NFC: llcp: Fix zero octets length SDU handling

LLCP Validation test #2 (Connection-less information transfer) send a
service data unit of zero octets length. This is now handled correctly.

Signed-off-by: Olivier Guiter <olivier.guiter@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/net/nfc/llcp/commands.c b/net/nfc/llcp/commands.c
index c5535cc..199e8b5 100644 (file)
--- a/net/nfc/llcp/commands.c
+++ b/net/nfc/llcp/commands.c
@@ -694,8 +694,7 @@ int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
        remaining_len = len;
        msg_ptr = msg_data;
 
-       while (remaining_len > 0) {
-
+       do {
                frag_len = min_t(size_t, sock->remote_miu, remaining_len);
 
                pr_debug("Fragment %zd bytes remaining %zd",
@@ -708,7 +707,8 @@ int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
 
                skb_put(pdu, LLCP_SEQUENCE_SIZE);
 
-               memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
+               if (likely(frag_len > 0))
+                       memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
 
                skb_queue_tail(&sock->tx_queue, pdu);
 
@@ -720,7 +720,7 @@ int nfc_llcp_send_i_frame(struct nfc_llcp_sock *sock,
 
                remaining_len -= frag_len;
                msg_ptr += frag_len;
-       }
+       } while (remaining_len > 0);
 
        kfree(msg_data);
 
@@ -754,8 +754,7 @@ int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap,
        remaining_len = len;
        msg_ptr = msg_data;
 
-       while (remaining_len > 0) {
-
+       do {
                frag_len = min_t(size_t, sock->remote_miu, remaining_len);
 
                pr_debug("Fragment %zd bytes remaining %zd",
@@ -770,14 +769,15 @@ int nfc_llcp_send_ui_frame(struct nfc_llcp_sock *sock, u8 ssap, u8 dsap,
 
                pdu = llcp_add_header(pdu, dsap, ssap, LLCP_PDU_UI);
 
-               memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
+               if (likely(frag_len > 0))
+                       memcpy(skb_put(pdu, frag_len), msg_ptr, frag_len);
 
                /* No need to check for the peer RW for UI frames */
                skb_queue_tail(&local->tx_queue, pdu);
 
                remaining_len -= frag_len;
                msg_ptr += frag_len;
-       }
+       } while (remaining_len > 0);
 
        kfree(msg_data);