tipc: don't assume linear buffer when reading ancillary data

The code for reading ancillary data from a received buffer is assuming
the buffer is linear. To make this assumption true we have to linearize
the buffer before message data is read.

Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 4 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 636e6131769d..b57b1be7252b 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -1555,16 +1555,17 @@ static void tipc_sk_set_orig_addr(struct msghdr *m, struct sk_buff *skb)
 /**
  * tipc_sk_anc_data_recv - optionally capture ancillary data for received message
  * @m: descriptor for message info
- * @msg: received message header
+ * @skb: received message buffer
  * @tsk: TIPC port associated with message
  *
  * Note: Ancillary data is not captured if not requested by receiver.
  *
  * Returns 0 if successful, otherwise errno
  */
-static int tipc_sk_anc_data_recv(struct msghdr *m, struct tipc_msg *msg,
+static int tipc_sk_anc_data_recv(struct msghdr *m, struct sk_buff *skb,
                                  struct tipc_sock *tsk)
 {
+        struct tipc_msg *msg;
         u32 anc_data[3];
         u32 err;
         u32 dest_type;
@@ -1573,6 +1574,7 @@ static int tipc_sk_anc_data_recv(struct msghdr *m, struct tipc_msg *msg,
 
         if (likely(m->msg_controllen == 0))
                 return 0;
+        msg = buf_msg(skb);
 
         /* Optionally capture errored message object(s) */
         err = msg ? msg_errcode(msg) : 0;
@@ -1583,6 +1585,9 @@ static int tipc_sk_anc_data_recv(struct msghdr *m, struct tipc_msg *msg,
                 if (res)
                         return res;
                 if (anc_data[1]) {
+                        if (skb_linearize(skb))
+                                return -ENOMEM;
+                        msg = buf_msg(skb);
                         res = put_cmsg(m, SOL_TIPC, TIPC_RETDATA, anc_data[1],
                                        msg_data(msg));
                         if (res)
@@ -1744,9 +1749,10 @@ static int tipc_recvmsg(struct socket *sock, struct msghdr *m,
 
         /* Collect msg meta data, including error code and rejected data */
         tipc_sk_set_orig_addr(m, skb);
-        rc = tipc_sk_anc_data_recv(m, hdr, tsk);
+        rc = tipc_sk_anc_data_recv(m, skb, tsk);
         if (unlikely(rc))
                 goto exit;
+        hdr = buf_msg(skb);
 
         /* Capture data if non-error msg, otherwise just set return value */
         if (likely(!err)) {
@@ -1856,9 +1862,10 @@ static int tipc_recvstream(struct socket *sock, struct msghdr *m,
                 /* Collect msg meta data, incl. error code and rejected data */
                 if (!copied) {
                         tipc_sk_set_orig_addr(m, skb);
-                        rc = tipc_sk_anc_data_recv(m, hdr, tsk);
+                        rc = tipc_sk_anc_data_recv(m, skb, tsk);
                         if (rc)
                                 break;
+                        hdr = buf_msg(skb);
                 }
 
                 /* Copy data if msg ok, otherwise return error/partial data */