qemu/0011-net-add-checks-to-validate-ring-buffer-pointers-CVE-.patch

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From: P J P <pjp@fedoraproject.org>
Date: Tue, 15 Sep 2015 16:40:49 +0530
Subject: [PATCH] net: add checks to validate ring buffer
pointers(CVE-2015-5279)
Ne2000 NIC uses ring buffer of NE2000_MEM_SIZE(49152)
bytes to process network packets. While receiving packets
via ne2000_receive() routine, a local 'index' variable
could exceed the ring buffer size, which could lead to a
memory buffer overflow. Added other checks at initialisation.
Reported-by: Qinghao Tang <luodalongde@gmail.com>
Signed-off-by: P J P <pjp@fedoraproject.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 9bbdbc66e5765068dce76e9269dce4547afd8ad4)
---
hw/net/ne2000.c | 19 +++++++++++++++----
1 file changed, 15 insertions(+), 4 deletions(-)
diff --git a/hw/net/ne2000.c b/hw/net/ne2000.c
index 44a4264..2bdb4c9 100644
--- a/hw/net/ne2000.c
+++ b/hw/net/ne2000.c
@@ -230,6 +230,9 @@ ssize_t ne2000_receive(NetClientState *nc, const uint8_t *buf, size_t size_)
}
index = s->curpag << 8;
+ if (index >= NE2000_PMEM_END) {
+ index = s->start;
+ }
/* 4 bytes for header */
total_len = size + 4;
/* address for next packet (4 bytes for CRC) */
@@ -315,13 +318,19 @@ static void ne2000_ioport_write(void *opaque, uint32_t addr, uint32_t val)
offset = addr | (page << 4);
switch(offset) {
case EN0_STARTPG:
- s->start = val << 8;
+ if (val << 8 <= NE2000_PMEM_END) {
+ s->start = val << 8;
+ }
break;
case EN0_STOPPG:
- s->stop = val << 8;
+ if (val << 8 <= NE2000_PMEM_END) {
+ s->stop = val << 8;
+ }
break;
case EN0_BOUNDARY:
- s->boundary = val;
+ if (val << 8 < NE2000_PMEM_END) {
+ s->boundary = val;
+ }
break;
case EN0_IMR:
s->imr = val;
@@ -362,7 +371,9 @@ static void ne2000_ioport_write(void *opaque, uint32_t addr, uint32_t val)
s->phys[offset - EN1_PHYS] = val;
break;
case EN1_CURPAG:
- s->curpag = val;
+ if (val << 8 < NE2000_PMEM_END) {
+ s->curpag = val;
+ }
break;
case EN1_MULT ... EN1_MULT + 7:
s->mult[offset - EN1_MULT] = val;