session-php-configuration-0

  • Installing/Configuring
  • Runtime Configuration

  • Runtime Configuration
  • Runtime Configuration

    Runtime Configuration

    The behaviour of these functions is affected by
    settings in php.ini.

    Session configuration options
    Name Default Changeable Changelog
    session.save_path “” PHP_INI_ALL  
    session.name “PHPSESSID” PHP_INI_ALL  
    session.save_handler “files” PHP_INI_ALL  
    session.auto_start “0” PHP_INI_PERDIR  
    session.gc_probability “1” PHP_INI_ALL  
    session.gc_divisor “100” PHP_INI_ALL  
    session.gc_maxlifetime “1440” PHP_INI_ALL  
    session.serialize_handler “php” PHP_INI_ALL  
    session.cookie_lifetime “0” PHP_INI_ALL  
    session.cookie_path “/” PHP_INI_ALL  
    session.cookie_domain “” PHP_INI_ALL  
    session.cookie_secure “” PHP_INI_ALL  
    session.cookie_httponly “” PHP_INI_ALL Available since PHP 5.2.0.
    session.cookie_samesite “” PHP_INI_ALL Available since PHP 7.3.0.
    session.use_strict_mode “0” PHP_INI_ALL Available since PHP 5.5.2.
    session.use_cookies “1” PHP_INI_ALL  
    session.use_only_cookies “1” PHP_INI_ALL  
    session.referer_check “” PHP_INI_ALL  
    session.cache_limiter “nocache” PHP_INI_ALL  
    session.cache_expire “180” PHP_INI_ALL  
    session.use_trans_sid “0” PHP_INI_ALL  
    session.trans_sid_tags “a=href,area=href,frame=src,form=” PHP_INI_ALL Available since PHP 7.1.0.
    session.trans_sid_hosts $_SERVER[‘HTTP_HOST’] PHP_INI_ALL Available since PHP 7.1.0.
    session.sid_length “32” PHP_INI_ALL Available since PHP 7.1.0.
    session.sid_bits_per_character “4” PHP_INI_ALL Available since PHP 7.1.0.
    session.upload_progress.enabled “1” PHP_INI_PERDIR Available since PHP 5.4.0.
    session.upload_progress.cleanup “1” PHP_INI_PERDIR Available since PHP 5.4.0.
    session.upload_progress.prefix “upload_progress_” PHP_INI_PERDIR Available since PHP 5.4.0.
    session.upload_progress.name “PHP_SESSION_UPLOAD_PROGRESS” PHP_INI_PERDIR Available since PHP 5.4.0.
    session.upload_progress.freq “1%” PHP_INI_PERDIR Available since PHP 5.4.0.
    session.upload_progress.min_freq “1” PHP_INI_PERDIR Available since PHP 5.4.0.
    session.lazy_write “1” PHP_INI_ALL Available since PHP 7.0.0.
    url_rewriter.tags “a=href,area=href,frame=src,form=” PHP_INI_ALL Since PHP 7.1.0, this INI is no longer used by session.
    session.hash_function “0” PHP_INI_ALL Removed in PHP 7.1.0.
    session.hash_bits_per_character “4” PHP_INI_ALL Removed in PHP 7.1.0.
    session.entropy_file “” PHP_INI_ALL Removed in PHP 7.1.0.
    session.entropy_length “0” PHP_INI_ALL Removed in PHP 7.1.0
    session.bug_compat_42 “1” PHP_INI_ALL Removed in PHP 5.4.0.
    session.bug_compat_warn “1” PHP_INI_ALL Removed in PHP 5.4.0.

    For further details and definitions of the PHP_INI_* modes, see the
    Where a
    configuration setting may be set
    .

    The session management system supports a number of
    configuration options which you can place in your php.ini file. We will give a short overview.

    session.save_handler string
    session.save_handler defines the
    name of the handler which is used for storing and retrieving data
    associated with a session. Defaults to files. Note that
    individual extensions may register their own
    save_handlers; registered handlers can be obtained on a
    per-installation basis by referring to phpinfo(). See also session_set_save_handler().
    session.save_path string
    session.save_path defines the
    argument which is passed to the save handler. If you choose the
    default files handler, this is the path where the files are
    created. See also session_save_path().

