Re: can't login as user?

ADAM Sulmicki (adam@cfar.umd.edu)
Thu, 14 May 1998 00:42:36 -0400 (EDT)


Ouh, I made a typo .. below..

On Wed, 13 May 1998, ADAM Sulmicki wrote:

->
->I did bit more testing.
->
->the nfs server is RedHat 4.2. It exports /usr and two tftpboot
->directories, the two dir are very similar, and based on 4.2, not
->identical though.
->
->After that I did made an 34pre13 kernel and NET-booted it on
->
->Cyrix686MMX-PR200 /w 64mb ram,
-> it appeared to work all fine, I could login as user etc.
->
->Afrter that I netbooted it on
->
->Cyrix486-66 w/ 8mb ram.
-> It would have exactly those symptom as other say:
-> I could login fine as user, but trying any of the following:

It should say "I could login fine as ROOT, but trying to do any
of the wollowing as USER would not work:"

-> login : it would fail w/ "no home/foo directory" message
-> su : would say "/bin/bash permission denied"
-> trying to run a program which first setuid() and
-> then to ties to system("/bin/bash"), makes fork to fail.
-> [program attached below]
->
->[root@bea /root]# su foo
->su: cannot run /bin/bash: Permission denied
->[root@bea /root]# whoami
->root
->[root@bea /root]# test3
->[root@bea /root]# whoami
->root
->[root@bea /root]# telnet localhost
->Trying 127.0.0.1...
->Connected to localhost.
->Escape character is '^]'.
->Red Hat Linux Red Hat Linux release 4.2 (Biltmore)
->Kernel 2.0.34 on an i486
->login: foo
->No directory /foo!
->Connection closed by foreign host.
->
->
->Note : kernels were identical, the /usr dir was identical,
-> the /tftpboot.<x> dirs are separate copies but
-> I think they are closely identical, and after all
-> they should not contribute to make system()
-> call to fail.
->
->[root@eax root]# cat test3.c
->#include<unistd.h>
->#include<stdlib.h>
->main () {
-> int err = setuid(500);
-> system("/bin/bash");
->}
->
->
->-Adam
->
->
->
->-
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->

-Adam

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