Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753129Ab2KSPRJ (ORCPT ); Mon, 19 Nov 2012 10:17:09 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:35508 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752903Ab2KSPRF (ORCPT ); Mon, 19 Nov 2012 10:17:05 -0500 From: "Eric W. Biederman" To: Linux Containers Cc: , , "Serge E. Hallyn" , "Eric W. Biederman" Date: Mon, 19 Nov 2012 07:12:37 -0800 Message-Id: <1353337961-12962-12-git-send-email-ebiederm@xmission.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1353337961-12962-1-git-send-email-ebiederm@xmission.com> References: <87lidx8wbo.fsf@xmission.com> <1353337961-12962-1-git-send-email-ebiederm@xmission.com> X-XM-AID: U2FsdGVkX1/sAryCx1jfLmZos0T6Ba8M2CmcWI95rBY= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.1 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -0.0 BAYES_20 BODY: Bayes spam probability is 5 to 20% * [score: 0.1631] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa05 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_04 7+ unique symbols in subject * 0.0 T_TooManySym_01 4+ unique symbols in subject * 2.2 XMSubMetaSxObfu_03 Obfuscated Sexy Noun-People * 1.6 XMSubMetaSx_00 1+ Sexy Words * 0.0 T_TooManySym_03 6+ unique symbols in subject * 0.0 T_TooManySym_02 5+ unique symbols in subject X-Spam-DCC: XMission; sa05 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ***;Linux Containers X-Spam-Relay-Country: Subject: [PATCH review 12/16] userns: For /proc/self/{uid,gid}_map derive the lower userns from the struct file X-SA-Exim-Version: 4.2.1 (built Sun, 08 Jan 2012 03:05:19 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2501 Lines: 77 From: "Eric W. Biederman" To keep things sane in the context of file descriptor passing derive the user namespace that uids are mapped into from the opener of the file instead of from current. When writing to the maps file the lower user namespace must always be the parent user namespace, or setting the mapping simply does not make sense. Enforce that the opener of the file was in the parent user namespace or the user namespace whose mapping is being set. Signed-off-by: "Eric W. Biederman" --- kernel/user_namespace.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index ce92f7e..89f6eae 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -391,7 +391,7 @@ static int uid_m_show(struct seq_file *seq, void *v) struct user_namespace *lower_ns; uid_t lower; - lower_ns = current_user_ns(); + lower_ns = seq_user_ns(seq); if ((lower_ns == ns) && lower_ns->parent) lower_ns = lower_ns->parent; @@ -412,7 +412,7 @@ static int gid_m_show(struct seq_file *seq, void *v) struct user_namespace *lower_ns; gid_t lower; - lower_ns = current_user_ns(); + lower_ns = seq_user_ns(seq); if ((lower_ns == ns) && lower_ns->parent) lower_ns = lower_ns->parent; @@ -688,10 +688,14 @@ ssize_t proc_uid_map_write(struct file *file, const char __user *buf, size_t siz { struct seq_file *seq = file->private_data; struct user_namespace *ns = seq->private; + struct user_namespace *seq_ns = seq_user_ns(seq); if (!ns->parent) return -EPERM; + if ((seq_ns != ns) && (seq_ns != ns->parent)) + return -EPERM; + return map_write(file, buf, size, ppos, CAP_SETUID, &ns->uid_map, &ns->parent->uid_map); } @@ -700,10 +704,14 @@ ssize_t proc_gid_map_write(struct file *file, const char __user *buf, size_t siz { struct seq_file *seq = file->private_data; struct user_namespace *ns = seq->private; + struct user_namespace *seq_ns = seq_user_ns(seq); if (!ns->parent) return -EPERM; + if ((seq_ns != ns) && (seq_ns != ns->parent)) + return -EPERM; + return map_write(file, buf, size, ppos, CAP_SETGID, &ns->gid_map, &ns->parent->gid_map); } -- 1.7.5.4 -- 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/