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net: add checks to validate ring buffer pointers(CVE-2015-5279)

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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>
This commit is contained in:
P J P 2015-09-15 16:40:49 +05:30 committed by Stefan Hajnoczi
parent b947ac2bf2
commit 9bbdbc66e5
1 changed files with 15 additions and 4 deletions
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19
hw/net/ne2000.c
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@ -221,6 +221,9 @@ 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) */
@ -306,13 +309,19 @@ 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;
@ -353,7 +362,9 @@ 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;