From: Junxiao Bi <junxiao.bi@xxxxxxxxxx> [ Upstream commit 3b5f307ef3cb5022bfe3c8ca5b8f2114d5bf6c29 ] 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.bi@xxxxxxxxxx> Acked-by: Sumit Saxena <sumit.saxena@xxxxxxxxxxxx> Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- 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 5b1c37e3913cd..d90693b2767fd 100644 --- a/drivers/scsi/megaraid/megaraid_sas_base.c +++ b/drivers/scsi/megaraid/megaraid_sas_base.c @@ -2847,6 +2847,7 @@ megasas_fw_crash_buffer_show(struct device *cdev, u32 size; unsigned long buff_addr; unsigned long dmachunk = CRASH_DMA_BUF_SIZE; + unsigned long chunk_left_bytes; unsigned long src_addr; unsigned long flags; u32 buff_offset; @@ -2872,6 +2873,8 @@ megasas_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] + -- 2.20.1
