Security in Plan 9 ABSTRACT. and. factotum Factotum. Factotum. 1. Introduction. security. Proc. of the 2002 Usenix Security Symposium,

Size: px

Start display at page:

Download "Security in Plan 9 ABSTRACT. and. factotum Factotum. Factotum. 1. Introduction. security. Proc. of the 2002 Usenix Security Symposium,"

Brooke Watts
7 years ago
Views:

1 Security in Plan 9 Russ Cox, MIT LCS Eric Grosse, Bell Labs Rob Pike, Bell Labs Dave Presotto, Avaya Labs and Bell Labs Sean Quinlan, Bell Labs {rsc,ehg,rob,presotto,seanq}@plan9.bell labs.com ABSTRACT and factotum Factotum Factotum 1. Introduction security Proc. of the 2002 Usenix Security Symposium,

{rsc,ehg,rob,presotto,seanq}@plan9.bell labs.

2 factotum factotum factotum factotum factotum factotum secstore 2. An Agent for Security

3 F T F C P T P C F F P F F X factotum P X factotum Secstore factotum factotum factotum factotum Factotum /mnt/factotum factotum factotum 2.1. Logging in gre factotum factotum \n

4 factotum user[none]: gre factotum!adding key: dom=cs.bell labs.com proto=p9sk1 user[gre]: \n password: ****!Adding key: proto=apop server=plan9.bell labs.com user[gre]: \n password: **** Factotum gre user[none]: gre secstore password: ********* STA PIN+SecurID: ********* gre factotum 2.2. The factotum host owner root factotum factotum factotum cpu P T cpu P C cpu P C P T factotums P T P C P T P C factotum F T F C factotum

$com user[gre]: \n password: **** Factotum gre user[none]: gre secstore password: ********* STA$

5 factotum factotum factotum /mnt/factotum factotum factotum factotum factotum factotum factotum factotum factotum 2.3. Local capabilities factotum /dev/caphash /dev/capuse /dev/caphash Factotum factotum string random string /dev/caphash Factotum userid1 /dev/capuse userid1 userid2 factotum 2.4. Keys key

Local capabilities factotum /dev/caphash /dev/capuse /dev/caphash Factotum factotum

6 Factotum attribute=value attribute value dom=bell labs.com proto=p9sk1 user=gre!password= don t tell proto=apop server=x.y.com user=gre!password= open sesame! secret Factotum query attribute=value attribute? server=x.y.com proto=apop factotum user!password server=x.y.com proto=apop user?!password? Factotum proto!password factotum server proto user password server

secret Factotum query attribute=value attribute? server=x.y.com proto=apop factotum user!

7 2.5. Protecting keys factotum factotum user!password proto=pass /proc factotum Factotum /proc /proc private factotum private /proc/pid/ctl factotum /proc /dev/kmem noswap /proc private noswap factotum dossrv noswap factotum confirm confirm factotum 2.6. Factotum transactions factotum key delkey /mnt/factotum/ctl Key Delkey ctl

/proc/pid/ctl factotum /proc /dev/kmem noswap /proc private noswap factotum

8 % cd /mnt/factotum % ls l lrw gre gre 0 Jan 30 22:17 confirm rw gre gre 0 Jan 30 22:17 ctl lr gre gre 0 Jan 30 22:17 log lrw gre gre 0 Jan 30 22:17 needkey r r r gre gre 0 Jan 30 22:17 proto rw rw rw gre gre 0 Jan 30 22:17 rpc % cat >ctl key dom=bell labs.com proto=p9sk1 user=gre!password= don t tell key proto=apop server=x.y.com user=gre!password= bite me ^D % cat ctl key dom=bell labs.com proto=p9sk1 user=gre key proto=apop server=x.y.com user=gre % echo delkey proto=apop >ctl % cat ctl key dom=bell labs.com proto=p9sk1 user=gre % l rpc factotum rpc transaction ok start read write authinfo attr start rpc P C factotum F C P S factotum F S factotum x.y.com factotum P S F S : start proto=apop role=server F S P S : ok P S F S : read F S P S : ok +OK POP3 challenge P S P C : +OK POP3 challenge factotum

com proto=p9sk1 user=gre key proto=apop server=x.y.com user=gre % echo delkey proto=apop >ctl % cat ctl key dom=bell labs.

9 P C F C : start proto=apop role=client server=x.y.com F C P C : ok P C F C : write +OK POP3 challenge F C P C : ok P C F C : read F C P C : ok APOP gre response Factotum start proto role start factotum start proto=apop server=x.y.com user!password factotum P C P S : APOP gre response factotum P S F S : write APOP gre response F S P S : ok P S F S : read F S P S : ok +OK welcome P S P C : +OK welcome P S F S : authinfo F S P S : ok client=gre capability=capability authinfo attr=value attr=value factotum confirm confirm= confirm confirm tag=1 attributes tag=1 answer=yes answer=no needkey start factotum

10 F C P C : needkey proto=apop server=x.y.com user?!password? ctl start needkey /mnt/factotum/needkey needkey tag=1 attributes ctl tag=1 proto cat /mnt/factotum/proto log debug factotum 3. Authentication in 9P authentication file fauth afd = fauth(int fd, char *servicename); fd servicename afd afd factotum afd mount

proto cat /mnt/factotum/proto log debug factotum 3.

