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MacOS 8.1

Win98

DOS

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+--------+-------------------------+-------------------------+--------+--------+
|00000000| 54 6f 3a 20 6c 69 6e 75 | 78 2d 73 65 63 75 72 69 |To: linu|x-securi|
|00000010| 74 79 40 74 61 72 73 69 | 65 72 2e 63 76 2e 6e 72 |ty@tarsi|er.cv.nr|
|00000020| 61 6f 2e 65 64 75 2c 20 | 62 65 73 74 2d 6f 66 2d |ao.edu, |best-of-|
|00000030| 73 65 63 75 72 69 74 79 | 40 73 75 62 75 72 62 69 |security|@suburbi|
|00000040| 61 2e 6e 65 74 0a 44 61 | 74 65 3a 20 54 75 65 2c |a.net.Da|te: Tue,|
|00000050| 20 32 31 20 4d 61 79 20 | 31 39 39 36 20 31 33 3a | 21 May |1996 13:|
|00000060| 31 30 3a 33 36 20 2d 30 | 34 30 30 20 28 45 44 54 |10:36 -0|400 (EDT|
|00000070| 29 0a 58 2d 4d 61 69 6c | 65 72 3a 20 45 4c 4d 20 |).X-Mail|er: ELM |
|00000080| 5b 76 65 72 73 69 6f 6e | 20 32 2e 34 20 50 4c 32 |[version| 2.4 PL2|
|00000090| 34 5d 0a 4d 49 4d 45 2d | 56 65 72 73 69 6f 6e 3a |4].MIME-|Version:|
|000000a0| 20 31 2e 30 0a 43 6f 6e | 74 65 6e 74 2d 54 79 70 | 1.0.Con|tent-Typ|
|000000b0| 65 3a 20 74 65 78 74 2f | 70 6c 61 69 6e 3b 20 63 |e: text/|plain; c|
|000000c0| 68 61 72 73 65 74 3d 55 | 53 2d 41 53 43 49 49 0a |harset=U|S-ASCII.|
|000000d0| 43 6f 6e 74 65 6e 74 2d | 54 72 61 6e 73 66 65 72 |Content-|Transfer|
|000000e0| 2d 45 6e 63 6f 64 69 6e | 67 3a 20 37 62 69 74 0a |-Encodin|g: 7bit.|
|000000f0| 52 65 73 65 6e 74 2d 4d | 65 73 73 61 67 65 2d 49 |Resent-M|essage-I|
|00000100| 44 3a 20 3c 22 78 37 79 | 37 44 32 2e 30 2e 78 73 |D: <"x7y|7D2.0.xs|
|00000110| 34 2e 6d 61 56 65 6e 22 | 40 73 75 62 75 72 62 69 |4.maVen"|@suburbi|
|00000120| 61 3e 0a 52 65 73 65 6e | 74 2d 46 72 6f 6d 3a 20 |a>.Resen|t-From: |
|00000130| 62 65 73 74 2d 6f 66 2d | 73 65 63 75 72 69 74 79 |best-of-|security|
|00000140| 40 73 75 62 75 72 62 69 | 61 2e 6e 65 74 0a 58 2d |@suburbi|a.net.X-|
|00000150| 4d 61 69 6c 69 6e 67 2d | 4c 69 73 74 3a 20 3c 62 |Mailing-|List: <b|
|00000160| 65 73 74 2d 6f 66 2d 73 | 65 63 75 72 69 74 79 40 |est-of-s|ecurity@|
|00000170| 73 75 62 75 72 62 69 61 | 2e 6e 65 74 3e 20 61 72 |suburbia|.net> ar|
|00000180| 63 68 69 76 65 2f 6c 61 | 74 65 73 74 2f 35 37 0a |chive/la|test/57.|
|00000190| 58 2d 4c 6f 6f 70 3a 20 | 62 65 73 74 2d 6f 66 2d |X-Loop: |best-of-|
|000001a0| 73 65 63 75 72 69 74 79 | 40 73 75 62 75 72 62 69 |security|@suburbi|
|000001b0| 61 2e 6e 65 74 0a 50 72 | 65 63 65 64 65 6e 63 65 |a.net.Pr|ecedence|
