[PATCH net-next] drivers/net/ethernet/sfc/falcon/ethtool: Use strscpy() to copy strings into arrays

[PATCH net-next] drivers/net/ethernet/sfc/falcon/ethtool: Use strscpy() to copy strings into arrays

[david.laight.linux]

From: David Laight <david.laight.linux@gmail.com>

Replacing strcpy() with strscpy() ensures that overflow of the target
buffer cannot happen.

Signed-off-by: David Laight <david.laight.linux@gmail.com>
---
This is one of a group of patches that remove potentially unbounded
strcpy() calls.

They are mostly replaced by strscpy() or, when strlen() has just been
called, with memcpy() (usually including the '\0').

Calls with copy string literals into arrays are left unchanged.
They are safe and easily detected as such.

The changes were made by getting the compiler to detect the calls and
then fixing the code by hand.

Note that all the changes are only compile tested.

Some Makefiles were changed to allow files to contain strcpy().
As well as 'difficult to fix' files, this included 'show' functions
as they really need to use sysfs_emit() or seq_printf().

All the patches are being sent individually to avoid very long cc lists.
Apologies for the terse commit messages and likely unexpected tags.
(There are about 100 patches in total.)

 drivers/net/ethernet/sfc/falcon/ethtool.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/sfc/falcon/ethtool.c b/drivers/net/ethernet/sfc/falcon/ethtool.c
index 3d81b3ca61e9..ef5a7117be5a 100644
--- a/drivers/net/ethernet/sfc/falcon/ethtool.c
+++ b/drivers/net/ethernet/sfc/falcon/ethtool.c
@@ -222,7 +222,7 @@ static void ef4_fill_test(unsigned int test_index, u8 *strings, u64 *data,
 			snprintf(unit_str, sizeof(unit_str),
 				 unit_format, unit_id);
 		else
-			strcpy(unit_str, unit_format);
+			strscpy(unit_str, unit_format);
 		snprintf(test_str, sizeof(test_str), test_format, test_id);
 		snprintf(strings + test_index * ETH_GSTRING_LEN,
 			 ETH_GSTRING_LEN,
-- 
2.39.5

Re: [PATCH net-next] drivers/net/ethernet/sfc/falcon/ethtool: Use strscpy() to copy strings into arrays

[Jakub Kicinski]

On Mon,  8 Jun 2026 10:54:45 +0100 david.laight.linux@gmail.com wrote:
> From: David Laight <david.laight.linux@gmail.com>
> 
> Replacing strcpy() with strscpy() ensures that overflow of the target
> buffer cannot happen.

all unit_formats are (obviously) compile time constants here
-- 
pw-bot: reject