From 7b50d00911ddd6d56a766ac5671e47304c20a21b Mon Sep 17 00:00:00 2001 From: Gonglei Date: Thu, 20 Nov 2014 19:35:02 +0800 Subject: pcnet: fix Negative array index read s->xmit_pos maybe assigned to a negative value (-1), but in this branch variable s->xmit_pos as an index to array s->buffer. Let's add a check for s->xmit_pos. Signed-off-by: Gonglei Signed-off-by: Paolo Bonzini Reviewed-by: Jason Wang Reviewed-by: Jason Wang Signed-off-by: Stefan Hajnoczi --- hw/net/pcnet.c | 55 ++++++++++++++++++++++++++++++------------------------- 1 file changed, 30 insertions(+), 25 deletions(-) (limited to 'hw/net') diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c index d344c15da0..f409b9293d 100644 --- a/hw/net/pcnet.c +++ b/hw/net/pcnet.c @@ -1212,7 +1212,7 @@ static void pcnet_transmit(PCNetState *s) hwaddr xmit_cxda = 0; int count = CSR_XMTRL(s)-1; int add_crc = 0; - + int bcnt; s->xmit_pos = -1; if (!CSR_TXON(s)) { @@ -1247,35 +1247,40 @@ static void pcnet_transmit(PCNetState *s) s->xmit_pos = -1; goto txdone; } + + if (s->xmit_pos < 0) { + goto txdone; + } + + bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT); + s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr), + s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s)); + s->xmit_pos += bcnt; + if (!GET_FIELD(tmd.status, TMDS, ENP)) { - int bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT); - s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr), - s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s)); - s->xmit_pos += bcnt; - } else if (s->xmit_pos >= 0) { - int bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT); - s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr), - s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s)); - s->xmit_pos += bcnt; + goto txdone; + } + #ifdef PCNET_DEBUG - printf("pcnet_transmit size=%d\n", s->xmit_pos); + printf("pcnet_transmit size=%d\n", s->xmit_pos); #endif - if (CSR_LOOP(s)) { - if (BCR_SWSTYLE(s) == 1) - add_crc = !GET_FIELD(tmd.status, TMDS, NOFCS); - s->looptest = add_crc ? PCNET_LOOPTEST_CRC : PCNET_LOOPTEST_NOCRC; - pcnet_receive(qemu_get_queue(s->nic), s->buffer, s->xmit_pos); - s->looptest = 0; - } else - if (s->nic) - qemu_send_packet(qemu_get_queue(s->nic), s->buffer, - s->xmit_pos); - - s->csr[0] &= ~0x0008; /* clear TDMD */ - s->csr[4] |= 0x0004; /* set TXSTRT */ - s->xmit_pos = -1; + if (CSR_LOOP(s)) { + if (BCR_SWSTYLE(s) == 1) + add_crc = !GET_FIELD(tmd.status, TMDS, NOFCS); + s->looptest = add_crc ? PCNET_LOOPTEST_CRC : PCNET_LOOPTEST_NOCRC; + pcnet_receive(qemu_get_queue(s->nic), s->buffer, s->xmit_pos); + s->looptest = 0; + } else { + if (s->nic) { + qemu_send_packet(qemu_get_queue(s->nic), s->buffer, + s->xmit_pos); + } } + s->csr[0] &= ~0x0008; /* clear TDMD */ + s->csr[4] |= 0x0004; /* set TXSTRT */ + s->xmit_pos = -1; + txdone: SET_FIELD(&tmd.status, TMDS, OWN, 0); TMDSTORE(&tmd, PHYSADDR(s,CSR_CXDA(s))); -- cgit v1.2.1