diff mbox series

staging: rtl8192e: prefer strscpy over strncpy

Message ID 20230805075114.15186-1-straube.linux@gmail.com
State New
Headers
Series staging: rtl8192e: prefer strscpy over strncpy |

Commit Message

Michael Straube Aug. 5, 2023, 7:51 a.m. UTC 
  Replace strncpy with strscpy in two places where the destination buffer
should be NUL-terminated. Found by checkpatch.

WARNING: Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90

Signed-off-by: Michael Straube <straube.linux@gmail.com>
---
 drivers/staging/rtl8192e/rtllib_softmac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Greg KH Aug. 9, 2023, 12:21 p.m. UTC | #1 
On Sat, Aug 05, 2023 at 09:51:14AM +0200, Michael Straube wrote:
> Replace strncpy with strscpy in two places where the destination buffer
> should be NUL-terminated. Found by checkpatch.
> 
> WARNING: Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90

If a global search/replace could be done, it would have happend a long
time ago.

How was this tested?  The functions work differently, are you sure there
is no change in functionality here?

thanks,

greg k-h
Michael Straube Aug. 9, 2023, 6:02 p.m. UTC | #2 
On 8/9/23 14:21, Greg KH wrote:
> On Sat, Aug 05, 2023 at 09:51:14AM +0200, Michael Straube wrote:
>> Replace strncpy with strscpy in two places where the destination buffer
>> should be NUL-terminated. Found by checkpatch.
>>
>> WARNING: Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90
> 
> If a global search/replace could be done, it would have happend a long
> time ago.
> 
> How was this tested?  The functions work differently, are you sure there
> is no change in functionality here?
> 

It was only compile tested. To me it looked as it does not change
functionality, but looking a bit deeper at it I'm not sure anymore.
So, we should leave it as is.

thank you
Michael
Dan Carpenter Aug. 10, 2023, 5:01 a.m. UTC | #3 
On Wed, Aug 09, 2023 at 08:02:05PM +0200, Michael Straube wrote:
> On 8/9/23 14:21, Greg KH wrote:
> > On Sat, Aug 05, 2023 at 09:51:14AM +0200, Michael Straube wrote:
> > > Replace strncpy with strscpy in two places where the destination buffer
> > > should be NUL-terminated. Found by checkpatch.
> > > 
> > > WARNING: Prefer strscpy, strscpy_pad, or __nonstring over strncpy - see: https://github.com/KSPP/linux/issues/90
> > 
> > If a global search/replace could be done, it would have happend a long
> > time ago.
> > 
> > How was this tested?  The functions work differently, are you sure there
> > is no change in functionality here?
> > 
> 
> It was only compile tested. To me it looked as it does not change
> functionality, but looking a bit deeper at it I'm not sure anymore.
> So, we should leave it as is.

So there are three main differences between strncpy() and strcpy().

1) The return.
2) strncpy() will always write net->hidden_ssid_len bytes.  If the
   string to copy is smaller than net->hidden_ssid_len bytes it will
   fill the rest with zeroes.  This can be important for preventing
   information leaks.
3) strscpy() will always add a NUL terminator where strncpy() just
   truncates a too long string without adding a terminator.

We want #3.  We don't care about #1.  The only thing to check is #2.

regards,
dan carpenter
diff mbox series

Patch

diff --git a/drivers/staging/rtl8192e/rtllib_softmac.c b/drivers/staging/rtl8192e/rtllib_softmac.c
index 0e52b207942d..bd19d6a2ce41 100644
--- a/drivers/staging/rtl8192e/rtllib_softmac.c
+++ b/drivers/staging/rtl8192e/rtllib_softmac.c
@@ -1564,7 +1564,7 @@  inline void rtllib_softmac_new_net(struct rtllib_device *ieee,
 				    (!strncmp(ieee->current_network.ssid,
 				    net->hidden_ssid, net->hidden_ssid_len));
 			if (net->hidden_ssid_len > 0) {
-				strncpy(net->ssid, net->hidden_ssid,
+				strscpy(net->ssid, net->hidden_ssid,
 					net->hidden_ssid_len);
 				net->ssid_len = net->hidden_ssid_len;
 				ssidbroad = 1;
@@ -2431,7 +2431,7 @@  static void rtllib_start_master_bss(struct rtllib_device *ieee)
 	ieee->assoc_id = 1;
 
 	if (ieee->current_network.ssid_len == 0) {
-		strncpy(ieee->current_network.ssid,
+		strscpy(ieee->current_network.ssid,
 			RTLLIB_DEFAULT_TX_ESSID,
 			IW_ESSID_MAX_SIZE);