From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50123) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrdFC-0004Cu-93 for qemu-devel@nongnu.org; Thu, 20 Nov 2014 20:42:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XrdF7-0004pm-Eh for qemu-devel@nongnu.org; Thu, 20 Nov 2014 20:42:42 -0500 Received: from mx1.redhat.com ([209.132.183.28]:39993) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrdF7-0004pi-7N for qemu-devel@nongnu.org; Thu, 20 Nov 2014 20:42:37 -0500 Message-ID: <546E986D.5000001@redhat.com> Date: Fri, 21 Nov 2014 09:42:05 +0800 From: Jason Wang MIME-Version: 1.0 References: <1416483303-12072-1-git-send-email-arei.gonglei@huawei.com> <1416483303-12072-4-git-send-email-arei.gonglei@huawei.com> In-Reply-To: <1416483303-12072-4-git-send-email-arei.gonglei@huawei.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 for-2.2 3/4] pcnet: fix Negative array index read List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: arei.gonglei@huawei.com, qemu-devel@nongnu.org Cc: pbonzini@redhat.com, peter.huangpeng@huawei.com, stefanha@redhat.com On 11/20/2014 07:35 PM, arei.gonglei@huawei.com wrote: > From: Gonglei > > 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 > --- > hw/net/pcnet.c | 55 ++++++++++++++++++++++++++++++------------------------- > 1 file changed, 30 insertions(+), 25 deletions(-) > > diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c > index d344c15..f409b92 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))); Reviewed-by: Jason Wang