+----- On Fri, 30 Jul 1999 11:46:05 +0200, "F. Steiner" writes: | Hi, | | we just considered the following problem: Assume that | a file system (let's say home directories of users) | is exported from a server to some other computers | (like in every university for instance). | | Now one comes with his laptop to the university, | plugs one computer off, gives his laptop the ip | of the unplugged computer and creates a user on | his laptop that exists in the university domain | with the identical name and id. | | Now the file system is exported to his laptop, too, | because it has an ip from a university computer, | and then the faker should be able to read and write the | home directory of the user which he created, | because NFS does not check the passwords but only | the user id. | | We tried that and it did work. | This is indeed a huge problem, because it looks | like we cannot prevent any student from doing this, | i.e. installing a user for instance with name and id | of a professor, and then having access to the professors | home directory. | | Has anyone any idea how to prevent this??? | Can NFS be told to check passwords during mounting? | For example, rlogin would not work in the situation | constructed above because it would realize the user | having two different passwords. | But can NFS be told to do that? There are better forms of security in NFS version 3 but I don't think that Linux supports them. /Michael