+
+/**
+ * Counts 8bit bytes in string
+ * @param string $string tested string
+ * @return integer number of 8bit bytes
+ */
+function sq_count8bit($string) {
+ $count=0;
+ for ($i=0; $i<strlen($string); $i++) {
+ if (ord($string[$i]) > 127) $count++;
+ }
+ return $count;
+}
+
+/**
+ * Callback function to trim whitespace from a value, to be used in array_walk
+ * @param string $value value to trim
+ * @since 1.5.2 and 1.4.7
+ */
+function sq_trim_value ( &$value ) {
+ $value = trim($value);
+}
+
+/**
+ * Truncates the given string so that it has at
+ * most $max_chars characters. NOTE that a "character"
+ * may be a multibyte character, or (optionally), an
+ * HTML entity , so this function is different than
+ * using substr() or mb_substr().
+ *
+ * NOTE that if $elipses is given and used, the returned
+ * number of characters will be $max_chars PLUS the
+ * length of $elipses
+ *
+ * @param string $string The string to truncate
+ * @param int $max_chars The maximum allowable characters
+ * @param string $elipses A string that will be added to
+ * the end of the truncated string
+ * (ONLY if it is truncated) (OPTIONAL;
+ * default not used)
+ * @param boolean $html_entities_as_chars Whether or not to keep
+ * HTML entities together
+ * (OPTIONAL; default ignore
+ * HTML entities)
+ *
+ * @return string The truncated string
+ *
+ * @since 1.4.20 and 1.5.2 (replaced truncateWithEntities())
+ *
+ */
+function sm_truncate_string($string, $max_chars, $elipses='',
+ $html_entities_as_chars=FALSE)
+{
+
+ // if the length of the string is less than
+ // the allowable number of characters, just
+ // return it as is (even if it contains any
+ // HTML entities, that would just make the
+ // actual length even smaller)
+ //
+ $actual_strlen = sq_strlen($string, 'auto');
+ if ($max_chars <= 0 || $actual_strlen <= $max_chars)
+ return $string;
+
+
+ // if needed, count the number of HTML entities in
+ // the string up to the maximum character limit,
+ // pushing that limit up for each entity found
+ //
+ $adjusted_max_chars = $max_chars;
+ if ($html_entities_as_chars)
+ {
+
+ // $loop_count is needed to prevent an endless loop
+ // which is caused by buggy mbstring versions that
+ // return 0 (zero) instead of FALSE in some rare
+ // cases. Thanks, PHP.
+ // see: http://bugs.php.net/bug.php?id=52731
+ // also: tracker $3053349
+ //
+ $loop_count = 0;
+ $entity_pos = $entity_end_pos = -1;
+ while ($entity_end_pos + 1 < $actual_strlen
+ && ($entity_pos = sq_strpos($string, '&', $entity_end_pos + 1)) !== FALSE
+ && ($entity_end_pos = sq_strpos($string, ';', $entity_pos)) !== FALSE
+ && $entity_pos <= $adjusted_max_chars
+ && $loop_count++ < $max_chars)
+ {
+ $adjusted_max_chars += $entity_end_pos - $entity_pos;
+ }
+
+
+ // this isn't necessary because sq_substr() would figure this
+ // out anyway, but we can avoid a sq_substr() call and we
+ // know that we don't have to add an elipses (this is now
+ // an accurate comparison, since $adjusted_max_chars, like
+ // $actual_strlen, does not take into account HTML entities)
+ //
+ if ($actual_strlen <= $adjusted_max_chars)
+ return $string;
+
+ }
+
+
+ // get the truncated string
+ //
+ $truncated_string = sq_substr($string, 0, $adjusted_max_chars);
+
+
+ // return with added elipses
+ //
+ return $truncated_string . $elipses;
+
+}
+
+/**
+ * Gathers the list of secuirty tokens currently
+ * stored in the user's preferences and optionally
+ * purges old ones from the list.
+ *
+ * @param boolean $purge_old Indicates if old tokens
+ * should be purged from the
+ * list ("old" is 2 days or
+ * older unless the administrator
+ * overrides that value using
+ * $max_token_age_days in
+ * config/config_local.php)
+ * (OPTIONAL; default is to always
+ * purge old tokens)
+ *
+ * @return array The list of tokens
+ *
+ * @since 1.4.19 and 1.5.2
+ *
+ */
+function sm_get_user_security_tokens($purge_old=TRUE)
+{
+
+ global $data_dir, $username, $max_token_age_days;
+
+ $tokens = getPref($data_dir, $username, 'security_tokens', '');
+ if (($tokens = unserialize($tokens)) === FALSE || !is_array($tokens))
+ $tokens = array();
+
+ // purge old tokens if necessary
+ //
+ if ($purge_old)
+ {
+ if (empty($max_token_age_days)) $max_token_age_days = 2;
+ $now = time();
+ $discard_token_date = $now - ($max_token_age_days * 86400);
+ $cleaned_tokens = array();
+ foreach ($tokens as $token => $timestamp)
+ if ($timestamp >= $discard_token_date)
+ $cleaned_tokens[$token] = $timestamp;
+ $tokens = $cleaned_tokens;
+ }
+
+ return $tokens;
+
+}
+
+/**
+ * Generates a security token that is then stored in
+ * the user's preferences with a timestamp for later
+ * verification/use.
