path: root/modules/pam_limits/limits.conf.5

.\"     Title: limits.conf
.\"    Author: [see the "AUTHOR" section]
.\" Generator: DocBook XSL Stylesheets v1.74.0 <http://docbook.sf.net/>
.\"      Date: 03/02/2009
.\"    Manual: Linux-PAM Manual
.\"    Source: Linux-PAM Manual
.\"  Language: English
.\"
.TH "LIMITS\&.CONF" "5" "03/02/2009" "Linux-PAM Manual" "Linux\-PAM Manual"
.\" -----------------------------------------------------------------
.\" * (re)Define some macros
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" toupper - uppercase a string (locale-aware)
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.de toupper
.tr aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ
\\$*
.tr aabbccddeeffgghhiijjkkllmmnnooppqqrrssttuuvvwwxxyyzz
..
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" SH-xref - format a cross-reference to an SH section
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.de SH-xref
.ie n \{\
.\}
.toupper \\$*
.el \{\
\\$*
.\}
..
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" SH - level-one heading that works better for non-TTY output
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.de1 SH
.\" put an extra blank line of space above the head in non-TTY output
.if t \{\
.sp 1
.\}
.sp \\n[PD]u
.nr an-level 1
.set-an-margin
.nr an-prevailing-indent \\n[IN]
.fi
.in \\n[an-margin]u
.ti 0
.HTML-TAG ".NH \\n[an-level]"
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
\." make the size of the head bigger
.ps +3
.ft B
.ne (2v + 1u)
.ie n \{\
.\" if n (TTY output), use uppercase
.toupper \\$*
.\}
.el \{\
.nr an-break-flag 0
.\" if not n (not TTY), use normal case (not uppercase)
\\$1
.in \\n[an-margin]u
.ti 0
.\" if not n (not TTY), put a border/line under subheading
.sp -.6
\l'\n(.lu'
.\}
..
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" SS - level-two heading that works better for non-TTY output
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.de1 SS
.sp \\n[PD]u
.nr an-level 1
.set-an-margin
.nr an-prevailing-indent \\n[IN]
.fi
.in \\n[IN]u
.ti \\n[SN]u
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
.ps \\n[PS-SS]u
\." make the size of the head bigger
.ps +2
.ft B
.ne (2v + 1u)
.if \\n[.$] \&\\$*
..
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" BB/BE - put background/screen (filled box) around block of text
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.de BB
.if t \{\
.sp -.5
.br
.in +2n
.ll -2n
.gcolor red
.di BX
.\}
..
.de EB
.if t \{\
.if "\\$2"adjust-for-leading-newline" \{\
.sp -1
.\}
.br
.di
.in
.ll
.gcolor
.nr BW \\n(.lu-\\n(.i
.nr BH \\n(dn+.5v
.ne \\n(BHu+.5v
.ie "\\$2"adjust-for-leading-newline" \{\
\M[\\$1]\h'1n'\v'+.5v'\D'P \\n(BWu 0 0 \\n(BHu -\\n(BWu 0 0 -\\n(BHu'\M[]
.\}
.el \{\
\M[\\$1]\h'1n'\v'-.5v'\D'P \\n(BWu 0 0 \\n(BHu -\\n(BWu 0 0 -\\n(BHu'\M[]
.\}
.in 0
.sp -.5v
.nf
.BX
.in
.sp .5v
.fi
.\}
..
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" BM/EM - put colored marker in margin next to block of text
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.de BM
.if t \{\
.br
.ll -2n
.gcolor red
.di BX
.\}
..
.de EM
.if t \{\
.br
.di
.ll
.gcolor
.nr BH \\n(dn
.ne \\n(BHu
\M[\\$1]\D'P -.75n 0 0 \\n(BHu -(\\n[.i]u - \\n(INu - .75n) 0 0 -\\n(BHu'\M[]
.in 0
.nf
.BX
.in
.fi
.\}
..
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "Name"
limits.conf \- configuration file for the pam_limits module
.SH "DESCRIPTION"
.PP
The syntax of the lines is as follows:
.PP

