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$NetBSD: patch-CVE-2016-7908,v 1.1 2016/10/30 14:48:00 spz Exp $
from:
http://git.qemu.org/?p=qemu.git;a=commitdiff;h=070c4b92b8cd5390889716677a0b92444d6e087a
net: mcf: limit buffer descriptor count
ColdFire Fast Ethernet Controller uses buffer descriptors to manage
data flow to/fro receive & transmit queues. While transmitting
packets, it could continue to read buffer descriptors if a buffer
descriptor has length of zero and has crafted values in bd.flags.
Set upper limit to number of buffer descriptors.
Reported-by: Li Qiang <liqiang6-s@360.cn>
--- hw/net/mcf_fec.c.orig 2016-09-02 15:34:19.000000000 +0000
+++ hw/net/mcf_fec.c
@@ -23,6 +23,7 @@ do { printf("mcf_fec: " fmt , ## __VA_AR
#define DPRINTF(fmt, ...) do {} while(0)
#endif
+#define FEC_MAX_DESC 1024
#define FEC_MAX_FRAME_SIZE 2032
typedef struct {
@@ -149,7 +150,7 @@ static void mcf_fec_do_tx(mcf_fec_state
uint32_t addr;
mcf_fec_bd bd;
int frame_size;
- int len;
+ int len, descnt = 0;
uint8_t frame[FEC_MAX_FRAME_SIZE];
uint8_t *ptr;
@@ -157,7 +158,7 @@ static void mcf_fec_do_tx(mcf_fec_state
ptr = frame;
frame_size = 0;
addr = s->tx_descriptor;
- while (1) {
+ while (descnt++ < FEC_MAX_DESC) {
mcf_fec_read_bd(&bd, addr);
DPRINTF("tx_bd %x flags %04x len %d data %08x\n",
addr, bd.flags, bd.length, bd.data);
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