|000001c0| 3a 20 6c 69 73 74 0a 52 | 65 73 65 6e 74 2d 53 65 |: list.R|esent-Se|
|000001d0| 6e 64 65 72 3a 20 62 65 | 73 74 2d 6f 66 2d 73 65 |nder: be|st-of-se|
|000001e0| 63 75 72 69 74 79 2d 72 | 65 71 75 65 73 74 40 73 |curity-r|equest@s|
|000001f0| 75 62 75 72 62 69 61 2e | 6e 65 74 0a 53 75 62 6a |uburbia.|net.Subj|
|00000200| 65 63 74 3a 20 42 6f 53 | 3a 20 54 68 69 6e 67 73 |ect: BoS|: Things|
|00000210| 20 4e 4f 54 20 74 6f 20 | 70 75 74 20 69 6e 20 72 | NOT to |put in r|
|00000220| 6f 6f 74 27 73 20 63 72 | 6f 6e 74 61 62 0a 0a 53 |oot's cr|ontab..S|
|00000230| 69 67 68 2e 20 20 48 65 | 72 65 20 61 72 65 20 73 |igh.  He|re are s|
|00000240| 65 76 65 72 61 6c 20 74 | 68 69 6e 67 73 20 49 27 |everal t|hings I'|
|00000250| 76 65 20 6a 75 73 74 20 | 72 65 6d 6f 76 65 64 20 |ve just |removed |
|00000260| 66 72 6f 6d 20 2f 65 74 | 63 2f 63 72 6f 6e 74 61 |from /et|c/cronta|
|00000270| 62 20 6f 6e 0a 65 76 65 | 72 79 20 52 65 64 48 61 |b on.eve|ry RedHa|
|00000280| 74 20 4c 69 6e 75 78 20 | 73 79 73 74 65 6d 20 49 |t Linux |system I|
|00000290| 20 63 61 6e 20 67 65 74 | 20 6d 79 20 68 61 6e 64 | can get| my hand|
|000002a0| 73 20 6f 6e 2e 20 20 54 | 68 65 79 20 63 6f 6e 74 |s on.  T|hey cont|
|000002b0| 61 69 6e 20 73 65 63 75 | 72 69 74 79 0a 68 6f 6c |ain secu|rity.hol|
|000002c0| 65 73 20 72 65 6c 61 74 | 65 64 20 74 6f 20 74 68 |es relat|ed to th|
|000002d0| 65 20 75 73 65 20 6f 66 | 20 27 66 69 6e 64 27 20 |e use of| 'find' |
|000002e0| 61 6e 64 20 27 72 6d 27 | 20 74 6f 20 65 78 70 69 |and 'rm'| to expi|
|000002f0| 72 65 20 6f 6c 64 20 66 | 69 6c 65 73 20 69 6e 20 |re old f|iles in |
|00000300| 2f 74 6d 70 0a 61 6e 64 | 20 6f 74 68 65 72 20 70 |/tmp.and| other p|
|00000310| 6c 61 63 65 73 2e 0a 0a | 49 74 20 73 65 65 6d 73 |laces...|It seems|
|00000320| 20 74 68 61 74 20 61 77 | 61 72 65 6e 65 73 73 20 | that aw|areness |
|00000330| 6f 66 20 74 68 69 73 20 | 74 79 70 65 20 6f 66 20 |of this |type of |
|00000340| 73 65 63 75 72 69 74 79 | 20 70 72 6f 62 6c 65 6d |security| problem|
|00000350| 20 69 73 20 72 61 74 68 | 65 72 20 6c 6f 77 2c 0a | is rath|er low,.|
|00000360| 73 6f 20 49 27 6c 6c 20 | 65 78 70 6c 61 69 6e 20 |so I'll |explain |
|00000370| 74 68 65 20 63 6c 61 73 | 73 20 6f 66 20 70 72 6f |the clas|s of pro|
|00000380| 62 6c 65 6d 20 61 6e 64 | 20 68 6f 77 20 74 6f 20 |blem and| how to |
|00000390| 66 69 78 20 69 74 2e 0a | 0a 3e 46 72 6f 6d 20 52 |fix it..|.>From R|
