Date: Thu, 25 Jan 2001 20:32:18 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: dwhite@resnet.uoregon.edu (Doug White) Cc: walton@onlinemusic.com (Dave Walton), freebsd-fs@FreeBSD.ORG Subject: Re: suiddir and samba Message-ID: <200101252032.NAA27330@usr08.primenet.com> In-Reply-To: <Pine.BSF.4.21.0101242319270.25771-100000@resnet.uoregon.edu> from "Doug White" at Jan 24, 2001 11:25:22 PM
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> Hm .. suiddir makes files inherits the perms AND owner/group from the > parent dir. This is kinda evil as it essentially is a hardwired file > giveaway, which is a BSD no-no. You should just set the dir > group-writable and add all the user's to the parent dir's group. > > I suppose if you *really*really* want the owner to propagate, then use > suiddir. Of course, unless you hack Samba the suid bit won't get set on > subdirectories. The problem this was intended to address is a shared per user filespace, which is exposed via multiple spaces (e.g. SMB, AppleTalk, FTP, WWW, etc.). The problem with _not_ doing this is that SMB can be made to do the least astonishing thing, which is give ownership of files to the user who owns the filespace. UNIX will let you delete files not owned by you, but placed in a directory owned by you. Consider now that you have this filespace owned by "fred", and a file is created there via SMB, with appropriate options: it will also be owned by "fred", the owner of the filespace. Now FTP something up there. It will be owned by the user logged in for the ftp session (whatever the current credential of the ftpd is at the time). Attempts by "fred" to delete this file from his filespace via SMB will fail. A similar problem is created if instead of being put there via FTP, the file is put there via AppleTalk. A similar problem also occurs if this is a UNIX shell user, writing a file into a writeable directory belonging to an SMB user. Now consider that "fred" is a Windows client user, and the person providing the file to "fred" is a UNIX or Macintosh user, and you will see the problem this is trying to (and does) solve. PS: I wasn't involved in the actual implementation, that was Julian, but I agree with him that it makes more sense to change the FS semantics than it does to have to hack every possible program to know about "dropbox"-style file giveaway semantics. PPS: I really can't see another way to allow a shell user, since the transaction is not intermediated by a daemon, to write files into the "fred" filespace, which is really the most simple Windows/UNIX interoperability scenario possible. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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