[Qemu-stable] [PATCH for 2.6.0] net: vmxnet: check fragments count at pkt initialisation

[P J P]

From: Li Qiang <address@hidden>

When Vmxnet device 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/vmxnet_tx_pkt.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/hw/net/vmxnet_tx_pkt.c b/hw/net/vmxnet_tx_pkt.c
index 32563d4..e58b0a3 100644
--- a/hw/net/vmxnet_tx_pkt.c
+++ b/hw/net/vmxnet_tx_pkt.c
@@ -55,9 +55,13 @@ struct VmxnetTxPkt {
     uint8_t l4proto;
 };
 
+#define VMXNET_PKT_MAX_FRAGS    16  /* ref: MAX_SKB_FRAGS in kernel driver */
+
 void vmxnet_tx_pkt_init(struct VmxnetTxPkt **pkt, uint32_t max_frags,
     bool has_virt_hdr)
 {
+    assert(max_frags <= VMXNET_PKT_MAX_FRAGS);
+
     struct VmxnetTxPkt *p = g_malloc0(sizeof *p);
 
     p->vec = g_malloc((sizeof *p->vec) *
-- 
2.5.5