source: branches/samba-3.2.x/source/lib/ldb/common/ldb_parse.c@ 1075

/* 
   ldb database library

   Copyright (C) Andrew Tridgell  2004

     ** NOTE! The following LGPL license applies to the ldb
     ** library. This does NOT imply that all of Samba is released
     ** under the LGPL
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/

/*
 *  Name: ldb
 *
 *  Component: ldb expression parsing
 *
 *  Description: parse LDAP-like search expressions
 *
 *  Author: Andrew Tridgell
 */

/*
  TODO:
      - add RFC2254 binary string handling
      - possibly add ~=, <= and >= handling
      - expand the test suite
      - add better parse error handling

*/

#include "includes.h"
#include "ldb/include/includes.h"
#include "system/locale.h"

struct ldb_val ldb_binary_decode(void *mem_ctx, const char *str);

/*
a filter is defined by:
               <filter> ::= '(' <filtercomp> ')'
               <filtercomp> ::= <and> | <or> | <not> | <simple>
               <and> ::= '&' <filterlist>
               <or> ::= '|' <filterlist>
               <not> ::= '!' <filter>
               <filterlist> ::= <filter> | <filter> <filterlist>
               <simple> ::= <attributetype> <filtertype> <attributevalue>
               <filtertype> ::= '=' | '~=' | '<=' | '>='
*/

/*
   decode a RFC2254 binary string representation of a buffer.
   Used in LDAP filters.
*/
struct ldb_val ldb_binary_decode(void *mem_ctx, const char *str)
{
        int i, j;
        struct ldb_val ret;
        int slen = str?strlen(str):0;

        ret.data = (uint8_t *)talloc_size(mem_ctx, slen+1);
        ret.length = 0;
        if (ret.data == NULL) return ret;

        for (i=j=0;i<slen;i++) {
                if (str[i] == '\\') {
                        unsigned c;
                        if (sscanf(&str[i+1], "%02X", &c) != 1) {
                                talloc_free(ret.data);
                                memset(&ret, 0, sizeof(ret));
                                return ret;
                        }
                        ((uint8_t *)ret.data)[j++] = c;
                        i += 2;
                } else {
                        ((uint8_t *)ret.data)[j++] = str[i];
                }
        }
        ret.length = j;
        ((uint8_t *)ret.data)[j] = 0;

        return ret;
}


/*
   encode a blob as a RFC2254 binary string, escaping any
   non-printable or '\' characters
*/
char *ldb_binary_encode(void *mem_ctx, struct ldb_val val)
{
        int i;
        char *ret;
        int len = val.length;
        unsigned char *buf = val.data;

        for (i=0;i<val.length;i++) {
                if (!isprint(buf[i]) || strchr(" *()\\&|!\"", buf[i])) {
                        len += 2;
                }
        }
        ret = talloc_array(mem_ctx, char, len+1);
        if (ret == NULL) return NULL;

        len = 0;
        for (i=0;i<val.length;i++) {
                if (!isprint(buf[i]) || strchr(" *()\\&|!\"", buf[i])) {
                        snprintf(ret+len, 4, "\\%02X", buf[i]);
                        len += 3;
                } else {
                        ret[len++] = buf[i];
                }
        }

        ret[len] = 0;

        return ret;     
}

/*
   encode a string as a RFC2254 binary string, escaping any
   non-printable or '\' characters.  This routine is suitable for use
   in escaping user data in ldap filters.
*/
char *ldb_binary_encode_string(void *mem_ctx, const char *string)
{
        struct ldb_val val;
        val.data = discard_const_p(uint8_t, string);
        val.length = strlen(string);
        return ldb_binary_encode(mem_ctx, val);
}

/* find the first matching wildcard */
static char *ldb_parse_find_wildcard(char *value)
{
        while (*value) {
                value = strpbrk(value, "\\*");
                if (value == NULL) return NULL;

                if (value[0] == '\\') {
                        if (value[1] == '\0') return NULL;
                        value += 2;
                        continue;
                }

                if (value[0] == '*') return value;
        }

        return NULL;
}

/* return a NULL terminated list of binary strings representing the value
   chunks separated by wildcards that makes the value portion of the filter
*/
static struct ldb_val **ldb_wildcard_decode(void *mem_ctx, const char *string)
{
        struct ldb_val **ret = NULL;
        int val = 0;
        char *wc, *str;

        wc = talloc_strdup(mem_ctx, string);
        if (wc == NULL) return NULL;

        while (wc && *wc) {
                str = wc;
                wc = ldb_parse_find_wildcard(str);
                if (wc && *wc) {
                        if (wc == str) {
                                wc++;
                                continue;
                        }
                        *wc = 0;
                        wc++;
                }

                ret = talloc_realloc(mem_ctx, ret, struct ldb_val *, val + 2);
                if (ret == NULL) return NULL;

                ret[val] = talloc(mem_ctx, struct ldb_val);
                if (ret[val] == NULL) return NULL;

