198 lines
6.8 KiB
C
198 lines
6.8 KiB
C
/*-
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* Copyright (c) 2001 Networks Associates Technology, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $Id: kernel_monitor.c,v 1.12 2001/10/16 15:25:02 bfeldman Exp $
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*/
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/*
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* This file contains functions which update LOMAC's internal
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* state in response to system events, such as successful
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* system calls. These updates allow LOMAC to keep an accurate
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* picture of the kernel's state, enabling LOMAC to make reasonable
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* decisions when it mediates processes' use of security-relevant
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* system calls. These functions perform no mediation themselves -
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* that is, they do not make access control decisions concerning
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* whether a given system call should be allowed or denied. This
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* mediation is handled by the functions in lomac_mediate.c.
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*/
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#include "kernel_interface.h"
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#include "kernel_monitor.h"
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#include "kernel_log.h"
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#include "kernel_util.h"
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/* monitor_read_object()
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*
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* in: p_subject - subject that read `p_object'.
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* p_object - object read by `p_subject'.
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* out: nothing
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* return: nothing
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*
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* This function examines the objects read by subjects. If a subject
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* reads from an object with a level lower than its own, this function
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* reduces the subject's level to match the object's. This lowering
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* is referred to as "demotion" in much of the LOMAC documentation.
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* This function performs no mediation.
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*
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* This function is for the following kinds of objects:
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* regular files and FIFOs.
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* It is also used to monitor reads on unnamed pipes. LOMAC does not
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* consider unnamed pipes to be objects, and treats them differently
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* from objects such as files. However, the differences are mostly
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* in the write-handling behavior. LOMAC's read-handling behavior is
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* the same both for objects and unnamed pipes, so this function
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* handles both cases.
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*/
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int
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monitor_read_object(lomac_subject_t *p_subject, lomac_object_t *p_object) {
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lattr_t subject_lattr; /* lattr of `p_subject' */
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lattr_t object_lattr; /* lattr of `p_object' */
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/* Get the lattrs of `p_subject' and `p_object' so we can compare them. */
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get_subject_lattr(p_subject, &subject_lattr);
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get_object_lattr(p_object, &object_lattr);
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/*
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* If `p_object's level is less than `p_subject's level,
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* we must demote `p_subject'. The level may be 0 to indicate
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* existence before LOMAC started.
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*/
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if (object_lattr.level &&
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lomac_must_demote(&subject_lattr, &object_lattr) &&
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(subject_lattr.flags & LOMAC_ATTR_NODEMOTE) == 0) {
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if (subject_do_not_demote(p_subject))
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return (0);
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set_subject_lattr(p_subject, object_lattr); /* demote! */
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if (lomac_verbose_demote_deny) {
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lomac_log_t *s = log_start();
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log_append_string(s, "LOMAC: level-");
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log_append_int(s, subject_lattr.level);
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log_append_string(s, " subject ");
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log_append_subject_id(s, p_subject);
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log_append_string(s, " demoted to level ");
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log_append_int(s, object_lattr.level);
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log_append_string(s, " after reading ");
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log_append_object_id(s, p_object);
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log_append_string(s, "\n");
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log_print(s);
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}
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} /* if we need to demote */
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return (0);
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} /* monitor_read_object() */
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/* monitor_pipe_write()
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*
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* in: p_subject - subject that just wrote to `p_pipe'.
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* p_pipe - pipe `p_subject' has written to.
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* out: p_pipe - pipe may have its level adjusted.
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* return: 0
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*
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* This function should be called after a successful write to
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* `p_pipe'. If the level of `p_subject' is less than the level of
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* `p_pipe', this function reduces `p_pipe's level to match
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* `current's.
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*
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*
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*/
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int
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monitor_pipe_write(lomac_subject_t *p_subject, lomac_object_t *p_pipe) {
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lattr_t pipe_lattr; /* lattr of `p_pipe' */
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lattr_t subject_lattr; /* lattr of `p_subject' */
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get_subject_lattr(p_subject, &subject_lattr);
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get_object_lattr(p_pipe, &pipe_lattr);
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if (lomac_must_demote(&pipe_lattr, &subject_lattr)) {
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subject_lattr.flags = 0;
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set_object_lattr(p_pipe, subject_lattr);
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#ifdef LOMAC_DEBUG_PIPE
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if (lomac_verbose_pipe) {
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lomac_log_t *s = log_start();
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log_append_string(s, "LOMAC: level-");
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log_append_int(s, subject_lattr.level);
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log_append_string(s, " subject ");
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log_append_subject_id(s, p_subject);
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log_append_string(s, " contaminated level-");
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log_append_int(s, pipe_lattr.level);
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log_append_string(s, " ");
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log_append_object_id(s, p_pipe);
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log_append_string(s, "\n");
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log_print(s);
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}
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#endif /* LOMAC_DEBUG_PIPE */
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}
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return (0);
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} /* monitor_pipe_write() */
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/* monitor_read_net_socket()
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*
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* in: p_subject - subject that read from network socket.
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* out: nothing
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* return: 0
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*
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*
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*/
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int
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monitor_read_net_socket(lomac_subject_t *p_subject) {
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lattr_t subject_lattr; /* lattr of `p_subject' */
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lattr_t socket_lattr; /* lattr of socket (always lowest) */
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socket_lattr.level = LOMAC_LOWEST_LEVEL;
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socket_lattr.flags = 0;
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get_subject_lattr(p_subject, &subject_lattr);
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if (lomac_must_demote(&subject_lattr, &socket_lattr) &&
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(subject_lattr.flags &
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(LOMAC_ATTR_NODEMOTE | LOMAC_ATTR_NONETDEMOTE)) == 0) {
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if (subject_do_not_demote(p_subject))
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return (0);
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socket_lattr.flags = subject_lattr.flags;
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set_subject_lattr(p_subject, socket_lattr); /* demote! */
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if (lomac_verbose_demote_deny) {
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lomac_log_t *s = log_start();
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log_append_string(s, "LOMAC: level-");
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log_append_int(s, subject_lattr.level);
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log_append_string(s, " subject ");
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log_append_subject_id(s, p_subject);
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log_append_string(s, " demoted to level ");
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log_append_int(s, socket_lattr.level);
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log_append_string(s, " after reading from "
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"the network\n");
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log_print(s);
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}
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}
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return (0);
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}
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