net: don't call strlen on non-terminated string in dev_set_alias()

KMSAN reported a use of uninitialized memory in dev_set_alias(),
which was caused by calling strlcpy() (which in turn called strlen())
on the user-supplied non-terminated string.

Signed-off-by: Alexander Potapenko <glider@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index fca407b4a6ea178d9224949bc57f89a26c97c5c1..84e1e86a4bce93579dbcfa6e79bcd8c13f1852fc 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -1253,8 +1253,9 @@ int dev_set_alias(struct net_device *dev, const char *alias, size_t len)
        if (!new_ifalias)
                return -ENOMEM;
        dev->ifalias = new_ifalias;
+       memcpy(dev->ifalias, alias, len);
+       dev->ifalias[len] = 0;
 
-       strlcpy(dev->ifalias, alias, len+1);
        return len;
 }