gem_receive copies a packet received from network into an rxbuf[2048]
array on stack, with size limited by descriptor length set by guest. If
guest is malicious and specifies a descriptor length that is too large,
and should packet size exceed array size, this results in a buffer
overflow.
Reported-by: 刘令 <liuling...@360.cn>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
hw/net/cadence_gem.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/hw/net/cadence_gem.c b/hw/net/cadence_gem.c
index 3639fc1..15a0786 100644
--- a/hw/net/cadence_gem.c
+++ b/hw/net/cadence_gem.c
@@ -862,6 +862,14 @@ static void gem_transmit(CadenceGEMState *s)
break;
}
+ if (tx_desc_get_length(desc) > sizeof(tx_packet) - (p - tx_packet)) {
+ DB_PRINT("TX descriptor @ 0x%x too large: size 0x%x space 0x%x\n",
+ (unsigned)packet_desc_addr,
+ (unsigned)tx_desc_get_length(desc),
+ sizeof(tx_packet) - (p - tx_packet));
+ break;
+ }
+
/* Gather this fragment of the packet from "dma memory" to our contig.
* buffer.
*/
--
MST
