Commit 5c9f7b04 authored by justinstitt@google.com's avatar justinstitt@google.com Committed by David S. Miller
Browse files

net: dsa: remove deprecated strncpy 

`strncpy` is deprecated for use on NUL-terminated destination strings [1].

Even call sites utilizing length-bounded destination buffers should
switch over to using `strtomem` or `strtomem_pad`. In this case,
however, the compiler is unable to determine the size of the `data`
buffer which renders `strtomem` unusable. Due to this, `strscpy`
should be used.

It should be noted that most call sites already zero-initialize the
destination buffer. However, I've opted to use `strscpy_pad` to maintain
the same exact behavior that `strncpy` produced (zero-padded tail up to
`len`).

Also see [3].

[1]: www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings
[2]: elixir.bootlin.com/linux/v6.3/source/net/ethtool/ioctl.c#L1944
[3]: manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html

Link: https://github.com/KSPP/linux/issues/90


Reviewed-by: default avatarNick Desaulniers <ndesaulniers@google.com>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarJustin Stitt <justinstitt@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 2e60314c

net/dsa/slave.c

+5 −4
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <linux/if_hsr.h>

#include <net/dcbnl.h>

#include <linux/netpoll.h>

#include <linux/string.h>



#include "dsa.h"

#include "port.h"
@@ -1056,10 +1057,10 @@ static void dsa_slave_get_strings(struct net_device *dev, 
	if (stringset == ETH_SS_STATS) {

		int len = ETH_GSTRING_LEN;



		strncpy(data, "tx_packets", len);

		strncpy(data + len, "tx_bytes", len);

		strncpy(data + 2 * len, "rx_packets", len);

		strncpy(data + 3 * len, "rx_bytes", len);

		strscpy_pad(data, "tx_packets", len);

		strscpy_pad(data + len, "tx_bytes", len);

		strscpy_pad(data + 2 * len, "rx_packets", len);

		strscpy_pad(data + 3 * len, "rx_bytes", len);

		if (ds->ops->get_strings)

			ds->ops->get_strings(ds, dp->index, stringset,

					     data + 4 * len);