Messages in this thread | | | From | (H. Peter Anvin) | Subject | Re: suidpid( UID, credential? ) ? secure IPC? | Date | 7 Oct 1997 06:03:25 GMT |
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Followup to: <199710061649.MAA21893@dcl.MIT.EDU> By author: "Theodore Y. Ts'o" <tytso@MIT.EDU> In newsgroup: linux.dev.kernel > > This allows you to do all sorts of very interesting things all in > userspace, without needing extra special-purpose system calls and > without requiring an IPC mechanism. It does require a kernel > context-switch to enter and leave a PSL, but if it's done properly, that > should be the only overhead. >
Actually, at least on the i386 you can do a single context switch straight into the PSL.
The danger is that it is a lot harder to write a safe PSL than it is to write a safe setuid program, and we all know how easy that is...
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