Re: [PATCH] [SECURITY] suid procs exec'd with bad 0,1,2 fds

[Perry Harrington]

> Also true.
> 
> But I have yet another technical argument.  It BREAKS the existing elf
> ABI's of all systems I know of.
> 
> I have the 32-bit Sparc and 32-bit MIPS ELF specifications here for
> reference and both specify:
> 
> "The stack segment has READ, WRITE, and EXECUTE permissions."
> 

But what uses exec stacks, other than exploits?

I know that breaking certain specs is bad, but what if the perceived value
is worth more than full adherence to the spec?

> I don't have it handy, but I would not be surprised if the x86 ELF
> specs say the same thing.  Someone can easily check this.
> 
> Dean Gaudet made a reference to Solaris2.7 and the fact that they've
> turned off execute permission for the stack on Sparc.  This is for
> 64-bit Sparc binaries covered on the new 64-bit V9 processor ABI.
> They did not turn off execution for the stack segment when existing
> 32-bit binaries run.
> 
> Later,
> David S. Miller
> [e-mail]

-- 
Perry Harrington       Linux rules all OSes.    APSoft      ()
email: [e-mail] 			Think Blue. /\