                *(ret[val]) = ldb_binary_decode(mem_ctx, str);
                if ((ret[val])->data == NULL) return NULL;

                val++;
        }

        if (ret != NULL) {
                ret[val] = NULL;
        }

        return ret;
}

static struct ldb_parse_tree *ldb_parse_filter(void *mem_ctx, const char **s);


/*
  parse an extended match

  possible forms:
        (attr:oid:=value)
        (attr:dn:oid:=value)
        (attr:dn:=value)
        (:dn:oid:=value)

  the ':dn' part sets the dnAttributes boolean if present
  the oid sets the rule_id string
  
*/
static struct ldb_parse_tree *ldb_parse_extended(struct ldb_parse_tree *ret, 
                                                 char *attr, char *value)
{
        char *p1, *p2;

        ret->operation = LDB_OP_EXTENDED;
        ret->u.extended.value = ldb_binary_decode(ret, value);
        if (ret->u.extended.value.data == NULL) goto failed;

        p1 = strchr(attr, ':');
        if (p1 == NULL) goto failed;
        p2 = strchr(p1+1, ':');

        *p1 = 0;
        if (p2) *p2 = 0;

        ret->u.extended.attr = attr;
        if (strcmp(p1+1, "dn") == 0) {
                ret->u.extended.dnAttributes = 1;
                if (p2) {
                        ret->u.extended.rule_id = talloc_strdup(ret, p2+1);
                        if (ret->u.extended.rule_id == NULL) goto failed;
                } else {
                        ret->u.extended.rule_id = NULL;
                }
        } else {
                ret->u.extended.dnAttributes = 0;
                ret->u.extended.rule_id = talloc_strdup(ret, p1+1);
                if (ret->u.extended.rule_id == NULL) goto failed;
        }

        return ret;

failed:
        talloc_free(ret);
        return NULL;
}

static enum ldb_parse_op ldb_parse_filtertype(void *mem_ctx, char **type, char **value, const char **s)
{
        enum ldb_parse_op filter = 0;
        char *name, *val, *k;
        const char *p = *s;
        const char *t, *t1;

        /* retrieve attributetype name */
        t = p;

        while ((isascii(*p) && isalnum((unsigned char)*p)) || (*p == '-')) { /* attribute names can only be alphanums */
                p++;
        }

        if (*p == ':') { /* but extended searches have : and . chars too */
                p = strstr(p, ":=");
                if (p == NULL) { /* malformed attribute name */
                        return 0;
                }
        }

        t1 = p;

        while (isspace((unsigned char)*p)) p++;

        if (!strchr("=<>~:", *p)) {
                return 0;
        }

        /* save name */
        name = (char *)talloc_memdup(mem_ctx, t, t1 - t + 1);
        if (name == NULL) return 0;
        name[t1 - t] = '\0';

        /* retrieve filtertype */

        if (*p == '=') {
                filter = LDB_OP_EQUALITY;
        } else if (*(p + 1) == '=') {
                switch (*p) {
                case '<':
                        filter = LDB_OP_LESS;
                        p++;
                        break;
                case '>':
                        filter = LDB_OP_GREATER;
                        p++;
                        break;
                case '~':
                        filter = LDB_OP_APPROX;
                        p++;
                        break;
                case ':':
                        filter = LDB_OP_EXTENDED;
                        p++;
                        break;
                }
        }
        if (!filter) {
                talloc_free(name);
                return filter;
        }
        p++;

        while (isspace((unsigned char)*p)) p++;

        /* retrieve value */
        t = p;

        while (*p && ((*p != ')') || ((*p == ')') && (*(p - 1) == '\\')))) p++;

        val = (char *)talloc_memdup(mem_ctx, t, p - t + 1);
        if (val == NULL) {
                talloc_free(name);
                return 0;
        }
        val[p - t] = '\0';

        k = &(val[p - t]);

        /* remove trailing spaces from value */
        while ((k > val) && (isspace((unsigned char)*(k - 1)))) k--;
        *k = '\0';

