regex.c

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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/*
 * $Id: 47ee33a0c4131f3e3589d4b70c4dfa93874b8444 $
 *
 * @file src/lib/server/regex.c
 * @brief Regular expression functions used by the server library.
 *
 * @copyright 2014 The FreeRADIUS server project
 */
 
RCSID("$Id: 47ee33a0c4131f3e3589d4b70c4dfa93874b8444 $")
 
#include <freeradius-devel/server/regex.h>
#include <freeradius-devel/server/request_data.h>
#include <freeradius-devel/util/debug.h>
 
#ifdef HAVE_REGEX
 
#define REQUEST_DATA_REGEX (0xadbeef00)
 
typedef struct {
#if defined(HAVE_REGEX_PCRE2)
        regex_t         *preg;          //!< Compiled pattern.
#endif
        fr_regmatch_t   *regmatch;      //!< Match vectors.
 
        fr_value_box_safe_for_t safe_for;
        bool                    secret;
} fr_regcapture_t;
 
/** Adds subcapture values to request data
 *
 * Allows use of %{n} expansions.
 *
 * @note If preg was runtime-compiled, it will be consumed and *preg will be set to NULL.
 * @note regmatch will be consumed and *regmatch will be set to NULL.
 * @note Their lifetimes will be bound to the match request data.
 *
 * @param[in] request           Current request.
 * @param[in,out] preg          Compiled pattern. May be set to NULL if
 *                              reparented to the regcapture struct.
 * @param[in,out] regmatch      Pointers into value. May be set to NULL if
 *                              reparented to the regcapture struct.
 * @param[in] in                value-box which we matched against
 */
void regex_sub_to_request(request_t *request, regex_t **preg, fr_regmatch_t **regmatch, fr_value_box_t const *in)
{
        fr_regcapture_t *old_rc, *new_rc;       /* lldb doesn't like bare new *sigh* */
 
        /*
         *      Clear out old_rc matches
         */
        old_rc = request_data_get(request, request, REQUEST_DATA_REGEX);
        if (old_rc) {
                DEBUG4("Clearing %zu matches", old_rc->regmatch->used);
                talloc_free(old_rc);
        } else {
                DEBUG4("No matches");
        }
 
        if (!regmatch || ((*regmatch)->used == 0)) return;
 
        fr_assert(preg && *preg);
        fr_assert(regmatch);
        fr_assert(in);
 
        DEBUG4("Adding %zu matches", (*regmatch)->used);
 
        /*
         *      Container struct for all the match data
         */
        MEM(new_rc = talloc(request, fr_regcapture_t));
 
        /*
         *      Steal runtime pregs, leave precompiled ones
         */
#if defined(HAVE_REGEX_PCRE2)
        if (!(*preg)->precompiled) {
                new_rc->preg = talloc_steal(new_rc, *preg);
                *preg = NULL;
        } else {
                new_rc->preg = *preg;   /* Compiled on startup, will hopefully stick around */
        }
#endif
 
        /*
         *      Steal match data
         */
        new_rc->regmatch = talloc_steal(new_rc, *regmatch);
        new_rc->safe_for = in->safe_for;
        new_rc->secret = in->secret;
        *regmatch = NULL;
 
        request_data_talloc_add(request, request, REQUEST_DATA_REGEX, fr_regcapture_t, new_rc, true, false, false);
}
 
#  if defined(HAVE_REGEX_PCRE2)
/** Extract a subcapture value from the request
 *
 * @note This is the PCRE variant of the function.
 *
 * @param[in] ctx       To allocate subcapture buffer in.
 * @param[out] out      Where to write the subcapture string.
 * @param[in] request   to extract.
 * @param[in] num       Subcapture index (0 for entire match).
 * @return
 *      - 0 on success.
 *      - -1 on notfound.
 */
int regex_request_to_sub(TALLOC_CTX *ctx, fr_value_box_t *out, request_t *request, uint32_t num)
{
        fr_regcapture_t         *rc;
        char                    *buff;
        size_t                  len;
        int                     ret;
        pcre2_match_data        *match_data;
 
        rc = request_data_reference(request, request, REQUEST_DATA_REGEX);
        if (!rc) {
                RDEBUG4("No subcapture data found");
                return -1;
        }
        match_data = talloc_get_type_abort(rc->regmatch->match_data, pcre2_match_data);
 
        ret = pcre2_substring_length_bynumber(match_data, num, &len);
        switch (ret) {
        case PCRE2_ERROR_NOMEMORY:
                MEM(NULL);
                break;
 
        /*
         *      Not finding a substring is fine
         */
        case PCRE2_ERROR_NOSUBSTRING:
                RDEBUG4("%i/%zu Not found", num + 1, rc->regmatch->used);
                return -1;
 
        default:
                if (ret < 0) {
                        return -1;
                }
 
