Messages in this thread | | | Date | Tue, 27 Nov 2018 08:22:47 +0800 | From | PanBian <> | Subject | Re: [PATCH] f2fs: read page index before freeing |
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On Mon, Nov 26, 2018 at 07:07:08PM +0800, Chao Yu wrote: > On 2018/11/26 18:28, PanBian wrote: > > On Mon, Nov 26, 2018 at 05:13:53PM +0800, Chao Yu wrote: > >> Hi Pan, > >> > >> On 2018/11/22 18:58, Pan Bian wrote: > >>> The function truncate_node frees the page with f2fs_put_page. However, > >>> the page index is read after that. So, the patch reads the index before > >>> freeing the page. > >> > >> I notice that you found another use-after-free bug in ext4, out of > >> curiosity, I'd like to ask how do you find those bugs? by tool or code review? > > > > I found such bugs by the aid of a tool I wrote recently. I designed a method > > to automatically find paired alloc/free functions. With such functions, I > > wrote two checkers, one to check mismatched alloc/free bugs, the other to > > check use-after-free and double-free bugs. > > Excellent! Do you have any plan to open its source or announce it w/ binary > to linux kernel developers, I think w/ it we can help to improve kernel's > code quality efficiently.
Yes. I am now writing a paper about the method. I will open the source code as soon as I complete the paper and some optimizations.
Best, Pan
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