Настройка во время выполнения
Поведение этих функций зависит от установок в php.ini.
| 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_ALL | |
| session.gc_probability | "1" | PHP_INI_ALL | |
| session.gc_divisor | "100" | PHP_INI_ALL | Available since PHP 4.3.2. |
| 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 | Available since PHP 4.0.4. |
| session.cookie_httponly | "" | PHP_INI_ALL | Available since PHP 5.2.0. |
| session.use_cookies | "1" | PHP_INI_ALL | |
| session.use_only_cookies | "1" | PHP_INI_ALL | Available since PHP 4.3.0. |
| session.referer_check | "" | PHP_INI_ALL | |
| session.entropy_file | "" | PHP_INI_ALL | |
| session.entropy_length | "0" | 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 | PHP_INI_ALL in PHP <= 4.2.3. PHP_INI_PERDIR in PHP < 5. Available since PHP 4.0.3. |
| session.bug_compat_42 | "1" | PHP_INI_ALL | Available since PHP 4.3.0. Removed in PHP 6.0.0. |
| session.bug_compat_warn | "1" | PHP_INI_ALL | Available since PHP 4.3.0. Removed in PHP 6.0.0. |
| session.hash_function | "0" | PHP_INI_ALL | Available since PHP 5.0.0. |
| session.hash_bits_per_character | "4" | PHP_INI_ALL | Available since PHP 5.0.0. |
| url_rewriter.tags | "a=href,area=href,frame=src,form=,fieldset=" | PHP_INI_ALL | Available since PHP 4.0.4. |
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. 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.
ВниманиеIf 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.
Замечание: 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. Currently, a PHP internal format (name php or php_binary) and WDDX are supported (name wddx). WDDX is only available, if PHP is compiled with WDDX support. 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
cleaned up. Garbage collection occurs during session start.
Замечание: 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.
Замечание: If you are using the default file-based session handler, your filesystem must keep track of access times (atime). Windows FAT does not so you will have to come up with another way to handle garbage collecting your session if you are stuck with a FAT filesystem or any other filesystem where atime tracking is not available. Since PHP 4.2.3 it has used mtime (modified date) instead of atime. So, you won't have problems with filesystems where atime tracking is not available.
- 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.
- session.entropy_length integer
- session.entropy_length specifies the number of bytes which will be read from the file specified above. Defaults to 0 (disabled).
- 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 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. This setting was added in PHP 4.3.0. Defaults to 1 (enabled) since PHP 6.0.
-
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().
Замечание: 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 specifies path to set in session_cookie. Defaults to /. See also session_get_cookie_params() and session_set_cookie_params().
- session.cookie_domain specifies the domain to set in 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 specifies whether cookies should only be sent over secure connections. Defaults to off. This setting was added in PHP 4.0.4. See also session_get_cookie_params() and session_set_cookie_params().
- 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.cache_limiter string
- session.cache_limiter specifies cache control method to use for session pages (none/nocache/private/private_no_expire/public). Defaults to nocache. See also session_cache_limiter().
- 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).
Замечание: For PHP 4.1.2 or less, it is enabled by compiling with --enable-trans-sid. From PHP 4.2.0, trans-sid feature is always compiled. 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.
- 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.
- 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.
- 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 6.0.0 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.
Замечание: This was introduced in PHP 5.
- 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, "-", ",").
Замечание: This was introduced in PHP 5.
-
url_rewriter.tags specifies which HTML tags
are rewritten to include session id if transparent sid support
is enabled. Defaults to
a=href,area=href,frame=src,input=src,form=fakeentry,fieldset=
Замечание: If you want HTML/XHTML strict conformity, remove the form entry and use the <fieldset> tags around your form fields.
The track_vars and register_globals configuration settings influence how the session variables get stored and restored.
Замечание: As of PHP 4.0.3, track_vars is always turned on.
Коментарии
After having many problems with garbage collection not clearing my sessions I have resolved it through the following.
First I found this in the php.ini (not something i noticed as i use phpinfo(); to see my hosting ini).
; NOTE: If you are using the subdirectory option for storing session files
; (see session.save_path above), then garbage collection does *not*
; happen automatically. You will need to do your own garbage
; collection through a shell script, cron entry, or some other method. ; For example, the following script would is the equivalent of
; setting session.gc_maxlifetime to 1440 (1440 seconds = 24 minutes):
; cd /path/to/sessions; find -cmin +24 | xargs rm
With this is mind there are options.
1. dont use a custom save_path.
