389-ds-base/lib/libaccess/lasip.cpp

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 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2005 Red Hat, Inc.
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 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#  include <config.h>
#endif


/*    aclip.c
 *    This file contains the IP LAS code.
 */

#include <stdio.h>
#include <string.h>
#include <netsite.h>
#include <base/plist.h>
#include <libaccess/nserror.h>
#include <libaccess/nsauth.h>
#include <libaccess/acl.h>
#include "aclpriv.h"
#include <libaccess/aclproto.h>
#include <libaccess/las.h>
#include "lasip.h"
#include "aclutil.h"
#include "aclcache.h"
#include <libaccess/dbtlibaccess.h>
#include <libaccess/aclerror.h>

#define        LAS_IP_IS_CONSTANT(x)    (((x) == (LASIpTree_t *)LAS_EVAL_TRUE) || ((x) == (LASIpTree_t *)LAS_EVAL_FALSE))

#ifdef	UTEST
extern int LASIpGetIp();
#endif

static int
LASIpAddPattern(NSErr_t *errp, int netmask, int pattern, LASIpTree_t **treetop);

/*    dotdecimal
 *    Takes netmask and ip strings and returns the numeric values,
 *    accounting for wildards in the ip specification.  Wildcards in the
 *    ip override the netmask where they conflict.
 *    INPUT
 *    ipstr        e.g. "123.45.67.89"
 *    netmaskstr    e.g. "255.255.255.0"
 *    RETURNS
 *    *ip        
 *    *netmask    e.g. 0xffffff00
 *    result        NULL on success or else one of the LAS_EVAL_* codes.
 */
int
dotdecimal(char *ipstr, char *netmaskstr, int *ip, int *netmask)
{
    int     i;
    char    token[64];
    char    *dotptr;    /* location of the "."        */
    int     dotidx;     /* index of the period char    */

    /* Sanity check the patterns */

    /* Netmask can only have digits and periods. */
    if (strcspn(netmaskstr, "0123456789."))
        return LAS_EVAL_INVALID;

    /* IP can only have digits, periods and "*" */
    if (strcspn(ipstr, "0123456789.*"))
        return LAS_EVAL_INVALID;

	if (strlen(netmaskstr) >= sizeof(token)) {
        return LAS_EVAL_INVALID;
	}

	if (strlen(ipstr) >= sizeof(token)) {
        return LAS_EVAL_INVALID;
	}

    *netmask = *ip = 0;    /* Start with "don't care"    */

    for (i=0; i<4; i++) {
        dotptr    = strchr(netmaskstr, '.');

        /* copy out the token, then point beyond it */
        if (dotptr == NULL)
            strcpy(token, netmaskstr);
        else {
            dotidx    = dotptr-netmaskstr;
            strncpy(token, netmaskstr, dotidx);
            token[dotidx] = '\0';
            netmaskstr = ++dotptr;    /* skip the period */
        }

        /* Turn into a number and shift left as appropriate */
        *netmask    += (atoi(token))<<(8*(4-i-1));

        if (dotptr == NULL)
            break;
    }

    for (i=0; i<4; i++) {
        dotptr    = strchr(ipstr, '.');

        /* copy out the token, then point beyond it */
        if (dotptr == NULL)
            strcpy(token, ipstr);
        else {
            dotidx    = dotptr-ipstr;
            strncpy(token, ipstr, dotidx);
            token[dotidx] = '\0';
            ipstr    = ++dotptr;
        }

        /* check for wildcard    */
        if (strcmp(token, "*") == 0) {
            switch(i) {
            case 0:
                if (dotptr == NULL)
                    *netmask &= 0x00000000;
                else
                    *netmask &= 0x00ffffff;
                break;
            case 1:
                if (dotptr == NULL)
                    *netmask &= 0xff000000;
                else
                    *netmask &= 0xff00ffff;
                break;
            case 2:
                if (dotptr == NULL)
                    *netmask &= 0xffff0000;
                else
                    *netmask &= 0xffff00ff;
                break;
            case 3:
                *netmask &= 0xffffff00;
                break;
            }
            continue;
        } else {
            /* Turn into a number and shift left as appropriate */
            *ip    += (atoi(token))<<(8*(4-i-1));
        }

