sysv_ipc.c broken in v1.30 (was Re: sysvshm appearse broken in -current)

[Andrey Chernov]

On Sat, Dec 16, 2006 at 01:00:56PM +0000, Robert Watson wrote:
> Only if IPC_M is being requested.  Is IPC_M being requested in the case 
> where you are seeing an error?  I can read code too, so what I'm asking is 
> how the system is behaving.

I'll track exact case a bit later. For now I just speak about differences 
between new code and old code I found. New code check all bits match while 
old code check IPC_M bit match only at this place.

> is requested.  We grant valid rights, not all rights, to the super user.  

This is clearly wrong.
Think about files. Even file is read-only, root _can_ write into it while 
normal user in the same situation can't.

root> touch aaa
root> chmod 444 aaa
root> cat > aaa
OK
^D

> As I said, this is something that I hope to revisit in the next few days. 
> However, it would be helpful if you could tell me the arguments and call 
> path to the ipcperm() function instance that's generating the improper 
> failure. It could be that both a bug in ipcperm() and a big in shmget() 

I'll try to make ktrace output, a bit later.

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