[14738] in Athena Bugs
sun4 8.0I: attach
daemon@ATHENA.MIT.EDU (mhpower@MIT.EDU)
Tue Oct 8 04:07:05 1996
From: mhpower@MIT.EDU
To: bugs@MIT.EDU
Date: Tue, 08 Oct 1996 04:06:53 EDT
System name: bill-the-cat
Type and version: SPARC/Classic 8.0I (2 update(s) to same version)
Display type: cgthree
What were you trying to do?
attach a filesystem in a situation where the mountpoint was
a symlink to an AFS directory for which I had no access
permission, but the AFS directory I wanted to attach was one
for which I did have access permission, e.g.,
% ls -ld /mit/dce
lrwxrwxrwx 1 root other 38 Oct 8 03:04 /mit/dce -> /afs/athena.mit.edu/astaff/project/dce
% attach | grep dce
% attach -d -t afs -m /mit/dce -e /afs/athena.mit.edu/contrib/sipb
/afs/athena.mit.edu/contrib/sipb resolves to:
AFS /afs/athena.mit.edu/contrib/sipb w /mit/dce
Locking attachtab....Checking lock on /tmp/attach_@afs@athena.mit.edu@contrib@sipb
Setting lock on /tmp/attach_@afs@athena.mit.edu@contrib@sipb: 5
Unlocking attachtab
Processing line AFS /afs/athena.mit.edu/contrib/sipb w /mit/dce
performing an /bin/athena/aklog -path /afs/athena.mit.edu/contrib/sipb -hosts -zsubs
zsub: athena.mit.edu:root.cell
Subscribing to zephyr instance athena.mit.edu:root.cell.
zsub: athena.mit.edu
Subscribing to zephyr instance athena.mit.edu.
zsub: athena.mit.edu:contrib
Subscribing to zephyr instance athena.mit.edu:contrib.
zsub: athena.mit.edu:contrib.sipb
Subscribing to zephyr instance athena.mit.edu:contrib.sipb.
zsub: TARTARUS.MIT.EDU
Subscribing to zephyr instance TARTARUS.MIT.EDU.
host: 18.183.0.29
lstating /afs/athena.mit.edu/contrib/sipb...
lstating /mit/dce....
Segmentation fault
What's wrong:
The "Segmentation fault" should not have occurred. I believe
it occurs at this line of the source file afs.c:
(void) strcpy(buf, path_canon(buf));
in which path_canon returns NULL. Presumably at least the
return value of path_canon needs to be checked. I would also
recommend that some of the uses of strcpy in the attach source
code be changed to avoid the possibility of buffer overflows,
e.g., in main.c there's
hent = gethostbyname(argv[i]);
if (!hent) {
fprintf(stderr, "%s: Can't resolve %s\n", progname, argv[i]);
error_status = ERR_NFSIDBADHOST;
}
else {
strcpy(hostname, hent->h_name);
What should have happened:
attach should have told me that there was already a symlink
from /mit/dce, and that I wasn't allowed to remove that symlink
and replace it with a symlink to a different directory.
The current behavior (in similar situations) of simply removing
the symlink and creating a new symlink to a different directory
would probably be better than "Segmentation fault", though.
Please describe any relevant documentation references:
attach(1)