        *type = name;
        *value = val;
        *s = p;
        return filter;
}

/*
  <simple> ::= <attributetype> <filtertype> <attributevalue>
*/
static struct ldb_parse_tree *ldb_parse_simple(void *mem_ctx, const char **s)
{
        char *attr, *value;
        struct ldb_parse_tree *ret;
        enum ldb_parse_op filtertype;

        ret = talloc(mem_ctx, struct ldb_parse_tree);
        if (!ret) {
                errno = ENOMEM;
                return NULL;
        }

        filtertype = ldb_parse_filtertype(ret, &attr, &value, s);
        if (!filtertype) {
                talloc_free(ret);
                return NULL;
        }

        switch (filtertype) {

                case LDB_OP_PRESENT:
                        ret->operation = LDB_OP_PRESENT;
                        ret->u.present.attr = attr;
                        break;

                case LDB_OP_EQUALITY:

                        if (strcmp(value, "*") == 0) {
                                ret->operation = LDB_OP_PRESENT;
                                ret->u.present.attr = attr;
                                break;
                        }

                        if (ldb_parse_find_wildcard(value) != NULL) {
                                ret->operation = LDB_OP_SUBSTRING;
                                ret->u.substring.attr = attr;
                                ret->u.substring.start_with_wildcard = 0;
                                ret->u.substring.end_with_wildcard = 0;
                                ret->u.substring.chunks = ldb_wildcard_decode(ret, value);
                                if (ret->u.substring.chunks == NULL){
                                        talloc_free(ret);
                                        return NULL;
                                }
                                if (value[0] == '*')
                                        ret->u.substring.start_with_wildcard = 1;
                                if (value[strlen(value) - 1] == '*')
                                        ret->u.substring.end_with_wildcard = 1;
                                talloc_free(value);

                                break;
                        }

                        ret->operation = LDB_OP_EQUALITY;
                        ret->u.equality.attr = attr;
                        ret->u.equality.value = ldb_binary_decode(ret, value);
                        if (ret->u.equality.value.data == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        talloc_free(value);
                        break;

                case LDB_OP_GREATER:
                        ret->operation = LDB_OP_GREATER;
                        ret->u.comparison.attr = attr;
                        ret->u.comparison.value = ldb_binary_decode(ret, value);
                        if (ret->u.comparison.value.data == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        talloc_free(value);
                        break;

                case LDB_OP_LESS:
                        ret->operation = LDB_OP_LESS;
                        ret->u.comparison.attr = attr;
                        ret->u.comparison.value = ldb_binary_decode(ret, value);
                        if (ret->u.comparison.value.data == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        talloc_free(value);
                        break;

                case LDB_OP_APPROX:
                        ret->operation = LDB_OP_APPROX;
                        ret->u.comparison.attr = attr;
                        ret->u.comparison.value = ldb_binary_decode(ret, value);
                        if (ret->u.comparison.value.data == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        talloc_free(value);
                        break;

                case LDB_OP_EXTENDED:

                        ret = ldb_parse_extended(ret, attr, value);
                        break;

                default:
                        talloc_free(ret);
                        return NULL;
        }

        return ret;
}


/*
  parse a filterlist
  <and> ::= '&' <filterlist>
  <or> ::= '|' <filterlist>
  <filterlist> ::= <filter> | <filter> <filterlist>
*/
static struct ldb_parse_tree *ldb_parse_filterlist(void *mem_ctx, const char **s)
{
        struct ldb_parse_tree *ret, *next;
        enum ldb_parse_op op;
        const char *p = *s;

        switch (*p) {
                case '&':
                        op = LDB_OP_AND;
                        break;
                case '|':
                        op = LDB_OP_OR;
                        break;
                default:
                        return NULL;
        }
        p++;

        while (isspace((unsigned char)*p)) p++;

        ret = talloc(mem_ctx, struct ldb_parse_tree);
        if (!ret) {
                errno = ENOMEM;
                return NULL;
        }

        ret->operation = op;
        ret->u.list.num_elements = 1;
        ret->u.list.elements = talloc(ret, struct ldb_parse_tree *);
        if (!ret->u.list.elements) {
                errno = ENOMEM;
                talloc_free(ret);
                return NULL;
        }

        ret->u.list.elements[0] = ldb_parse_filter(ret->u.list.elements, &p);
        if (!ret->u.list.elements[0]) {
                talloc_free(ret);
                return NULL;
        }

        while (isspace((unsigned char)*p)) p++;

        while (*p && (next = ldb_parse_filter(ret->u.list.elements, &p))) {
                struct ldb_parse_tree **e;
                e = talloc_realloc(ret, ret->u.list.elements, 
                                     struct ldb_parse_tree *, 
                                     ret->u.list.num_elements + 1);
                if (!e) {
                        errno = ENOMEM;
                        talloc_free(ret);
                        return NULL;
                }
                ret->u.list.elements = e;
                ret->u.list.elements[ret->u.list.num_elements] = next;
                ret->u.list.num_elements++;
                while (isspace((unsigned char)*p)) p++;
        }