|000003a0| 65 64 68 61 74 27 73 20 | 2f 65 74 63 2f 63 72 6f |edhat's |/etc/cro|
|000003b0| 6e 74 61 62 20 66 69 6c | 65 3a 0a 3e 23 20 52 65 |ntab fil|e:.># Re|
|000003c0| 6d 6f 76 65 20 2f 76 61 | 72 2f 74 6d 70 20 66 69 |move /va|r/tmp fi|
|000003d0| 6c 65 73 20 6e 6f 74 20 | 61 63 63 65 73 73 65 64 |les not |accessed|
|000003e0| 20 69 6e 20 31 30 20 64 | 61 79 73 0a 3e 34 33 20 | in 10 d|ays.>43 |
|000003f0| 30 32 20 2a 20 2a 20 2a | 20 72 6f 6f 74 20 66 69 |02 * * *| root fi|
|00000400| 6e 64 20 2f 76 61 72 2f | 74 6d 70 2f 2a 20 2d 61 |nd /var/|tmp/* -a|
|00000410| 74 69 6d 65 20 2b 33 20 | 2d 65 78 65 63 20 72 6d |time +3 |-exec rm|
|00000420| 20 2d 66 20 7b 7d 20 5c | 3b 20 32 3e 20 2f 64 65 | -f {} \|; 2> /de|
|00000430| 76 2f 6e 75 6c 6c 0a 3e | 0a 3e 23 20 52 65 6d 6f |v/null.>|.># Remo|
|00000440| 76 65 20 2f 74 6d 70 20 | 66 69 6c 65 73 20 6e 6f |ve /tmp |files no|
|00000450| 74 20 61 63 63 65 73 73 | 65 64 20 69 6e 20 31 30 |t access|ed in 10|
|00000460| 20 64 61 79 73 0a 3e 23 | 20 49 20 63 6f 6d 6d 65 | days.>#| I comme|
|00000470| 6e 74 65 64 20 6f 75 74 | 20 74 68 69 73 20 6c 69 |nted out| this li|
|00000480| 6e 65 20 62 65 63 61 75 | 73 65 20 49 20 74 65 6e |ne becau|se I ten|
|00000490| 64 20 74 6f 20 22 73 74 | 6f 72 65 22 20 73 74 75 |d to "st|ore" stu|
|000004a0| 66 66 20 69 6e 20 2f 74 | 6d 70 0a 3e 23 20 34 31 |ff in /t|mp.># 41|
|000004b0| 20 30 32 20 2a 20 2a 20 | 2a 20 72 6f 6f 74 20 66 | 02 * * |* root f|
|000004c0| 69 6e 64 20 2f 74 6d 70 | 2f 2a 20 2d 61 74 69 6d |ind /tmp|/* -atim|
|000004d0| 65 20 2b 31 30 20 2d 65 | 78 65 63 20 72 6d 20 2d |e +10 -e|xec rm -|
|000004e0| 66 20 7b 7d 20 5c 3b 20 | 32 3e 20 2f 64 65 76 2f |f {} \; |2> /dev/|
|000004f0| 6e 75 6c 6c 0a 3e 0a 3e | 23 20 52 65 6d 6f 76 65 |null.>.>|# Remove|
|00000500| 20 66 6f 72 6d 61 74 74 | 65 64 20 6d 61 6e 20 70 | formatt|ed man p|
|00000510| 61 67 65 73 20 6e 6f 74 | 20 61 63 63 65 73 73 65 |ages not| accesse|
|00000520| 64 20 69 6e 20 31 30 20 | 64 61 79 73 0a 3e 33 39 |d in 10 |days.>39|
|00000530| 20 30 32 20 2a 20 2a 20 | 2a 20 72 6f 6f 74 20 66 | 02 * * |* root f|
|00000540| 69 6e 64 20 2f 76 61 72 | 2f 63 61 74 6d 61 6e 2f |ind /var|/catman/|
|00000550| 63 61 74 3f 2f 2a 20 2d | 61 74 69 6d 65 20 2b 31 |cat?/* -|atime +1|
|00000560| 30 20 2d 65 78 65 63 20 | 72 6d 20 2d 66 20 7b 7d |0 -exec |rm -f {}|
|00000570| 20 5c 3b 20 32 3e 20 2f | 64 65 76 2f 6e 75 6c 6c | \; 2> /|dev/null|
|00000580| 0a 3e 0a 3e 23 20 52 65 | 6d 6f 76 65 20 61 6e 64 |.>.># Re|move and|
