From c920d20c101e1ca7475e2f758b9823eb21693b5a Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Thu, 17 Sep 2015 14:08:31 -0400 Subject: [PATCH] net: add checks to validate ring buffer pointers(CVE-2015-5279) RH-Author: Stefan Hajnoczi Message-id: <1442498911-32447-2-git-send-email-stefanha@redhat.com> Patchwork-id: 67810 O-Subject: [RHEL-6.7.z qemu-kvm PATCH 1/1] net: add checks to validate ring buffer pointers(CVE-2015-5279) Bugzilla: 1263274 RH-Acked-by: Fam Zheng RH-Acked-by: John Snow RH-Acked-by: Thomas Huth From: P J P 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 Signed-off-by: P J P Signed-off-by: Stefan Hajnoczi (cherry picked from commit 9bbdbc66e5765068dce76e9269dce4547afd8ad4) Signed-off-by: Jeff E. Nelson Conflicts: The downstream filename is hw/ne2000.c while the upstream filename is hw/net/ne2000.c. Signed-off-by: Stefan Hajnoczi --- hw/ne2000.c | 19 +++++++++++++++---- 1 file changed, 15 insertions(+), 4 deletions(-) diff --git a/hw/ne2000.c b/hw/ne2000.c index 9946c63..cad7905 100644 --- a/hw/ne2000.c +++ b/hw/ne2000.c @@ -254,6 +254,9 @@ ssize_t ne2000_receive(VLANClientState *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) */ @@ -338,13 +341,19 @@ 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; @@ -385,7 +394,9 @@ 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; -- 2.1.0