From b2472117867fc233fcb634b7370051bcb7fc892c Mon Sep 17 00:00:00 2001

From: Kevin Wolf <kwolf@redhat.com>

Date: Tue, 25 Mar 2014 14:23:52 +0100

Subject: [PATCH 45/49] qcow2: Check maximum L1 size in qcow2_snapshot_load_tmp() (CVE-2014-0143)

RH-Author: Kevin Wolf <kwolf@redhat.com>

Message-id: <1395753835-7591-46-git-send-email-kwolf@redhat.com>

Patchwork-id: n/a

O-Subject: [virt-devel] [EMBARGOED RHEL-7.0 qemu-kvm PATCH 45/48] qcow2: Check maximum L1 size in qcow2_snapshot_load_tmp() (CVE-2014-0143)

Bugzilla: 1079320

RH-Acked-by: Jeff Cody <jcody@redhat.com>

RH-Acked-by: Stefan Hajnoczi <stefanha@redhat.com>

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1079320

Upstream status: Embargoed

This avoids an unbounded allocation.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

RHEL 7.0 doesn't have commit 7b4c4781, so use error_report() instead of

error_setg().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>

---

 block/qcow2-snapshot.c     |    4 ++++

 block/qcow2.c              |    4 +---

 block/qcow2.h              |    4 ++++

 tests/qemu-iotests/080     |   15 ++++++++++++++-

 tests/qemu-iotests/080.out |    7 +++++++

 5 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c

index b29f7bd..626a8d4 100644

--- a/block/qcow2-snapshot.c

+++ b/block/qcow2-snapshot.c

@@ -635,6 +635,10 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs, const char *snapshot_name)

     sn = &s->snapshots[snapshot_index];

     /* Allocate and read in the snapshot's L1 table */

+    if (sn->l1_size > QCOW_MAX_L1_SIZE) {

+        error_report("Snapshot L1 table too large");

+        return -EFBIG;

+    }

     new_l1_bytes = sn->l1_size * sizeof(uint64_t);

     new_l1_table = g_malloc0(align_offset(new_l1_bytes, 512));

diff --git a/block/qcow2.c b/block/qcow2.c

index 33b46b8..3f8febc 100644

--- a/block/qcow2.c

+++ b/block/qcow2.c

@@ -637,9 +637,7 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags,

     }

     /* read the level 1 table */

-    if (header.l1_size > 0x2000000) {

-        /* 32 MB L1 table is enough for 2 PB images at 64k cluster size

-         * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */

+    if (header.l1_size > QCOW_MAX_L1_SIZE) {

         error_setg(errp, "Active L1 table too large");

         ret = -EFBIG;

         goto fail;

diff --git a/block/qcow2.h b/block/qcow2.h

index 9f9f5ae..87e256a 100644

--- a/block/qcow2.h

+++ b/block/qcow2.h

@@ -44,6 +44,10 @@

  * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */

 #define QCOW_MAX_REFTABLE_SIZE 0x800000

+/* 32 MB L1 table is enough for 2 PB images at 64k cluster size

+ * (128 GB for 512 byte clusters, 2 EB for 2 MB clusters) */

+#define QCOW_MAX_L1_SIZE 0x2000000

+

 /* indicate that the refcount of the referenced cluster is exactly one. */

 #define QCOW_OFLAG_COPIED     (1LL << 63)

 /* indicate that the cluster is compressed (they never have the copied flag) */

diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080

index 59e7a44..6b3a3e7 100755

--- a/tests/qemu-iotests/080

+++ b/tests/qemu-iotests/080

@@ -30,7 +30,8 @@ status=1	# failure is the default!

 _cleanup()

 {

-	_cleanup_test_img

+    rm -f $TEST_IMG.snap

+    _cleanup_test_img

 }

 trap "_cleanup; exit \$status" 0 1 2 3 15

@@ -58,6 +59,10 @@ offset_ext_size=$((header_size + 4))

 offset_l2_table_0=$((0x40000))

+offset_snap1=$((0x70000))

+offset_snap1_l1_offset=$((offset_snap1 + 0))

+offset_snap1_l1_size=$((offset_snap1 + 8))

+

 echo

 echo "== Huge header size =="

 _make_test_img 64M

@@ -161,6 +166,14 @@ poke_file "$TEST_IMG" "$offset_l2_table_0" "\xbf\xff\xff\xff\xff\xff\x00\x00"

 poke_file "$TEST_IMG" "$offset_l2_table_0" "\x80\x00\x00\xff\xff\xff\x00\x00"

 { $QEMU_IMG snapshot -c test $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir

+echo

+echo "== Invalid snapshot L1 table =="

+_make_test_img 64M

+{ $QEMU_IO -c "write 0 512" $TEST_IMG; } 2>&1 | _filter_qemu_io | _filter_testdir

+{ $QEMU_IMG snapshot -c test $TEST_IMG; } 2>&1 | _filter_testdir

+poke_file "$TEST_IMG" "$offset_snap1_l1_size" "\x10\x00\x00\x00"

+{ $QEMU_IMG convert -s test $TEST_IMG $TEST_IMG.snap; } 2>&1 | _filter_testdir

+

 # success, all done

 echo "*** done"

 rm -f $seq.full

diff --git a/tests/qemu-iotests/080.out b/tests/qemu-iotests/080.out

index 4d84fbf..1fa0672 100644

--- a/tests/qemu-iotests/080.out

+++ b/tests/qemu-iotests/080.out

@@ -74,4 +74,11 @@ wrote 512/512 bytes at offset 0

 512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

 qemu-img: Could not create snapshot 'test': -27 (File too large)

 qemu-img: Could not create snapshot 'test': -11 (Resource temporarily unavailable)

+

+== Invalid snapshot L1 table ==

+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864 

+wrote 512/512 bytes at offset 0

+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)

+qemu-img: Snapshot L1 table too large

+qemu-img: Failed to load snapshot

 *** done

-- 

1.7.1