Messages in this thread | | | Date | Sat, 13 Jul 1996 09:56:28 +0300 (EET DST) | From | Linus Torvalds <> | Subject | Re: How does chown(2) works with symlinks? |
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On Thu, 11 Jul 1996, Michiel Boland wrote: > > And permissions for a symbolic link /are/ relevant; you cannot > readlink() a symbolic link that has no read permission. > (try ls -l /proc/1)
Umm, that's a special case. I made the /proc symlinks work the way _I_ personally think symlinks should work, but for "normal" symlinks the standard UNIX behaviour is that they are always of mode lrxwrxwrxw..
I have a few other "sick" ideas for symlinks if I would like to extend them:
- permission checks according to mode bits (not just for /proc). The kernel actually does this already, it's just that the /proc filesystem is the only filesystem that has other than full read/write. - setgid/setuid links would change the fsgid/fsuid for the process that follows them for the duration of the lookup to the group/owner of the symlink.
Especially the second point is "strange". But it could be very useful for allowing controlled r/w access to _certain_ files without allowing general execute access to the directory the files reside in. It would be a huge security hole if used incorrectly, though (like doing a root setuid symlink to a directory, and then people do a
vi directory/../../../etc/passwd
heh ;)
Linus
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