Messages in this thread | | | Date | Fri, 23 Sep 2022 14:58:21 +0300 | Subject | Re: [PATCH] fs/ntfs3: fix negative shift size in true_sectors_per_clst() | From | Konstantin Komarov <> |
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On 9/23/22 03:38, Randy Dunlap wrote: > Hi, > > On 9/20/22 08:59, 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; >> } >> > > I slightly prefer the earlier patch: > > https://lore.kernel.org/all/20220823144625.1627736-1-syoshida@redhat.com/ > > but it appears that the NTFS3 maintainer is MIA again. :( >
Hello
I've sent patches on 12.09, so I'm not MIA. I plan to look at patches next week, there are quite a lot of them.
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