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    SubjectRe: [syzbot] [hfs?] WARNING in hfs_write_inode
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    Hi Arnd,

    Am 05.01.23 um 11:33 schrieb Arnd Bergmann:
    > On Wed, Jan 4, 2023, at 20:06, Linus Torvalds wrote:
    >> I suspect this code is basically all dead. From what I can tell, hfs
    >> only gets updates for
    >>
    >> (a) syzbot reports
    >>
    >> (b) vfs interface changes
    > There is clearly no new work going into it, and most data exchange
    > with MacOS would use HFS+, but I think there are still some users.
    PowerPC yaboot boot partitions spring to mind here. Plain HFS is still
    used in places where it can't be replaced AFAIK.
    >
    >> and the last real changes seem to have been by Ernesto A. Fernández
    >> back in 2018.
    >>
    >> Hmm. Looking at that code, we have another bug in there, introduced by
    >> an earlier fix for a similar issue: commit 8d824e69d9f3 ("hfs: fix OOB
    >> Read in __hfs_brec_find") added
    >>
    >> + if (HFS_I(main_inode)->cat_key.CName.len > HFS_NAMELEN)
    >> + return -EIO;
    >>
    >> but it's after hfs_find_init(), so it should actually have done a
    >> hfs_find_exit() to not leak memory.
    >>
    >> So we should probably fix that too.
    >>
    >> Something like this ENTIRELY UNTESTED patch?

    Looking at Linus' patch, I wonder whether the missing fd.entrylength
    size test in the HFS_IS_RSRC(inode) case was due to the fact that a
    file's resource fork may be empty?

    Adding Brad Boyer (bfind.c author) to Cc. Brad might know what
    fd.entrylength should be set to in such a case.

    Cheers,

        Michael


    >>
    >> Do we have anybody who looks at hfs?
    > Adding Viacheslav Dubeyko to Cc, he's at least been reviewing
    > patches for HFS and HFS+ somewhat recently. The linux-m68k
    > list may have some users dual-booting old MacOS.
    >
    > Viacheslav, see the start of the thread at
    > https://lore.kernel.org/lkml/000000000000dbce4e05f170f289@google.com/
    >
    > Arnd

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