    There is an optional N argument to this
    directive that determines the number of directory levels your
    session files will be spread around in. For example, setting to
    ‘5;/tmp’ may end up creating a session file and location
    like
    /tmp/4/b/1/e/3/sess_4b1e384ad74619bd212e236e52a5a174If .
    In order to use N you must create all of these directories
    before use. A small shell script exists in ext/session to do this, it’s called mod_files.sh, with a Windows version called
    mod_files.bat. Also note that if
    N is used and greater than 0 then automatic garbage
    collection will not be performed, see a copy of php.ini for further information. Also, if you use
    N, be sure to surround session.save_path in
    “quotes” because the separator (;) is also used for
    comments in php.ini.

    The file storage module creates files using mode
    600 by default. This default can be changed with the optional
    MODE argument: N;MODE;/path where MODE
    is the octal representation of the mode. Setting MODE does
    not affect the process umask.

    Warning

    If you leave this set to a world-readable
    directory, such as /tmp (the default),
    other users on the server may be able to hijack sessions by getting
    the list of files in that directory.

    Caution

    When using the optional directory level argument
    N, as described above, note that using a value higher than
    1 or 2 is inappropriate for most sites due to the large number of
    directories required: for example, a value of 3 implies that (2
    ** session.sid_bits_per_character) ** 3
    directories exist on
    the filesystem, which can result in a lot of wasted space and
    inodes.

    Only use N greater than 2 if you are
    absolutely certain that your site is large enough to require
    it.

    Note: Prior
    to PHP 4.3.6, Windows users had to change this variable in order to
    use PHP’s session functions. A valid path must be specified, e.g.:
    c:/temp.

    session.name string
    session.name specifies the name
    of the session which is used as cookie name. It should only contain
    alphanumeric characters. Defaults to PHPSESSID. See also
    session_name().
    session.auto_start boolean
    session.auto_start specifies
    whether the session module starts a session automatically on
    request startup. Defaults to 0 (disabled).
    session.serialize_handler string
    session.serialize_handler
    defines the name of the handler which is used to
    serialize/deserialize data. PHP serialize format (name
    php_serialize), PHP internal formats (name php
    and php_binary) and WDDX are supported (name
    wddx). WDDX is only available, if PHP is compiled with
    WDDX support.
    php_serialize is available from PHP 5.5.4.
    php_serialize uses plain serialize/unserialize function
    internally and does not have limitations that php and
    php_binary have. Older serialize handlers cannot store
    numeric index nor string index contains special characters
    (| and !) in $_SESSION. Use
    php_serialize to avoid numeric index or special character
    errors at script shutdown. Defaults to php.
    session.gc_probability integer
    session.gc_probability in
    conjunction with session.gc_divisor is used to manage
    probability that the gc (garbage collection) routine is started.
    Defaults to 1. See session.gc_divisor for details.
    session.gc_divisor integer
    session.gc_divisor coupled with
    session.gc_probability defines the probability that the gc
    (garbage collection) process is started on every session
    initialization. The probability is calculated by using
    gc_probability/gc_divisor, e.g. 1/100 means there is a 1% chance
    that the GC process starts on each request.
    session.gc_divisor defaults to 100.
    session.gc_maxlifetime integer
    session.gc_maxlifetime specifies
    the number of seconds after which data will be seen as ‘garbage’
    and potentially cleaned up. Garbage collection may occur during
    session start (depending on session.gc_probability and session.gc_divisor).

    Note: If
    different scripts have different values of
    session.gc_maxlifetime but share the same place for
    storing the session data then the script with the minimum value
    will be cleaning the data. In this case, use this directive
    together with session.save_path.

    session.referer_check string
    session.referer_check contains
    the substring you want to check each HTTP Referer for. If the
    Referer was sent by the client and the substring was not found, the
    embedded session id will be marked as invalid. Defaults to the
    empty string.
    session.entropy_file string
    session.entropy_file gives a
    path to an external resource (file) which will be used as an
    additional entropy source in the session id creation process.
    Examples are /dev/random or /dev/urandom which
    are available on many Unix systems.
    This feature is supported on Windows since PHP 5.3.3.
    Setting session.entropy_length to a non zero value will
    make PHP use the Windows Random API as entropy source.

    Note: Removed in PHP 7.1.0. As of
    PHP 5.4.0 session.entropy_file defaults to
    /dev/urandom or /dev/arandom if it is available.
    In PHP 5.3.0 this directive is left empty by default.

    session.entropy_length integer
    session.entropy_length specifies
    the number of bytes which will be read from the file specified
    above. Defaults to 32.
    Removed in PHP 7.1.0.
    session.use_strict_mode boolean
    session.use_strict_mode
    specifies whether the module will use strict session id mode. If
    this mode is enabled, the module does not accept uninitialized
    session ID. If uninitialized session ID is sent from browser, new
    session ID is sent to browser. Applications are protected from
    session fixation via session adoption with strict mode. Defaults to
    0 (disabled).

