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2016-01-21 23:41:46 +01:00

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$NetBSD: patch-XSA135,v 1.1 2015/06/23 17:45:33 bouyer Exp $
pcnet: fix Negative array index read
From: Gonglei <arei.gonglei@huawei.com>
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.
upstream-commit-id: 7b50d00911ddd6d56a766ac5671e47304c20a21b
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>
diff --git a/hw/pcnet.c b/hw/pcnet.c
index 7cc0637..9f3e1cc 100644
--- qemu-xen-traditional/hw/pcnet.c.orig
+++ qemu-xen-traditional/hw/pcnet.c
@@ -1250,7 +1250,7 @@ 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)) {
@@ -1276,34 +1276,39 @@ static void pcnet_transmit(PCNetState *s)
if (BCR_SWSTYLE(s) != 1)
add_crc = GET_FIELD(tmd.status, TMDS, ADDFCS);
}
+
+ 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, s->buffer, s->xmit_pos);
- s->looptest = 0;
- } else
- if (s->vc)
- qemu_send_packet(s->vc, 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, s->buffer, s->xmit_pos);
+ s->looptest = 0;
+ } else {
+ if (s->vc) {
+ qemu_send_packet(s->vc, 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)));
if (!CSR_TOKINTD(s) || (CSR_LTINTEN(s) && GET_FIELD(tmd.status, TMDS, LTINT)))
From 2630672ab22255de252f877709851c0557a1c647 Mon Sep 17 00:00:00 2001
From: Petr Matousek <pmatouse@redhat.com>
Date: Sun, 24 May 2015 10:53:44 +0200
Subject: [PATCH] pcnet: force the buffer access to be in bounds during tx
4096 is the maximum length per TMD and it is also currently the size of
the relay buffer pcnet driver uses for sending the packet data to QEMU
for further processing. With packet spanning multiple TMDs it can
happen that the overall packet size will be bigger than sizeof(buffer),
which results in memory corruption.
Fix this by only allowing to queue maximum sizeof(buffer) bytes.
This is CVE-2015-3209.
Signed-off-by: Petr Matousek <pmatouse@redhat.com>
Reported-by: Matt Tait <matttait@google.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
---
hw/pcnet.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/hw/pcnet.c b/hw/pcnet.c
index bdfd38f..6d32e4c 100644
--- qemu-xen-traditional/hw/pcnet.c.orig
+++ qemu-xen-traditional/hw/pcnet.c
@@ -1241,6 +1241,14 @@ static void pcnet_transmit(PCNetState *s)
}
bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
+
+ /* if multi-tmd packet outsizes s->buffer then skip it silently.
+ Note: this is not what real hw does */
+ if (s->xmit_pos + bcnt > sizeof(s->buffer)) {
+ s->xmit_pos = -1;
+ goto txdone;
+ }
+
s->phys_mem_read(s->dma_opaque, PHYSADDR(s, tmd.tbadr),
s->buffer + s->xmit_pos, bcnt, CSR_BSWP(s));
s->xmit_pos += bcnt;
--
2.1.0