                MEM(buff = talloc_array(ctx, char, ++len));     /* +1 for \0, it'll get reset by pcre2_substring */
                pcre2_substring_copy_bynumber(match_data, num, (PCRE2_UCHAR *)buff, &len); /* can't error */
 
                fr_value_box_init(out, FR_TYPE_STRING, NULL, false);
                fr_value_box_bstrndup_shallow(out, NULL, buff, len, false);
                fr_value_box_mark_safe_for(out, rc->safe_for);
                fr_value_box_set_secret(out, rc->secret);
 
                RDEBUG4("%i/%zu Found: %pV (%zu)", num + 1, rc->regmatch->used, out, out->vb_length);
                break;
        }
 
        return 0;
}
 
/** Extract a named subcapture value from the request
 *
 * @note This is the PCRE variant of the function.
 *
 * @param[in] ctx       To allocate subcapture buffer in.
 * @param[out] out      Where to write the subcapture string.
 * @param[in] request   to extract.
 * @param[in] name      of subcapture.
 * @return
 *      - 0 on success.
 *      - -1 on notfound.
 */
int regex_request_to_sub_named(TALLOC_CTX *ctx, fr_value_box_t *out, request_t *request, char const *name)
{
        fr_regcapture_t         *rc;
        char                    *buff;
        int                     ret;
        size_t                  len;
        pcre2_match_data        *match_data;
 
        rc = request_data_reference(request, request, REQUEST_DATA_REGEX);
        if (!rc) {
                RDEBUG4("No subcapture data found");
                return -1;
        }
        match_data = rc->regmatch->match_data;
 
        ret = pcre2_substring_length_byname(match_data, (PCRE2_UCHAR const *)name, &len);
        switch (ret) {
        case PCRE2_ERROR_NOMEMORY:
                MEM(NULL);
                break;
 
        /*
         *      Not finding a substring is fine
         */
        case PCRE2_ERROR_NOSUBSTRING:
                RDEBUG4("No named capture group \"%s\"", name);
                return -1;
 
        default:
                if (ret < 0) return -1;
 
                MEM(buff = talloc_array(ctx, char, ++len));     /* +1 for \0, it'll get reset by pcre2_substring */
                pcre2_substring_copy_byname(match_data, (PCRE2_UCHAR const *)name, (PCRE2_UCHAR *)buff, &len); /* can't error */
 
                fr_value_box_init(out, FR_TYPE_STRING, NULL, false);
                fr_value_box_bstrndup_shallow(out, NULL, buff, len, false);
                fr_value_box_mark_safe_for(out, rc->safe_for);
                fr_value_box_set_secret(out, rc->secret);
 
                RDEBUG4("Found \"%s\": %pV (%zu)", name, out, out->vb_length);
                break;
        }
 
        return 0;
}
#  else
/** Extract a subcapture value from the request
 *
 * @note This is the POSIX variant of the function.
 *
 * @param[in] ctx       To allocate subcapture buffer in.
 * @param[out] out      Where to write the subcapture string.
 * @param[in] request   to extract.
 * @param[in] num       Subcapture index (0 for entire match).
 * @return
 *      - 0 on success.
 *      - -1 on notfound.
 */
int regex_request_to_sub(TALLOC_CTX *ctx, fr_value_box_t *out, request_t *request, uint32_t num)
{
        fr_regcapture_t *rc;
        char            *buff;
        char const      *start;
        size_t          len;
        regmatch_t      *match_data;
 
        rc = request_data_reference(request, request, REQUEST_DATA_REGEX);
        if (!rc) {
                RDEBUG4("No subcapture data found");
                return -1;
        }
        match_data = rc->regmatch->match_data;
 
        /*
         *      Greater than our capture array
         *
         *      -1 means no value in this capture group.
         */
        if ((num >= rc->regmatch->used) || (match_data[num].rm_eo == -1) || (match_data[num].rm_so == -1)) {
                RDEBUG4("%i/%zu Not found", num + 1, rc->regmatch->used);
                return -1;
        }
 
        /*
         *      Sanity checks on the offsets
         */
        fr_assert(match_data[num].rm_eo <= (regoff_t)talloc_array_length(rc->regmatch->subject));
        fr_assert(match_data[num].rm_so <= (regoff_t)talloc_array_length(rc->regmatch->subject));
 
        start = rc->regmatch->subject + match_data[num].rm_so;
        len = match_data[num].rm_eo - match_data[num].rm_so;
 
        MEM(buff = talloc_bstrndup(ctx, start, len));
 
        fr_value_box_init(out, FR_TYPE_STRING, NULL, false);
        fr_value_box_bstrndup_shallow(out, NULL, buff, len, false);
        fr_value_box_mark_safe_for(out, rc->safe_for);
        fr_value_box_set_secret(out, rc->secret);
 
        RDEBUG4("%i/%zu Found: %pV (%zu)", num + 1, rc->regmatch->used, out, out->vb_length);
 
        return 0;
}
#  endif
#endif