[PATCH 4.20 26/76] sctp: call iov_iter_revert() after sending ABORT

[Greg Kroah-Hartman]

4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Xin Long <lucien.xin@xxxxxxxxx>

[ Upstream commit 901efe12318b1ea8d3e2c88a7b75ed6e6d5d7245 ]

The user msg is also copied to the abort packet when doing SCTP_ABORT in
sctp_sendmsg_check_sflags(). When SCTP_SENDALL is set, iov_iter_revert()
should have been called for sending abort on the next asoc with copying
this msg. Otherwise, memcpy_from_msg() in sctp_make_abort_user() will
fail and return error.

Fixes: 4910280503f3 ("sctp: add support for snd flag SCTP_SENDALL process in sendmsg")
Reported-by: Ying Xu <yinxu@xxxxxxxxxx>
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/sctp/socket.c |    1 +
 1 file changed, 1 insertion(+)

--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1866,6 +1866,7 @@ static int sctp_sendmsg_check_sflags(str
 
 		pr_debug("%s: aborting association:%p\n", __func__, asoc);
 		sctp_primitive_ABORT(net, asoc, chunk);
+		iov_iter_revert(&msg->msg_iter, msg_len);
 
 		return 0;
 	}