    Note: Enabling session.use_strict_mode is mandatory
    for general session security. All sites are advised to enable this.
    See session_create_id() example code for more
    details.

    session.use_cookies boolean
    session.use_cookies specifies
    whether the module will use cookies to store the session id on the
    client side. Defaults to 1 (enabled).
    session.use_only_cookies boolean
    session.use_only_cookies
    specifies whether the module will only
    use cookies to store the session id on the client side. Enabling
    this setting prevents attacks involved passing session ids in URLs.
    Defaults to 1 (enabled) since PHP 5.3.0.
    session.cookie_lifetime integer
    session.cookie_lifetime
    specifies the lifetime of the cookie in seconds which is sent to
    the browser. The value 0 means “until the browser is closed.”
    Defaults to 0. See also session_get_cookie_params() and session_set_cookie_params().

    Note: The
    expiration timestamp is set relative to the server time, which is
    not necessarily the same as the time in the client’s
    browser.

    session.cookie_path string
    session.cookie_path specifies
    path to set in the session cookie. Defaults to /. See also
    session_get_cookie_params() and session_set_cookie_params().
    session.cookie_domain string
    session.cookie_domain specifies
    the domain to set in the session cookie. Default is none at all
    meaning the host name of the server which generated the cookie
    according to cookies specification. See also session_get_cookie_params() and session_set_cookie_params().
    session.cookie_secure boolean
    session.cookie_secure specifies
    whether cookies should only be sent over secure connections.
    Defaults to off. See also session_get_cookie_params() and session_set_cookie_params().
    session.cookie_httponly boolean
    Marks the cookie as accessible only
    through the HTTP protocol. This means that the cookie won’t be
    accessible by scripting languages, such as JavaScript. This setting
    can effectively help to reduce identity theft through XSS attacks
    (although it is not supported by all browsers).
    session.cookie_samesite string
    Allows servers to assert that a cookie
    ought not to be sent along with cross-site requests. This assertion
    allows user agents to mitigate the risk of cross-origin information
    leakage, and provides some protection against cross-site request
    forgery attacks. Note that this is not supported by all browsers.
    An empty value means that no SameSite cookie attribute will be set.
    Lax and Strict mean that the cookie will not be
    sent cross-domain for POST requests; Lax will sent the
    cookie for cross-domain GET requests, while Strict will
    not.
    session.cache_limiter string
    session.cache_limiter specifies
    the cache control method used for session pages. It may be one of
    the following values: nocache, private,
    private_no_expire, or public. Defaults to
    nocache. See also the session_cache_limiter() documentation for
    information about what these values mean.
    session.cache_expire integer
    session.cache_expire specifies
    time-to-live for cached session pages in minutes, this has no
    effect for nocache limiter. Defaults to 180. See also
    session_cache_expire().
    session.use_trans_sid boolean
    session.use_trans_sid whether
    transparent sid support is enabled or not. Defaults to 0
    (disabled).

    Note: URL
    based session management has additional security risks compared to
    cookie based session management. Users may send a URL that contains
    an active session ID to their friends by email or users may save a
    URL that contains a session ID to their bookmarks and access your
    site with the same session ID always, for example.

    Since PHP 7.1.0, full URL path, e.g.
    https://php.net/, is handled by trans sid feature. Previous PHP
    handled relative URL path only. Rewrite target hosts are defined by
    session.trans_sid_hosts.

    session.trans_sid_tags string
    session.trans_sid_tags specifies
    which HTML tags are rewritten to include session id when
    transparent sid support is enabled. Defaults to
    a=href,area=href,frame=src,input=src,form=

    form is special tag. <input
    hidden=”session_id” name=”session_name”>
    is added as form
    variable.

    Note: Before
    PHP 7.1.0, url_rewriter.tags was used for this purpose. Since PHP
    7.1.0, fieldset is no longer considered as special
    tag.

    session.trans_sid_hosts string
    session.trans_sid_hosts
    specifies which hosts are rewritten to include session id when
    transparent sid support is enabled. Defaults to
    $_SERVER[‘HTTP_HOST’] Multiple hosts can be specified by
    “,”, no space is allowed between hosts. e.g.
    php.net,wiki.php.net,bugs.php.net
    session.bug_compat_42 boolean
    PHP versions 4.2.3 and lower have an
    undocumented feature/bug that allows you to initialize a session
    variable in the global scope, albeit register_globals is disabled. PHP 4.3.0 and later will
    warn you, if this feature is used, and if session.bug_compat_warn is also enabled. This
    feature/bug can be disabled by disabling this directive.

