libbsm/common/audit_class.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright (c) 1992, 2011, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * Interfaces to audit_class(5)  (/etc/security/audit_class)
 */

#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include <sys/types.h>
#include <bsm/audit.h>
#include <bsm/libbsm.h>
#include <string.h>
#include <synch.h>

/*
 *  Macros to produce a quoted string containing the value of a
 *  preprocessor macro. For example, if SIZE is defined to be 256,
 *  VAL2STR(SIZE) is "256". This is used to construct format
 *  strings for scanf-family functions below.
 */
#define QUOTE(x)    #x
#define VAL2STR(x)  QUOTE(x)

static char au_class_fname[PATH_MAX] = AUDITCLASSFILE;
static FILE *au_class_file = NULL;
static mutex_t  mutex_classfile = DEFAULTMUTEX;
static mutex_t  mutex_classcache = DEFAULTMUTEX;

#ifdef DEBUG2
void
printclass(au_class_ent_t *p_c)
{
    (void) printf("%llx:%s:%s\n", p_c->ac_class, p_c->ac_name,
        p_c->ac_desc);
    (void) fflush(stdout);
}
#endif

void
setauclass()
{
    (void) mutex_lock(&mutex_classfile);
    if (au_class_file != NULL) {
        (void) fseek(au_class_file, 0L, 0);
    }
    (void) mutex_unlock(&mutex_classfile);
}


void
endauclass()
{
    (void) mutex_lock(&mutex_classfile);
    if (au_class_file != NULL) {
        (void) fclose(au_class_file);
        au_class_file = NULL;
    }
    (void) mutex_unlock(&mutex_classfile);
}

/*
 * getauclassent():
 *  This is not MT-safe because of the static variables.
 */
au_class_ent_t *
getauclassent()
{
    static au_class_ent_t e;
    static char cname[AU_CLASS_NAME_MAX];
    static char cdesc[AU_CLASS_DESC_MAX];

    e.ac_name = cname;
    e.ac_desc = cdesc;

    return (getauclassent_r(&e));
}

/*
 * getauclassent_r
 *  This is MT-safe if each thread passes in its own pointer
 *  to the space where the class entry is returned.  Be careful
 *  to also allocate space from the cname and cdesc pointers
 *  in the au_class_ent structure.
 */
au_class_ent_t *
getauclassent_r(au_class_ent_t *au_class_entry)
{
    int     i;
    int     c_int;
    char        *s, input[AU_CLASS_LINE_MAX+1];
    char        trim_buf[AU_CLASS_NAME_MAX+1];
    au_class_t  v;
    boolean_t   found = B_FALSE;

    /* open audit class file if it isn't already */
    (void) mutex_lock(&mutex_classfile);
    if (au_class_file == NULL) {
        if ((au_class_file = fopen(au_class_fname, "rF")) == NULL) {
            (void) mutex_unlock(&mutex_classfile);
            return (NULL);
        }
    }

    for (;;) {

        i = 0;
        while ((c_int = fgetc(au_class_file)) != EOF && c_int != '\n') {
            if (i < AU_CLASS_LINE_MAX) {
                input[i++] = c_int;
            }
        }
        input[i] = '\0';

        s = input + strspn(input, " \t\r\n");
        if ((*s != '\0') && (*s != '#')) {
            found = B_TRUE;
            s = input;

            /* parse bitfield */
            i = strcspn(s, ":");
            s[i] = '\0';
            if (strncmp(s, "0x", 2) == 0) {
                (void) sscanf(&s[2], "%" SCNx64, &v);
            } else {
                (void) sscanf(s, "%" SCNu64, &v);
            }
            au_class_entry->ac_class = v;
            s = &s[i+1];

            /* parse class name */
            i = strcspn(s, ":");
            s[i] = '\0';
            (void) sscanf(s, "%" VAL2STR(AU_CLASS_NAME_MAX) "s",
                trim_buf);
            (void) strncpy(au_class_entry->ac_name, trim_buf,
                AU_CLASS_NAME_MAX);
            s = &s[i+1];

            /* parse class description */
            i = strcspn(s, "\n\0");
            s[i] = '\0';
            (void) strncpy(au_class_entry->ac_desc, s,
                AU_CLASS_DESC_MAX);

            break;
        }

        if (c_int == EOF) {
            break;
        }
    }

    (void) mutex_unlock(&mutex_classfile);

    return (found ? au_class_entry : NULL);
}


au_class_ent_t *
getauclassnam(char *name)
{
    static au_class_ent_t e;
    static char cname[AU_CLASS_NAME_MAX];
    static char cdesc[AU_CLASS_DESC_MAX];

    e.ac_name = cname;
    e.ac_desc = cdesc;

    return (getauclassnam_r(&e, name));
}

au_class_ent_t *
getauclassnam_r(au_class_ent_t *e, char *name)
{
    while (getauclassent_r(e) != NULL) {
        if (strncmp(e->ac_name, name, AU_CLASS_NAME_MAX) == 0) {
            return (e);
        }
    }
    return (NULL);
}


