return n;
}
+
+
+/**
+ * wpabuf_zeropad - Pad buffer with 0x00 octets (prefix) to specified length
+ * @buf: Buffer to be padded
+ * @len: Length for the padded buffer
+ * Returns: wpabuf padded to len octets or %NULL on failure
+ *
+ * If buf is longer than len octets or of same size, it will be returned as-is.
+ * Otherwise a new buffer is allocated and prefixed with 0x00 octets followed
+ * by the source data. The source buffer will be freed on error, i.e., caller
+ * will only be responsible on freeing the returned buffer. If buf is %NULL,
+ * %NULL will be returned.
+ */
+struct wpabuf * wpabuf_zeropad(struct wpabuf *buf, size_t len)
+{
+ struct wpabuf *ret;
+ size_t blen;
+
+ if (buf == NULL)
+ return NULL;
+
+ blen = wpabuf_len(buf);
+ if (blen >= len)
+ return buf;
+
+ ret = wpabuf_alloc(len);
+ if (ret) {
+ os_memset(wpabuf_put(ret, len - blen), 0, len - blen);
+ wpabuf_put_buf(ret, buf);
+ }
+ wpabuf_free(buf);
+
+ return ret;
+}
void wpabuf_free(struct wpabuf *buf);
void * wpabuf_put(struct wpabuf *buf, size_t len);
struct wpabuf * wpabuf_concat(struct wpabuf *a, struct wpabuf *b);
+struct wpabuf * wpabuf_zeropad(struct wpabuf *buf, size_t len);
/**
wpa_printf(MSG_DEBUG, "WPS: * Public Key");
pubkey = dh_init(dh_groups_get(WPS_DH_GROUP), &wps->dh_privkey);
+ pubkey = wpabuf_zeropad(pubkey, 192);
if (pubkey == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Failed to initialize "
"Diffie-Hellman handshake");
dh_shared = dh_derive_shared(pubkey, wps->dh_privkey,
dh_groups_get(WPS_DH_GROUP));
+ dh_shared = wpabuf_zeropad(dh_shared, 192);
if (dh_shared == NULL) {
wpa_printf(MSG_DEBUG, "WPS: Failed to derive DH shared key");
return -1;