Re: [Qemu-devel] net: vmxnet3: memory leakage issue

[P J P <ppandit@redhat.com>]

   Hello Dmitry,

+-- On Mon, 14 Dec 2015, Dmitry Fleytman wrote --+
| The patch looks basically good.
| The only issue I can think of is that now vmxnet_tx_pkt_uninit and 
| vmxnet_rx_pkt_uninit may be called a few times in a row. For example guest 
| may quiesce device and then shutdown. In this case vmxnet_tx_pkt_uninit may 
| try to free the same memory twice. Could you take a look at this please?

  Yes, I've added a check in vmxnet3_deactivate_device() to avoid double free. 
Please see below an updated patch.

===
>From 3ef66b01874fcc2fe3bfc73d2b61ee3a5b29fdb6 Mon Sep 17 00:00:00 2001
From: Prasad J Pandit <pjp@fedoraproject.org>
Date: Tue, 15 Dec 2015 12:17:28 +0530
Subject: [PATCH] net: vmxnet3: avoid memory leakage in activate_device

Vmxnet3 device emulator does not check if the device is active
before activating it, also it did not free the transmit & receive
buffers while deactivating the device, thus resulting in memory
leakage on the host. This patch fixes both these issues to avoid
host memory leakage.

Reported-by: Qinghao Tang <luodalongde@gmail.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/net/vmxnet3.c | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c
index 37373e5..2b4aad7 100644
--- a/hw/net/vmxnet3.c
+++ b/hw/net/vmxnet3.c
@@ -1194,8 +1194,13 @@ static void vmxnet3_reset_mac(VMXNET3State *s)
 
 static void vmxnet3_deactivate_device(VMXNET3State *s)
 {
-    VMW_CBPRN("Deactivating vmxnet3...");
-    s->device_active = false;
+    if (s->device_active) {
+        VMW_CBPRN("Deactivating vmxnet3...");
+        vmxnet_tx_pkt_reset(s->tx_pkt);
+        vmxnet_tx_pkt_uninit(s->tx_pkt);
+        vmxnet_rx_pkt_uninit(s->rx_pkt);
+        s->device_active = false;
+    }
 }
 
 static void vmxnet3_reset(VMXNET3State *s)
@@ -1204,7 +1209,6 @@ static void vmxnet3_reset(VMXNET3State *s)
 
     vmxnet3_deactivate_device(s);
     vmxnet3_reset_interrupt_states(s);
-    vmxnet_tx_pkt_reset(s->tx_pkt);
     s->drv_shmem = 0;
     s->tx_sop = true;
     s->skip_current_tx_pkt = false;
@@ -1431,6 +1435,12 @@ static void vmxnet3_activate_device(VMXNET3State *s)
         return;
     }
 
+    /* Verify if device is active */
+    if (s->device_active) {
+        VMW_CFPRN("Vmxnet3 device is active");
+        return;
+    }
+
     vmxnet3_adjust_by_guest_type(s);
     vmxnet3_update_features(s);
     vmxnet3_update_pm_state(s);
@@ -1627,7 +1637,7 @@ static void vmxnet3_handle_command(VMXNET3State *s, uint64_t cmd)
         break;
 
     case VMXNET3_CMD_QUIESCE_DEV:
-        VMW_CBPRN("Set: VMXNET3_CMD_QUIESCE_DEV - pause the device");
+        VMW_CBPRN("Set: VMXNET3_CMD_QUIESCE_DEV - deactivate the device");
         vmxnet3_deactivate_device(s);
         break;
 
@@ -1741,7 +1751,7 @@ vmxnet3_io_bar1_write(void *opaque,
          * shared address only after we get the high part
          */
         if (val == 0) {
-            s->device_active = false;
+            vmxnet3_deactivate_device(s);
         }
         s->temp_shared_guest_driver_memory = val;
         s->drv_shmem = 0;
@@ -2021,9 +2031,7 @@ static bool vmxnet3_peer_has_vnet_hdr(VMXNET3State *s)
 static void vmxnet3_net_uninit(VMXNET3State *s)
 {
     g_free(s->mcast_list);
-    vmxnet_tx_pkt_reset(s->tx_pkt);
-    vmxnet_tx_pkt_uninit(s->tx_pkt);
-    vmxnet_rx_pkt_uninit(s->rx_pkt);
+    vmxnet3_deactivate_device(s);
     qemu_del_nic(s->nic);
 }
 
-- 
2.4.3
===


Thank you.
--
Prasad J Pandit / Red Hat Product Security Team
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