On Fri, Apr 29, 2022 at 01:01:00PM -0700, Randy Dunlap wrote:
> When the NTFS BOOT sectors_per_clusters field is > 0x80,
> it represents a shift value. Make sure that the shift value is
> not too large (> 31) before using it. Return 0xffffffff if it is.
>
> This prevents negative shift values and shift values that are
> larger than the field size.
>
> Prevents this UBSAN error:
>
> UBSAN: shift-out-of-bounds in ../fs/ntfs3/super.c:673:16
> shift exponent -192 is negative
>
> Fixes: 82cae269cfa9 ("fs/ntfs3: Add initialization of super block")
> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Reported-by: syzbot+1631f09646bc214d2e76@xxxxxxxxxxxxxxxxxxxxxxxxx
Reviewed-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
