Messages in this thread | | | Date | Thu, 20 May 1999 19:42:44 +1000 | From | Richard Gooch <> | Subject | Re: Capabilities done right [diff against 2.3.1] |
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Theodore Y. Ts'o writes: > Date: Tue, 18 May 1999 11:04:55 +0200 > From: Pavel Machek <pavel@bug.ucw.cz> > > That's hard part, because this way dynamic linker + anything run > before main() runs with elevated priviledges. That's problem, at least > for me. > > I just came up with a random thought ---- and I'd need to do more > investigating about the ELF format to make sure this is actually doable, > but I believe we can control the order in which constructurs get run, > yes? > > So why not simply put the code which drops the privileges in a > constructor which is engineered to be run first? If the way that > constructor is setup uses a stylized code can be easily found by a > setcap or checkcap program (i.e., give the constructor a standard name, > and store the capability restriction in a standard variable referenced > by the constructor), then you can get the ability to query/set the > capabilities, but it's done in such a way which doesn't require any > special kernel hacks to enable the feature. > > This is actually a really cool thing, since it means that people could > start using it with the current stable kernel, without needing any > kernel patches or needing to wait for Linux 2.4 to ship.
Yes, that has its attractions. A couple of months ago I suggested doing it in the dynamic linker for dynamically linked binaries and in an ELF code section for statically linked binaries.
Regards,
Richard....
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