        /* check for end of string    */
        if (dotptr == NULL) {
            switch(i) {
            case 0:
                *netmask &= 0xff000000;
                break;
            case 1:
                *netmask &= 0xffff0000;
                break;
            case 2:
                *netmask &= 0xffffff00;
                break;
            }
            break;
        }
    }

    return 0;
}


/*    LASIpTreeAlloc
 *    Malloc a node and set the actions to LAS_EVAL_FALSE
 */
static LASIpTree_t *
LASIpTreeAllocNode(NSErr_t *errp)
{
    LASIpTree_t    *newnode;

    newnode = (LASIpTree_t *)PERM_MALLOC(sizeof(LASIpTree_t));
    if (newnode == NULL) {
	nserrGenerate(errp, ACLERRNOMEM, ACLERR5000, ACL_Program, 1, XP_GetAdminStr(DBT_lasiptreeallocNoMemoryN_));
        return NULL;
    }
    newnode->action[0] = (LASIpTree_t *)LAS_EVAL_FALSE;
    newnode->action[1] = (LASIpTree_t *)LAS_EVAL_FALSE;
    return newnode;
}


/*    LASIpTreeDealloc
 *    Deallocates a Tree starting from a given node down.
 *    INPUT
 *    startnode    Starting node to remove.  Could be a constant in 
 *            which case, just return success.
 *    OUTPUT
 *    N/A
 */
static void
LASIpTreeDealloc(LASIpTree_t *startnode)
{
    int    i;

    if (startnode == NULL)
        return;

    /* If this is just a constant then we're done             */
    if (LAS_IP_IS_CONSTANT(startnode))
        return;

    /* Else recursively call ourself for each branch down        */
    for (i=0; i<2; i++) {
        if (!(LAS_IP_IS_CONSTANT(startnode->action[i])))
            LASIpTreeDealloc(startnode->action[i]);
    }

    /* Now deallocate the local node                */
    PERM_FREE(startnode);
}

/*
 *    LASIpBuild
 *    INPUT
 *    attr_name    The string "ip" - in lower case.
 *    comparator    CmpOpEQ or CmpOpNE only
 *    attr_pattern    A comma-separated list of IP addresses and netmasks
 *            in dotted-decimal form.  Netmasks are optionally
 *            prepended to the IP address using a plus sign.  E.g.
 *            255.255.255.0+123.45.67.89.  Any byte in the IP address
 *            (but not the netmask) can be wildcarded using "*"
 *    context         A pointer to the IP LAS context structure.
 *    RETURNS
 *    ret code    The usual LAS return codes.
 */
static int
LASIpBuild(NSErr_t *errp, char *attr_name, CmpOp_t comparator, char *attr_pattern, LASIpTree_t **treetop)
{
    unsigned int delimiter;                /* length of valid token     */
    char        token[64], token2[64];    /* a single ip[+netmask]     */
    char        *curptr;                /* current place in attr_pattern */
    int            netmask, ip;
    char        *plusptr;
    int            retcode;

    if (NULL == treetop) {
        return ACL_RES_ERROR;
    }

    /* ip address can be delimited by space, tab, comma, or carriage return
     * only.
     */
    curptr = attr_pattern;
    do {
        delimiter    = strcspn(curptr, ", \t");
        delimiter    = (delimiter <= strlen(curptr)) ? delimiter : strlen(curptr);
        strncpy(token, curptr, delimiter);
		if (delimiter >= sizeof(token)) {
            return LAS_EVAL_INVALID;
		}
			
        token[delimiter] = '\0';
        /* skip all the white space after the token */
        curptr = strpbrk((curptr+delimiter), "1234567890+.*");

        /* Is there a netmask?    */
        plusptr    = strchr(token, '+');
        if (plusptr == NULL) {
            if (curptr && (*curptr == '+')) {
                /* There was a space before (and possibly after) the plus sign*/
                curptr = strpbrk((++curptr), "1234567890.*");
                delimiter    = strcspn(curptr, ", \t");
                delimiter    = (delimiter <= strlen(curptr)) ? delimiter : strlen(curptr);
				if (delimiter >= sizeof(token2)) {
					return LAS_EVAL_INVALID;
				}
                strncpy(token2, curptr, delimiter);
                token2[delimiter] = '\0';
                retcode = dotdecimal(token, token2, &ip, &netmask);
                if (retcode)
                    return (retcode);
                curptr = strpbrk((++curptr), "1234567890+.*");
            } else {
                retcode =dotdecimal(token, "255.255.255.255", &ip, &netmask);
                if (retcode)
                    return (retcode);
            }
        } else {
            /* token is the IP addr string in both cases */
            *plusptr ='\0';    /* truncate the string */
            retcode =dotdecimal(token, ++plusptr, &ip, &netmask);
            if (retcode)
                return (retcode);
        }

        if (LASIpAddPattern(errp, netmask, ip, treetop) != 0)
            return LAS_EVAL_INVALID;

