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>
This commit is contained in:
Prasad J Pandit 2016-09-22 16:02:37 +05:30 committed by Jason Wang
parent b38636b837
commit 070c4b92b8
1 changed files with 3 additions and 2 deletions

View File

@ -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);