block: DAC960: shut up format-overflow warning

gcc-7 points out that a large controller number would overflow the
string length for the procfs name and the firmware version string:

drivers/block/DAC960.c: In function 'DAC960_Probe':
drivers/block/DAC960.c:6591:38: warning: 'sprintf' may write a terminating nul past the end of the destination [-Wformat-overflow=]
drivers/block/DAC960.c: In function 'DAC960_V1_ReadControllerConfiguration':
drivers/block/DAC960.c:1681:40: error: '%02d' directive writing between 2 and 3 bytes into a region of size between 2 and 5 [-Werror=format-overflow=]
drivers/block/DAC960.c:1681:40: note: directive argument in the range [0, 255]
drivers/block/DAC960.c:1681:3: note: 'sprintf' output between 10 and 14 bytes into a destination of size 12

Both of these seem appropriately sized, and using snprintf()
instead of sprintf() improves this by ensuring that even
incorrect data won't cause undefined behavior here.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/drivers/block/DAC960.c b/drivers/block/DAC960.c
index 245a879..255591a 100644 (file)
--- a/drivers/block/DAC960.c
+++ b/drivers/block/DAC960.c
@@ -1678,9 +1678,12 @@ static bool DAC960_V1_ReadControllerConfiguration(DAC960_Controller_T
       Enquiry2->FirmwareID.FirmwareType = '0';
       Enquiry2->FirmwareID.TurnID = 0;
     }
-  sprintf(Controller->FirmwareVersion, "%d.%02d-%c-%02d",
-         Enquiry2->FirmwareID.MajorVersion, Enquiry2->FirmwareID.MinorVersion,
-         Enquiry2->FirmwareID.FirmwareType, Enquiry2->FirmwareID.TurnID);
+  snprintf(Controller->FirmwareVersion, sizeof(Controller->FirmwareVersion),
+          "%d.%02d-%c-%02d",
+          Enquiry2->FirmwareID.MajorVersion,
+          Enquiry2->FirmwareID.MinorVersion,
+          Enquiry2->FirmwareID.FirmwareType,
+          Enquiry2->FirmwareID.TurnID);
   if (!((Controller->FirmwareVersion[0] == '5' &&
         strcmp(Controller->FirmwareVersion, "5.06") >= 0) ||
        (Controller->FirmwareVersion[0] == '4' &&
@@ -6588,7 +6591,8 @@ static void DAC960_CreateProcEntries(DAC960_Controller_T *Controller)
                            &dac960_proc_fops);
        }
 
-       sprintf(Controller->ControllerName, "c%d", Controller->ControllerNumber);
+       snprintf(Controller->ControllerName, sizeof(Controller->ControllerName),
+                "c%d", Controller->ControllerNumber);
        ControllerProcEntry = proc_mkdir(Controller->ControllerName,
                                         DAC960_ProcDirectoryEntry);
        proc_create_data("initial_status", 0, ControllerProcEntry, &dac960_initial_status_proc_fops, Controller);