49 lines
1.7 KiB
Diff
49 lines
1.7 KiB
Diff
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From 9f7c594c006289ad41169b854d70f5da6e400a2a Mon Sep 17 00:00:00 2001
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From: Petr Matousek <pmatouse@redhat.com>
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Date: Sun, 24 May 2015 10:53:44 +0200
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Subject: [PATCH] pcnet: force the buffer access to be in bounds during tx
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4096 is the maximum length per TMD and it is also currently the size of
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the relay buffer pcnet driver uses for sending the packet data to QEMU
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for further processing. With packet spanning multiple TMDs it can
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happen that the overall packet size will be bigger than sizeof(buffer),
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which results in memory corruption.
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Fix this by only allowing to queue maximum sizeof(buffer) bytes.
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This is CVE-2015-3209.
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[Fixed 3-space indentation to QEMU's 4-space coding standard.
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--Stefan]
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Signed-off-by: Petr Matousek <pmatouse@redhat.com>
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Reported-by: Matt Tait <matttait@google.com>
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Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
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Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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---
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hw/net/pcnet.c | 8 ++++++++
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1 files changed, 8 insertions(+), 0 deletions(-)
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diff --git hw/net/pcnet.c hw/net/pcnet.c
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index bdfd38f..68b9981 100644
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--- hw/net/pcnet.c
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+++ hw/net/pcnet.c
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@@ -1241,6 +1241,14 @@ static void pcnet_transmit(PCNetState *s)
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}
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bcnt = 4096 - GET_FIELD(tmd.length, TMDL, BCNT);
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+
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+ /* if multi-tmd packet outsizes s->buffer then skip it silently.
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+ Note: this is not what real hw does */
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+ if (s->xmit_pos + bcnt > sizeof(s->buffer)) {
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+ s->xmit_pos = -1;
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+ goto txdone;
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+ }
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+
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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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--
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1.7.0.4
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