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    SubjectRe: [GIT PULL] ksmbd server security fixes
    On Mon, Sep 20, 2021 at 5:46 PM Linus Torvalds
    <torvalds@linux-foundation.org> wrote:
    >
    > On Sun, Sep 19, 2021 at 7:22 AM Steve French <smfrench@gmail.com> wrote:
    > >
    > > 3 ksmbd fixes: including an important security fix for path
    > > processing, and a missing buffer overflow check, and a trivial fix for
    > > incorrect header inclusion
    > >
    > > There are three additional patches (and also a patch to improve
    > > symlink checks) for other buffer overflow cases that are being
    > > reviewed and tested.
    >
    > Note that if you are working on a path basis, you should really take a
    > look at our vfs lookup_flags, and LOOKUP_BENEATH in particular.

    This was also something that Ralph brought up, and Namjae is looking
    at now.

    > The way to deal with '..' and symlinks is not to try to figure it out
    > yourself. You'll get it wrong, partly because the races with rename
    > are quite interesting. The VFS layer knows how to limit pathname
    > lookup to the particular directory you started in these days.
    >
    > Of course, that is only true for the actual path lookup functions.
    > Once you start doing things manually one component at a time yourself,
    > you're on your own.

    Agreed. Also FYI I removed the "ksmbd: Use LOOKUP_NO_SYMLINKS"
    changeset from for-next (I left the first two buffer validation changesets
    in, since those have been reviewed), since Namjae is working on
    an updated version following your suggestion (and others' review feedback).

    --
    Thanks,

    Steve

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