|00000590| 20 54 65 58 20 66 6f 6e | 74 73 20 6e 6f 74 20 75 | TeX fon|ts not u|
|000005a0| 73 65 64 20 69 6e 20 31 | 30 20 64 61 79 73 0a 3e |sed in 1|0 days.>|
|000005b0| 33 35 20 30 32 20 2a 20 | 2a 20 2a 20 72 6f 6f 74 |35 02 * |* * root|
|000005c0| 20 66 69 6e 64 20 2f 76 | 61 72 2f 6c 69 62 2f 74 | find /v|ar/lib/t|
|000005d0| 65 78 6d 66 2f 2a 20 2d | 74 79 70 65 20 66 20 2d |exmf/* -|type f -|
|000005e0| 61 74 69 6d 65 20 2b 31 | 30 20 2d 65 78 65 63 20 |atime +1|0 -exec |
|000005f0| 72 6d 20 2d 66 20 7b 7d | 20 5c 3b 20 32 3e 20 2f |rm -f {}| \; 2> /|
|00000600| 64 65 76 2f 6e 75 6c 6c | 0a 0a 46 6f 6c 6b 73 2c |dev/null|..Folks,|
|00000610| 20 64 6f 20 4e 4f 54 20 | 75 73 65 20 27 66 69 6e | do NOT |use 'fin|
|00000620| 64 27 20 6f 6e 20 61 20 | 70 75 62 6c 69 63 20 64 |d' on a |public d|
|00000630| 69 72 65 63 74 6f 72 79 | 20 77 69 74 68 20 27 2d |irectory| with '-|
|00000640| 65 78 65 63 20 72 6d 20 | 2d 66 27 20 61 73 20 72 |exec rm |-f' as r|
|00000650| 6f 6f 74 2e 0a 50 65 72 | 69 6f 64 2e 20 20 45 76 |oot..Per|iod.  Ev|
|00000660| 65 72 2e 20 20 44 65 6c | 65 74 65 20 69 74 20 66 |er.  Del|ete it f|
|00000670| 72 6f 6d 20 79 6f 75 72 | 20 63 72 6f 6e 74 61 62 |rom your| crontab|
|00000680| 20 2a 6e 6f 77 2a 20 61 | 6e 64 20 66 69 6e 69 73 | *now* a|nd finis|
|00000690| 68 20 72 65 61 64 69 6e | 67 20 74 68 65 0a 72 65 |h readin|g the.re|
|000006a0| 73 74 20 6f 66 20 74 68 | 69 73 20 6d 65 73 73 61 |st of th|is messa|
|000006b0| 67 65 20 6c 61 74 65 72 | 2e 0a 0a 2a 20 50 52 4f |ge later|...* PRO|
|000006c0| 42 4c 45 4d 20 44 49 53 | 43 55 53 53 49 4f 4e 20 |BLEM DIS|CUSSION |
|000006d0| 41 4e 44 20 45 58 50 4c | 4f 49 54 41 54 49 4f 4e |AND EXPL|OITATION|
|000006e0| 0a 0a 54 68 65 20 69 6d | 6d 65 64 69 61 74 65 20 |..The im|mediate |
|000006f0| 73 65 63 75 72 69 74 79 | 20 70 72 6f 62 6c 65 6d |security| problem|
|00000700| 20 69 73 20 74 68 61 74 | 20 27 72 6d 27 20 64 6f | is that| 'rm' do|
|00000710| 65 73 6e 27 74 20 63 68 | 65 63 6b 20 74 68 61 74 |esn't ch|eck that|
|00000720| 0a 63 6f 6d 70 6f 6e 65 | 6e 74 73 20 6f 66 20 74 |.compone|nts of t|
|00000730| 68 65 20 64 69 72 65 63 | 74 6f 72 79 20 6e 61 6d |he direc|tory nam|
|00000740| 65 20 61 72 65 20 6e 6f | 74 20 73 79 6d 6c 69 6e |e are no|t symlin|
|00000750| 6b 73 2e 20 20 54 68 69 | 73 20 6d 65 61 6e 73 20 |ks.  Thi|s means |
|00000760| 74 68 61 74 20 79 6f 75 | 0a 63 61 6e 20 64 65 6c |that you|.can del|
