Messages in this thread | | | Date | Mon, 27 Sep 1999 22:06:03 +0200 (CEST) | From | David Weinehall <> | Subject | Re: [PATCH] i386 ptrace patch needed for user-mode port |
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On Mon, 27 Sep 1999, Nate Eldredge wrote:
> Horst von Brand wrote: > > > > Nate Eldredge <neldredge@hmc.edu> said: > > > Jeff Dike wrote: > > > > Below is a small patch to ptrace which enables it to change system call > > > > numbers. This is needed in order to run the user-mode port. > > > > > > > > It adds range checks to ptrace and to the slow system call path. > > > > > > > > I've been feeding this sporadically to Linus for the last couple of months > > > > with no result. If anyone can clue me in as to what would make this more > > > > acceptable, please do so. > > > > > > This patch also enables a feature in strace that lets it trace child > > > processes spawned by vfork(). I am strongly in favor of its inclusion. > > > > > > I have been running an equivalent patch through several versions of > > > 2.2.x for some months and have experienced absolutely no ill effects. > > > > Has anybody looked closely at possible security implications? I.e., switch > > system call numbers so "read" becomes "write" (or "exec") and run a > > program... > > You need permission to trace the process (you must be its owner or > root). And if you have that you can do POKE_DATA and any number of > other exciting things. So I don't think this adds any security issues.
Hmmm, but how does it works in a capability system? I don't know capabilities, but presumably you can have TRACE-permissions without having MEM_WRITE permissions.
/David _ _ // David Weinehall <tao@acc.umu.se> /> Northern lights wander \\ // Project MCA Linux hacker // Dance across the winter sky // \> http://www.acc.umu.se/~tao/ </ Full colour fire </
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