Messages in this thread | | | Date | Fri, 30 Sep 2022 19:34:34 +0300 | Subject | Re: [PATCH] fs/ntfs3: fix negative shift size in true_sectors_per_clst() | From | Konstantin Komarov <> |
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On 9/20/22 18:59, Tetsuo Handa wrote: > syzbot is reporting shift-out-of-bounds in true_sectors_per_clst() [1], for > commit a3b774342fa752a5 ("fs/ntfs3: validate BOOT sectors_per_clusters") > did not address that (0 - boot->sectors_per_clusters) < 0 because "u8" was > chosen for type of boot->sectors_per_clusters because 0x80 needs to be > positive in order to support 64K clusters. Use "s8" cast in order to make > sure that (0 - (s8) boot->sectors_per_clusters) > 0. > > Link: https://syzkaller.appspot.com/bug?extid=1631f09646bc214d2e76 [1] > Reported-by: syzbot <syzbot+1631f09646bc214d2e76@syzkaller.appspotmail.com> > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> > Tested-by: syzbot <syzbot+1631f09646bc214d2e76@syzkaller.appspotmail.com> > Fixes: a3b774342fa752a5 ("fs/ntfs3: validate BOOT sectors_per_clusters") > > diff --git a/fs/ntfs3/super.c b/fs/ntfs3/super.c > index 47012c9bf505..c7ffd21fb255 100644 > --- a/fs/ntfs3/super.c > +++ b/fs/ntfs3/super.c > @@ -672,7 +672,7 @@ static u32 true_sectors_per_clst(const struct NTFS_BOOT *boot) > if (boot->sectors_per_clusters <= 0x80) > return boot->sectors_per_clusters; > if (boot->sectors_per_clusters >= 0xf4) /* limit shift to 2MB max */ > - return 1U << (0 - boot->sectors_per_clusters); > + return 1U << (0 - (s8) boot->sectors_per_clusters); > return -EINVAL; > } >
Hello Thanks for patch, but there was already a similar patch by Shigeru Yoshida, so I chose it. Sorry about that, thanks again for your work.
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