11 afd mount mount(int fd, int afd, char *mountpoint, int flag, char *servicename) mount factotum afd a priori 3.1. Plan 9 shared key protocol factotum P9sk1 C S nonce C S C nonce S uid S domain S C A A C nonce S uid S domain S uid C factotum C K C nonce S uid C uid S K n K S nonce S uid C uid S K n C S S C K S nonce S uid C uid S K n K n nonce S counter K n nonce C counter K x x K nonce S K S uid C uid S K n K n nonce S counter K n uid C K n nonce C counter K n uid S

factotum C K C nonce S uid C uid S K n K S nonce S uid C uid S K n C S S C K S nonce S uid C uid S K n K n nonce S

12 3.2. The authentication server keyfs authsrv Keyfs key secret log expire status disabled key secret Authsrv authsrv C S nonce C S C nonce S uid S domain S C A nonce S uid S domain S hostid C uid C A C K C nonce S uid C uid S K n K S nonce S uid C uid S K n C S K S nonce S uid C uid S K n K n nonce S S C K n nonce C C A A C C A A C uid C K c K n K n password old password new OK 3.3. Protocol negotiation p9any v.n n proto k factotum domain k

nonce S uid C uid S K n C S K S nonce S uid C uid S K n K n nonce S S C K n nonce C C A A C C A A C uid C K c K n K n

13 OK factotum 4. Library Interface to Factotum factotum fauth mount afd factotum afd amount fauth mount Amount factotum afd int amount(int fd, char *mntpt, int flags, char *aname) { int afd, ret; AuthInfo *ai; } afd = fauth(fd, aname); if(afd >= 0){ ai = auth_proxy(afd, amount_getkey, "proto=p9any role=client"); if(ai!= NULL) auth_freeai(ai); } ret = mount(fd, afd, mntpt, flags, aname); if(afd >= 0) close(afd); return ret; fd open dial factotum auth_proxy p9any client Auth_proxy factotum afd AuthInfo mount afd. fauth

$*mntpt, int flags, char *aname) { int afd, ret; AuthInfo *ai; } afd = fauth(fd, aname); if(afd >= 0){ ai = auth_proxy(afd,$

14 auth_proxy amount_getkey factotum key /mnt/factotum/ctl auth_proxy printf cpu cpu exportfs cpu exportfs cpu factotum /* client */ int p9auth(int fd) { AuthInfo *ai; ai = auth_proxy(fd, auth_getkey, "proto=p9any role=client"); if(ai == NULL) return 1; } /* start cpu protocol here */ /* server */ int srvp9auth(int fd, char *user) { AuthInfo *ai; } ai = auth_proxy(fd, NULL, "proto=p9any role=server"); if(ai == NULL) return 1; /* set user id for server process */ if(auth_chuid(ai, NULL) < 0) return 1; /* start cpu protocol here */ Auth_chuid caphash capuse auth_getkey NULL

$here */ /* server */ int srvp9auth(int fd, char *user) { AuthInfo *ai; } ai = auth_proxy(fd, NULL, "proto=p9any role=server"); if(ai == NULL)$

15 5. Secure Store Factotum factotum /mnt/factotum/ctl secstore key file Secstore factotum secstore C S C g x H S C S g y hash g xy C S C S hash g xy S C H C S C S secstore secstore secstore secstore H secstore H factotum secstore secstore

C S g y hash g xy C S C S hash g xy S C H C S C S secstore

16 6. Transport Layer Security int pushtls(int fd, char *hashalg, char *cryptalg, int isclient, char *secret, char *dir); pushtls dir cpu exportfs pushtls int tlsclient(int fd, TLSconn *conn) pushtls conn 7. Related Work and Discussion

char *dir); pushtls dir cpu exportfs pushtls int

17 Factotum factotum O n factotum O n rlogind telnetd ftpd sshd Factotum Factotum none nobody factotum su login secstore secstore secstore

18 write sslwrite 8. Conclusion root Factotum labs.com/plan9 Acknowledgments secstore References

19 passsafe.html Kerberos Appendix: Summary of the PAK protocol q> p> p = rq + r q h Z * p g h r C H H C r H H Z * p H p H S x m g x H C m m p y g y mh y S k sha1 C S m H = x k k sha1 C S m H k K sha1 C S m H S H

Security in Plan 9. Russ Cox, MIT LCS Eric Grosse, Bell Labs Rob Pike, Bell Labs Dave Presotto, Avaya Labs and Bell Labs Sean Quinlan, Bell Labs

Security in Plan 9. Russ Cox, MIT LCS Eric Grosse, Bell Labs Rob Pike, Bell Labs Dave Presotto, Avaya Labs and Bell Labs Sean Quinlan, Bell Labs Security in Plan 9 Russ Cox, MIT LCS Eric Grosse, Bell Labs Rob Pike, Bell Labs Dave Presotto, Avaya Labs and Bell Labs Sean Quinlan, Bell Labs rsc,ehg,rob,presotto,seanq @ plan9.bell labs.com What comprises