[ovs-dev] [PATCH] packets: Fix misaligned data accesses for MPLS and SCTP fields.

Ben Pfaff blp at nicira.com
Sat Apr 5 03:22:07 UTC 2014


The other 32-bit data fields in protocol headers were already using
ovs_16aligned_be32, but MPLS and SCTP had been overlooked.  This fixes
the failure of test 681 seen here:
https://buildd.debian.org/status/fetch.php?pkg=openvswitch&arch=sparc&ver=2.1.0%2Bgit20140325-1&stamp=1396438624

Signed-off-by: Ben Pfaff <blp at nicira.com>
---
 lib/flow.c      |  5 +++--
 lib/ofp-print.c |  3 ++-
 lib/packets.c   | 12 ++++++------
 lib/packets.h   |  6 +++---
 4 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/lib/flow.c b/lib/flow.c
index e1ea75e..f97d7a9 100644
--- a/lib/flow.c
+++ b/lib/flow.c
@@ -88,10 +88,11 @@ parse_mpls(struct ofpbuf *b, struct flow *flow)
     int idx = 0;
 
     while ((mh = ofpbuf_try_pull(b, sizeof *mh))) {
+        ovs_be32 mpls_lse = get_16aligned_be32(&mh->mpls_lse);
         if (idx < FLOW_MAX_MPLS_LABELS) {
-            flow->mpls_lse[idx++] = mh->mpls_lse;
+            flow->mpls_lse[idx++] = mpls_lse;
         }
-        if (mh->mpls_lse & htonl(MPLS_BOS_MASK)) {
+        if (mpls_lse & htonl(MPLS_BOS_MASK)) {
             break;
         }
     }
diff --git a/lib/ofp-print.c b/lib/ofp-print.c
index e0e565c..02f3db0 100644
--- a/lib/ofp-print.c
+++ b/lib/ofp-print.c
@@ -78,7 +78,8 @@ ofp_packet_to_string(const void *data, size_t len)
         ds_put_format(&ds, " udp_csum:%"PRIx16, ntohs(uh->udp_csum));
     } else if (flow.nw_proto == IPPROTO_SCTP && l4_size >= SCTP_HEADER_LEN) {
         struct sctp_header *sh = ofpbuf_l4(&buf);
-        ds_put_format(&ds, " sctp_csum:%"PRIx32, ntohl(sh->sctp_csum));
+        ds_put_format(&ds, " sctp_csum:%"PRIx32,
+                      ntohl(get_16aligned_be32(&sh->sctp_csum)));
     }
 
     ds_put_char(&ds, '\n');
diff --git a/lib/packets.c b/lib/packets.c
index 89ee324..6244c3f 100644
--- a/lib/packets.c
+++ b/lib/packets.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
+ * Copyright (c) 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -288,7 +288,7 @@ set_mpls_lse(struct ofpbuf *packet, ovs_be32 mpls_lse)
         struct mpls_hdr *mh = ofpbuf_l2_5(packet);
 
         /* Update mpls label stack entry. */
-        mh->mpls_lse = mpls_lse;
+        put_16aligned_be32(&mh->mpls_lse, mpls_lse);
     }
 }
 
@@ -331,7 +331,7 @@ pop_mpls(struct ofpbuf *packet, ovs_be16 ethtype)
         size_t len = packet->l2_5_ofs;
 
         set_ethertype(packet, ethtype);
-        if (mh->mpls_lse & htonl(MPLS_BOS_MASK)) {
+        if (get_16aligned_be32(&mh->mpls_lse) & htonl(MPLS_BOS_MASK)) {
             ofpbuf_set_l2_5(packet, NULL);
         }
         /* Shift the l2 header forward. */
@@ -858,15 +858,15 @@ packet_set_sctp_port(struct ofpbuf *packet, ovs_be16 src, ovs_be16 dst)
     ovs_be32 old_csum, old_correct_csum, new_csum;
     uint16_t tp_len = ofpbuf_l4_size(packet);
 
-    old_csum = sh->sctp_csum;
-    sh->sctp_csum = 0;
+    old_csum = get_16aligned_be32(&sh->sctp_csum);
+    put_16aligned_be32(&sh->sctp_csum, 0);
     old_correct_csum = crc32c((void *)sh, tp_len);
 
     sh->sctp_src = src;
     sh->sctp_dst = dst;
 
     new_csum = crc32c((void *)sh, tp_len);
-    sh->sctp_csum = old_csum ^ old_correct_csum ^ new_csum;
+    put_16aligned_be32(&sh->sctp_csum, old_csum ^ old_correct_csum ^ new_csum);
 }
 
 const char *
diff --git a/lib/packets.h b/lib/packets.h
index 22817af..eca24d5 100644
--- a/lib/packets.h
+++ b/lib/packets.h
@@ -363,7 +363,7 @@ BUILD_ASSERT_DECL(VLAN_ETH_HEADER_LEN == sizeof(struct vlan_eth_header));
 #define MPLS_HLEN           4
 
 struct mpls_hdr {
-    ovs_be32 mpls_lse;
+    ovs_16aligned_be32 mpls_lse;
 };
 BUILD_ASSERT_DECL(MPLS_HLEN == sizeof(struct mpls_hdr));
 
@@ -510,8 +510,8 @@ BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));
 struct sctp_header {
     ovs_be16 sctp_src;
     ovs_be16 sctp_dst;
-    ovs_be32 sctp_vtag;
-    ovs_be32 sctp_csum;
+    ovs_16aligned_be32 sctp_vtag;
+    ovs_16aligned_be32 sctp_csum;
 };
 BUILD_ASSERT_DECL(SCTP_HEADER_LEN == sizeof(struct sctp_header));
 
-- 
1.8.5.3




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