Messages in this thread | | | From | "Petr Vandrovec" <> | Date | Wed, 6 Oct 2004 19:18:53 +0200 | Subject | Re: ESP corruption bug - what CPUs are affected? (patch att |
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On 6 Oct 04 at 20:18, Stas Sergeev wrote: > Yes, if not for that anonymous guy, who kept posting > to me until he finally convinced me that the Ring-0 > approach is not that difficult at all. > So I tried... It was much more difficult to code > up, but at the end it looks a little better > and localized to entry.S completely. OTOH it > touches the exception handlers, but not too much - > it adds only 5 insns on the fast path. And the > code is very fragile, but after I made all the > magic numbers a #define consts, it actually looks > not so bad. > I don't know which patch is really better, so > I am attaching both.
CPL0 solution is certainly more localized, but I have hard problems to convice myself that it is actually safe.
I would appreciate if you could add comments what values are set by ESPFIX_SWITCH_16 + 8 + 4 and simillar moves, and what they actually do. And convicing myself that ESPFIX_SWITCH_32 has just right value so
pushl %eax pushl %es lss ESPFIX_SWITCH_32,%esp popl %es popl %eax
actually works took almost an hour... Petr
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