    } while ((curptr != NULL) && (delimiter != 0));

    return 0;
}


/*    LASIpAddPattern
 *    Takes a netmask and IP address and a pointer to an existing IP
 *    tree and adds nodes as appropriate to recognize the new pattern.
 *    INPUT
 *    netmask        e.g. 0xffffff00
 *    pattern        IP address in 4 bytes
 *    *treetop    An existing IP tree or 0 if a new tree
 *    RETURNS
 *    ret code    NULL on success, ACL_RES_ERROR on failure
 *    **treetop    If this is a new tree, the head of the tree.
 */
static int
LASIpAddPattern(NSErr_t *errp, int netmask, int pattern, LASIpTree_t **treetop)
{
    int        stopbit;    /* Don't care after this point    */
    int        curbit;        /* current bit we're working on    */
    int        curval;        /* value of pattern[curbit]    */
    LASIpTree_t    *curptr = NULL;    /* pointer to the current node    */
    LASIpTree_t    *newptr;

    if (NULL == treetop) {
        return ACL_RES_ERROR;
    }

    /* stop at the first 1 in the netmask from low to high         */
    for (stopbit=0; stopbit<32; stopbit++) {
        if ((netmask&(1<<stopbit)) != 0)
            break;
    }

    /* Special case if there's no tree.  Allocate the first node    */
    if (*treetop == (LASIpTree_t *)NULL) {    /* No tree at all */
        curptr = LASIpTreeAllocNode(errp);
        if (curptr == NULL) {
            nserrGenerate(errp, ACLERRFAIL, ACLERR5100, ACL_Program, 1, XP_GetAdminStr(DBT_ipLasUnableToAllocateTreeNodeN_));
            return ACL_RES_ERROR;
        }
        *treetop = curptr;
    }

    /* Special case if the netmask is 0.
     */
    if (stopbit > 31) {
        (*treetop)->action[0] = (LASIpTree_t *)LAS_EVAL_TRUE;
        (*treetop)->action[1] = (LASIpTree_t *)LAS_EVAL_TRUE;
        return 0;
    }


    /* follow the tree down the pattern path bit by bit until the
     * end of the tree is reached (i.e. a constant).
     */
    for (curbit=31,curptr=*treetop; curbit >= 0; curbit--) {

        /* Is the current bit ON?  If so set curval to 1 else 0    */
        curval = (pattern & (1<<curbit)) ? 1 : 0;

        /* Are we done, if so remove the rest of the tree     */
        if (curbit == stopbit) {
            LASIpTreeDealloc(curptr->action[curval]);
            curptr->action[curval] = 
                    (LASIpTree_t *)LAS_EVAL_TRUE;

            /* This is the normal exit point.  Most other 
             * exits must be due to errors.
             */
            return 0;
        }

        /* Oops reached the end - must allocate        */
        if (LAS_IP_IS_CONSTANT(curptr->action[curval])) {
            newptr = LASIpTreeAllocNode(errp);
            if (newptr == NULL) {
                LASIpTreeDealloc(*treetop);
	        nserrGenerate(errp, ACLERRFAIL, ACLERR5110, ACL_Program, 1, XP_GetAdminStr(DBT_ipLasUnableToAllocateTreeNodeN_1));
                return ACL_RES_ERROR;
            }
            curptr->action[curval] = newptr;
        }

        /* Keep going down the tree                */
        curptr = curptr->action[curval];
    }

    return ACL_RES_ERROR;
}

/*    LASIpFlush
 *    Deallocates any memory previously allocated by the LAS
 */
void
LASIpFlush(void **las_cookie)
{
    if (*las_cookie    == NULL)
        return;

    LASIpTreeDealloc(((LASIpContext_t *)*las_cookie)->treetop);
    PERM_FREE(*las_cookie);
    *las_cookie = NULL;
    return;
}

