Re: [PATCH v2 2/3] scsi: mpi3mr: use number of bits to manage bitmap sizes

[Damien Le Moal <damien.lemoal@opensource.wdc.com>]

On 12/13/22 09:52, Shin'ichiro Kawasaki wrote:
> To allocate bitmaps, the mpi3mr driver calculates sizes of bitmaps using
> byte as unit. However, bitmap helper functions assume that bitmaps are
> allocated using unsigned long as unit. This gap causes memory access
> beyond the bitmap sizes and results in "BUG: KASAN: slab-out-of-bounds".
> The BUG was observed at firmware download to eHBA-9600. Call trace
> indicated that the out-of-bounds access happened in find_first_zero_bit
> called from mpi3mr_send_event_ack for miroc->evtack_cmds_bitmap.
> 
> To fix the BUG, do not use bytes to manage bitmap sizes. Instead, use
> number of bits, and call bitmap helper functions which take number of
> bits as arguments. For memory allocation, call bitmap_zalloc instead of
> kzalloc. For zero clear, call bitmap_clear instead of memset. For
> resize, call bitmap_zalloc and bitmap_copy instead of krealloc.
> 
> Remove three fields for bitmap byte sizes in struct scmd_priv, which are
> no longer required. Replace the field dev_handle_bitmap_sz with
> dev_handle_bitmap_bits to keep number of bits of removepend_bitmap
> across resize.
> 
> Fixes: c5758fc72b92 ("scsi: mpi3mr: Gracefully handle online FW update operation")
> Fixes: e844adb1fbdc ("scsi: mpi3mr: Implement SCSI error handler hooks")
> Fixes: c1af985d27da ("scsi: mpi3mr: Add Event acknowledgment logic")
> Fixes: 824a156633df ("scsi: mpi3mr: Base driver code")
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>

Looks good to me.

Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>

-- 
Damien Le Moal
Western Digital Research