Commit dcda138d authored by Sjur Braendeland's avatar Sjur Braendeland Committed by David S. Miller

caif: Bugfix - use MSG_TRUNC in receive

Fixed handling when skb don't fit in user buffer,
instead of returning -EMSGSIZE, the buffer is truncated (just
as unix seqpakcet does).
Signed-off-by: default avatarSjur Braendeland <>
Signed-off-by: default avatarDavid S. Miller <>
parent a9a8f107
......@@ -292,53 +292,42 @@ static void caif_check_flow_release(struct sock *sk)
caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
* Copied from sock.c:sock_queue_rcv_skb(), and added check that user buffer
* has sufficient size.
* Copied from unix_dgram_recvmsg, but removed credit checks,
* changed locking, address handling and added MSG_TRUNC.
static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
struct msghdr *m, size_t buf_len, int flags)
struct msghdr *m, size_t len, int flags)
struct sock *sk = sock->sk;
struct sk_buff *skb;
int ret = 0;
int len;
int ret;
int copylen;
if (unlikely(!buf_len))
return -EINVAL;
if (m->msg_flags&MSG_OOB)
goto read_error;
skb = skb_recv_datagram(sk, flags, 0 , &ret);
if (!skb)
goto read_error;
len = skb->len;
if (skb && skb->len > buf_len && !(flags & MSG_PEEK)) {
len = buf_len;
* Push skb back on receive queue if buffer too small.
* This has a built-in race where multi-threaded receive
* may get packet in wrong order, but multiple read does
* not really guarantee ordered delivery anyway.
* Let's optimize for speed without taking locks.
skb_queue_head(&sk->sk_receive_queue, skb);
ret = -EMSGSIZE;
goto read_error;
copylen = skb->len;
if (len < copylen) {
m->msg_flags |= MSG_TRUNC;
copylen = len;
ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, len);
ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
if (ret)
goto read_error;
goto out_free;
ret = (flags & MSG_TRUNC) ? skb->len : copylen;
skb_free_datagram(sk, skb);
return len;
return ret;
return ret;
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