** This means if your isp hasnt defaulted your session temp to something safer than install default or you are using a shared directory for session data then you would be wise to use named sessions to keep your session from being viewable in other people's scripts. Creating a unique_id name for this is the common method. **
2. use your custom folder but write a garbage collection script.
3. use a custom handler and a database
Recently, I needed to change the session save_path in my program under Windows. With an ini_set('session.save_path', '../data/sessions'); (and session.gc_divisor = 1 for test), I always obtain 'Error #8 session_start(): ps_files_cleanup_dir: opendir(../data/sessions) failed: Result too large'.
I corrected this by changing with ini_set('session.save_path', realpath('../data/sessions'));
When setting the session.cookie_lifetime directive in a .htaccess use string format like;
php_value session.cookie_lifetime "123456"
and not
php_value session.cookie_lifetime 123456
Using a integer as stated above dit not work in my case (Apache/2.2.11 (Ubuntu) PHP/5.2.6-3ubuntu4.5 with Suhosin-Patch mod_ssl/2.2.11 OpenSSL/0.9.8g)
Transient sessions do not appear to be working in 5.3.3
E.g.
<?php
ini_set("session.use_cookies", 0);
ini_set("session.use_trans_sid", 1);
session_start();
if (isset($_SESSION["foo"])) {
echo "Foo: " . $_SESSION["foo"];
} else {
$_SESSION["foo"] = "Bar";
echo "<a href=?" . session_name() . "=" . session_id() . ">Begin test</a>";
}
?>
This works in 5.2.5, but not 5.3.3
apparently the default value for session.use_only_cookies has changed in 5.3.3 from 0 to 1. If you haven't set this in your php.ini or your code to 0 transparent sessions won't work.This is how I set my session.save_path
session.save_path = "1;/home/askapache/tmp/s"
So to create the folder structure you can use this compatible shell script, if you want to create with 777 permissions change the umask to 0000;
sh -o braceexpand -c "umask 0077;mkdir -p s/{0..9}/{a..z} s/{a..z}/{0..9}"
Then you can create a cronjob to clean the session folder by adding this to your crontab which deletes any session files older than an hour:
@daily find /home/askapache/tmp/s -type f -mmin +60 -exec rm -f {} \; &>/dev/null
That will create sessions in folder like:
/home/askapache/tmp/s/b/sess_b1aba5q6io4lv01bpc6t52h0ift227j6
I don't think any non-mega site will need to go more than 1 levels deep. Otherwise you create so many directories that it slows the performance gained by this.
max value for "session.gc_maxlifetime" is 65535. values bigger than this may cause php session stops working.Being unable to find an actual copy of mod_files.sh, and seeing lots of complaints/bug fix requests for it, here's one that works. It gets all its parameters from PHP.INI, so you don't have the opportunity to mess up:
#!/bin/bash
#
# Creates directories for PHP session storage.
# Replaces the one that "comes with" PHP, which (a) doesn't always come with it
# and (b) doesn't work so great.
#
# This version takes no parameters, and uses the values in PHP.INI (if it
# can find it).
#
# Works in OS-X and CentOS (and probably all other) Linux.
#
# Feb '13 by Jeff Levene.
[[ $# -gt 0 ]] && echo "$0 requires NO command-line parameters.
It gets does whatever is called for in the PHP.INI file (if it can find it).
" && exit 1
# Find the PHP.INI file, if possible:
phpIni=/usr/local/lib/php.ini # Default PHP.INI location
[[ ! -f "$phpIni" ]] && phpIni=/etc/php.ini # Secondary location
[[ ! -f "$phpIni" ]] && phpIni= # Found it?
# Outputs the given (as $1) parameter from the PHP.INI file:
# The "empty" brackets have a SPACE and a TAB in them.
#
PhpConfigParam() {
[[ ! "$phpIni" ]] && return
# Get the line from the INI file:
varLine=`grep "^[ ]*$1[ ]*=" "$phpIni"`
# Extract the value:
value=`expr "$varLine" : ".*$1[ ]*=[ ]*['\"]*\([^'\"]*\)"`
echo "$value"
}
if [[ "$phpIni" ]]
then
savePath=`PhpConfigParam session.save_path`
# If there's a number and semicolon at the front, remove them:
dirDepth=`expr "$savePath" : '\([0-9]*\)'`
[[ "$dirDepth" ]] && savePath=`expr "$savePath" : '[0-9]*;\(.*\)'` || dirDepth=0
bits=`PhpConfigParam session.hash_bits_per_character`
case "x$bits" in
x) echo "hash_bits_per_character not defined. Not running." ; exit 2 ;;
x4) alphabet='0 1 2 3 4 5 6 7 8 9 a b c d e f' ;;
x5) alphabet='0 1 2 3 4 5 6 7 8 9 a b c d e f g h i j k l m n o p q r s t u v' ;;
x6) alphabet='0 1 2 3 4 5 6 7 8 9 a b c d e f g h i j k l m n o p q r s t u v'
alphabet="$alphabet w x y z A B C D E F G H I J K L M N O P Q R S T U V W"
alphabet="$alphabet X Y Z - ,"
;;
*) echo "unrecognized hash_bits_per_character. Not running." ; exit 2 ;;
esac
else
echo "Cannot find the PHP.INI file. Not running. Sorry."