|00000770| 65 74 65 20 61 6e 79 20 | 66 69 6c 65 20 6f 6e 20 |ete any |file on |
|00000780| 74 68 65 20 73 79 73 74 | 65 6d 3b 20 69 6e 64 65 |the syst|em; inde|
|00000790| 65 64 2c 20 77 69 74 68 | 20 61 20 6c 69 74 74 6c |ed, with| a littl|
|000007a0| 65 20 77 6f 72 6b 20 79 | 6f 75 20 63 61 6e 0a 64 |e work y|ou can.d|
|000007b0| 65 6c 65 74 65 20 2a 65 | 76 65 72 79 2a 20 66 69 |elete *e|very* fi|
|000007c0| 6c 65 20 6f 6e 20 74 68 | 65 20 73 79 73 74 65 6d |le on th|e system|
|000007d0| 2c 20 70 72 6f 76 69 64 | 65 64 20 74 68 61 74 20 |, provid|ed that |
|000007e0| 79 6f 75 20 63 61 6e 20 | 64 65 74 65 72 6d 69 6e |you can |determin|
|000007f0| 65 20 74 68 65 0a 66 69 | 6c 65 20 6e 61 6d 65 73 |e the.fi|le names|
|00000800| 20 28 74 68 6f 75 67 68 | 20 79 6f 75 20 6d 69 67 | (though| you mig|
|00000810| 68 74 20 62 65 20 6c 69 | 6d 69 74 65 64 20 74 6f |ht be li|mited to|
|00000820| 20 64 65 6c 65 74 69 6e | 67 20 66 69 6c 65 73 20 | deletin|g files |
|00000830| 6d 6f 72 65 20 74 68 61 | 6e 20 74 65 6e 0a 64 61 |more tha|n ten.da|
|00000840| 79 73 20 6f 6c 64 29 2e | 0a 0a 46 69 72 73 74 2c |ys old).|..First,|
|00000850| 20 63 72 65 61 74 65 20 | 74 68 65 20 64 69 72 65 | create |the dire|
|00000860| 63 74 6f 72 69 65 73 20 | 61 6e 64 20 66 69 6c 65 |ctories |and file|
|00000870| 3a 0a 0a 09 2f 74 6d 70 | 2f 68 61 63 6b 65 72 2d |:.../tmp|/hacker-|
|00000880| 66 65 73 74 2f 73 6f 6d | 65 2f 61 72 62 69 74 72 |fest/som|e/arbitr|
|00000890| 61 72 79 2f 73 65 74 2f | 6f 66 2f 70 61 74 68 2f |ary/set/|of/path/|
|000008a0| 6e 61 6d 65 73 2f 65 74 | 63 2f 70 61 73 73 77 64 |names/et|c/passwd|
|000008b0| 0a 0a 77 68 65 72 65 20 | 61 6c 6c 20 62 75 74 20 |..where |all but |
|000008c0| 74 68 65 20 6c 61 73 74 | 20 63 6f 6d 70 6f 6e 65 |the last| compone|
|000008d0| 6e 74 20 69 73 20 61 20 | 64 69 72 65 63 74 6f 72 |nt is a |director|
|000008e0| 79 2e 20 20 42 65 20 72 | 65 61 64 79 20 74 6f 20 |y.  Be r|eady to |
|000008f0| 0a 72 65 70 6c 61 63 65 | 20 27 65 74 63 27 20 77 |.replace| 'etc' w|
|00000900| 69 74 68 20 61 20 73 79 | 6d 6c 69 6e 6b 20 74 6f |ith a sy|mlink to|
|00000910| 20 27 2f 65 74 63 27 2c | 20 73 6f 20 74 68 61 74 | '/etc',| so that|
|00000920| 3a 0a 09 0a 09 2f 74 6d | 70 2f 68 61 63 6b 65 72 |:..../tm|p/hacker|
|00000930| 2d 66 65 73 74 2f 73 6f | 6d 65 2f 61 72 62 69 74 |-fest/so|me/arbit|
|00000940| 72 61 72 79 2f 73 65 74 | 2f 6f 66 2f 70 61 74 68 |rary/set|/of/path|
|00000950| 2f 6e 61 6d 65 73 2f 65 | 74 63 20 2d 3e 20 2f 65 |/names/e|tc -> /e|
