Messages in this thread | | | Date | Fri, 25 Jul 2008 10:02:03 +0200 | From | Dieter Ries <> | Subject | Re: [regression] nf_iterate(), BUG: unable to handle kernel NULL pointer dereference |
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Pekka Enberg schrieb: > On Thu, 2008-07-24 at 11:51 -0700, Andrew Morton wrote: >> On Thu, 24 Jul 2008 16:34:36 +0300 Pekka Enberg <penberg@cs.helsinki.fi> wrote: >> >>>>>> Your patch introduced a use-after-free and double-free. >>>>>> krealloc() frees the old pointer, but it is still used >>>>>> for the ->move operations, then freed again. >>>>>> >>>>>> To fix this I think we need a __krealloc() that doesn't >>>>>> free the old memory, especially since it must not be >>>>>> freed immediately because it may still be used in a RCU >>>>>> read side (see the last part in the patch attached to >>>>>> this mail (based on a kernel without your patch)). >>>>> Agreed. Something like this, perhaps? >>>>> >>>>> [PATCH] netfilter: fix double-free and use-after free >>>>> >>>>> As suggested by Patrick McHardy, introduce a __krealloc() that doesn't >>>>> free the original buffer to fix a double-free and use-after-free bug >>>>> introduced by me in netfilter that uses RCU. >>>>> >>>>> Reported-by: Patrick McHardy <kaber@trash.net> >>>>> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> >>>> Looks good to me, thanks. >>> Ingo, can you please test this? Andrew, I'm at OLS so can you pick up >>> the patch in your tree? >> Sure. Or Patrick can do so and it can be merged via the net tree. >> >> Ingo, did this patch actually fix something over there? > > Apparently it didn't but it did fix Dieter's problem: > > http://lkml.org/lkml/2008/7/24/337 > > Dieter, can we add a Tested-by tag from you to this patch? >
Yes, it definitely fixed my issue and I have not encountered further problems with the patch. The machine is running fine with it.
Do I have to explicitly add my Tested-by: Dieter Ries <clip2@gmx.de> tag somewhere (if yes, where?) or is this enough for you?
cu Dieter
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