exit 2
fi
# The depth of directories to create is $1. 0 means just create the named
# directory. Directory to start with is $2.
#
# Used recursively, so variables must be "local".
doDir() {
local dir="$2"
if [[ -d "$dir" ]]
then
echo "Directory '$dir' already exists. No problem."
elif [[ -f "$dir" ]]
then
echo "FILE '$dir' exists. Aborting." ; exit 2
else
if mkdir "$dir"
then
echo "Directory '$dir' created."
else
echo "Cannot create directory '$dir'. Aborting." ; exit 2
fi
fi
chmod a+rwx "$dir"
if [[ $1 -gt 0 ]]
then
local depth=$(( $1 - 1 ))
for letter in $alphabet
do doDir $depth "$dir/$letter"
done
fi
}
echo "Running with savePath='$savePath', dirDepth=$dirDepth, and bitsPerCharacter=$bits."
sleep 3
doDir $dirDepth "$savePath"
exit 0
On debian (based) systems, changing session.gc_maxlifetime at runtime has no real effect. Debian disables PHP's own garbage collector by setting session.gc_probability=0. Instead it has a cronjob running every 30 minutes (see /etc/cron.d/php5) that cleans up old sessions. This cronjob basically looks into your php.ini and uses the value of session.gc_maxlifetime there to decide which sessions to clean (see /usr/lib/php5/maxlifetime).
You can adjust the global value in your php.ini (usually /etc/php5/apache2/php.ini). Or you can change the session.save_path so debian's cronjob will not clean up your sessions anymore. Then you need to either do your own garbage collection with your own cronjob or enable PHP's garbage collection (php then needs sufficient privileges on the save_path).
Why does Debian not use PHP's garbarage collection?
For security reasons, they store session data in a place (/var/lib/php5) with very stringent permissions. With the sticky bit set, only root is allowed to rename or delete files there, so PHP itself cannot clean up old session data. See https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=267720 .
We found a session.save_path depth of 3 led to excessive wastage of inodes and in fact disk space in storing the directory tree. dir_indexes option on ext2/3/4 makes larger directories more feasible anyway, so we decided to move to a depth of 2 instead.
It took a little puzzling to figure out how to move the existing PHP sessions up one directory tree, but we ended up running this in the root sessions directory:
#!/bin/sh
for a in ./* ; do
cd ./$a
pwd
for b in ./* ; do
cd ./$b
pwd
# Move existing sessions out
find ./* -xdev -type f -print0 | xargs -0 mv -t .
# Remove subdirectories
find ./* -xdev -type d -print0 | xargs -0 rmdir
cd ..
done
cd ..
done
This script may not be the best way to do it, but it got the job done fast. You can modify it for different depths by adding or removing "for" loops.
The documentation gives a depth of 5 as an example, but five is right out. If you're going beyond 2, you're at the scale where you may want to to look at a large memcached or redis instance instead.
I found out that if you need to set custom session settings, you only need to do it once when session starts. Then session maintains its settings, even if you use ini_set and change them, original session still will use it's original setting until it expires.
Just thought it might be useful to someone.
You should take more care configuring session.gc_maxlifetime when virtual hosts share the same session-saving directory. One host's session data may be gc'ed when another host runs php.session.use_strict_mode does very little to strengthen your security: only one very specific variant of attack is migitated by this (where the attacker hands an "empty" sid to the victim to adapt his own browser to that session later) - versus for example the case where he pre-opens a session, handing the sid of that one to the victim, so the victim gets adapted to the pre-opened session. In the latter case this flag does nothing to help. In every other scenario with other vulnerabilities where the session id gets leaked, the flag helps nigher.
But this flag renders the php function session_id() useless in its parameterized variant, thus preventing any php functionality that builds upon this function.