        *s = p;

        return ret;
}


/*
  <not> ::= '!' <filter>
*/
static struct ldb_parse_tree *ldb_parse_not(void *mem_ctx, const char **s)
{
        struct ldb_parse_tree *ret;
        const char *p = *s;

        if (*p != '!') {
                return NULL;
        }
        p++;

        ret = talloc(mem_ctx, struct ldb_parse_tree);
        if (!ret) {
                errno = ENOMEM;
                return NULL;
        }

        ret->operation = LDB_OP_NOT;
        ret->u.isnot.child = ldb_parse_filter(ret, &p);
        if (!ret->u.isnot.child) {
                talloc_free(ret);
                return NULL;
        }

        *s = p;

        return ret;
}

/*
  parse a filtercomp
  <filtercomp> ::= <and> | <or> | <not> | <simple>
*/
static struct ldb_parse_tree *ldb_parse_filtercomp(void *mem_ctx, const char **s)
{
        struct ldb_parse_tree *ret;
        const char *p = *s;

        while (isspace((unsigned char)*p)) p++;

        switch (*p) {
        case '&':
                ret = ldb_parse_filterlist(mem_ctx, &p);
                break;

        case '|':
                ret = ldb_parse_filterlist(mem_ctx, &p);
                break;

        case '!':
                ret = ldb_parse_not(mem_ctx, &p);
                break;

        case '(':
        case ')':
                return NULL;

        default:
                ret = ldb_parse_simple(mem_ctx, &p);

        }

        *s = p;
        return ret;
}


/*
  <filter> ::= '(' <filtercomp> ')'
*/
static struct ldb_parse_tree *ldb_parse_filter(void *mem_ctx, const char **s)
{
        struct ldb_parse_tree *ret;
        const char *p = *s;

        if (*p != '(') {
                return NULL;
        }
        p++;

        ret = ldb_parse_filtercomp(mem_ctx, &p);

        if (*p != ')') {
                return NULL;
        }
        p++;

        while (isspace((unsigned char)*p)) {
                p++;
        }

        *s = p;

        return ret;
}


/*
  main parser entry point. Takes a search string and returns a parse tree

  expression ::= <simple> | <filter>
*/
struct ldb_parse_tree *ldb_parse_tree(void *mem_ctx, const char *s)
{
        if (s == NULL || *s == 0) {
                s = "(|(objectClass=*)(distinguishedName=*))";
        }

        while (isspace((unsigned char)*s)) s++;

        if (*s == '(') {
                return ldb_parse_filter(mem_ctx, &s);
        }

        return ldb_parse_simple(mem_ctx, &s);
}


/*
  construct a ldap parse filter given a parse tree
*/
char *ldb_filter_from_tree(void *mem_ctx, struct ldb_parse_tree *tree)
{
        char *s, *s2, *ret;
        int i;

        if (tree == NULL) {
                return NULL;
        }

        switch (tree->operation) {
        case LDB_OP_AND:
        case LDB_OP_OR:
                ret = talloc_asprintf(mem_ctx, "(%c", tree->operation==LDB_OP_AND?'&':'|');
                if (ret == NULL) return NULL;
                for (i=0;i<tree->u.list.num_elements;i++) {
                        s = ldb_filter_from_tree(mem_ctx, tree->u.list.elements[i]);
                        if (s == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        s2 = talloc_asprintf_append(ret, "%s", s);
                        talloc_free(s);
                        if (s2 == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        ret = s2;
                }
                s = talloc_asprintf_append(ret, ")");
                if (s == NULL) {
                        talloc_free(ret);
                        return NULL;
                }
                return s;
        case LDB_OP_NOT:
                s = ldb_filter_from_tree(mem_ctx, tree->u.isnot.child);
                if (s == NULL) return NULL;

