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From: Gonglei <arei.gonglei@huawei.com>
Date: Thu Nov 20 19:35:02 2014 +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 <arei.gonglei@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Backported-to-1.1: Michael Tokarev <mjt@tls.msk.ru>
(deal with qemu_get_queue() changes)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
---
hw/pcnet.c | 53 +++++++++++++++++++++++++++++------------------------
1 file changed, 29 insertions(+), 24 deletions(-)
diff --git a/hw/pcnet.c b/hw/pcnet.c
index d769b08..046f82f 100644
--- a/hw/pcnet.c
+++ b/hw/pcnet.c
@@ -1209,7 +1209,7 @@ static void pcnet_transmit(PCNetState *s)
target_phys_addr_t xmit_cxda = 0;
int count = CSR_XMTRL(s)-1;
int add_crc = 0;
-
+ int bcnt;
s->xmit_pos = -1;
if (!CSR_TXON(s)) {
@@ -1244,34 +1244,39 @@ 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(&s->nic->nc, s->buffer, s->xmit_pos);
- s->looptest = 0;
- } else
- if (s->nic)
- qemu_send_packet(&s->nic->nc, 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(&s->nic->nc, s->buffer, s->xmit_pos);
+ s->looptest = 0;
+ } else {
+ if (s->nic) {
+ qemu_send_packet(&s->nic->nc, 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)));
--
2.1.4
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