'\" t
.\"     Title: sk_chk_filter
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: May 2018
.\"    Manual: Linux Networking
.\"    Source: Kernel Hackers Manual 3.16.56
.\"  Language: English
.\"
.TH "SK_CHK_FILTER" "9" "May 2018" "Kernel Hackers Manual 3\&.16\&" "Linux Networking"
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.SH "NAME"
sk_chk_filter \- verify socket filter code
.SH "SYNOPSIS"
.HP \w'int\ sk_chk_filter('u
.BI "int sk_chk_filter(struct\ sock_filter\ *\ " "filter" ", unsigned\ int\ " "flen" ");"
.SH "ARGUMENTS"
.PP
\fIfilter\fR
.RS 4
filter to verify
.RE
.PP
\fIflen\fR
.RS 4
length of filter
.RE
.SH "DESCRIPTION"
.PP
Check the user\*(Aqs filter code\&. If we let some ugly filter code slip through kaboom! The filter must contain no references or jumps that are out of range, no illegal instructions, and must end with a RET instruction\&.
.PP
All jumps are forward as they are not signed\&.
.PP
Returns 0 if the rule set is legal or \-EINVAL if not\&.
.SH "COPYRIGHT"
.br