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authorGonglei <arei.gonglei@huawei.com>2014-11-20 19:35:02 +0800
committerStefan Hajnoczi <stefanha@redhat.com>2014-11-21 10:50:54 +0000
commit7b50d00911ddd6d56a766ac5671e47304c20a21b (patch)
treeb2ac5239d4f3f80cfd5609b5c8dbb33063e11957 /hw/net
parent8db804ac412010fc96397c2d67ee6417eccd9d34 (diff)
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>
Diffstat (limited to 'hw/net')
-rw-r--r--hw/net/pcnet.c55
1 files changed, 30 insertions, 25 deletions
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)));