Messages in this thread | | | Date | Wed, 14 Apr 1999 09:54:16 -0400 (EDT) | From | "David L. Parsley (lkml account)" <> | Subject | Re: caps in elf, next itteration (the hack get's bigger) |
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On Wed, 14 Apr 1999, Pavel Machek wrote:
> _IF_ you go for ext2-only solution, you may as well add capabilities > into ext2 directly.
No, the stickable solution also has the nice property of working with current tools right away (and I didn't explain this before). We just have to change the kernel's behavior wrt setting the sticky bit. Under this scheme, setting the sticky bit is a priviledged operation requiring CAP_SETFCAP. If the current process has this cap raised, the kernel will comply by setting _both_ the sticky bit and the immutable bit; otherwise, neither gets set. This way, tar, rpm, dpkg, etc... can all be made to work fine by just setting their inheritable bits properly.
> Well - it changes something. You'll have to go out and tell everyone > "stickybit + immutable is deadly combination". Many times.
Yes, but consider _who_ will be the pioneers to first check the "CAP-ELF support (experimental)" box in kernel configuration. The help should say "Don't check this box without knowing what you're doing; it completely changes the UNIX security model. For documentation, see..."
I also espouse an option where the kernel will still honor 'setuid root' the old way, with all caps, to help during transition.
> I do not have to do such things. setuid-marked executables actually > look more dangerous than they are. WHICH IS RIGHT.
Yes, but as I've shown, you'll have to mark a _lot_ of files setuid0 that weren't previously. Capabilities support is a big change from traditional UNIX security, and we'll just have to deal with it. Fortunately, the stickable solution gives us a really easy upgrade path without having to patch all the system utilities. (except to run 'setcap' or whatever on them)
> Pavel > -- > The best software in life is free (not shareware)! Pavel > GCM d? s-: !g p?:+ au- a--@ w+ v- C++@ UL+++ L++ N++ E++ W--- M- Y- R+ >
- -- David L. Parsley Network Specialist City of Salem Schools
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