|00000960| 74 63 0a 0a 69 2e 65 2e | 20 74 68 65 20 70 61 74 |tc..i.e.| the pat|
|00000970| 68 20 63 6f 6d 70 6f 6e | 65 6e 74 73 20 6f 66 20 |h compon|ents of |
|00000980| 74 68 65 20 66 69 6c 65 | 20 6e 61 6d 65 20 77 69 |the file| name wi|
|00000990| 6c 6c 20 70 6f 69 6e 74 | 20 74 6f 20 61 20 66 69 |ll point| to a fi|
|000009a0| 6c 65 20 6e 61 6d 65 64 | 0a 27 70 61 73 73 77 64 |le named|.'passwd|
|000009b0| 27 20 69 6e 20 61 20 64 | 69 66 66 65 72 65 6e 74 |' in a d|ifferent|
|000009c0| 20 64 69 72 65 63 74 6f | 72 79 2e 0a 0a 49 66 20 | directo|ry...If |
|000009d0| 74 68 65 20 72 65 70 6c | 61 63 65 6d 65 6e 74 20 |the repl|acement |
|000009e0| 6f 70 65 72 61 74 69 6f | 6e 20 6f 63 63 75 72 73 |operatio|n occurs|
|000009f0| 20 62 65 74 77 65 65 6e | 20 77 68 65 6e 20 27 66 | between| when 'f|
|00000a00| 69 6e 64 27 20 73 65 74 | 73 20 7b 7d 20 74 6f 0a |ind' set|s {} to.|
|00000a10| 22 2f 74 6d 70 2f 68 61 | 63 6b 65 72 2e 2e 2e 65 |"/tmp/ha|cker...e|
|00000a20| 74 63 2f 70 61 73 73 77 | 64 22 20 61 6e 64 20 77 |tc/passw|d" and w|
|00000a30| 68 65 6e 20 27 72 6d 27 | 20 63 61 6c 6c 73 20 75 |hen 'rm'| calls u|
|00000a40| 6e 6c 69 6e 6b 20 6f 6e | 0a 22 2f 74 6d 70 2f 68 |nlink on|."/tmp/h|
|00000a50| 61 63 6b 65 72 2e 2e 2e | 65 74 63 2f 70 61 73 73 |acker...|etc/pass|
|00000a60| 77 64 22 2c 20 74 68 65 | 6e 20 72 6d 20 77 69 6c |wd", the|n rm wil|
|00000a70| 6c 20 69 6e 20 66 61 63 | 74 20 64 65 6c 65 74 65 |l in fac|t delete|
|00000a80| 20 27 2f 65 74 63 2f 70 | 61 73 73 77 64 27 2c 0a | '/etc/p|asswd',.|
|00000a90| 61 6e 64 20 6e 6f 74 20 | 61 20 66 69 6c 65 20 69 |and not |a file i|
|00000aa0| 6e 20 2f 74 6d 70 2e 20 | 20 44 65 6c 65 74 69 6e |n /tmp. | Deletin|
|00000ab0| 67 20 6f 74 68 65 72 20 | 66 69 6c 65 73 20 69 73 |g other |files is|
|00000ac0| 20 6c 65 66 74 20 61 73 | 20 61 6e 20 65 78 65 72 | left as| an exer|
|00000ad0| 63 69 73 65 2e 0a 0a 54 | 68 65 20 72 61 63 65 20 |cise...T|he race |
|00000ae0| 63 6f 6e 64 69 74 69 6f | 6e 20 69 73 20 72 65 61 |conditio|n is rea|
|00000af0| 6c 6c 79 20 65 61 73 79 | 20 74 6f 20 77 69 6e 2e |lly easy| to win.|
|00000b00| 20 20 43 72 65 61 74 65 | 20 61 20 64 69 72 65 63 |  Create| a direc|
|00000b10| 74 6f 72 79 20 77 69 74 | 68 20 34 30 30 0a 70 61 |tory wit|h 400.pa|
|00000b20| 74 68 20 63 6f 6d 70 6f | 6e 65 6e 74 73 2c 20 6c |th compo|nents, l|
|00000b30| 69 6b 65 20 74 68 69 73 | 3a 0a 0a 09 2f 74 6d 70 |ike this|:.../tmp|
