diff options
author | Oliver Hartkopp <socketcan@hartkopp.net> | 2022-03-16 19:42:58 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 15:40:22 +0300 |
commit | c037e135391c70d4a3304b5df012d404ad8d3d58 (patch) | |
tree | df044fe0fc19322f5534e83790073decd1d2ae97 /net/can | |
parent | f402c498651993de361f349ac0cedb9f8622319f (diff) | |
download | linux-c037e135391c70d4a3304b5df012d404ad8d3d58.tar.xz |
can: isotp: support MSG_TRUNC flag when reading from socket
[ Upstream commit 42bf50a1795a1854d48717b7361dbdbce496b16b ]
When providing the MSG_TRUNC flag via recvmsg() syscall the return value
provides the real length of the packet or datagram, even when it was longer
than the passed buffer.
Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
Link: https://github.com/linux-can/can-utils/issues/347#issuecomment-1065932671
Link: https://lore.kernel.org/all/20220316164258.54155-3-socketcan@hartkopp.net
Suggested-by: Derek Will <derekrobertwill@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'net/can')
-rw-r--r-- | net/can/isotp.c | 27 |
1 files changed, 15 insertions, 12 deletions
diff --git a/net/can/isotp.c b/net/can/isotp.c index aad4ca62c9fd..671c3673b7ea 100644 --- a/net/can/isotp.c +++ b/net/can/isotp.c @@ -1004,29 +1004,28 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, struct sock *sk = sock->sk; struct sk_buff *skb; struct isotp_sock *so = isotp_sk(sk); - int err = 0; - int noblock; + int noblock = flags & MSG_DONTWAIT; + int ret = 0; - noblock = flags & MSG_DONTWAIT; - flags &= ~MSG_DONTWAIT; + if (flags & ~(MSG_DONTWAIT | MSG_TRUNC)) + return -EINVAL; if (!so->bound) return -EADDRNOTAVAIL; - skb = skb_recv_datagram(sk, flags, noblock, &err); + flags &= ~MSG_DONTWAIT; + skb = skb_recv_datagram(sk, flags, noblock, &ret); if (!skb) - return err; + return ret; if (size < skb->len) msg->msg_flags |= MSG_TRUNC; else size = skb->len; - err = memcpy_to_msg(msg, skb->data, size); - if (err < 0) { - skb_free_datagram(sk, skb); - return err; - } + ret = memcpy_to_msg(msg, skb->data, size); + if (ret < 0) + goto out_err; sock_recv_timestamp(msg, sk, skb); @@ -1036,9 +1035,13 @@ static int isotp_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, memcpy(msg->msg_name, skb->cb, msg->msg_namelen); } + /* set length of return value */ + ret = (flags & MSG_TRUNC) ? skb->len : size; + +out_err: skb_free_datagram(sk, skb); - return size; + return ret; } static int isotp_release(struct socket *sock) |