net: sched: Replace strlcpy with strscpy

strlcpy() reads the entire source buffer first.
This read may exceed the destination size limit.
This is both inefficient and can lead to linear read
overflows if a source string is not NUL-terminated [1].
In an effort to remove strlcpy() completely [2], replace
strlcpy() here with strscpy().

Direct replacement is safe here since return value of -errno
is used to check for truncation instead of sizeof(dest).

[1] https://www.kernel.org/doc/html/latest/process/deprecated.html#strlcpy
[2] https://github.com/KSPP/linux/issues/89

Signed-off-by: Azeem Shaikh <azeemshaikh38@gmail.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index f7887f42d5427f352c58fc1b213a7f04a7f02f17..9d3f26bf0440d9d2296e73ad39157e9122cc0b1d 100644 (file)
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -1320,7 +1320,7 @@ struct tc_action_ops *tc_action_load_ops(struct nlattr *nla, bool police,
                        return ERR_PTR(err);
                }
        } else {
-               if (strlcpy(act_name, "police", IFNAMSIZ) >= IFNAMSIZ) {
+               if (strscpy(act_name, "police", IFNAMSIZ) < 0) {
                        NL_SET_ERR_MSG(extack, "TC action name too long");
                        return ERR_PTR(-EINVAL);
                }