|00000b40| 2f 68 61 63 6b 65 72 2d | 66 65 73 74 2f 61 2f 61 |/hacker-|fest/a/a|
|00000b50| 2f 61 2f 61 2f 61 2f 61 | 2f 61 2e 2e 2e 2f 61 2f |/a/a/a/a|/a.../a/|
|00000b60| 61 2f 61 2f 65 74 63 2f | 70 61 73 73 77 64 09 28 |a/a/etc/|passwd.(|
|00000b70| 31 29 0a 0a 54 68 65 6e | 20 61 72 72 61 6e 67 65 |1)..Then| arrange|
|00000b80| 20 66 6f 72 20 65 61 63 | 68 20 6f 66 20 74 68 65 | for eac|h of the|
|00000b90| 20 27 61 27 20 63 6f 6d | 70 6f 6e 65 6e 74 73 20 | 'a' com|ponents |
|00000ba0| 74 6f 20 62 65 20 61 20 | 73 79 6d 6c 69 6e 6b 20 |to be a |symlink |
|00000bb0| 74 6f 20 61 0a 64 69 72 | 65 63 74 6f 72 79 20 73 |to a.dir|ectory s|
|00000bc0| 6f 6d 65 77 68 65 72 65 | 20 6e 65 61 72 20 74 68 |omewhere| near th|
|00000bd0| 65 20 62 6f 74 74 6f 6d | 20 6f 66 20 61 20 73 69 |e bottom| of a si|
|00000be0| 6d 69 6c 61 72 20 74 72 | 65 65 2e 20 20 46 6f 72 |milar tr|ee.  For|
|00000bf0| 20 65 78 61 6d 70 6c 65 | 2c 0a 0a 09 2f 74 6d 70 | example|,.../tmp|
|00000c00| 2f 68 61 63 6b 65 72 2d | 66 65 73 74 2f 61 0a 0a |/hacker-|fest/a..|
|00000c10| 63 6f 75 6c 64 20 62 65 | 20 61 20 73 79 6d 6c 69 |could be| a symli|
|00000c20| 6e 6b 20 74 6f 0a 0a 09 | 2f 74 6d 70 2f 68 61 63 |nk to...|/tmp/hac|
|00000c30| 6b 65 72 2d 66 65 73 74 | 2f 62 2f 62 2f 62 2f 62 |ker-fest|/b/b/b/b|
|00000c40| 2f 62 2f 62 2f 62 2f 62 | 2f 62 2f 2e 2e 2e 2f 62 |/b/b/b/b|/b/.../b|
|00000c50| 2f 62 2f 62 2f 62 2f 62 | 2f 62 2f 61 0a 0a 77 68 |/b/b/b/b|/b/a..wh|
|00000c60| 69 63 68 20 63 6f 75 6c | 64 20 62 65 20 61 20 73 |ich coul|d be a s|
|00000c70| 79 6d 6c 69 6e 6b 20 74 | 6f 0a 0a 09 2f 74 6d 70 |ymlink t|o.../tmp|
|00000c80| 2f 68 61 63 6b 65 72 2d | 66 65 73 74 2f 63 2f 63 |/hacker-|fest/c/c|
|00000c90| 2f 63 2f 63 2f 63 2f 63 | 2f 2e 2e 2e 2f 63 2f 63 |/c/c/c/c|/.../c/c|
|00000ca0| 2f 63 2f 63 2f 63 2f 63 | 2f 63 0a 0a 61 6e 64 20 |/c/c/c/c|/c..and |
|00000cb0| 73 6f 20 6f 6e 2e 20 20 | 49 6e 20 66 61 63 74 2c |so on.  |In fact,|
|00000cc0| 20 2a 65 61 63 68 2a 20 | 70 61 74 68 20 63 6f 6d | *each* |path com|
|00000cd0| 70 6f 6e 65 6e 74 20 63 | 61 6e 20 62 65 20 61 20 |ponent c|an be a |
|00000ce0| 73 79 6d 6c 69 6e 6b 20 | 75 70 20 74 6f 20 61 62 |symlink |up to ab|
|00000cf0| 6f 75 74 0a 38 20 6c 65 | 76 65 6c 73 20 6f 72 20 |out.8 le|vels or |
|00000d00| 73 6f 2e 20 20 41 6e 79 | 20 6f 70 65 72 61 74 69 |so.  Any| operati|
|00000d10| 6f 6e 20 73 75 63 68 20 | 61 73 20 73 74 61 74 28 |on such |as stat(|
|00000d20| 29 2c 20 6f 70 65 6e 28 | 29 2c 20 6c 73 74 61 74 |), open(|), lstat|
