2021-12-20 08:46:45

by Jason Wang

Subject: [PATCH] net: xtensa: use strscpy to copy strings

The strlcpy should not be used because it doesn't limit the source
length. So that it will lead some potential bugs.

But the strscpy doesn't require reading memory from the src string
beyond the specified "count" bytes, and since the return value is
easier to error-check than strlcpy()'s. In addition, the implementation
is robust to the string changing out from underneath it, unlike the
current strlcpy() implementation.

Thus, replace strlcpy with strscpy.

Signed-off-by: Jason Wang <[email protected]>
---
arch/xtensa/platforms/iss/network.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/xtensa/platforms/iss/network.c b/arch/xtensa/platforms/iss/network.c
index 962e5e145209..e62e31c88956 100644
--- a/arch/xtensa/platforms/iss/network.c
+++ b/arch/xtensa/platforms/iss/network.c
@@ -174,7 +174,7 @@ static int tuntap_open(struct iss_net_private *lp)

memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
- strlcpy(ifr.ifr_name, dev_name, sizeof(ifr.ifr_name));
+ strscpy(ifr.ifr_name, dev_name, sizeof(ifr.ifr_name));

err = simc_ioctl(fd, TUNSETIFF, &ifr);
if (err < 0) {
@@ -249,7 +249,7 @@ static int tuntap_probe(struct iss_net_private *lp, int index, char *init)
return 0;
}

- strlcpy(lp->tp.info.tuntap.dev_name, dev_name,
+ strscpy(lp->tp.info.tuntap.dev_name, dev_name,
sizeof(lp->tp.info.tuntap.dev_name));

setup_etheraddr(dev, mac_str);
--
2.34.1

2021-12-24 11:28:59

by Max Filippov

Subject: Re: [PATCH] net: xtensa: use strscpy to copy strings

On Mon, Dec 20, 2021 at 12:46 AM Jason Wang <[email protected]> wrote:
>
> The strlcpy should not be used because it doesn't limit the source
> length. So that it will lead some potential bugs.
>
> But the strscpy doesn't require reading memory from the src string
> beyond the specified "count" bytes, and since the return value is
> easier to error-check than strlcpy()'s. In addition, the implementation
> is robust to the string changing out from underneath it, unlike the
> current strlcpy() implementation.
>
> Thus, replace strlcpy with strscpy.
>
> Signed-off-by: Jason Wang <[email protected]>
> ---
> arch/xtensa/platforms/iss/network.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)

Applied to my xtensa tree. Thanks.

-- Max