[Qemu-devel] [PATCH] net: vmxnet: check fragments count at pkt initialisation

[P J P]

From: Li Qiang <address@hidden>

When net transport abstraction layer initialises the pkt,
the maximum fragmentation count is not checked. This could
lead to an integer overflow causing a NULL pointer dereference.
Add check to avoid it.

Reported-by: Li Qiang <address@hidden>
Signed-off-by: Prasad J Pandit <address@hidden>
---
 hw/net/net_tx_pkt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index 53dfaa2..7ea3c17 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -58,9 +58,12 @@ struct NetTxPkt {
     bool is_loopback;
 };
 
+#define NET_PKT_MAX_FRAGS    16  /* ref: MAX_SKB_FRAGS in kernel driver */
+
 void net_tx_pkt_init(struct NetTxPkt **pkt, PCIDevice *pci_dev,
     uint32_t max_frags, bool has_virt_hdr)
 {
+    assert(max_frags <= NET_PKT_MAX_FRAGS);
     struct NetTxPkt *p = g_malloc0(sizeof *p);
 
     p->pci_dev = pci_dev;
-- 
2.5.5