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From 77824d3e0c00074d30f345be594d4ca941585edd Mon Sep 17 00:00:00 2001
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From: Fam Zheng <famz@redhat.com>
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Date: Mon, 1 Jun 2015 08:23:51 +0200
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Subject: [PATCH 01/30] vmdk: Fix overflow if l1_size is 0x20000000
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Message-id: <1433147031-14770-1-git-send-email-famz@redhat.com>
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Patchwork-id: 65160
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O-Subject: [RHEL-7.2 qemu-kvm PATCH] vmdk: Fix overflow if l1_size is 0x20000000
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Bugzilla: 1217351
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RH-Acked-by: Max Reitz <mreitz@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
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Richard Jones caught this bug with afl fuzzer.
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In fact, that's the only possible value to overflow (extent->l1_size =
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0x20000000) l1_size:
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l1_size = extent->l1_size * sizeof(long) => 0x80000000;
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g_try_malloc returns NULL because l1_size is interpreted as negative
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during type casting from 'int' to 'gsize', which yields a enormous
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value. Hence, by coincidence, we get a "not too bad" behavior:
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qemu-img: Could not open '/tmp/afl6.img': Could not open
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'/tmp/afl6.img': Cannot allocate memory
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Values larger than 0x20000000 will be refused by the validation in
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vmdk_add_extent.
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Values smaller than 0x20000000 will not overflow l1_size.
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Cc: qemu-stable@nongnu.org
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Reported-by: Richard W.M. Jones <rjones@redhat.com>
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Reviewed-by: Max Reitz <mreitz@redhat.com>
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Tested-by: Richard W.M. Jones <rjones@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 13c4941cdd8685d28c7e3a09e393a5579b58db46)
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Signed-off-by: Fam Zheng <famz@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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block/vmdk.c | 3 ++-
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1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/block/vmdk.c b/block/vmdk.c
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index 24e9458..6b015ab 100644
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--- a/block/vmdk.c
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+++ b/block/vmdk.c
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@@ -451,7 +451,8 @@ static int vmdk_init_tables(BlockDriverState *bs, VmdkExtent *extent,
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Error **errp)
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{
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int ret;
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- int l1_size, i;
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+ size_t l1_size;
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+ int i;
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/* read the L1 table */
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l1_size = extent->l1_size * sizeof(uint32_t);
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--
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1.8.3.1
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