1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
|
'\" t
.\" <!-- Copyright 1998 - 2007 Double Precision, Inc. See COPYING for -->
.\" <!-- distribution information. -->
.\" Title: userdbpw
.\" Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\" Date: 10/28/2020
.\" Manual: Double Precision, Inc.
.\" Source: Double Precision, Inc.
.\" Language: English
.\"
.TH "USERDBPW" "8" "10/28/2020" "Double Precision, Inc." "Double Precision, Inc."
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
userdbpw \- create an encrypted password
.SH "SYNOPSIS"
.HP \w'\fBuserdbpw\fR\fBuserdb\fR\ 'u
\fBuserdbpw\fR [[\-md5] | [\-hmac\-md5] | [\-hmac\-sha1]] |\fBuserdb\fR {\fIname\fR} set {\fIfield\fR}
.SH "DESCRIPTION"
.PP
\fBuserdbpw\fR
enables secure entry of encrypted passwords into
@userdb@\&.
.PP
\fBuserdbpw\fR
reads a single line of text on standard input, encrypts it, and prints the encrypted result to standard output\&.
.PP
If standard input is attached to a terminal device,
\fBuserdbpw\fR
explicitly issues a "Password: " prompt on standard error, and turns off echo while the password is entered\&.
.PP
The
\fB\-md5\fR
option is available on systems that use MD5\-hashed passwords (such as systems that use the current version of the PAM library for authenticating, with MD5 passwords enabled)\&. This option creates an MD5 password hash, instead of using the traditional
\fBcrypt()\fR
function\&.
.PP
\fB\-hmac\-md5\fR
and
\fB\-hmac\-sha1\fR
options are available only if the userdb library is installed by an application that uses a challenge/response authentication mechanism\&.
\fB\-hmac\-md5\fR
creates an intermediate HMAC context using the MD5 hash function\&.
\fB\-hmac\-sha1\fR
uses the SHA1 hash function instead\&. Whether either HMAC function is actually available depends on the actual application that installs the
\fBuserdb\fR
library\&.
.PP
Note that even though the result of HMAC hashing looks like an encrypted password, it\*(Aqs really not\&. HMAC\-based challenge/response authentication mechanisms require the cleartext password to be available as cleartext\&. Computing an intermediate HMAC context does scramble the cleartext password, however if its compromised, it WILL be possible for an attacker to succesfully authenticate\&. Therefore, applications that use challenge/response authentication will store intermediate HMAC contexts in the "pw" fields in the userdb database, which will be compiled into the
userdbshadow\&.dat
database, which has group and world permissions turned off\&. The userdb library also requires that the cleartext userdb source for the
userdb\&.dat
and
userdbshadow\&.dat
databases is also stored with the group and world permissions turned off\&.
.PP
\fBuserdbpw\fR
is usually used together in a pipe with
\fBuserdb\fR, which reads from standard input\&. For example:
.sp
.if n \{\
.RS 4
.\}
.nf
\fBuserdbpw \-md5 | userdb users/john set systempw\fR
.fi
.if n \{\
.RE
.\}
.PP
or:
.sp
.if n \{\
.RS 4
.\}
.nf
\fBuserdbpw \-hmac\-md5 | userdb users/john set hmac\-md5pw\fR
.fi
.if n \{\
.RE
.\}
.PP
These commands set the
\fBsystempw\fR
field in the record for the user
\fBjohn\fR
in
@userdb@/users
file, and the
\fBhmac\-md5pw\fR
field\&. Don\*(Aqt forget to run
\fBmakeuserdb\fR
for the change to take effect\&.
.PP
The following command does the same thing:
.sp
.if n \{\
.RS 4
.\}
.nf
\fBuserdb users/john set systempw=\fR\fB\fBSECRETPASSWORD\fR\fR
.fi
.if n \{\
.RE
.\}
.PP
However, this command passes the secret password as an argument to the
\fBuserdb\fR
command, which can be viewed by anyone who happens to run
\fBps\fR(1)
at the same time\&. Using
\fBuserdbpw\fR
allows the secret password to be specified in a way that cannot be easily viewed by
\fBps\fR(1)\&.
.SH "SEE ALSO"
.PP
\m[blue]\fB\fBuserdb\fR(8)\fR\m[]\&\s-2\u[1]\d\s+2,
\m[blue]\fB\fBmakeuserdb\fR(8)\fR\m[]\&\s-2\u[2]\d\s+2
.SH "NOTES"
.IP " 1." 4
\fBuserdb\fR(8)
.RS 4
\%[set $man.base.url.for.relative.links]/userdb.html
.RE
.IP " 2." 4
\fBmakeuserdb\fR(8)
.RS 4
\%[set $man.base.url.for.relative.links]/makeuserdb.html
.RE
|
