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From 6d68fdd3f1fa51b2f1524f1984089057e6d1b081 Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Tue, 25 Mar 2014 14:23:48 +0100
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Subject: [PATCH 41/49] block: Limit request size (CVE-2014-0143)
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <1395753835-7591-42-git-send-email-kwolf@redhat.com>
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Patchwork-id: n/a
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O-Subject: [virt-devel] [EMBARGOED RHEL-7.0 qemu-kvm PATCH 41/48] block: Limit request size (CVE-2014-0143)
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Bugzilla: 1079320
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RH-Acked-by: Jeff Cody <jcody@redhat.com>
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RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1079320
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Upstream status: Embargoed
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Limiting the size of a single request to INT_MAX not only fixes a
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direct integer overflow in bdrv_check_request() (which would only
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trigger bad behaviour with ridiculously huge images, as in close to
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2^64 bytes), but can also prevent overflows in all block drivers.
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 block.c |    4 ++++
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 1 files changed, 4 insertions(+), 0 deletions(-)
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diff --git a/block.c b/block.c
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index 0321c74..4906f6b 100644
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--- a/block.c
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+++ b/block.c
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@@ -2425,6 +2425,10 @@ static int bdrv_check_byte_request(BlockDriverState *bs, int64_t offset,
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 static int bdrv_check_request(BlockDriverState *bs, int64_t sector_num,
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                               int nb_sectors)
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 {
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+    if (nb_sectors > INT_MAX / BDRV_SECTOR_SIZE) {
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+        return -EIO;
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+    }
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+
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     return bdrv_check_byte_request(bs, sector_num * BDRV_SECTOR_SIZE,
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                                    nb_sectors * BDRV_SECTOR_SIZE);
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 }
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-- 
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1.7.1
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