--- /dev/null
+From 8ffb7265af64ec81748335ec8f20e7ab542c3850 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <pjp@fedoraproject.org>
+Date: Tue, 24 Mar 2020 22:57:22 +0530
+Subject: [PATCH] net: tulip: check frame size and r/w data length
+
+Tulip network driver while copying tx/rx buffers does not check
+frame size against r/w data length. This may lead to OOB buffer
+access. Add check to avoid it.
+
+Limit iterations over descriptors to avoid potential infinite
+loop issue in tulip_xmit_list_update.
+
+Reported-by: Li Qiang <pangpei.lq@antfin.com>
+Reported-by: Ziming Zhang <ezrakiez@gmail.com>
+Reported-by: Jason Wang <jasowang@redhat.com>
+Tested-by: Li Qiang <liq3ea@gmail.com>
+Reviewed-by: Li Qiang <liq3ea@gmail.com>
+Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
+Signed-off-by: Jason Wang <jasowang@redhat.com>
+
+Upstream-Status: Backport [https://git.qemu.org/?p=qemu.git;a=commit;h=8ffb7265af64ec81748335ec8f20e7ab542c3850]
+CVE: CVE-2020-11102
+Signed-off-by: Chee Yang Lee <chee.yang.lee@intel.com>
+---
+ hw/net/tulip.c | 36 +++++++++++++++++++++++++++---------
+ 1 file changed, 27 insertions(+), 9 deletions(-)
+
+diff --git a/hw/net/tulip.c b/hw/net/tulip.c
+index cfac271..1295f51 100644
+--- a/hw/net/tulip.c
++++ b/hw/net/tulip.c
+@@ -170,6 +170,10 @@ static void tulip_copy_rx_bytes(TULIPState *s, struct tulip_descriptor *desc)
+ } else {
+ len = s->rx_frame_len;
+ }
++
++ if (s->rx_frame_len + len > sizeof(s->rx_frame)) {
++ return;
++ }
+ pci_dma_write(&s->dev, desc->buf_addr1, s->rx_frame +
+ (s->rx_frame_size - s->rx_frame_len), len);
+ s->rx_frame_len -= len;
+@@ -181,6 +185,10 @@ static void tulip_copy_rx_bytes(TULIPState *s, struct tulip_descriptor *desc)
+ } else {
+ len = s->rx_frame_len;
+ }
++
++ if (s->rx_frame_len + len > sizeof(s->rx_frame)) {
++ return;
++ }
+ pci_dma_write(&s->dev, desc->buf_addr2, s->rx_frame +
+ (s->rx_frame_size - s->rx_frame_len), len);
+ s->rx_frame_len -= len;
+@@ -227,7 +235,8 @@ static ssize_t tulip_receive(TULIPState *s, const uint8_t *buf, size_t size)
+
+ trace_tulip_receive(buf, size);
+
+- if (size < 14 || size > 2048 || s->rx_frame_len || tulip_rx_stopped(s)) {
++ if (size < 14 || size > sizeof(s->rx_frame) - 4
++ || s->rx_frame_len || tulip_rx_stopped(s)) {
+ return 0;
+ }
+
+@@ -275,7 +284,6 @@ static ssize_t tulip_receive_nc(NetClientState *nc,
+ return tulip_receive(qemu_get_nic_opaque(nc), buf, size);
+ }
+
+-
+ static NetClientInfo net_tulip_info = {
+ .type = NET_CLIENT_DRIVER_NIC,
+ .size = sizeof(NICState),
+@@ -558,7 +566,7 @@ static void tulip_tx(TULIPState *s, struct tulip_descriptor *desc)
+ if ((s->csr[6] >> CSR6_OM_SHIFT) & CSR6_OM_MASK) {
+ /* Internal or external Loopback */
+ tulip_receive(s, s->tx_frame, s->tx_frame_len);
+- } else {
++ } else if (s->tx_frame_len <= sizeof(s->tx_frame)) {
+ qemu_send_packet(qemu_get_queue(s->nic),
+ s->tx_frame, s->tx_frame_len);
+ }
+@@ -570,23 +578,31 @@ static void tulip_tx(TULIPState *s, struct tulip_descriptor *desc)
+ }
+ }
+
+-static void tulip_copy_tx_buffers(TULIPState *s, struct tulip_descriptor *desc)
++static int tulip_copy_tx_buffers(TULIPState *s, struct tulip_descriptor *desc)
+ {
+ int len1 = (desc->control >> TDES1_BUF1_SIZE_SHIFT) & TDES1_BUF1_SIZE_MASK;
+ int len2 = (desc->control >> TDES1_BUF2_SIZE_SHIFT) & TDES1_BUF2_SIZE_MASK;
+
++ if (s->tx_frame_len + len1 > sizeof(s->tx_frame)) {
++ return -1;
++ }
+ if (len1) {
+ pci_dma_read(&s->dev, desc->buf_addr1,
+ s->tx_frame + s->tx_frame_len, len1);
+ s->tx_frame_len += len1;
+ }
+
++ if (s->tx_frame_len + len2 > sizeof(s->tx_frame)) {
++ return -1;
++ }
+ if (len2) {
+ pci_dma_read(&s->dev, desc->buf_addr2,
+ s->tx_frame + s->tx_frame_len, len2);
+ s->tx_frame_len += len2;
+ }
+ desc->status = (len1 + len2) ? 0 : 0x7fffffff;
++
++ return 0;
+ }
+
+ static void tulip_setup_filter_addr(TULIPState *s, uint8_t *buf, int n)
+@@ -651,13 +667,15 @@ static uint32_t tulip_ts(TULIPState *s)
+
+ static void tulip_xmit_list_update(TULIPState *s)
+ {
++#define TULIP_DESC_MAX 128
++ uint8_t i = 0;
+ struct tulip_descriptor desc;
+
+ if (tulip_ts(s) != CSR5_TS_SUSPENDED) {
+ return;
+ }
+
+- for (;;) {
++ for (i = 0; i < TULIP_DESC_MAX; i++) {
+ tulip_desc_read(s, s->current_tx_desc, &desc);
+ tulip_dump_tx_descriptor(s, &desc);
+
+@@ -675,10 +693,10 @@ static void tulip_xmit_list_update(TULIPState *s)
+ s->tx_frame_len = 0;
+ }
+
+- tulip_copy_tx_buffers(s, &desc);
+-
+- if (desc.control & TDES1_LS) {
+- tulip_tx(s, &desc);
++ if (!tulip_copy_tx_buffers(s, &desc)) {
++ if (desc.control & TDES1_LS) {
++ tulip_tx(s, &desc);
++ }
+ }
+ }
+ tulip_desc_write(s, s->current_tx_desc, &desc);
+--
+1.8.3.1
+