/*
 * xcacheauclass:
 *  Read the entire audit_class file into memory.
 *  Return a pointer to the requested entry in the cache
 *  or a pointer to an invalid entry if the the class
 *  requested is not known.
 *
 *  Return < 0, do not set result pointer, if error.
 *  Return   0, set result pointer to invalid entry, if class not in cache.
 *  Return   1, set result pointer to a valid entry, if class is in cache.
 */
static int
xcacheauclass(au_class_ent_t **result, char *class_name, au_class_t class_no,
    int flags)
{
    static int  invalid;
    static au_class_ent_t **class_tbl;
    static int  called_once;
    static int  lines = 0;

    char        line[AU_CLASS_LINE_MAX+1];
    FILE        *fp;
    au_class_ent_t  *p_class;
    int     i;
    int     c_int;
    int     hit = 0;
    char        *s;

    (void) mutex_lock(&mutex_classcache);
    if (called_once == 0) {

        /* Count number of lines in the class file */
        if ((fp = fopen(au_class_fname, "rF")) == NULL) {
            (void) mutex_unlock(&mutex_classcache);
            return (-1);
        }
        for (;;) {

            i = 0;
            while ((c_int = fgetc(fp)) != EOF && (c_int != '\n')) {
                if (i < AU_CLASS_LINE_MAX) {
                    line[i++] = c_int;
                }
            }
            line[i] = '\0';

            s = line + strspn(line, " \t\r\n");
            if ((*s != '\0') && (*s != '#')) {
                lines++;
            }

            if (c_int == EOF) {
                break;
            }
        }
        (void) fclose(fp);
        class_tbl = (au_class_ent_t **)calloc((size_t)lines + 1,
            sizeof (class_tbl));
        if (class_tbl == NULL) {
            (void) mutex_unlock(&mutex_classcache);
            return (-2);
        }

        lines = 0;
        setauclass();
        /*
         * This call to getauclassent is protected by
         * mutex_classcache, so we don't need to use the thread-
         * safe version (getauclassent_r).
         */
        while ((p_class = getauclassent()) != NULL) {
            class_tbl[lines] = (au_class_ent_t *)
                malloc(sizeof (au_class_ent_t));
            if (class_tbl[lines] == NULL) {
                (void) mutex_unlock(&mutex_classcache);
                return (-3);
            }
            class_tbl[lines]->ac_name = strdup(p_class->ac_name);
            class_tbl[lines]->ac_class = p_class->ac_class;
            class_tbl[lines]->ac_desc = strdup(p_class->ac_desc);
#ifdef DEBUG2
            printclass(class_tbl[lines]);
#endif
            lines++;
        }
        endauclass();
        invalid = lines;
        class_tbl[invalid] = (au_class_ent_t *)
            malloc(sizeof (au_class_ent_t));
        if (class_tbl[invalid] == NULL) {
            (void) mutex_unlock(&mutex_classcache);
            return (-4);
        }
        class_tbl[invalid]->ac_name = "invalid class";
        class_tbl[invalid]->ac_class = AU_MASK_NONE;
        class_tbl[invalid]->ac_desc = class_tbl[invalid]->ac_name;

        called_once = 1;

#ifdef DEBUG2
        for (i = 0; i <= lines; i++) {
            printclass(class_tbl[i]);
        }
#endif

    } /* END if called_once */
    *result = class_tbl[invalid];
    if (flags & AU_CACHE_NAME) {
        for (i = 0; i < lines; i++) {
            if (strncmp(class_name, class_tbl[i]->ac_name,
                AU_CLASS_NAME_MAX) == 0) {
                *result = class_tbl[i];
                hit = 1;
                break;
            }
        }
    } else if (flags & AU_CACHE_NUMBER) {
        for (i = 0; i < lines; i++) {
            if (class_no == class_tbl[i]->ac_class) {
                *result = class_tbl[i];
                hit = 1;
                break;
            }
        }
    }
    (void) mutex_unlock(&mutex_classcache);
    return (hit);
}

int
cacheauclass(au_class_ent_t **result, au_class_t class_no)
{
    return (xcacheauclass(result, "", class_no, AU_CACHE_NUMBER));
}

int
cacheauclassnam(au_class_ent_t **result, char *class_name)
{
    return (xcacheauclass(result, class_name, (au_class_t)AU_MASK_NONE,
        AU_CACHE_NAME));
}