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    SubjectRe: [PATCH v7 08/24] erofs: add namei functions
    Hi Pavel,

    On Thu, Aug 15, 2019 at 09:01:32AM +0200, Pavel Machek wrote:
    > Hi!
    >
    > > > > + /*
    > > > > + * on-disk error, let's only BUG_ON in the debugging mode.
    > > > > + * otherwise, it will return 1 to just skip the invalid name
    > > > > + * and go on (in consideration of the lookup performance).
    > > > > + */
    > > > > + DBG_BUGON(qd->name > qd->end);
    > > >
    > > > I believe you should check for errors in non-debug mode, too.
    > >
    > > Thanks for your kindly reply!
    > >
    > > The following is just my personal thought... If I am wrong, please
    > > kindly point out...
    > >
    > > As you can see, this is a new prefixed string binary search algorithm
    > > which can provide similar performance with hashed approach (but no
    > > need to store hash value at all), so I really care about its lookup
    > > performance.
    > >
    > > There is something needing to be concerned, is, whether namei() should
    > > report any potential on-disk issues or just return -ENOENT for these
    > > corrupted dirs, I think I tend to use the latter one.
    >
    > -ENOENT is okay for corrupted directories, as long as corrupted
    > directories do not cause some kind of security bugs (memory
    > corruption, crashes, ...)

    Yes, I am certain that it will return -ENOENT for such corrupted
    directories and it will certainly not crash the kernel as well.

    I have fuzzed it for several months and it seems fine after
    commit 419d6efc50e9 ("staging: erofs: keep corrupted fs from crashing kernel in erofs_namei()")

    Don't worry about that :)

    Thanks,
    Gao Xiang

    >
    >
    > Best regards,
    > Pavel
    > --
    > DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
    > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany


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