On Tue, Jul 24, 2018 at 2:40 AM, Selvin Xavier <selvin.xavier@xxxxxxxxxxxx> wrote: > On Tue, Jul 24, 2018 at 3:03 AM, Jason Gunthorpe <jgg@xxxxxxxx> wrote: >> On Wed, Jul 18, 2018 at 09:01:35AM -0700, Bart Van Assche wrote: >>> This patch avoids that the following compiler warning is reported when >>> building with gcc 8 and W=1: >>> >>> In function 'ocrdma_mbx_get_ctrl_attribs', >>> inlined from 'ocrdma_init_hw' at drivers/infiniband/hw/ocrdma/ocrdma_hw.c:3224:11: >>> drivers/infiniband/hw/ocrdma/ocrdma_hw.c:1368:3: warning: 'strncpy' output may be truncated copying 31 bytes from a string of length 31 [-Wstringop-truncation] >>> strncpy(dev->model_number, >>> ^~~~~~~~~~~~~~~~~~~~~~~~~~ >>> hba_attribs->controller_model_number, 31); >>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> >>> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxx> >>> Cc: Selvin Xavier <selvin.xavier@xxxxxxxxxxxx> >>> Cc: Devesh Sharma <devesh.sharma@xxxxxxxxxxxx> >>> drivers/infiniband/hw/ocrdma/ocrdma_hw.c | 5 +++-- >>> 1 file changed, 3 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_hw.c b/drivers/infiniband/hw/ocrdma/ocrdma_hw.c >>> index c6c87cba943b..e578281471af 100644 >>> +++ b/drivers/infiniband/hw/ocrdma/ocrdma_hw.c >>> @@ -1365,8 +1365,9 @@ static int ocrdma_mbx_get_ctrl_attribs(struct ocrdma_dev *dev) >>> dev->hba_port_num = (hba_attribs->ptpnum_maxdoms_hbast_cv & >>> OCRDMA_HBA_ATTRB_PTNUM_MASK) >>> >> OCRDMA_HBA_ATTRB_PTNUM_SHIFT; >>> - strncpy(dev->model_number, >>> - hba_attribs->controller_model_number, 31); >>> + strlcpy(dev->model_number, >>> + hba_attribs->controller_model_number, >>> + sizeof(dev->model_number)); >> >> Yikes this code is weird. Why was it hard coded at 31 when both arrays >> are length 32? Selvin? >> > Seems like a bug. FW structure defines model_number as 32 byte array. > But usually FW populates only 12 bytes out of 32 bytes for > model_number. So it was > never reported as an issue. So, the issue is the NULL termination, ideally we want to copy up to 32 bytes from the firmware into 33 bytes of destination array, so that there is no truncation and it is always null terminated. Unless you think we need to trust the firmware, then the strlcpy is fine. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