+ *
+ * NOTE: The administrator can force SquirrelMail to generate
+ * a new token every time one is requested (which may increase
+ * obscurity through token randomness at the cost of some
+ * performance) by adding the following to
+ * config/config_local.php: $do_not_use_single_token = TRUE;
+ * Otherwise, only one token will be generated per user which
+ * will change only after it expires or is used outside of the
+ * validity period specified when calling sm_validate_security_token()
+ *
+ * WARNING: If the administrator has turned the token system
+ * off by setting $disable_security_tokens to TRUE in
+ * config/config.php or the configuration tool, this
+ * function will not store tokens in the user
+ * preferences (but it will still generate and return
+ * a random string).
+ *
+ * @param boolean $force_generate_new When TRUE, a new token will
+ * always be created even if current
+ * configuration dictates otherwise
+ * (OPTIONAL; default FALSE)
+ *
+ * @return string A security token
+ *
+ * @since 1.4.19 and 1.5.2
+ *
+ */
+function sm_generate_security_token($force_generate_new=FALSE)
+{
+
+ global $data_dir, $username, $disable_security_tokens, $do_not_use_single_token;
+ $max_generation_tries = 1000;
+
+ $tokens = sm_get_user_security_tokens();
+
+ if (!$force_generate_new && !$do_not_use_single_token && !empty($tokens))
+ return key($tokens);
+
+ $new_token = GenerateRandomString(12, '', 7);
+ $count = 0;
+ while (isset($tokens[$new_token]))
+ {
+ $new_token = GenerateRandomString(12, '', 7);
+ if (++$count > $max_generation_tries)
+ {
+ logout_error(_("Fatal token generation error; please contact your system administrator or the SquirrelMail Team"));
+ exit;
+ }
+ }
+
+ // is the token system enabled? CAREFUL!
+ //
+ if (!$disable_security_tokens)
+ {
+ $tokens[$new_token] = time();
+ setPref($data_dir, $username, 'security_tokens', serialize($tokens));
+ }
+
+ return $new_token;
+
+}
+
+/**
+ * Validates a given security token and optionally remove it
+ * from the user's preferences if it was valid. If the token
+ * is too old but otherwise valid, it will still be rejected.
+ *
+ * "Too old" is 2 days or older unless the administrator
+ * overrides that value using $max_token_age_days in
+ * config/config_local.php
+ *
+ * WARNING: If the administrator has turned the token system
+ * off by setting $disable_security_tokens to TRUE in
+ * config/config.php or the configuration tool, this
+ * function will always return TRUE.
+ *
+ * @param string $token The token to validate
+ * @param int $validity_period The number of seconds tokens are valid
+ * for (set to zero to remove valid tokens
+ * after only one use; use 3600 to allow
+ * tokens to be reused for an hour)
+ * (OPTIONAL; default is to only allow tokens
+ * to be used once)
+ * NOTE this is unrelated to $max_token_age_days
+ * or rather is an additional time constraint on
+ * tokens that allows them to be re-used (or not)
+ * within a more narrow timeframe
+ * @param boolean $show_error Indicates that if the token is not
+ * valid, this function should display
+ * a generic error, log the user out
+ * and exit - this function will never
+ * return in that case.
+ * (OPTIONAL; default FALSE)
+ *
+ * @return boolean TRUE if the token validated; FALSE otherwise
+ *
+ * @since 1.4.19 and 1.5.2
+ *
+ */
+function sm_validate_security_token($token, $validity_period=0, $show_error=FALSE)
+{
+
+ global $data_dir, $username, $max_token_age_days,
+ $disable_security_tokens;
+
+ // bypass token validation? CAREFUL!
+ //
+ if ($disable_security_tokens) return TRUE;
+
+ // don't purge old tokens here because we already
+ // do it when generating tokens
+ //
+ $tokens = sm_get_user_security_tokens(FALSE);
+
+ // token not found?
+ //
+ if (empty($tokens[$token]))
+ {
+ if (!$show_error) return FALSE;
+ logout_error(_("This page request could not be verified and appears to have expired."));
+ exit;
+ }
+
+ $now = time();
+ $timestamp = $tokens[$token];
+
+ // whether valid or not, we want to remove it from
+ // user prefs if it's old enough
+ //
+ if ($timestamp < $now - $validity_period)
+ {
+ unset($tokens[$token]);
+ setPref($data_dir, $username, 'security_tokens', serialize($tokens));
+ }
+
+ // reject tokens that are too old
+ //
+ if (empty($max_token_age_days)) $max_token_age_days = 2;
+ $old_token_date = $now - ($max_token_age_days * 86400);
+ if ($timestamp < $old_token_date)
+ {
+ if (!$show_error) return FALSE;
+ logout_error(_("The current page request appears to have originated from an untrusted source."));
+ exit;
+ }
+
+ // token OK!
+ //
+ return TRUE;
+
+}
+