Date: Fri, 20 Jul 2001 23:50:02 -0700 (PDT) From: Alex Kapranoff <kapr@acm.org> To: freebsd-doc@freebsd.org Subject: Re: docs/28916: DocBook conversion of doc/articles/ipsec-must Message-ID: <200107210650.f6L6o2L10472@freefall.freebsd.org>
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The following reply was made to PR docs/28916; it has been noted by GNATS. From: Alex Kapranoff <kapr@acm.org> To: Dima Dorfman <dima@unixfreak.org> Cc: freebsd-doc@FreeBSD.ORG, freebsd-gnats-submit@FreeBSD.ORG Subject: Re: docs/28916: DocBook conversion of doc/articles/ipsec-must Date: Sat, 21 Jul 2001 10:42:33 +0400 * Dima Dorfman <dima@unixfreak.org> [July 19 2001, 15:57]: > Alex Kapranoff <kapr@acm.org> writes: > > And why do you say that sharballs are less convenient to work with? > > Seems that it's true only if the diff is readable. > > Well, for one it *would* be readable, at least for the Makefile. Two, Okay, now try to read the diff below. ;) > it'd be nice to know that you wouldn't be overwriting other people's > changes (e.g., chern made a spelling fix, and if I just unshar'd your > files it'd be overwritten). And three, with a diff I can save the > e-mail to a file then pass it through patch; I can't just pass a shar > archive through sh because of the cruft above the archive (okay, okay, > I'm lazy :-) ). Points taken. > > --- /usr/doc/en_US.ISO8859-1/articles/ipsec-must/article.sgml Wed Jun13 18:16:55 2001 > > +++ article.html Mon Jul 16 08:22:26 2001 > > I've applied this. Now that that's done, could you send me a diff > that converts this mess to DocBook? Thanks! Sorry for confusion. With this patch applied the PR could be closed. This is all obtained from FreeBSD Russian Documentation Project. diff -u /usr/doc/en_US.ISO8859-1/articles/ipsec-must/Makefile ./Makefile --- /usr/doc/en_US.ISO8859-1/articles/ipsec-must/Makefile Mon Jun 26 13:10:24 2000 +++ ./Makefile Thu Jul 12 18:55:10 2001 @@ -2,8 +2,6 @@ DOC?= article -DOCFORMAT= html - FORMATS?= html INSTALL_COMPRESSED?=gz diff -u /usr/doc/en_US.ISO8859-1/articles/ipsec-must/article.sgml ./article.sgml --- /usr/doc/en_US.ISO8859-1/articles/ipsec-must/article.sgml Fri Jul 20 18:55:28 2001 +++ ./article.sgml Sat Jul 21 10:39:56 2001 @@ -1,92 +1,138 @@ -<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!-- + The FreeBSD Documentation Project -<html> - <head> - <title>Independent Verification of IPsec Functionality in FreeBSD</title> - </head> - - <body text="#000000" bgcolor="#FFFFFF"> - - <h1>Independent Verification of IPsec Functionality in FreeBSD</h1> - - <p align="center"><i>You installed IPsec and it seems to be working. - How do you know? I describe a method for experimentally verifying - that IPsec is working</i></p> - - <h2>The Problem</h2> - - <p>First, let's assume you have <a href="#Installing IPsec">installed - <i>IPsec</i></a>. How do you know its <a href="#Caveat">working</a>? - Sure, your connection won't work if its misconfigured, and it will work - when you finally get it right. <i>Netstat</i> will list it. But can you - independently confirm it?</p> - - <h2>The Solution</h2> - - <p>First, some crypto-relevent info theory:</p> - - <ol> - <li> - <p>encrypted data is uniformly distributed, i.e., has maximal entropy - per symbol;</p> - </li> - - <li> - <p>raw, uncompressed data is typically redundant, i.e., has - sub-maximal entropy.</p> - </li> - </ol> - - <p>Suppose you could measure the entropy of the data to- and from- your - network interface. Then you could see the difference between unencrypted - data and encrypted data. This would be true even if some of the data - in "encrypted mode" was not encrypted---as the outermost IP header must - be, if the packet is to be routable.