    Note: Removed in PHP 5.4.0.

    session.bug_compat_warn boolean
    PHP versions 4.2.3 and lower have an
    undocumented feature/bug that allows you to initialize a session
    variable in the global scope, albeit register_globals is disabled. PHP 4.3.0 and later will
    warn you, if this feature is used by enabling both session.bug_compat_42 and session.bug_compat_warn.

    Note: Removed in PHP 5.4.0.

    session.sid_length integer
    session.sid_length allows you to
    specify the length of session ID string. Session ID length can be
    between 22 to 256.
    The default is 32.
    If you need compatibility you may specify 32, 40, etc. Longer
    session ID is harder to guess. At least 32 chars are
    recommended.

    Tip

    Compatibility Note: Use 32 instead of
    session.hash_function=0 (MD5) and
    session.hash_bits_per_character=4,
    session.hash_function=1 (SHA1) and
    session.hash_bits_per_character=6. Use 26 instead of
    session.hash_function=0 (MD5) and
    session.hash_bits_per_character=5. Use 22 instead of
    session.hash_function=0 (MD5) and
    session.hash_bits_per_character=6. You must configure INI
    values to have at least 128 bits in session ID. Do not forget to
    set an appropriate value for
    session.sid_bits_per_character, otherwise you will have
    weaker session ID.

    Note: This
    setting is introduced in PHP 7.1.0.

    session.sid_bits_per_character integer
    session.sid_per_character allows
    you to specify the number of bits in encoded session ID character.
    The possible values are ‘4’ (0-9, a-f), ‘5’ (0-9, a-v), and ‘6’
    (0-9, a-z, A-Z, “-“, “,”).
    The default
    is 4. The more bits results in stronger session ID. 5 is
    recommended value for most environments.

    Note: This
    setting is introduced in PHP 7.1.0.

    session.hash_function mixed
    session.hash_function allows you
    to specify the hash algorithm used to generate the session IDs. ‘0’
    means MD5 (128 bits) and ‘1’ means SHA-1 (160 bits).

    Since PHP 5.3.0 it is also possible to specify any
    of the algorithms provided by the hash extension (if it is available), like
    sha512 or whirlpool. A complete list of supported
    algorithms can be obtained with the hash_algos()
    function.

    Note: This
    setting was introduced in PHP 5. Removed in PHP 7.1.0.

    session.hash_bits_per_character integer
    session.hash_bits_per_character
    allows you to define how many bits are stored in each character
    when converting the binary hash data to something readable. The
    possible values are ‘4’ (0-9, a-f), ‘5’ (0-9, a-v), and ‘6’ (0-9,
    a-z, A-Z, “-“, “,”).

    Note: Removed in PHP 7.1.0.

    session.upload_progress.enabled boolean
    Enables upload progress tracking,
    populating the $_SESSION variable. Defaults to 1,
    enabled.
    session.upload_progress.cleanup boolean
    Cleanup the progress information as soon
    as all POST data has been read (i.e. upload completed). Defaults to
    1, enabled.

    Note: It is
    highly recommended to keep this feature enabled.

    session.upload_progress.prefix string
    A prefix used for the upload progress key
    in the $_SESSION. This key will be
    concatenated with the value of
    $_POST[ini_get(“session.upload_progress.name”)] to provide
    a unique index.
    Defaults to
    “upload_progress_”.
    session.upload_progress.name string
    The name of the key to be used in
    $_SESSION storing the progress
    information. See also session.upload_progress.prefix.

    If
    $_POST[ini_get(“session.upload_progress.name”)] is not
    passed or available, upload progressing will not be
    recorded.
    Defaults to
    “PHP_SESSION_UPLOAD_PROGRESS”.
    session.upload_progress.freq mixed
    Defines how often the upload progress
    information should be updated. This can be defined in bytes (i.e.
    “update progress information after every 100 bytes”), or in
    percentages (i.e. “update progress information after receiving
    every 1% of the whole filesize”).
    Defaults to “1%”.
    session.upload_progress.min_freq integer
    The minimum delay between updates, in
    seconds. Defaults to “1” (one second).
    session.lazy_write boolean
    session.lazy_write, when set to
    1, means that session data is only rewritten if it changes.
    Defaults to 1, enabled.

    The register_globals configuration settings
    influence how the session variables get stored and restored.

    Upload progress will not be registered unless
    session.upload_progress.enabled is enabled, and the
    $_POST[ini_get(“session.upload_progress.name”)] variable is set.
    See Session
    Upload Progress
    for more details on this functionality.