From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8093DC433E0 for ; Sat, 27 Jun 2020 13:24:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 55BD8208B6 for ; Sat, 27 Jun 2020 13:24:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QwkEoKOX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726636AbgF0NYC (ORCPT ); Sat, 27 Jun 2020 09:24:02 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:23005 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726960AbgF0NX7 (ORCPT ); Sat, 27 Jun 2020 09:23:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1593264237; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:in-reply-to:in-reply-to:in-reply-to: references:references:references; bh=Vbsz74jx639O45NZJ//E5urMuCAJMJoLkV3YW2Jxk5M=; b=QwkEoKOXI14Cyj4uSi8GimqBkq1i3GmtiInD1DVMVfk+Ult6ic9GeXidl5OGHOjuU/KgOh W6IPWToESRCk8vNdYdMWf0WXo3iT8ZomQsj9zDk0ffTMzrFVp5eIMEXSUO0HM44P+1gHUs LgYF6HEGay7ISkbmurYV05rhu+pb9vQ= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-300-C3L9deshP0OUCzQ5IpSj0Q-1; Sat, 27 Jun 2020 09:23:55 -0400 X-MC-Unique: C3L9deshP0OUCzQ5IpSj0Q-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 8D191A0BD7; Sat, 27 Jun 2020 13:23:53 +0000 (UTC) Received: from madcap2.tricolour.ca (unknown [10.10.110.28]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5A07D8205F; Sat, 27 Jun 2020 13:23:43 +0000 (UTC) From: Richard Guy Briggs To: containers@lists.linux-foundation.org, linux-api@vger.kernel.org, Linux-Audit Mailing List , linux-fsdevel@vger.kernel.org, LKML , netdev@vger.kernel.org, netfilter-devel@vger.kernel.org Cc: Paul Moore , sgrubb@redhat.com, omosnace@redhat.com, dhowells@redhat.com, simo@redhat.com, eparis@parisplace.org, serge@hallyn.com, ebiederm@xmission.com, nhorman@tuxdriver.com, dwalsh@redhat.com, mpatel@redhat.com, Richard Guy Briggs Subject: [PATCH ghak90 V9 13/13] audit: add capcontid to set contid outside init_user_ns Date: Sat, 27 Jun 2020 09:20:46 -0400 Message-Id: In-Reply-To: References: In-Reply-To: References: X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Provide a mechanism similar to CAP_AUDIT_CONTROL to explicitly give a process in a non-init user namespace the capability to set audit container identifiers of individual children. Provide the /proc/$PID/audit_capcontid interface to capcontid. Valid values are: 1==enabled, 0==disabled Writing a "1" to this special file for the target process $PID will enable the target process to set audit container identifiers of its descendants. A process must already have CAP_AUDIT_CONTROL in the initial user namespace or have had audit_capcontid enabled by a previous use of this feature by its parent on this process in order to be able to enable it for another process. The target process must be a descendant of the calling process. Report this action in new message type AUDIT_SET_CAPCONTID 1022 with fields opid= capcontid= old-capcontid= Signed-off-by: Richard Guy Briggs --- fs/proc/base.c | 57 +++++++++++++++++++++++++++++++++++++++++++++- include/linux/audit.h | 14 ++++++++++++ include/uapi/linux/audit.h | 1 + kernel/audit.c | 38 ++++++++++++++++++++++++++++++- 4 files changed, 108 insertions(+), 2 deletions(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 794474cd8f35..1083db2ce345 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1329,7 +1329,7 @@ static ssize_t proc_contid_read(struct file *file, char __user *buf, if (!task) return -ESRCH; /* if we don't have caps, reject */ - if (!capable(CAP_AUDIT_CONTROL)) + if (!capable(CAP_AUDIT_CONTROL) && !audit_get_capcontid(current)) return -EPERM; length = scnprintf(tmpbuf, TMPBUFLEN, "%llu", audit_get_contid(task)); put_task_struct(task); @@ -1370,6 +1370,59 @@ static ssize_t proc_contid_write(struct file *file, const char __user *buf, .write = proc_contid_write, .llseek = generic_file_llseek, }; + +static ssize_t proc_capcontid_read(struct file *file, char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(file); + struct task_struct *task = get_proc_task(inode); + ssize_t length; + char tmpbuf[TMPBUFLEN]; + + if (!task) + return -ESRCH; + /* if we don't have caps, reject */ + if (!capable(CAP_AUDIT_CONTROL) && !audit_get_capcontid(current)) + return -EPERM; + length = scnprintf(tmpbuf, TMPBUFLEN, "%u", audit_get_capcontid(task)); + put_task_struct(task); + return simple_read_from_buffer(buf, count, ppos, tmpbuf, length); +} + +static ssize_t proc_capcontid_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(file); + u32 capcontid; + int rv; + struct task_struct *task = get_proc_task(inode); + + if (!task) + return -ESRCH; + if (*ppos != 0) { + /* No partial writes. */ + put_task_struct(task); + return -EINVAL; + } + + rv = kstrtou32_from_user(buf, count, 