/*
 *    LASIpEval
 *    INPUT
 *    attr_name      The string "ip" - in lower case.
 *    comparator     CMP_OP_EQ or CMP_OP_NE only
 *    attr_pattern   A comma-separated list of IP addresses and netmasks
 *                   in dotted-decimal form.  Netmasks are optionally
 *                   prepended to the IP address using a plus sign.  E.g.
 *                   255.255.255.0+123.45.67.89.  Any byte in the IP address
 *                   (but not the netmask) can be wildcarded using "*"
 *    *cachable      Always set to ACL_INDEF_CACHABLE
 *    subject        Subject property list
 *    resource       Resource property list
 *    auth_info      The authentication info if any
 *    RETURNS
 *    ret code       The usual LAS return codes.
 */
int LASIpEval(NSErr_t *errp, char *attr_name, CmpOp_t comparator,
          char *attr_pattern, ACLCachable_t *cachable, void **LAS_cookie,
          PList_t subject, PList_t resource, PList_t auth_info,
          PList_t global_auth)
{
    int                bit;
    int                value;
    IPAddr_t           ip;
    int                retcode;
    LASIpTree_t        *node;
    LASIpContext_t     *context = NULL;
    int		       rv;
    char	       ip_str[124];

    *cachable = ACL_INDEF_CACHABLE;

    if (strcmp(attr_name, "ip") != 0) {
	nserrGenerate(errp, ACLERRINVAL, ACLERR5200, ACL_Program, 2, XP_GetAdminStr(DBT_lasIpBuildReceivedRequestForAttr_), attr_name);
        return LAS_EVAL_INVALID;
    }

    if ((comparator != CMP_OP_EQ) && (comparator != CMP_OP_NE)) {
	nserrGenerate(errp, ACLERRINVAL, ACLERR5210, ACL_Program, 2, XP_GetAdminStr(DBT_lasipevalIllegalComparatorDN_), comparator_string(comparator));
        return LAS_EVAL_INVALID;
    }

    /* GET THE IP ADDR FROM THE SESSION CONTEXT AND STORE IT IN THE
     * VARIABLE ip.
     */
#ifndef    UTEST
    rv = ACL_GetAttribute(errp, ACL_ATTR_IP, (void **)&ip,
			  subject, resource, auth_info, global_auth);

    if (rv != LAS_EVAL_TRUE) {
        if (subject || resource) {
            /* Don't ereport if called from ACL_CachableAclList */
	    char rv_str[16];
	    sprintf(rv_str, "%d", rv);
	    nserrGenerate(errp, ACLERRINVAL, ACLERR5220, ACL_Program, 2, XP_GetAdminStr(DBT_lasipevalUnableToGetSessionAddre_), rv_str);
        }
	return LAS_EVAL_FAIL;
    }
#else
    ip    = (IPAddr_t)LASIpGetIp();
#endif

    /* If this is the first time through, build the pattern tree first.
     */
    if (*LAS_cookie == NULL) {
        if (strcspn(attr_pattern, "0123456789.*,+ \t")) {
            return LAS_EVAL_INVALID;
        }
        ACL_CritEnter();
        if (*LAS_cookie == NULL) {    /* must check again */
            *LAS_cookie = context = 
                (LASIpContext_t *)PERM_MALLOC(sizeof(LASIpContext_t));
            if (context == NULL) {
                nserrGenerate(errp, ACLERRNOMEM, ACLERR5230, ACL_Program, 1, XP_GetAdminStr(DBT_lasipevalUnableToAllocateContext_));
                ACL_CritExit();
                return LAS_EVAL_FAIL;
            }
            context->treetop = NULL;
            retcode = LASIpBuild(errp, attr_name, comparator, attr_pattern, 
                                 &context->treetop);
            if (retcode) {
                ACL_CritExit();
                return (retcode);
            }
        } else {
            context = (LASIpContext *) *LAS_cookie;
        }
        ACL_CritExit();
    } else {
        ACL_CritEnter();
        context = (LASIpContext *) *LAS_cookie;
        ACL_CritExit();
    }

    node    = context->treetop;

    for (bit=31; bit >=0; bit--) {
        value    = (ip & (IPAddr_t) (1<<bit)) ? 1 : 0;
        if (LAS_IP_IS_CONSTANT(node->action[value]))
            /* Reached a result, so return it */
            if (comparator == CMP_OP_EQ)
                return((int)(PRSize)node->action[value]);
            else
                return(((int)(PRSize)node->action[value] == 
                    LAS_EVAL_TRUE) ? 
                    LAS_EVAL_FALSE : LAS_EVAL_TRUE);

        else
            /* Move on to the next bit */
            node = node->action[value];
    }

    /* Cannot reach here.  Even a 32 bit mismatch has a conclusion in 
     * the pattern tree.
     */
    sprintf(ip_str, "%x", (unsigned int)ip);
    nserrGenerate(errp, ACLERRINTERNAL, ACLERR5240, ACL_Program, 2, XP_GetAdminStr(DBT_lasipevalReach32BitsWithoutConcl_), ip_str);
    return LAS_EVAL_INVALID;
}