI30FWa0Q06gn F6gUv9/mo6riv3A5bem/BdbgaJoPnWQD9D8wSyci9G4LKC+HQAMdLmGoeZfpJzKHMYIE0TCC BM0CAQEwgYAweTEQMA4GA1UEChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNl cnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcN AQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DANBglghkgBZQMEAgMFAKCCAiEwGAYJKoZI hvcNAQkDMQsGCSqGSIb3DQEHATAcBgkqhkiG9w0BCQUxDxcNMTUxMTEwMTMzNTUxWjBPBgkq hkiG9w0BCQQxQgRAHpeJiuP2+karNVz8/tj0AUE5vbJ/+sPiqOrOzkECkf8RVzAqOyrysaYe 2Z/nazCpQBxvqmxc4SHG1BJeAIiNXTBsBgkqhkiG9w0BCQ8xXzBdMAsGCWCGSAFlAwQBKjAL BglghkgBZQMEAQIwCgYIKoZIhvcNAwcwDgYIKoZIhvcNAwICAgCAMA0GCCqGSIb3DQMCAgFA MAcGBSsOAwIHMA0GCCqGSIb3DQMCAgEoMIGRBgkrBgEEAYI3EAQxgYMwgYAweTEQMA4GA1UE ChMHUm9vdCBDQTEeMBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlD QSBDZXJ0IFNpZ25pbmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2Vy dC5vcmcCAxEt+DCBkwYLKoZIhvcNAQkQAgsxgYOggYAweTEQMA4GA1UEChMHUm9vdCBDQTEe MBwGA1UECxMVaHR0cDovL3d3dy5jYWNlcnQub3JnMSIwIAYDVQQDExlDQSBDZXJ0IFNpZ25p bmcgQXV0aG9yaXR5MSEwHwYJKoZIhvcNAQkBFhJzdXBwb3J0QGNhY2VydC5vcmcCAxEt+DAN BgkqhkiG9w0BAQEFAASCAgA7XfhXpXXtMWvVRylK9+97vIbPn6enIu2I2QnhwjBlWtPadp9v rKjkFo9lStQDCuu+IrNLYQgTCIPG0jYFzy8vRfX6S/9w6Bnf1R3BokTrh5p7hdoD6s05RmbI pMgzGMXlAUEP7lMOD160zdLr7sK45ZU5Xl/3gEednA5dsKD6P+e8m+8pQQnFEEEYkPOrVlxk mM52Co+8TfC92xcz2QVckToo/GNlc1cFD/AIIvEWitVxWURzSBa/BDSgMFikJZe1P25Ik9k1 JlsrCWe9kVoj+GLfgkF+2/G265ESsCoCWLrkq4Kw2xFOJKPwFoxocF0GvYlOtdsU/45kUROM j0bObJEi9ZAuEHWGUgQOeupPinMuOPwA080ecU8jJn0w1uIGkWO1eoZdUGcksH/mK/Bg1LnR NElj6llqEkDoc5hdiHJsjFexdcwetuAi1UFbKU0pMQc6AOM1IkaB1shi1n1WAMcRJ0Wk4DAD U0fNGZ2qyEvBm2LkhWYLA0TNdgah8qZ1CgQX5jQDhB7IBuZXKBferstsd6hqtldkpcovbpPw 2pqxmSk6Bn5ItbT51UfVdAlIA341+ANxIHnlax3z5CZKlHQmbkL5SYASp1H4ZdB07wQ8T8hP D6cnhlCh1WzSVKlXJI9j9y+ezTi52ugPLBr+1f0RsRHdJAyfNDDcabNMkAAAAAAAAA== --------------ms060805010103030702040309--