Function decode_u_encoding_path

htp/htp_util.c:1177–1223

* Decode a %u-encoded character, using best-fit mapping as necessary. Path version. * * @param[in] cfg * @param[in] tx * @param[in] data * @return decoded byte */

 * @return decoded byte
 */
static uint8_t decode_u_encoding_path(htp_cfg_t *cfg, htp_tx_t *tx, unsigned char *data) {
    uint8_t c1 = x2c(data);
    uint8_t c2 = x2c(data + 2);
    uint8_t r = cfg->decoder_cfgs[HTP_DECODER_URL_PATH].bestfit_replacement_byte;

    if (c1 == 0x00) {
        r = c2;
        tx->flags |= HTP_PATH_OVERLONG_U;
    } else {
        // Check for fullwidth form evasion
        if (c1 == 0xff) {
            tx->flags |= HTP_PATH_HALF_FULL_RANGE;
        }

        if (cfg->decoder_cfgs[HTP_DECODER_URL_PATH].u_encoding_unwanted != HTP_UNWANTED_IGNORE) {
            tx->response_status_expected_number = cfg->decoder_cfgs[HTP_DECODER_URL_PATH].u_encoding_unwanted;
        }

        // Use best-fit mapping
        unsigned char *p = cfg->decoder_cfgs[HTP_DECODER_URL_PATH].bestfit_map;

        // TODO Optimize lookup.

        for (;;) {
            // Have we reached the end of the map?
            if ((p[0] == 0) && (p[1] == 0)) {
                break;
            }

            // Have we found the mapping we're looking for?
            if ((p[0] == c1) && (p[1] == c2)) {
                r = p[2];
                break;
            }

            // Move to the next triplet
            p += 3;
        }
    }

    // Check for encoded path separators
    if ((r == '/') || ((cfg->decoder_cfgs[HTP_DECODER_URL_PATH].backslash_convert_slashes) && (r == '\\'))) {
        tx->flags |= HTP_PATH_ENCODED_SEPARATOR;
    }

    return r;
}

/**
 * Decode a %u-encoded character, using best-fit mapping as necessary. Params version.