|00000d30| 28 29 2c 20 65 74 63 2e | 0a 6f 6e 20 6f 6e 65 20 |(), etc.|.on one |
|00000d40| 6f 66 20 74 68 65 73 65 | 20 70 61 74 68 6e 61 6d |of these| pathnam|
|00000d50| 65 73 20 77 69 6c 6c 20 | 63 61 75 73 65 20 74 68 |es will |cause th|
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|000028f0| 61 63 6b 20 74 68 69 6e | 67 73 20 75 70 20 61 20 |ack thin|gs up a |
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|00002910| 72 74 69 63 6c 65 20 64 | 61 74 61 62 61 73 65 73 |rticle d|atabases|
|00002920| 20 77 68 65 6e 20 61 72 | 74 69 63 6c 65 0a 66 69 | when ar|ticle.fi|
|00002930| 6c 65 73 20 64 69 73 61 | 70 70 65 61 72 2e 0a 0a |les disa|ppear...|
|00002940| 2d 2d 20 0a 5a 79 67 6f | 20 42 6c 61 78 65 6c 6c |-- .Zygo| Blaxell|
|00002950| 2e 20 20 46 6f 72 6d 65 | 72 20 55 6e 69 78 2f 73 |.  Forme|r Unix/s|
|00002960| 6f 66 74 2f 68 61 72 64 | 77 61 72 65 20 67 75 72 |oft/hard|ware gur|
|00002970| 75 2c 20 55 20 6f 66 20 | 57 61 74 65 72 6c 6f 6f |u, U of |Waterloo|
|00002980| 20 43 6f 6d 70 75 74 65 | 72 20 53 63 69 65 6e 63 | Compute|r Scienc|
|00002990| 65 20 0a 43 6c 75 62 2e | 20 20 43 75 72 72 65 6e |e .Club.|  Curren|
|000029a0| 74 20 73 79 73 61 64 6d | 69 6e 20 66 6f 72 20 4d |t sysadm|in for M|
|000029b0| 79 72 75 73 20 44 65 73 | 69 67 6e 2c 20 49 6e 63 |yrus Des|ign, Inc|
|000029c0| 2e 20 20 31 30 74 68 20 | 70 6c 61 63 65 2c 20 41 |.  10th |place, A|
|000029d0| 43 4d 20 49 6e 74 6c 20 | 43 6f 6c 6c 65 67 69 61 |CM Intl |Collegia|
|000029e0| 74 65 0a 50 72 6f 67 72 | 61 6d 6d 69 6e 67 20 43 |te.Progr|amming C|
|000029f0| 6f 6e 74 65 73 74 20 46 | 69 6e 61 6c 73 2c 20 31 |ontest F|inals, 1|
|00002a00| 39 39 34 2e 20 20 41 64 | 6d 69 6e 69 73 74 65 72 |994.  Ad|minister|
|00002a10| 20 4c 69 6e 75 78 20 6e | 65 74 73 20 66 6f 72 20 | Linux n|ets for |
|00002a20| 66 6f 6f 64 2c 20 63 6c | 6f 74 68 69 6e 67 2c 20 |food, cl|othing, |
|00002a30| 0a 61 6e 64 20 61 6e 69 | 6d 65 2e 20 20 22 49 20 |.and ani|me.  "I |
|00002a40| 67 61 76 65 20 75 70 20 | 24 31 30 30 30 20 74 6f |gave up |$1000 to|
|00002a50| 20 61 76 6f 69 64 20 77 | 6f 72 6b 69 6e 67 20 6f | avoid w|orking o|
|00002a60| 6e 20 77 69 6e 64 6f 7a | 65 2e 2e 2e 20 2a 73 69 |n windoz|e... *si|
|00002a70| 67 68 2a 22 20 2d 20 41 | 6d 79 20 46 6f 6e 67 0a |gh*" - A|my Fong.|
|00002a80| 0a                      |                         |.       |        |
+--------+-------------------------+-------------------------+--------+--------+