1 | <sect1 id="ch06-shadow" xreflabel="Shadow">
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2 | <title>Installing Shadow-&shadow-version;</title>
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3 | <?dbhtml filename="shadow.html" dir="chapter06"?>
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4 |
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5 | <para>The Shadow package contains programs for handling passwords in a secure
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6 | way.</para>
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7 |
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8 | <screen>Estimated build time: &shadow-time;
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9 | Estimated required disk space: &shadow-compsize;</screen>
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10 |
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11 | &aa-shadowpwd-down;
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12 | &aa-shadowpwd-dep;
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13 |
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14 | <sect2><title> </title><para> </para></sect2>
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15 |
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16 | <sect2>
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17 | <title>Installation of Shadow</title>
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18 |
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19 | <para>Shadow hard-wires the path to the <userinput>passwd</userinput> binary
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20 | within the binary itself, but does this the wrong way. If a
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21 | <userinput>passwd</userinput> binary is not present before installing Shadow,
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22 | the package incorrectly assumes it is going to be located at
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23 | <filename>/bin/passwd</filename>, but then installs it in
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24 | <filename>/usr/bin/passwd</filename>. This will lead to errors about not finding
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25 | <filename>/bin/passwd</filename>. To work around this bug, create a dummy
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26 | <filename>passwd</filename> file, so that it gets hard-wired properly:</para>
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27 |
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28 | <screen><userinput>touch /usr/bin/passwd</userinput></screen>
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29 |
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30 | <para>The current Shadow suite has a problem that causes the
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31 | <userinput>newgrp</userinput> command to fail. The following patch (also
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32 | appearing in Shadow's CVS code) fixes this problem:</para>
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33 |
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34 | <screen><userinput>patch -Np1 -i ../&shadow-patch;</userinput></screen>
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35 |
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36 | <para>Now prepare Shadow for compilation:</para>
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37 |
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38 | <screen><userinput>./configure --prefix=/usr --libdir=/usr/lib --enable-shared</userinput></screen>
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39 |
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40 | <para>Compile the package:</para>
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41 |
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42 | <screen><userinput>make</userinput></screen>
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43 |
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44 | <para>And install it:</para>
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45 |
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46 | <screen><userinput>make install</userinput></screen>
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47 |
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48 | <para>Shadow uses two files to configure authentication settings for the
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49 | system. Install these two config files:</para>
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50 |
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51 | <screen><userinput>cp etc/{limits,login.access} /etc</userinput></screen>
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52 |
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53 | <para>We want to change the password method to enable MD5 passwords which are
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54 | theoretically more secure than the default "crypt" method and also allow
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55 | password lengths greater than 8 characters. We also need to change the old
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56 | <filename class="directory">/var/spool/mail</filename> location for user
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57 | mailboxes to the current location at
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58 | <filename class="directory">/var/mail</filename>. We do this by changing the
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59 | relevant configuration file while copying it to its destination:</para>
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60 |
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61 | <screen><userinput>sed -e 's%/var/spool/mail%/var/mail%' \
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62 | -e 's%#MD5_CRYPT_ENAB.no%MD5_CRYPT_ENAB yes%' \
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63 | etc/login.defs.linux > /etc/login.defs</userinput></screen>
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64 |
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65 | <note><para>Be extra careful when typing all of the above. It is probably safer
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66 | to cut-and-paste it rather than try and type it all in.</para></note>
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67 |
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68 | <para>According to the man page of <userinput>vipw</userinput>, a
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69 | <userinput>vigr</userinput> program should exist too. Since the installation
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70 | procedure doesn't create this program, create a symlink manually:</para>
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71 |
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72 | <screen><userinput>ln -s vipw /usr/sbin/vigr</userinput></screen>
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73 |
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74 | <para>As the <filename>/bin/vipw</filename> symlink is redundant (and even
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75 | pointing to a non-existent file), remove it:</para>
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76 |
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77 | <screen><userinput>rm /bin/vipw</userinput></screen>
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78 |
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79 | <para>Now move the <userinput>sg</userinput> program to its proper place:</para>
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80 |
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81 | <screen><userinput>mv /bin/sg /usr/bin</userinput></screen>
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82 |
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83 | <para>And move Shadow's dynamic libraries to a more appropriate location:</para>
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84 |
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85 | <screen><userinput>mv /usr/lib/lib{shadow,misc}.so.0* /lib</userinput></screen>
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86 |
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87 | <para>As some packages expect to find the just-moved libraries in
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88 | <filename>/usr/lib</filename>, create the following symlinks:</para>
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89 |
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90 | <screen><userinput>ln -sf ../../lib/libshadow.so.0 /usr/lib/libshadow.so
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91 | ln -sf ../../lib/libmisc.so.0 /usr/lib/libmisc.so</userinput></screen>
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92 |
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93 | <para>The -D option of the <filename>useradd</filename> program requires this
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94 | directory for it to work properly:</para>
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95 |
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96 | <screen><userinput>mkdir /etc/default</userinput></screen>
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97 |
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98 | <para>Coreutils has already installed a <userinput>groups</userinput> program
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99 | in <filename>/usr/bin</filename>. If you wish, you can remove the one
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100 | installed by Shadow:</para>
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101 |
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102 | <screen><userinput>rm /bin/groups</userinput></screen>
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103 |
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104 | </sect2>
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105 |
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106 | &c6-cf-shadowpwd;
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107 | &c6-cf-password;
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108 |
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109 | &aa-shadowpwd-shortdesc;
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110 | &aa-shadowpwd-desc;
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111 |
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112 | </sect1>
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113 |
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