</p> - - <h4><a name="MUST"></a>MUST</h4> - - <p>Ueli Maurer's "Universal Statistical Test for Random Bit Generators" - (<a href="http://www.geocities.com/SiliconValley/Code/4704/universal.pdf">MUST</a>) - quickly measures the entropy of a sample. It uses a - compression-like algorithm. <a href="#Maurer's Universal Statistical - Test">The code is given below</a> for a variant which measures successive - (~quarter megabyte) chunks of a file.</p> - - <h4><a NAME="Tcpdump"></a>Tcpdump</h4> - - <p>We also need a way to capture the raw network data. A program called - "<i>tcpdump</i>" lets you do this, if you have enabled the <i>Berkeley - Packet Filter</i> interface in your <a - href="#KERNELNAME">kernel's config file</a>.</p> - - <p>The command</p> - - <blockquote><b>tcpdump</b> <b>-c</b> 4000 <b>-s</b> 10000 <b>-w</b> - <i>dumpfile.bin</i></blockquote> - - <p>will capture 4000 raw packets to <i>dumpfile.bin</i>. Up to 10,000 - bytes per packet will be captured in this example.</p> - - <h2>The Experiment</h2> - - <p>Here's the experiment. Open a window to an IPsec host and another - window to an insecure host.</p> - - <p>Now start <a href="#Tcpdump">capturing packets</a>.</p> - - <p>In the "secure" window, run the unix command "yes", which will stream - the "y" character. After a while, stop this. Switch to the insecure - window, and repeat. After a while, stop.</p> - - <p>Now run <a href="#Maurer's Universal Statistical Test">MUST</a> on the - captured packets. You should see something like the following. - The important thing to note is that the secure connection has 93% (6.7) - of the expected value (7.18), and the "normal" connection has 29% (2.1) - of the expected value.</p> - - - <pre>% tcpdump -c 4000 -s 10000 -w ipsecdemo.bin -% uliscan ipsecdemo.bin + $FreeBSD$ +--> + +<!DOCTYPE article PUBLIC "-//FreeBSD//DTD DocBook V4.1-Based Extension//EN" [ +<!ENTITY % man PUBLIC "-//FreeBSD//ENTITIES DocBook Manual Page Entities//EN"> +%man; +]> + +<article> + <articleinfo> + <title>Independent Verification of IPSec Functionality in FreeBSD</title> + + <author> + <firstname>David</firstname> + <surname>Honig</surname> + + <affiliation> + <address><email>honig@sprynet.com</email></address> + </affiliation> + </author> + + <pubdate>3 May 1999</pubdate> + + <abstract> + <para>You installed IPsec and it seems to be working. How do you + know? I describe a method for experimentally verifying that IPsec is + working.</para> + </abstract> + </articleinfo> + + <sect1> + <title>The Problem</title> + + <para>First, let's assume you have <link linkend="ipsec-install"> + installed <emphasis>IPsec</emphasis></link>. How do you know + it's <link linkend="caveat">working</link>? Sure, your + connection won't work if its misconfigured, and it will work + when you finally get it right. &man.netstat.1; will list it. + But can you independently confirm it?</para> + </sect1> + + <sect1> + <title>The Solution</title> + + <para>First, some crypto-relevant info theory:</para> + + <orderedlist> + <listitem> + <para>encrypted data is uniformly distributed, i.e., has maximal + entropy per symbol;</para> + </listitem> + + <listitem> + <para>raw, uncompressed data is typically redundant, i.e., has + sub-maximal entropy.</para> + </listitem> + </orderedlist> + + <para>Suppose you could measure the entropy of the data to- and + from- your network interface. Then you could see the difference + between unencrypted data and encrypted data. This would be true + even if some of the data in <quote>encrypted mode</quote> was + not encrypted---as the outermost IP header must be, if the + packet is to be routable.</para> + + <sect2 id="MUST"> + <title>MUST</title> + + <para>Ueli Maurer's <quote>Universal Statistical Test for Random + Bit Generators</quote>(<ulink + url="http://www.geocities.com/SiliconValley/Code/4704/universal.pdf">; + <acronym>MUST</acronym></ulink>) quickly measures the entropy + of a sample. It uses a compression-like algorithm. <link + linkend="code">The code is given below</link> for a variant + which measures successive (~quarter megabyte) chunks of a + file.