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Blame SOURCES/kvm-dmg-sanitize-chunk-length-and-sectorcount-CVE-2014-0.patch

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From ec4d254830e3da2ebb1cd9fec16c407e5b644ca6 Mon Sep 17 00:00:00 2001
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From: Stefan Hajnoczi <stefanha@redhat.com>
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Date: Tue, 25 Mar 2014 14:23:44 +0100
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Subject: [PATCH 37/49] dmg: sanitize chunk length and sectorcount (CVE-2014-0145)
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <1395753835-7591-38-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 37/48] dmg: sanitize chunk length and sectorcount (CVE-2014-0145)
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Bugzilla: 1079325
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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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From: Stefan Hajnoczi <stefanha@redhat.com>
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1079325
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Upstream status: Embargoed
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Chunk length and sectorcount are used for decompression buffers as well
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as the bdrv_pread() count argument. Ensure that they have reasonable
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values so neither memory allocation nor conversion from uint64_t to int
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will cause problems.
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Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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---
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 block/dmg.c |   24 ++++++++++++++++++++++++
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 1 files changed, 24 insertions(+), 0 deletions(-)
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diff --git a/block/dmg.c b/block/dmg.c
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index f98c94d..ad253fe 100644
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--- a/block/dmg.c
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+++ b/block/dmg.c
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@@ -27,6 +27,14 @@
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 #include "qemu/module.h"
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 #include <zlib.h>
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+enum {
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+    /* Limit chunk sizes to prevent unreasonable amounts of memory being used
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+     * or truncating when converting to 32-bit types
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+     */
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+    DMG_LENGTHS_MAX = 64 * 1024 * 1024, /* 64 MB */
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+    DMG_SECTORCOUNTS_MAX = DMG_LENGTHS_MAX / 512,
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+};
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+
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 typedef struct BDRVDMGState {
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     CoMutex lock;
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     /* each chunk contains a certain number of sectors,
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@@ -208,6 +216,14 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
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                 }
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                 offset += 8;
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+                if (s->sectorcounts[i] > DMG_SECTORCOUNTS_MAX) {
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+                    error_report("sector count %" PRIu64 " for chunk %u is "
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+                                 "larger than max (%u)",
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+                                 s->sectorcounts[i], i, DMG_SECTORCOUNTS_MAX);
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+                    ret = -EINVAL;
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+                    goto fail;
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+                }
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+
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                 ret = read_uint64(bs, offset, &s->offsets[i]);
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                 if (ret < 0) {
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                     goto fail;
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@@ -221,6 +237,14 @@ static int dmg_open(BlockDriverState *bs, QDict *options, int flags,
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                 }
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                 offset += 8;
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+                if (s->lengths[i] > DMG_LENGTHS_MAX) {
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+                    error_report("length %" PRIu64 " for chunk %u is larger "
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+                                 "than max (%u)",
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+                                 s->lengths[i], i, DMG_LENGTHS_MAX);
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+                    ret = -EINVAL;
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+                    goto fail;
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+                }
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+
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                 if (s->lengths[i] > max_compressed_size) {
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                     max_compressed_size = s->lengths[i];
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                 }
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-- 
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1.7.1
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