svn commit: r317258 - stable/11/sys/kern

[Andrey V. Elsukov]

Author: ae
Date: Fri Apr 21 16:45:43 2017
New Revision: 317258
URL: https://svnweb.freebsd.org/changeset/base/317258

Log:
  MFC r316770:
    Clear h/w csum flags on mbuf handled by UDP.
  
    When checksums of received IP and UDP header already checked, UDP uses
    sbappendaddr_locked() to pass received data to the socket.
    sbappendaddr_locked() uses given mbuf as is, and if NIC supports checksum
    offloading, mbuf contains csum_data and csum_flags that were calculated
    for already stripped headers. Some NICs support only limited checksums
    offloading and do not use CSUM_PSEUDO_HDR flag, and csum_data contains
    some value that UDP/TCP should use for pseudo header checksum calculation.
  
    When L2TP is used for tunneling with mpd5, ng_ksocket receives mbuf with
    filled csum_flags and csum_data, that were calculated for outer headers.
    When L2TP header is stripped, a packet that was tunneled goes to the IP
    layer and due to presence of csum_flags (without CSUM_PSEUDO_HDR) and
    csum_data, the UDP/TCP checksum check fails for this packet.
  
    Reported by:	Irina Liakh <spell at itl ua>
    Tested by:	Irina Liakh <spell at itl ua>
  
  MFC r316822,316823:
    Rework r316770 to make it protocol independent and general, like we
    do for streaming sockets.
  
    And do more cleanup in the sbappendaddr_locked_internal() to prevent
    leak information from existing mbuf to the one, that will be possible
    created later by netgraph.
  
    Suggested by:	glebius
    Tested by:	Irina Liakh <spell at itl ua>

Modified:
  stable/11/sys/kern/uipc_sockbuf.c
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/kern/uipc_sockbuf.c
==============================================================================
--- stable/11/sys/kern/uipc_sockbuf.c	Fri Apr 21 15:59:58 2017	(r317257)
+++ stable/11/sys/kern/uipc_sockbuf.c	Fri Apr 21 16:45:43 2017	(r317258)
@@ -794,8 +794,20 @@ sbappendaddr_locked_internal(struct sock
 		return (0);
 	m->m_len = asa->sa_len;
 	bcopy(asa, mtod(m, caddr_t), asa->sa_len);
-	if (m0)
+	if (m0) {
 		m_clrprotoflags(m0);
+		m_tag_delete_chain(m0, NULL);
+		/*
+		 * Clear some persistent info from pkthdr.
+		 * We don't use m_demote(), because some netgraph consumers
+		 * expect M_PKTHDR presence.
+		 */
+		m0->m_pkthdr.rcvif = NULL;
+		m0->m_pkthdr.flowid = 0;
+		m0->m_pkthdr.csum_flags = 0;
+		m0->m_pkthdr.fibnum = 0;
+		m0->m_pkthdr.rsstype = 0;
+	}
 	if (ctrl_last)
 		ctrl_last->m_next = m0;	/* concatenate data to control */
 	else