Messages in this thread | | | Subject | Re: [PATCH] f2fs: read page index before freeing | From | Chao Yu <> | Date | Tue, 27 Nov 2018 11:12:40 +0800 |
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On 2018/11/27 8:22, PanBian wrote: > 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.
Cool, if there is any progress, please let f2fs guys know, thank you in advance. :)
Thanks,
> > Best, > Pan > > > . >
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