On Mon, Jul 22, 2019 at 9:45 PM Junxiao Bi <junxiao...@oracle.com> wrote:
>
> While loading fw crashdump in function fw_crash_buffer_show(),
> left bytes in one dma chunk was not checked, if copying size
> over it, overflow access will cause kernel panic.
>
> Signed-off-by: Junxiao Bi <junxiao...@oracle.com>
Acked-by: Sumit Saxena <sumit.sax...@broadcom.com>
> ---
> drivers/scsi/megaraid/megaraid_sas_base.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c
> b/drivers/scsi/megaraid/megaraid_sas_base.c
> index 80ab9700f1de..3eef0858fa8e 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -3153,6 +3153,7 @@ fw_crash_buffer_show(struct device *cdev,
> (struct megasas_instance *) shost->hostdata;
> u32 size;
> unsigned long dmachunk = CRASH_DMA_BUF_SIZE;
> + unsigned long chunk_left_bytes;
> unsigned long src_addr;
> unsigned long flags;
> u32 buff_offset;
> @@ -3176,6 +3177,8 @@ fw_crash_buffer_show(struct device *cdev,
> }
>
> size = (instance->fw_crash_buffer_size * dmachunk) - buff_offset;
> + chunk_left_bytes = dmachunk - (buff_offset % dmachunk);
> + size = (size > chunk_left_bytes) ? chunk_left_bytes : size;
> size = (size >= PAGE_SIZE) ? (PAGE_SIZE - 1) : size;
>
> src_addr = (unsigned long)instance->crash_buf[buff_offset / dmachunk]
> +
> --
> 2.17.1
>