                ret = talloc_asprintf(mem_ctx, "(!%s)", s);
                talloc_free(s);
                return ret;
        case LDB_OP_EQUALITY:
                s = ldb_binary_encode(mem_ctx, tree->u.equality.value);
                if (s == NULL) return NULL;
                ret = talloc_asprintf(mem_ctx, "(%s=%s)", 
                                      tree->u.equality.attr, s);
                talloc_free(s);
                return ret;
        case LDB_OP_SUBSTRING:
                ret = talloc_asprintf(mem_ctx, "(%s=%s", tree->u.substring.attr,
                                      tree->u.substring.start_with_wildcard?"*":"");
                if (ret == NULL) return NULL;
                for (i = 0; tree->u.substring.chunks[i]; i++) {
                        s2 = ldb_binary_encode(mem_ctx, *(tree->u.substring.chunks[i]));
                        if (s2 == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        if (tree->u.substring.chunks[i+1] ||
                            tree->u.substring.end_with_wildcard) {
                                s = talloc_asprintf_append(ret, "%s*", s2);
                        } else {
                                s = talloc_asprintf_append(ret, "%s", s2);
                        }
                        if (s == NULL) {
                                talloc_free(ret);
                                return NULL;
                        }
                        ret = s;
                }
                s = talloc_asprintf_append(ret, ")");
                if (s == NULL) {
                        talloc_free(ret);
                        return NULL;
                }
                ret = s;
                return ret;
        case LDB_OP_GREATER:
                s = ldb_binary_encode(mem_ctx, tree->u.equality.value);
                if (s == NULL) return NULL;
                ret = talloc_asprintf(mem_ctx, "(%s>=%s)", 
                                      tree->u.equality.attr, s);
                talloc_free(s);
                return ret;
        case LDB_OP_LESS:
                s = ldb_binary_encode(mem_ctx, tree->u.equality.value);
                if (s == NULL) return NULL;
                ret = talloc_asprintf(mem_ctx, "(%s<=%s)", 
                                      tree->u.equality.attr, s);
                talloc_free(s);
                return ret;
        case LDB_OP_PRESENT:
                ret = talloc_asprintf(mem_ctx, "(%s=*)", tree->u.present.attr);
                return ret;
        case LDB_OP_APPROX:
                s = ldb_binary_encode(mem_ctx, tree->u.equality.value);
                if (s == NULL) return NULL;
                ret = talloc_asprintf(mem_ctx, "(%s~=%s)", 
                                      tree->u.equality.attr, s);
                talloc_free(s);
                return ret;
        case LDB_OP_EXTENDED:
                s = ldb_binary_encode(mem_ctx, tree->u.extended.value);
                if (s == NULL) return NULL;
                ret = talloc_asprintf(mem_ctx, "(%s%s%s%s:=%s)", 
                                      tree->u.extended.attr?tree->u.extended.attr:"", 
                                      tree->u.extended.dnAttributes?":dn":"",
                                      tree->u.extended.rule_id?":":"", 
                                      tree->u.extended.rule_id?tree->u.extended.rule_id:"", 
                                      s);
                talloc_free(s);
                return ret;
        }
        
        return NULL;
}


/*
  replace any occurances of an attribute name in the parse tree with a
  new name
*/
void ldb_parse_tree_attr_replace(struct ldb_parse_tree *tree, 
                                 const char *attr, 
                                 const char *replace)
{
        int i;
        switch (tree->operation) {
        case LDB_OP_AND:
        case LDB_OP_OR:
                for (i=0;i<tree->u.list.num_elements;i++) {
                        ldb_parse_tree_attr_replace(tree->u.list.elements[i],
                                                    attr, replace);
                }
                break;
        case LDB_OP_NOT:
                ldb_parse_tree_attr_replace(tree->u.isnot.child, attr, replace);
                break;
        case LDB_OP_EQUALITY:
        case LDB_OP_GREATER:
        case LDB_OP_LESS:
        case LDB_OP_APPROX:
                if (ldb_attr_cmp(tree->u.equality.attr, attr) == 0) {
                        tree->u.equality.attr = replace;
                }
                break;
        case LDB_OP_SUBSTRING:
                if (ldb_attr_cmp(tree->u.substring.attr, attr) == 0) {
                        tree->u.substring.attr = replace;
                }
                break;
        case LDB_OP_PRESENT:
                if (ldb_attr_cmp(tree->u.present.attr, attr) == 0) {
                        tree->u.present.attr = replace;
                }
                break;
        case LDB_OP_EXTENDED:
                if (tree->u.extended.attr &&
                    ldb_attr_cmp(tree->u.extended.attr, attr) == 0) {
                        tree->u.extended.attr = replace;
                }
                break;
        }
}