• Artem Bityutskiy's avatar
    mtd: mtdpart: disallow reading OOB past the end of the partition · 154bf89f
    Artem Bityutskiy authored
    This patch fixes the mtdpart bug which allows users reading OOB past the
    end of the partition. This happens because 'part_read_oob()' allows reading
    multiple OOB areas in one go, and mtdparts does not validate the OOB
    length in the request.
    
    Although there is such check in 'nand_do_read_oob()' in nand_base.c, but
    it checks that we do not read past the flash chip, not the partition,
    because in nand_base.c we work with the whole chip (e.g., mtd->size
    in nand_base.c is the size of the whole chip). So this check cannot
    be done correctly in nand_base.c and should be instead done in mtdparts.c.
    
    This problem was reported by Jason Liu <r64343@freescale.com> and reproduced
    with nandsim:
    
    $ modprobe nandsim first_id_byte=0x20 second_id_byte=0xaa third_id_byte=0x00 \
                       fourth_id_byte=0x15 parts=0x400,0x400
    $ modprobe nandsim mtd_oobtest.ko dev=0
    $ dmesg
    = snip =
    mtd_oobtest: attempting to read past end of device
    mtd_oobtest: an error is expected...
    mtd_oobtest: error: read past end of device
    = snip =
    mtd_oobtest: finished with 2 errors
    Reported-by: default avatarJason Liu <liu.h.jason@gmail.com>
    Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
    Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
    154bf89f
mtdpart.c 19.9 KB