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 f7887f4..9d3f26b 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);
                }