Messages in this thread | | | From | Hawkins Jiawei <> | Subject | Re: [PATCH] ntfs: change check order in ntfs_attr_find | Date | Fri, 26 Aug 2022 23:42:32 +0800 |
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On Fri, 26 Aug 2022 at 23:15, Dan Carpenter <dan.carpenter@oracle.com> wrote: > > On Fri, Aug 26, 2022 at 08:32:57PM +0800, Hawkins Jiawei wrote: > > > syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > > > > > Looks like it is improper check order that causes this bug. > > > > Sorry for wrong command. > > #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master > > > > diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c > > index 52615e6090e1..6480cd2d371d 100644 > > --- a/fs/ntfs/attrib.c > > +++ b/fs/ntfs/attrib.c > > @@ -594,10 +594,11 @@ static int ntfs_attr_find(const ATTR_TYPE type, const ntfschar *name, > > for (;; a = (ATTR_RECORD*)((u8*)a + le32_to_cpu(a->length))) { > > u8 *mrec_end = (u8 *)ctx->mrec + > > le32_to_cpu(ctx->mrec->bytes_allocated); > > + if ((u8*)a < (u8*)ctx->mrec || (u8*)a > mrec_end) > > + break; > > This definitely seems like a bug. But your code won't build. Syzbot > must have -Werror turned off? Hi Dan, Did you mean we should put the variable declares at the beginning of the function? (Correct me if I understand anything wrong)
> > Btw, this was in the original code, but those casts are ugly. Ideally > there would be some way to get rid of them. But otherwise at least > put a space after the u8. "(u8 *)a < (u8 *)ctx->mrec". > > > u8 *name_end = (u8 *)a + le16_to_cpu(a->name_offset) + > > a->name_length * sizeof(ntfschar); > > - if ((u8*)a < (u8*)ctx->mrec || (u8*)a > mrec_end || > > - name_end > mrec_end) > > + if (name_end > mrec_end) > > break; > > regards, > dan carpenter So maybe I can try to refactor these codes. But I wonder if this can be done in a seperate bug
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