From: Arnd Bergmann <arnd@xxxxxxxx>
When -Wstringop-truncation is enabled, gcc finds a function that
always does a short copy:
In function 'inquiry',
inlined from 'rtsx_scsi_handler' at drivers/staging/rts5208/rtsx_scsi.c:3210:12:
drivers/staging/rts5208/rtsx_scsi.c:526:17: error: 'strncpy' output truncated copying between 1 and 28 bytes from a string of length 28 [-Werror=stringop-truncation]
526 | strncpy(buf + 8, inquiry_string, sendbytes - 8);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The code originally had a memcpy() that would overread the source string,
and commit 88a5b39b69ab ("staging/rts5208: Fix read overflow in memcpy")
fixed this but introduced the warning about truncation in the process.
As Dan points out, the final space in the inquiry_string always gets
cut off, so remove it here for clarity, leaving exactly the 28 non-NUL
characters that can get copied into the output. In the 'pro_formatter_flag'
this is followed by another 20 bytes from the 'formatter_inquiry_str'
array, but there the output never contains a NUL-termination, and the
length is known, so memcpy() is the more logical choice.
Cc: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Link: https://lore.kernel.org/lkml/695be581-548f-4e5e-a211-5f3b95568e77@moroto.mountain/
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
v2: remove unneeded space byte from input string for clarity,
rework changelog text
---
drivers/staging/rts5208/rtsx_scsi.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/rts5208/rtsx_scsi.c b/drivers/staging/rts5208/rtsx_scsi.c
index 08bd768ad34d..c27cffb9ad8f 100644
--- a/drivers/staging/rts5208/rtsx_scsi.c
+++ b/drivers/staging/rts5208/rtsx_scsi.c
@@ -463,10 +463,10 @@ static unsigned char formatter_inquiry_str[20] = {
static int inquiry(struct scsi_cmnd *srb, struct rtsx_chip *chip)
{
unsigned int lun = SCSI_LUN(srb);
- char *inquiry_default = (char *)"Generic-xD/SD/M.S. 1.00 ";
- char *inquiry_sdms = (char *)"Generic-SD/MemoryStick 1.00 ";
- char *inquiry_sd = (char *)"Generic-SD/MMC 1.00 ";
- char *inquiry_ms = (char *)"Generic-MemoryStick 1.00 ";
+ char *inquiry_default = (char *)"Generic-xD/SD/M.S. 1.00";
+ char *inquiry_sdms = (char *)"Generic-SD/MemoryStick 1.00";
+ char *inquiry_sd = (char *)"Generic-SD/MMC 1.00";
+ char *inquiry_ms = (char *)"Generic-MemoryStick 1.00";
char *inquiry_string;
unsigned char sendbytes;
unsigned char *buf;
@@ -523,7 +523,7 @@ static int inquiry(struct scsi_cmnd *srb, struct rtsx_chip *chip)
if (sendbytes > 8) {
memcpy(buf, inquiry_buf, 8);
- strncpy(buf + 8, inquiry_string, sendbytes - 8);
+ memcpy(buf + 8, inquiry_string, min(sendbytes, 36) - 8);
if (pro_formatter_flag) {
/* Additional Length */
buf[4] = 0x33;
--
2.39.2
