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>

1 files changed, 8 insertions, 8 deletions

diff --git a/net/nfc/llcp/commands.c b/net/nfc/llcp/commands.c
index c5535cc9ed3a..199e8b5514f9 100644
--- 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);