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>
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@ -1212,7 +1212,7 @@ static void pcnet_transmit(PCNetState *s)
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hwaddr xmit_cxda = 0;
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int count = CSR_XMTRL(s)-1;
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int add_crc = 0;
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int bcnt;
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s->xmit_pos = -1;
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if (!CSR_TXON(s)) {
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@ -1247,35 +1247,40 @@ static void pcnet_transmit(PCNetState *s)
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s->xmit_pos = -1;
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goto txdone;
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}
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if (!GET_FIELD(tmd.status, TMDS, ENP)) {
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int bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
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s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
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s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s));
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s->xmit_pos += bcnt;
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} else if (s->xmit_pos >= 0) {
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int bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
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s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
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s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s));
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s->xmit_pos += bcnt;
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#ifdef PCNET_DEBUG
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printf("pcnet_transmit size=%d\n", s->xmit_pos);
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#endif
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if (CSR_LOOP(s)) {
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if (BCR_SWSTYLE(s) == 1)
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add_crc = !GET_FIELD(tmd.status, TMDS, NOFCS);
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s->looptest = add_crc ? PCNET_LOOPTEST_CRC : PCNET_LOOPTEST_NOCRC;
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pcnet_receive(qemu_get_queue(s->nic), s->buffer, s->xmit_pos);
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s->looptest = 0;
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} else
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if (s->nic)
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qemu_send_packet(qemu_get_queue(s->nic), s->buffer,
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s->xmit_pos);
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s->csr[0] &= ~0x0008; /* clear TDMD */
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s->csr[4] |= 0x0004; /* set TXSTRT */
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s->xmit_pos = -1;
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if (s->xmit_pos < 0) {
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goto txdone;
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}
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bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
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s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
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s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s));
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s->xmit_pos += bcnt;
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if (!GET_FIELD(tmd.status, TMDS, ENP)) {
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goto txdone;
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}
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#ifdef PCNET_DEBUG
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printf("pcnet_transmit size=%d\n", s->xmit_pos);
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#endif
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if (CSR_LOOP(s)) {
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if (BCR_SWSTYLE(s) == 1)
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add_crc = !GET_FIELD(tmd.status, TMDS, NOFCS);
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s->looptest = add_crc ? PCNET_LOOPTEST_CRC : PCNET_LOOPTEST_NOCRC;
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pcnet_receive(qemu_get_queue(s->nic), s->buffer, s->xmit_pos);
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s->looptest = 0;
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} else {
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if (s->nic) {
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qemu_send_packet(qemu_get_queue(s->nic), s->buffer,
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s->xmit_pos);
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}
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}
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s->csr[0] &= ~0x0008; /* clear TDMD */
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s->csr[4] |= 0x0004; /* set TXSTRT */
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s->xmit_pos = -1;
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txdone:
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SET_FIELD(&tmd.status, TMDS, OWN, 0);
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TMDSTORE(&tmd, PHYSADDR(s,CSR_CXDA(s)));
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