42 lines
1.4 KiB
Diff
42 lines
1.4 KiB
Diff
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From: Petr Matousek <pmatouse@redhat.com>
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Date: Wed, 17 Jun 2015 10:46:11 +0000 (+0200)
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Subject: i8254: fix out-of-bounds memory access in pit_ioport_read()
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X-Git-Tag: v2.4.0-rc0~43^2~9
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X-Git-Url: http://git.qemu.org/?p=qemu.git;a=commitdiff_plain;h=d4862a87e31a51de9eb260f25c9e99a75efe3235;hp=9dacf32d2cbd66cbcce7944ebdfd6b2df20e33b8
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i8254: fix out-of-bounds memory access in pit_ioport_read()
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Due converting PIO to the new memory read/write api we no longer provide
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separate I/O region lenghts for read and write operations. As a result,
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reading from PIT Mode/Command register will end with accessing
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pit->channels with invalid index.
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Fix this by ignoring read from the Mode/Command register.
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This is CVE-2015-3214.
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Reported-by: Matt Tait <matttait@google.com>
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Fixes: 0505bcdec8228d8de39ab1a02644e71999e7c052
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Cc: qemu-stable@nongnu.org
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Signed-off-by: Petr Matousek <pmatouse@redhat.com>
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Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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---
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diff --git a/hw/timer/i8254.c b/hw/timer/i8254.c
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index 3450c98..9b65a33 100644
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--- a/hw/timer/i8254.c
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+++ b/hw/timer/i8254.c
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@@ -196,6 +196,12 @@ static uint64_t pit_ioport_read(void *opaque, hwaddr addr,
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PITChannelState *s;
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addr &= 3;
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+
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+ if (addr == 3) {
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+ /* Mode/Command register is write only, read is ignored */
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+ return 0;
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+ }
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+
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s = &pit->channels[addr];
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if (s->status_latched) {
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s->status_latched = 0;
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