</para> + </sect2> + + <sect2 id="tcpdump"> + <title>Tcpdump</title> + + <para>We also need a way to capture the raw network data. A + program called &man.tcpdump.1; lets you do this, if you have + enabled the <emphasis>Berkeley Packet Filter</emphasis> + interface in your <link linkend="kernel">kernel's config + file</link>.</para> + + <para>The command + + <screen> + <userinput><command>tcpdump</command> -c 4000 -s 10000 -w <replaceable>dumpfile.bin</replaceable></userinput> + </screen> + + will capture 4000 raw packets to + <replaceable>dumpfile.bin</replaceable>. Up to 10,000 bytes per + packet will be captured in this example.</para> + </sect2> + + <sect1> + <title>The Experiment</title> + + <para>Here's the experiment.</para> + + <procedure> + <step> + <para>Open a window to an IPsec host and another window to an + insecure host.</para> + </step> + + <step> + <para>Now start <link linkend="tcpdump">capturing + packets</link>.</para> + </step> + + <step> + <para>In the <quote>secure</quote> window, run the UNIX + command &man.yes.1;, which will stream the <quote>y</quote> + character. After a while, stop this. Switch to the + insecure window, and repeat. After a while, stop.</para> + </step> + + <step> + <para>Now run <link linkend="code">MUST</link> on the + captured packets. You should see something like the + following. The important thing to note is that the secure + connection has 93% (6.7) of the expected value (7.18), and + the <quote>normal</quote> connection has 29% (2.1) of the + expected value.</para> + + <screen> +&prompt.user; <userinput>tcpdump -c 4000 -s 10000 -w <replaceable>ipsecdemo.bin</replaceable></userinput> +&prompt.user; <userinput>uliscan <replaceable>ipsecdemo.bin</replaceable></userinput> Uliscan 21 Dec 98 L=8 256 258560 @@ -98,58 +144,75 @@ 6.4100 --------------------------------------------------- 2.1101 ----------------- 2.0838 ----------------- -2.0983 -----------------</pre> - - <h2><a NAME="Caveat"></a>Caveat</h2> - - <p>This experiment shows that IPsec <i>does</i> seem to be distributing the - payload data <i>uniformly</i>, as encryption should. However, the - experiment described here <i>cannot</i>detect many possible flaws in a - system (none of which do I have any evidence for). These include poor - key generation or exchange, data or keys being visible to others, use of - weak algorithms, kernel subversion, etc. Study the source; know the - code.</p> - - <h2><a NAME="IPsec"></a>IPsec---Definition</h2> - - <p>Internet Protocol security extensions to IPv4; required for IPv6. A - protocol for negotiating encryption and authentication at the IP - (host-to-host) level. SSL secures only one application socket; SSH - secures only a login; PGP secures only a specified file or - message. IPsec encrypts everything between two hosts.</p> - - <h2><a NAME="Installing IPsec"></a>Installing IPsec</h2> - - <p>Most of the modern versions of FreeBSD have IPsec support - in their base source. So you'll probably will need to - include <i>IPSEC</i> option in your kernel config - and, after kernel rebuild and reinstall, configure IPsec - connections using <i>setkey</i> command.</p> - - - <p>A comprehensive guide on running IPsec on FreeBSD is - provided in <a - href="http://www.freebsd.org/handbook/ipsec.html">FreeBSD - Handbook</a>. - - <h2><a NAME="KERNELNAME"></a>usr/src/sys/i386/conf/KERNELNAME</h2> - - <p>This needs to be present in the kernel config file in order to be able - to capture network data with <i>tcpdump</i>. - Be sure to run <i>config</i> after adding this, and rebuild and - reinstall.</p> - - <pre>device bpf -</pre> - - <h2><a name="Maurer's Universal Statistical Test"></a>Maurer's Universal Statistical Test (for block - size=8 bits)</h2> - - <p>You can find the same code at <a - href="http://www.geocities.com/SiliconValley/Code/4704/uliscanc.txt">; - this link</a>.