diff mbox series

[v3,07/14] dp8393x: Implement packet size limit and RBAE interrupt

Message ID 8b743099e180360402c7362cca7f30c47abe49e1.1579474761.git.fthain@telegraphics.com.au
State New
Headers show
Series Fixes for DP8393X SONIC device emulation | expand

Commit Message

Finn Thain Jan. 19, 2020, 10:59 p.m. UTC 
Add a bounds check to prevent a large packet from causing a buffer
overflow. This is defensive programming -- I haven't actually tried
sending an oversized packet or a jumbo ethernet frame.

The SONIC handles packets that are too big for the buffer by raising
the RBAE interrupt and dropping them. Linux uses that interrupt to
count dropped packets.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Laurent Vivier <laurent@vivier.eu>
---
Changed since v1:
 - Perform length check after Recieve Control Register initialization.
---
 hw/net/dp8393x.c | 9 +++++++++
 1 file changed, 9 insertions(+)
diff mbox series

Patch

diff --git a/hw/net/dp8393x.c b/hw/net/dp8393x.c
index 2e976781e2..0309365fda 100644
--- a/hw/net/dp8393x.c
+++ b/hw/net/dp8393x.c
@@ -137,6 +137,7 @@  do { printf("sonic ERROR: %s: " fmt, __func__ , ## __VA_ARGS__); } while (0)
 #define SONIC_TCR_CRCI   0x2000
 #define SONIC_TCR_PINT   0x8000
 
+#define SONIC_ISR_RBAE   0x0010
 #define SONIC_ISR_RBE    0x0020
 #define SONIC_ISR_RDE    0x0040
 #define SONIC_ISR_TC     0x0080
@@ -770,6 +771,14 @@  static ssize_t dp8393x_receive(NetClientState *nc, const uint8_t * buf,
     s->regs[SONIC_RCR] &= ~(SONIC_RCR_PRX | SONIC_RCR_LBK | SONIC_RCR_FAER |
         SONIC_RCR_CRCR | SONIC_RCR_LPKT | SONIC_RCR_BC | SONIC_RCR_MC);
 
+    if (pkt_size + 4 > dp8393x_rbwc(s) * 2) {
+        DPRINTF("oversize packet, pkt_size is %d\n", pkt_size);
+        s->regs[SONIC_ISR] |= SONIC_ISR_RBAE;
+        dp8393x_update_irq(s);
+        dp8393x_do_read_rra(s);
+        return pkt_size;
+    }
+
     packet_type = dp8393x_receive_filter(s, buf, pkt_size);
     if (packet_type < 0) {
         DPRINTF("packet not for netcard\n");