\fI<domain>\fR
\fI<type>\fR
\fI<item>\fR
\fI<value>\fR
.PP
The fields listed above should be filled as follows:
.PP
\fB<domain>\fR
.RS 4
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
a username
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
a groupname, with
\fB@group\fR
syntax\&. This should not be confused with netgroups\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
the wildcard
\fB*\fR, for default entry\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
the wildcard
\fB%\fR, for maxlogins limit only, can also be used with
\fI%group\fR
syntax\&.
.RE
.RE
.PP
\fB<type>\fR
.RS 4
.PP
\fBhard\fR
.RS 4
for enforcing
\fBhard\fR
resource limits\&. These limits are set by the superuser and enforced by the Kernel\&. The user cannot raise his requirement of system resources above such values\&.
.RE
.PP
\fBsoft\fR
.RS 4
for enforcing
\fBsoft\fR
resource limits\&. These limits are ones that the user can move up or down within the permitted range by any pre\-existing
\fBhard\fR
limits\&. The values specified with this token can be thought of as
\fIdefault\fR
values, for normal system usage\&.
.RE
.PP
\fB\-\fR
.RS 4
for enforcing both
\fBsoft\fR
and
\fBhard\fR
resource limits together\&.
.sp
Note, if you specify a type of \'\-\' but neglect to supply the item and value fields then the module will never enforce any limits on the specified user/group etc\&. \&.
.RE
.RE
.PP
\fB<item>\fR
.RS 4
.PP
\fBcore\fR
.RS 4
limits the core file size (KB)
.RE
.PP
\fBdata\fR
.RS 4
maximum data size (KB)
.RE
.PP
\fBfsize\fR
.RS 4
maximum filesize (KB)
.RE
.PP
\fBmemlock\fR
.RS 4
maximum locked\-in\-memory address space (KB)
.RE
.PP
\fBnofile\fR
.RS 4
maximum number of open files
.RE
.PP
\fBrss\fR
.RS 4
maximum resident set size (KB) (Ignored in Linux 2\&.4\&.30 and higher)
.RE
.PP
\fBstack\fR
.RS 4
maximum stack size (KB)
.RE
.PP
\fBcpu\fR
.RS 4
maximum CPU time (minutes)
.RE
.PP
\fBnproc\fR
.RS 4
maximum number of processes
.RE
.PP
\fBas\fR
.RS 4
address space limit (KB)
.RE
.PP
\fBmaxlogins\fR
.RS 4
maximum number of logins for this user except for this with
\fIuid=0\fR
.RE
.PP
\fBmaxsyslogins\fR
.RS 4
maximum number of logins on system
.RE
.PP
\fBpriority\fR
.RS 4
the priority to run user process with (negative values boost process priority)
.RE
.PP
\fBlocks\fR
.RS 4
maximum locked files (Linux 2\&.4 and higher)
.RE
.PP
\fBsigpending\fR
.RS 4
maximum number of pending signals (Linux 2\&.6 and higher)
.RE
.PP
\fBmsqqueue\fR
.RS 4
maximum memory used by POSIX message queues (bytes) (Linux 2\&.6 and higher)
.RE
.PP
\fBnice\fR
.RS 4
maximum nice priority allowed to raise to (Linux 2\&.6\&.12 and higher) values: [\-20,19]
.RE
.PP
\fBrtprio\fR
.RS 4
maximum realtime priority allowed for non\-privileged processes (Linux 2\&.6\&.12 and higher)
.RE
.RE
.PP
All items support the values
\fI\-1\fR,
\fIunlimited\fR
or
\fIinfinity\fR
indicating no limit, except for
\fBpriority\fR
and
\fBnice\fR\&.
.PP
If a hard limit or soft limit of a resource is set to a valid value, but outside of the supported range of the local system, the system may reject the new limit or unexpected behavior may occur\&. If the control value
\fIrequired\fR
is used, the module will reject the login if a limit could not be set\&.
.PP
In general, individual limits have priority over group limits, so if you impose no limits for
\fIadmin\fR
group, but one of the members in this group have a limits line, the user will have its limits set according to this line\&.
.PP
Also, please note that all limit settings are set
\fIper login\fR\&. They are not global, nor are they permanent; existing only for the duration of the session\&.
.PP
In the
\fIlimits\fR
configuration file, the \'\fB#\fR\' character introduces a comment \- after which the rest of the line is ignored\&.
.PP
The pam_limits module does report configuration problems found in its configuration file and errors via
\fBsyslog\fR(3)\&.
.SH "EXAMPLES"
.PP
These are some example lines which might be specified in
\FC/etc/security/limits\&.conf\F[]\&.
.sp
.if n \{\
.RS 4
.\}
.fam C
.ps -1
.nf
.if t \{\
.sp -1
.\}
.BB lightgray adjust-for-leading-newline
.sp -1

*               soft    core            0
*               hard    rss             10000
@student        hard    nproc           20
@faculty        soft    nproc           20
@faculty        hard    nproc           50
ftp             hard    nproc           0
@student        \-       maxlogins       4
    
.EB lightgray adjust-for-leading-newline
.if t \{\
.sp 1
.\}
.fi
.fam
.ps +1
.if n \{\
.RE
.\}
.SH "SEE ALSO"
.PP

\fBpam_limits\fR(8),
\fBpam.d\fR(5),
\fBpam\fR(8),
\fBgetrlimit\fR(2)
\fBgetrlimit\fR(3p)
.SH "AUTHOR"
.PP
pam_limits was initially written by Cristian Gafton <gafton@redhat\&.com>