</p> +2.0983 ----------------- +</screen> + </step> + </procedure> + </sect1> + + <sect1 id="caveat"> + <title>Caveat</title> + + <para>This experiment shows that IPsec <emphasis>does</emphasis> + seem to be distributing the payload data + <emphasis>uniformly</emphasis>, as encryption should. However, + the experiment described here <emphasis>cannot</emphasis> + detect many possible flaws in a system (none of which do I have + any evidence for). These include poor key generation or + exchange, data or keys being visible to others, use of weak + algorithms, kernel subversion, etc. Study the source; know the + code.</para> + </sect1> + + <sect1 id="IPsec"> + <title>IPsec---Definition</title> + + <para>Internet Protocol security extensions to IPv4; required for + IPv6. A protocol for negotiating encryption and authentication + at the IP (host-to-host) level. SSL secures only one application + socket; <application>SSH</application> secures only a login; + <application>PGP</application> secures only a specified file or + message. IPsec encrypts everything between two hosts.</para> + </sect1> + + <sect1 id="ipsec-install"> + <title>Installing IPsec</title> + + <para>Most of the modern versions of FreeBSD have IPsec support + in their base source. So you'll probably will need to include + <option>IPSEC</option> option in your kernel config and, after + kernel rebuild and reinstall, configure IPsec connections using + &man.setkey.8; command.</para> + + <para>A comprehensive guide on running IPsec on FreeBSD is + provided in <ulink + url="http://www.freebsd.org/handbook/ipsec.html">FreeBSD + Handbook</ulink>.</para> + </sect1> + + <sect1 id="kernel"> + <title>usr/src/sys/i386/conf/KERNELNAME</title> + + <para>This needs to be present in the kernel config file in order + to be able to capture network data with &man.tcpdump.1;. Be sure + to run &man.config.8; after adding this, and rebuild and + reinstall.</para> + +<programlisting> +device bpf +</programlisting> + </sect1> + + <sect1 id="code"> + <title>Maurer's Universal Statistical Test (for block size=8 + bits)</title> + + <para>You can find the same code at <ulink + url="http://www.geocities.com/SiliconValley/Code/4704/uliscanc.txt">; + this link</ulink>.</para> - <pre><![ CDATA [/* +<programlisting> +/* ULISCAN.c ---blocksize of 8 1 Oct 98 @@ -178,13 +241,13 @@ */ #define L 8 -#define V (1<<L) +#define V (1<<L) #define Q (10*V) #define K (100 *Q) #define MAXSAMP (Q + K) -#include <stdio.h> -#include <math.h> +#include <stdio.h> +#include <math.h> int main(argc, argv) int argc; @@ -202,7 +265,7 @@ printf("Uliscan 21 Dec 98 \nL=%d %d %d \n", L, V, MAXSAMP); - if (argc < 2) { + if (argc < 2) { printf("Usage: Uliscan filename\n"); exit(-1); } else { @@ -216,11 +279,11 @@ exit(-1); } - for (i = 0; i < V; i++) { + for (i = 0; i < V; i++) { table[i] = 0; } - for (i = 0; i < Q; i++) { + for (i = 0; i < Q; i++) { b = fgetc(fptr); table[b] = i; } @@ -236,15 +299,15 @@ iproduct = 1; if (run) - for (i = Q; run && i < Q + K; i++) { + for (i = Q; run && i < Q + K; i++) { j = i; b = fgetc(fptr); - if (b < 0) + if (b < 0) run = 0; if (run) { - if (table[b] > j) + if (table[b] > j) j += K; sum += log((double)(j-table[b])); @@ -259,16 +322,16 @@ sum = (sum/((double)(i - Q))) / log(2.0); printf("%4.4f ", sum); - for (i = 0; i < (int)(sum*8.0 + 0.50); i++) + for (i = 0; i < (int)(sum*8.0 + 0.50); i++) printf("-"); printf("\n"); /* refill initial table */ if (0) { - for (i = 0; i < Q; i++) { + for (i = 0; i < Q; i++) { b = fgetc(fptr); - if (b < 0) { + if (b < 0) { run = 0; } else { table[b] = i; @@ -276,8 +339,7 @@ } } } -}]]></pre> - </body> -</html> - - +} +</programlisting> + </sect1> +</article> -- Alex Kapranoff, Voice: +7(0832)791845 We've lived 201 days in the brand new millenium... 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