Re: [PATCH] new setprocuid syscall

From: Petr Vandrovec (VANDROVE@vc.cvut.cz)
Date: Tue Feb 20 2001 - 08:21:22 EST


On 20 Feb 01 at 7:11, Peter Samuelson wrote:
> [Alan Cox]
> > There is an assumption in the kernel that only the task changes its
> > own uid and other related data.
>
> Fair enough but could you explain the potential problems? And how is
> it different from sys_setpriority?

Look at what fs/open.c:sys_access does, at least. It switches
fsuid/fsgid/capabilities during its execution.

sys_setpriority is completely different, no piece of kernel changes that
and nothing except schedule() touches that. But {,fs,e}[ug]id are used
here and there through whole kernel. Also, changing priority does not
remove some access rights from your process, while changing uid/gid does...
                                        Petr Vandrovec
                                        vandrove@vc.cvut.cz
                                        
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This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:22 EST