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authorPrasad J Pandit <pjp@fedoraproject.org>2016-09-22 16:02:37 +0530
committerJason Wang <jasowang@redhat.com>2016-09-27 17:54:22 +0800
commit070c4b92b8cd5390889716677a0b92444d6e087a (patch)
treeebdc2121ceaed8049f19175f8c5b9320aa37ee2a
parentb38636b83727d611a354217fa9d17de5872d7da4 (diff)
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> Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Jason Wang <jasowang@redhat.com>
-rw-r--r--hw/net/mcf_fec.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/hw/net/mcf_fec.c b/hw/net/mcf_fec.c
index 0ee8ad9d66..d31fea1f18 100644
--- a/hw/net/mcf_fec.c
+++ b/hw/net/mcf_fec.c
@@ -23,6 +23,7 @@ do { printf("mcf_fec: " fmt , ## __VA_ARGS__); } while (0)
#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 *s)
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 *s)
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);