From: Prasad J Pandit Date: Thu, 22 Sep 2016 16:02:37 +0530 Subject: [PATCH] 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 Signed-off-by: Prasad J Pandit Reviewed-by: Paolo Bonzini Signed-off-by: Jason Wang (cherry picked from commit 070c4b92b8cd5390889716677a0b92444d6e087a) --- hw/net/mcf_fec.c | 5 +++-- 1 file 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);