10, &capcontid); + if (rv < 0) { + put_task_struct(task); + return rv; + } + + rv = audit_set_capcontid(task, capcontid); + put_task_struct(task); + if (rv < 0) + return rv; + return count; +} + +static const struct file_operations proc_capcontid_operations = { + .read = proc_capcontid_read, + .write = proc_capcontid_write, + .llseek = generic_file_llseek, +}; #endif #ifdef CONFIG_FAULT_INJECTION @@ -3273,6 +3326,7 @@ static int proc_stack_depth(struct seq_file *m, struct pid_namespace *ns, REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUGO, proc_sessionid_operations), REG("audit_containerid", S_IWUSR|S_IRUSR, proc_contid_operations), + REG("audit_capcontainerid", S_IWUSR|S_IRUSR, proc_capcontid_operations), #endif #ifdef CONFIG_FAULT_INJECTION REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), @@ -3613,6 +3667,7 @@ static int proc_tid_comm_permission(struct inode *inode, int mask) REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUGO, proc_sessionid_operations), REG("audit_containerid", S_IWUSR|S_IRUSR, proc_contid_operations), + REG("audit_capcontainerid", S_IWUSR|S_IRUSR, proc_capcontid_operations), #endif #ifdef CONFIG_FAULT_INJECTION REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), diff --git a/include/linux/audit.h b/include/linux/audit.h index 025b52ae8422..2b3a2b6020ed 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -122,6 +122,7 @@ struct audit_task_info { kuid_t loginuid; unsigned int sessionid; struct audit_contobj *cont; + u32 capcontid; #ifdef CONFIG_AUDITSYSCALL struct audit_context *ctx; #endif @@ -230,6 +231,14 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk) return tsk->audit->sessionid; } +static inline u32 audit_get_capcontid(struct task_struct *tsk) +{ + if (!tsk->audit) + return 0; + return tsk->audit->capcontid; +} + +extern int audit_set_capcontid(struct task_struct *tsk, u32 enable); extern int audit_set_contid(struct task_struct *tsk, u64 contid); static inline u64 audit_get_contid(struct task_struct *tsk) @@ -311,6 +320,11 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk) return AUDIT_SID_UNSET; } +static inline u32 audit_get_capcontid(struct task_struct *tsk) +{ + return 0; +} + static inline u64 audit_get_contid(struct task_struct *tsk) { return AUDIT_CID_UNSET; diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 831c12bdd235..5e30f4c95dc2 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -73,6 +73,7 @@ #define AUDIT_GET_FEATURE 1019 /* Get which features are enabled */ #define AUDIT_CONTAINER_OP 1020 /* Define the container id and info */ #define AUDIT_SIGNAL_INFO2 1021 /* Get info auditd signal sender */ +#define AUDIT_SET_CAPCONTID 1022 /* Set cap_contid of a task */ #define AUDIT_FIRST_USER_MSG 1100 /* Userspace messages mostly uninteresting to kernel */ #define AUDIT_USER_AVC 1107 /* We filter this differently */ diff --git a/kernel/audit.c b/kernel/audit.c index aaf74702e993..454473f2e193 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -307,6 +307,7 @@ int audit_alloc(struct task_struct *tsk) rcu_read_lock(); info->cont = _audit_contobj_get(current); rcu_read_unlock(); + info->capcontid = 0; tsk->audit = info; ret = audit_alloc_syscall(tsk); @@ -322,6 +323,7 @@ struct audit_task_info init_struct_audit = { .loginuid = INVALID_UID, .sessionid = AUDIT_SID_UNSET, .cont = NULL, + .capcontid = 0, #ifdef CONFIG_AUDITSYSCALL .ctx = NULL, #endif @@ -2763,6 +2765,40 @@ static bool audit_contid_isnesting(struct task_struct *tsk) return !isowner && ownerisparent; } +int audit_set_capcontid(struct task_struct *task, u32 enable) +{ + u32 oldcapcontid; + int rc = 0; + struct audit_buffer *ab; + + if (!task->audit) + return -ENOPROTOOPT; + oldcapcontid = audit_get_capcontid(task); + /* if task is not descendant, block */ + if (task == current || !task_is_descendant(current, task)) + rc = -EXDEV; + else if (current_user_ns() == &init_user_ns) { + if (!capable(CAP_AUDIT_CONTROL) && + !audit_get_capcontid(current)) + rc = -EPERM; + } + if (!rc) + task->audit->capcontid = enable; + + if (!audit_enabled) + return rc; + + ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_SET_CAPCONTID); + if (!ab) + return rc; + + audit_log_format(ab, + "opid=%d capcontid=%u old-capcontid=%u", + task_tgid_nr(task), enable, oldcapcontid); + audit_log_end(ab); + return rc; +} + /* * audit_set_contid - set current task's audit contid * @task: target task @@ -2795,7 +2831,7 @@ int audit_set_contid(struct task_struct *task, u64 contid) goto unlock; } /* if we don't have caps, reject */ - if (!capable(CAP_AUDIT_CONTROL)) { + if (!capable(CAP_AUDIT_CONTROL) && !audit_get_capcontid(current)) { rc = -EPERM; goto unlock; } -- 1.8.3.1