[PATCH net-next v4] NFC: pn544: i2c: Replace strcpy() with strscpy()

[tomasz . unger]

From: Tomasz Unger <tomasz.unger@xxxxxxxx>

Replace strcpy() with strscpy() which limits the copy to the size of
the destination buffer. Since phy->firmware_name is an array, the
two-argument variant of strscpy() is used - the compiler deduces
the buffer size automatically.

This is a defensive cleanup. As pointed out by Jakub Kicinski
<kuba@xxxxxxxxxx>, firmware_name is already bounded to
NFC_FIRMWARE_NAME_MAXSIZE via nla_strscpy() in net/nfc/netlink.c
before reaching this driver, so no actual buffer overflow is possible.

Signed-off-by: Tomasz Unger <tomasz.unger@xxxxxxxx>
---
Changes since v3:
- Reworded commit message: removed "bug fix" and "buffer overflow"
  language as pointed out by Jakub Kicinski <kuba@xxxxxxxxxx>;
  firmware_name is already bounded via nla_strscpy() in netlink.c
- Changed submission target from net to net-next (cleanup, not a fix)

Testing:
- checkpatch.pl: 0 errors, 0 warnings
- make M=drivers/nfc/pn544/: compiled successfully, 0 errors, 0 warnings

 drivers/nfc/pn544/i2c.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/nfc/pn544/i2c.c b/drivers/nfc/pn544/i2c.c
index a0dfb3f98d5a..b31b5bef7187 100644
--- a/drivers/nfc/pn544/i2c.c
+++ b/drivers/nfc/pn544/i2c.c
@@ -526,7 +526,7 @@ static int pn544_hci_i2c_fw_download(void *phy_id, const char *firmware_name,
 
 	pr_info("Starting Firmware Download (%s)\n", firmware_name);
 
-	strcpy(phy->firmware_name, firmware_name);
+	strscpy(phy->firmware_name, firmware_name);
 
 	phy->hw_variant = hw_variant;
 	phy->fw_work_state = FW_WORK_STATE_START;

-- 
2.53.0