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Diffstat (limited to 'sys/contrib/lomac/kernel_mediate.c')
| -rw-r--r-- | sys/contrib/lomac/kernel_mediate.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/sys/contrib/lomac/kernel_mediate.c b/sys/contrib/lomac/kernel_mediate.c new file mode 100644 index 0000000..c28ce00 --- /dev/null +++ b/sys/contrib/lomac/kernel_mediate.c @@ -0,0 +1,280 @@ +/*- + * Copyright (c) 2001 Networks Associates Technology, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $Id: kernel_mediate.c,v 1.9 2001/10/17 15:19:40 bfeldman Exp $ + */ + +/* + * This file contains functions that make access control decisions + * concerning wether or not given system calls should be allowed + * or denied. This activity is called "mediation". These functions + * generally consider both the parameters passed to a system call + * and the current internal state of LOMAC in the course of making + * a decision. However, they do not modify these parameters or + * LOMAC's internal state. Functions for modifying LOMAC's internal + * state can be found in lomac_monitor.c. + * + */ + +#include "kernel_interface.h" +#include "kernel_mediate.h" +#if 0 +#include "lomac_plm.h" +#endif +#include "kernel_log.h" + +/* mediate_subject_level_subject() + * + * in: op_s - name of operation to mediate + * p_subject_one - subject one (for informational purposes only) + * level_one - already-known level of the first subject + * p_subject_two - subject two + * out: nothing + * return: value condition + * ----- --------- + * 0 caller should deny operation + * 1 caller should allow operation + * + * This function returns 1 if `p_subject_one's level is at least + * as great as `p_subject_two's level. Otherwise, it logs a permission + * failure on operation `op_s' and returns 0. + * + * This function is used to mediate pgrp changes. + * + */ + +int +mediate_subject_level_subject(const char *op_s, + const lomac_subject_t *p_subject_one, level_t level_one, + lomac_subject_t *p_subject_two) { + + lattr_t lattr_two; /* lattr of `p_subject_two' */ + int ret_val; /* result to return to caller */ + +#ifdef NO_MEDIATION + ret_val = 1; /* no denials, just logging */ +#else + ret_val = 0; /* pessimistically assume deny */ +#endif + + get_subject_lattr(p_subject_two, &lattr_two); + + if (lattr_two.level <= level_one) { + ret_val = 1; /* OK, allow */ + } else if (lomac_verbose_demote_deny) { + lomac_log_t *logmsg = log_start(); + + log_append_string(logmsg, "LOMAC: denied level-"); + log_append_int(logmsg, level_one); + log_append_string(logmsg, " proc "); + log_append_subject_id(logmsg, p_subject_one); + log_append_string(logmsg, " "); + log_append_string(logmsg, op_s); + log_append_string(logmsg, " to level-"); + log_append_int(logmsg, lattr_two.level); + log_append_string(logmsg, " proc "); + log_append_subject_id(logmsg, p_subject_two); + log_print(logmsg); + } + return (ret_val); +} /* mediate_subject_subject() */ + +/* mediate_subject_object() + * + * in: op_s - string describing operation, like "write" or "writev" + * p_subject - subject trying to operate on `p_object'. + * p_object - object that `p_subject' is trying to operate on. + * out: nothing + * return: value condition + * ----- --------- + * 0 Caller should prevent operation + * 1 Caller should permit operation + * + * This function returns 1 if the level of `p_object' is less than or + * equal to the level of `p_subject'. Otherwise, it returns 0 and + * logs a permission denial on `op_s'. + * + * This function allows LOMAC to mediate write and writev system calls. + * + */ + +int +mediate_subject_object(const char *op_s, lomac_subject_t *p_subject, + const lomac_object_t *p_object) { + lattr_t subject_lattr; /* lattr of `p_subject' */ + lattr_t object_lattr; /* lattr of `p_object' */ + int ret_val; /* value to return to caller */ + +#ifdef NO_MEDIATION + ret_val = 1; /* allow operation regardless of decision */ +#else + ret_val = 0; /* pessimistically assume deny */ +#endif + + /* Get the lattrs of `p_subject' and `p_object' so we can compare them. */ + get_subject_lattr(p_subject, &subject_lattr); + get_object_lattr(p_object, &object_lattr); + + /* + * If `p_subject's level is less than `p_object's level, + * we indicate that the operation must not be allowed. + */ + + if (!lomac_must_deny(&subject_lattr, &object_lattr) || + object_lattr.flags & LOMAC_ATTR_LOWWRITE) { + ret_val = 1; /* allow operation */ + } else if (lomac_verbose_demote_deny) { + lomac_log_t *logmsg = log_start(); + log_append_string(logmsg, "LOMAC: level-"); + log_append_int(logmsg, subject_lattr.level); + log_append_string(logmsg, " proc "); + log_append_subject_id(logmsg, p_subject); + log_append_string(logmsg, " denied "); + log_append_string(logmsg, op_s); + log_append_string(logmsg, " to level-"); + log_append_int(logmsg, object_lattr.level); + log_append_string(logmsg, " object "); + log_append_object_id(logmsg, p_object); + log_append_string(logmsg, "\n"); + log_print(logmsg); + } + return (ret_val); +} /* mediate_subject_object() */ + + +/* mediate_subject_object_open() + * + * in: p_subject - subject trying to operate on `p_object'. + * p_object - object that `p_subject' is trying to operate on. + * out: nothing + * return: value condition + * ----- --------- + * 0 Caller should prevent operation + * 1 Caller should permit operation + * + * This function returns 1 if the level of `p_object' is less than or + * equal to the level of `p_subject'. Otherwise, it returns 0 and + * logs a permission denial on `op_s'. + * + * This function allows LOMAC to mediate open system calls. + * + */ + +int +mediate_subject_object_open(lomac_subject_t *p_subject, + const lomac_object_t *p_object) { + lattr_t subject_lattr; /* lattr of `p_subject' */ + lattr_t object_lattr; /* lattr of `p_object' */ + int ret_val; /* value to return to caller */ + +#ifdef NO_MEDIATION + ret_val = 1; /* allow operation regardless of decision */ +#else + ret_val = 0; /* pessimistically assume deny */ +#endif + + /* Get the lattrs of `p_subject' and `p_object' so we can compare them. */ + get_subject_lattr(p_subject, &subject_lattr); + get_object_lattr(p_object, &object_lattr); + + /* + * If `p_subject's level is less than `p_object's level, + * we must indicate that the operation should not be allowed. + */ + if (lomac_must_deny(&subject_lattr, &object_lattr) && + object_lattr.flags & LOMAC_ATTR_LOWNOOPEN) { + if (lomac_verbose_demote_deny) { + lomac_log_t *logmsg = log_start(); + + log_append_string(logmsg, "LOMAC: level-"); + log_append_int(logmsg, subject_lattr.level); + log_append_string(logmsg, " proc "); + log_append_subject_id(logmsg, p_subject); + log_append_string(logmsg, " denied open to level-"); + log_append_int(logmsg, object_lattr.level); + log_append_string(logmsg, " object "); + log_append_object_id(logmsg, p_object); + log_append_string(logmsg, "\n"); + log_print(logmsg); + } + } else { + ret_val = 1; /* allow operation */ + } /* if/else allow/deny */ + return (ret_val); +} /* mediate_subject_object() */ + + +/* mediate_subject_at_level() + * + * in: op_s - name of operation being mediated + * p_subject - subject whose level we want to check + * target_level - level to compare to `p_subject's level + * + * out: nothing + * return: value condition + * ----- --------- + * 0 `p_subject' is not at `target_level' + * 1 `p_subject' is at `target_level' + * + * This function provides a predicate for determining whether or not + * `p_subject' is at the level specified by `target_level'. This + * function compares `p_subject's level to `target_level'. If the + * levels match, it retruns 1. Otherwise, it logs a permission denial + * on `op_s' and returns 0. + * + */ + +int +mediate_subject_at_level(const char *op_s, lomac_subject_t *p_subject, + const level_t target_level) { + lattr_t subject_lattr; /* lattr of `p_subject' */ + int ret_val; /* value returned to caller */ + +#ifdef NO_MEDIATION + ret_val = 1; /* allow operation regardless of decision */ +#else + ret_val = 0; /* pessimistically assume deny */ +#endif + + /* Make `subject_lattr' the lattr of `p_subject'. */ + get_subject_lattr(p_subject, &subject_lattr); + + /* compare with `target_lattr */ + if (subject_lattr.level == target_level) { + ret_val = 1; /* allow operation */ + } else if (lomac_verbose_demote_deny) { + lomac_log_t *logmsg = log_start(); + + log_append_string(logmsg, "LOMAC: denied level-"); + log_append_int(logmsg, subject_lattr.level); + log_append_string(logmsg, " proc "); + log_append_subject_id(logmsg, p_subject); + log_append_string(logmsg, "'s "); + log_append_string(logmsg, op_s); + log_append_string(logmsg, ".\n"); + log_print(logmsg); + } + return (ret_val); +} /* mediate_subject_at_level() */ |
