Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752540AbaLIUlr (ORCPT ); Tue, 9 Dec 2014 15:41:47 -0500 Received: from out03.mta.xmission.com ([166.70.13.233]:35766 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751492AbaLIUlm (ORCPT ); Tue, 9 Dec 2014 15:41:42 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Andy Lutomirski Cc: Linux Containers , Josh Triplett , Andrew Morton , Kees Cook , Michael Kerrisk-manpages , Linux API , linux-man , "linux-kernel\@vger.kernel.org" , LSM , Casey Schaufler , "Serge E. Hallyn" , Richard Weinberger , Kenton Varda , stable References: <52e0643bd47b1e5c65921d6e00aea1f724bb510a.1417281801.git.luto@amacapital.net> <87h9xez20g.fsf@x220.int.ebiederm.org> <87mw75ygwp.fsf@x220.int.ebiederm.org> <87fvcxyf28.fsf_-_@x220.int.ebiederm.org> <874mtdyexp.fsf_-_@x220.int.ebiederm.org> <87a935u3nj.fsf@x220.int.ebiederm.org> <87388xodlj.fsf@x220.int.ebiederm.org> <87h9x5re41.fsf_-_@x220.int.ebiederm.org> <87mw6xpzb0.fsf_-_@x220.int.ebiederm.org> <87ppbtn4mv.fsf@x220.int.ebiederm.org> <87a92xn2io.fsf@x220.int.ebiederm.org> <87r3w8liw4.fsf@x220.int.ebiederm.org> <87iohklfvj.fsf_-_@x220.int.ebiederm.org> Date: Tue, 09 Dec 2014 14:39:25 -0600 In-Reply-To: <87iohklfvj.fsf_-_@x220.int.ebiederm.org> (Eric W. Biederman's message of "Tue, 09 Dec 2014 14:36:48 -0600") Message-ID: <874mt4lfr6.fsf_-_@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX1/6xrquMRus3wxieDvenW6SqJYcH/REQIw= X-SA-Exim-Connect-IP: 67.3.210.55 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 TVD_RCVD_IP Message was received from an IP address * 0.7 XMSubLong Long Subject * 1.5 TR_Symld_Words too many words that have symbols inside * 1.5 XMNoVowels Alpha-numberic number with no vowels * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.5000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa05 1397; Body=1 Fuz1=1 Fuz2=2] * 1.2 XMSubMetaSxObfu_03 Obfuscated Sexy Noun-People * 1.0 XMSubMetaSx_00 1+ Sexy Words * 1.0 T_XMDrugObfuBody_08 obfuscated drug references * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa05 1397; Body=1 Fuz1=1 Fuz2=2 X-Spam-Combo: ******;Andy Lutomirski X-Spam-Relay-Country: X-Spam-Timing: total 203 ms - load_scoreonly_sql: 0.05 (0.0%), signal_user_changed: 3.1 (1.5%), b_tie_ro: 2.2 (1.1%), parse: 0.69 (0.3%), extract_message_metadata: 10 (4.7%), get_uri_detail_list: 0.96 (0.5%), tests_pri_-1000: 5 (2.7%), tests_pri_-950: 1.07 (0.5%), tests_pri_-900: 0.90 (0.4%), tests_pri_-400: 19 (9.5%), check_bayes: 18 (9.0%), b_tokenize: 6 (2.8%), b_tok_get_all: 7 (3.5%), b_comp_prob: 1.53 (0.8%), b_tok_touch_all: 2.2 (1.1%), b_finish: 0.65 (0.3%), tests_pri_0: 156 (77.0%), tests_pri_500: 4.1 (2.0%), rewrite_mail: 0.00 (0.0%) Subject: [CFT][PATCH 3/8] userns: Don't allow unprivileged creation of gid mappings X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Wed, 24 Sep 2014 11:00:52 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org As any gid mapping will allow and must allow for backwards compatibility dropping groups don't allow any gid mappings to be established without CAP_SETGID in the parent user namespace. For a small class of applications this change breaks userspace and removes useful functionality. This small class of applications includes tools/testing/selftests/mount/unprivilged-remount-test.c Most of the removed functionality will be added back with the addition of a one way knob to disable setgroups. Once setgroups is disabled setting the gid_map becomes as safe as setting the uid_map. For more common applications that set the uid_map and the gid_map with privilege this change will have no affect. This is part of a fix for CVE-2014-8989. Cc: stable@vger.kernel.org Signed-off-by: "Eric W. Biederman" --- kernel/user_namespace.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 27c8dab48c07..1ce6d67c07b7 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -821,10 +821,6 @@ static bool new_idmap_permitted(const struct file *file, kuid_t uid = make_kuid(ns->parent, id); if (uid_eq(uid, file->f_cred->fsuid)) return true; - } else if (cap_setid == CAP_SETGID) { - kgid_t gid = make_kgid(ns->parent, id); - if (gid_eq(gid, file->f_cred->fsgid)) - return true; } } -- 1.9.1 -- 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/