55 lines
1.4 KiB
Groff
55 lines
1.4 KiB
Groff
.\" mcookie.1 --
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.\" Public Domain 1995 Rickard E. Faith (faith@cs.unc.edu)
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.TH MCOOKIE 1 "25 September 1995" "" "Linux Programmer's Manual"
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.SH NAME
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mcookie \- generate magic cookies for xauth
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.SH SYNOPSIS
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.B mcookie
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.RB [ \-v ]
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.RB [ \-f
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.IR filename ]
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.SH DESCRIPTION
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.B mcookie
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generates a 128-bit random hexadecimal number for use with the X authority
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system. Typical usage:
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.RS
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xauth add :0 . `mcookie`
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.RE
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.PP
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The "random" number generated is actually the output of the MD5 message
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digest fed with various pieces of random information: the current time, the
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process id, the parent process id, the contents of an input file (if
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.B \-f
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is specified), and several bytes of information from the first of the
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following devices which is present:
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.IR /dev/random ,
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.IR /dev/urandom ,
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files in
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.IR /proc ,
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.IR /dev/audio .
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.SH BUGS
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The entropy in the generated 128-bit is probably quite small (and,
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therefore, vulnerable to attack) unless a non-pseudorandom number generator
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is used (e.g.,
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.I /dev/random
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under Linux).
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.PP
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It is assumed that none of the devices opened will block.
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.SH FILES
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.I /dev/random
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.br
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.I /dev/urandom
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.br
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.I /dev/audio
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.br
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.I /proc/stat
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.br
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.I /proc/loadavg
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.SH "SEE ALSO"
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.BR X (1),
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.BR xauth (1),
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.BR md5sum (1)
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.SH AVAILABILITY
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The mcookie command is part of the util-linux-ng package and is available from
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ftp://ftp.kernel.org/pub/linux/utils/util-linux-ng/.
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