Merge remote-tracking branch 'remotes/jasowang/tags/net-pull-request' into staging

# gpg: Signature made Tue 21 Jul 2020 14:31:13 BST
# gpg:                using RSA key EF04965B398D6211
# gpg: Good signature from "Jason Wang (Jason Wang on RedHat) <jasowang@redhat.com>" [marginal]
# gpg: WARNING: This key is not certified with sufficiently trusted signatures!
# gpg:          It is not certain that the signature belongs to the owner.
# Primary key fingerprint: 215D 46F4 8246 689E C77F  3562 EF04 965B 398D 6211

* remotes/jasowang/tags/net-pull-request:
  hw/net/xgmac: Fix buffer overflow in xgmac_enet_send()
  hw/net: Added plen fix for IPv6

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 50 insertions, 2 deletions

diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index 331c73c..9560e4a 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -626,6 +626,7 @@ bool net_tx_pkt_send(struct NetTxPkt *pkt, NetClientState *nc)
 
     if (pkt->has_virt_hdr ||
         pkt->virt_hdr.gso_type == VIRTIO_NET_HDR_GSO_NONE) {
+        net_tx_pkt_fix_ip6_payload_len(pkt);
         net_tx_pkt_sendv(pkt, nc, pkt->vec,
             pkt->payload_frags + NET_TX_PKT_PL_START_FRAG);
         return true;
@@ -644,3 +645,25 @@ bool net_tx_pkt_send_loopback(struct NetTxPkt *pkt, NetClientState *nc)
 
     return res;
 }
+
+void net_tx_pkt_fix_ip6_payload_len(struct NetTxPkt *pkt)
+{
+    struct iovec *l2 = &pkt->vec[NET_TX_PKT_L2HDR_FRAG];
+    if (eth_get_l3_proto(l2, 1, l2->iov_len) == ETH_P_IPV6) {
+        struct ip6_header *ip6 = (struct ip6_header *) pkt->l3_hdr;
+        /*
+         * TODO: if qemu would support >64K packets - add jumbo option check
+         * something like that:
+         * 'if (ip6->ip6_plen == 0 && !has_jumbo_option(ip6)) {'
+         */
+        if (ip6->ip6_plen == 0) {
+            if (pkt->payload_len <= ETH_MAX_IP_DGRAM_LEN) {
+                ip6->ip6_plen = htons(pkt->payload_len);
+            }
+            /*
+             * TODO: if qemu would support >64K packets
+             * add jumbo option for packets greater then 65,535 bytes
+             */
+        }
+    }
+}
diff --git a/hw/net/net_tx_pkt.h b/hw/net/net_tx_pkt.h
index 212ecc6..4ec8bbe 100644
--- a/hw/net/net_tx_pkt.h
+++ b/hw/net/net_tx_pkt.h
@@ -187,4 +187,18 @@ bool net_tx_pkt_parse(struct NetTxPkt *pkt);
 */
 bool net_tx_pkt_has_fragments(struct NetTxPkt *pkt);
 
+/**
+ * Fix IPv6 'plen' field.
+ * If ipv6 payload length field is 0 - then there should be Hop-by-Hop
+ * option for packets greater than 65,535.
+ * For packets with a payload less than 65,535: fix 'plen' field.
+ * For backends with vheader, we need just one packet with proper
+ * payload size. For now, qemu drops every packet with size greater 64K
+ * (see net_tx_pkt_send()) so, there is no reason to add jumbo option to ip6
+ * hop-by-hop extension if it's missed
+ *
+ * @pkt            packet
+ */
+void net_tx_pkt_fix_ip6_payload_len(struct NetTxPkt *pkt);
+
 #endif
diff --git a/hw/net/xgmac.c b/hw/net/xgmac.c
index 574dd47..5bf1b61 100644
--- a/hw/net/xgmac.c
+++ b/hw/net/xgmac.c
@@ -220,21 +220,31 @@ static void xgmac_enet_send(XgmacState *s)
         }
         len = (bd.buffer1_size & 0xfff) + (bd.buffer2_size & 0xfff);
 
+        /*
+         * FIXME: these cases of malformed tx descriptors (bad sizes)
+         * should probably be reported back to the guest somehow
+         * rather than simply silently stopping processing, but we
+         * don't know what the hardware does in this situation.
+         * This will only happen for buggy guests anyway.
+         */
         if ((bd.buffer1_size & 0xfff) > 2048) {
             DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
                         "xgmac buffer 1 len on send > 2048 (0x%x)\n",
                          __func__, bd.buffer1_size & 0xfff);
+            break;
         }
         if ((bd.buffer2_size & 0xfff) != 0) {
             DEBUGF_BRK("qemu:%s:ERROR...ERROR...ERROR... -- "
                         "xgmac buffer 2 len on send != 0 (0x%x)\n",
                         __func__, bd.buffer2_size & 0xfff);
+            break;
         }
-        if (len >= sizeof(frame)) {
+        if (frame_size + len >= sizeof(frame)) {
             DEBUGF_BRK("qemu:%s: buffer overflow %d read into %zu "
-                        "buffer\n" , __func__, len, sizeof(frame));
+                        "buffer\n" , __func__, frame_size + len, sizeof(frame));
             DEBUGF_BRK("qemu:%s: buffer1.size=%d; buffer2.size=%d\n",
                         __func__, bd.buffer1_size, bd.buffer2_size);
+            break;
         }
 
         cpu_physical_memory_read(bd.buffer1_addr, ptr, len);
diff --git a/include/net/eth.h b/include/net/eth.h
index 7f45c67..0671be6 100644
--- a/include/net/eth.h
+++ b/include/net/eth.h
@@ -186,6 +186,7 @@ struct tcp_hdr {
 
 #define ip6_nxt      ip6_ctlun.ip6_un1.ip6_un1_nxt
 #define ip6_ecn_acc  ip6_ctlun.ip6_un3.ip6_un3_ecn
+#define ip6_plen     ip6_ctlun.ip6_un1.ip6_un1_plen
 
 #define PKT_GET_ETH_HDR(p)        \
     ((struct eth_header *)(p))