Use SessionHandlerInterface interface Custom redis session, found the following:
Use ini_set ('session.save_path', "tcp: //127.0.0.1: 6379? Auth = password"); will be reported:
PHP Fatal error: session_start (): Failed to initialize storage module: user (path: tcp: //127.0.0.1: 6379? Auth = password);
Using session_save_path ("tcp: //127.0.0.1: 6379? Auth = password") will not
session.cache_limiter may be empty string to disable cache headers entirely.
Quote:
> Setting the cache limiter to '' will turn off automatic sending of cache headers entirely.
function.session-cache-limiter
In php.ini, session.save_handler defines the name of the handler which is used for storing and retrieving data associated with a session. [Defaults to files.]
By default session.save_handler has support for below
session.save_handler = files
session.save_handler = sqlite
session.save_handler = redis
session.save_handler = memcached
These locks the session by default for any HTTP request using session.
Locking means, a user can't access session related pages until current request is completed.
So, if you are thinking that switching to these will increase performance; the answer is NO! because of locking behaviour.
To overcome/customise the session locking behaviour use as below.
session.save_handler = user
This is for all (including list above) modes of session storage.
For "user" type save_handler, we can ignore locks for better performance (as explained in function session_set_save_handler). But for this we need to take care to use sessions only for authenticity and not for passing data from one script to other.
For passing data accross scripts use GET method to achieve the goal.
You should set `session.name` to use either prefix `__Host-` or `__Secure-`. See https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#attributesCan't find mod_files.sh? Here it is:
▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬▬
#!/usr/bin/env bash
if [[ "$2" = "" ]] || [[ "$3" = "" ]]; then
echo "Usage: $0 BASE_DIRECTORY DEPTH BITS_PER_CHAR"
echo "BASE_DIRECTORY will be created if it doesn't exist"
echo "DEPTH must be an integer number >0"
echo "BITS_PER_CHAR(session.sid_bits_per_character) should be one of 4, 5, or 6."
# session.configuration#ini.session.sid-bits-per-character
exit 1
fi
if [[ "$2" = "0" ]] && [[ ! "$4" = "recurse" ]]; then
echo "Can't create a directory tree with depth of 0, exiting."
fi
if [[ "$2" = "0" ]]; then
exit 0
fi
directory="$1"
depth="$2"
bitsperchar="$3"
hash_chars="0 1 2 3 4 5 6 7 8 9 a b c d e f"
if [[ "$bitsperchar" -ge "5" ]]; then
hash_chars="$hash_chars g h i j k l m n o p q r s t u v"
fi
if [[ "$bitsperchar" -ge "6" ]]; then
hash_chars="$hash_chars w x y z A B C D E F G H I J K L M N O P Q R S T U V W X Y Z - ,"
fi
while [[ -d $directory ]] && [[ $( ls $directory ) ]]; do
echo "Directory $directory is not empty! What would you like to do?"
options="\"Delete directory contents\" \"Choose another directory\" \"Quit\""
eval set $options
select opt in "$@"; do
if [[ $opt = "Delete directory contents" ]]; then
echo "Deleting $directory contents... "
rm -rf $directory/*
elif [[ $opt = "Choose another directory" ]]; then
echo "Which directory would you like to choose?"
read directory
elif [[ $opt = "Quit" ]]; then
exit 0
fi
break;
done
done
if [[ ! -d $directory ]]; then
mkdir -p $directory
fi
echo "Creating session path in $directory with a depth of $depth for session.sid_bits_per_character = $bitsperchar"
for i in $hash_chars; do
newpath="$directory/$i"
mkdir $newpath || exit 1
bash $0 $newpath `expr $depth - 1` $bitsperchar recurse
done
the pwd should be urlencode when it contanis special chars.
eg:
save_handler:redis
save_path: tcp://127.0.0.1:6739?auth=urlencode('xxxxx')
Please be careful with the 'sid_length' when setting 'sid_bits_per_character' to six.
Setting sid_bits_per_character to 6 includes the character "," to the list of possible characters. A comma will be escaped and transmitted as "%2C" (tested on Chromium Version 119.0.6045.199) adding two extra characters for each comma to the SESSION_ID.
To prevent mitm-attacks you want to make sure the session cookie is only transmitted over a secure channel prefix it with the magic string "__Secure-". [1]
Like :
<?php
session_start( [ 'name' => '__Secure-Session-ID' ] );
?>
The cookie will not be available on non-secure channel.
(Putting this note it here probably goes unnoticed because of all the noise)
[1]: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie#attributes