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authorKevin Wolf <kwolf@redhat.com>2014-03-26 13:06:06 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2014-04-01 15:22:35 +0200
commit6a83f8b5bec6f59e56cc49bd49e4c3f8f805d56f (patch)
tree4063692109e5f06ece922daad860641ec0fe8421
parentc05e4667be91b46ab42b5a11babf8e84d476cc6b (diff)
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qcow2: Check maximum L1 size in qcow2_snapshot_load_tmp() (CVE-2014-0143)
This avoids an unbounded allocation. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
-rw-r--r--block/qcow2-snapshot.c4
-rw-r--r--block/qcow2.c4
-rw-r--r--block/qcow2.h4
-rwxr-xr-xtests/qemu-iotests/08015
-rw-r--r--tests/qemu-iotests/080.out6
5 files changed, 29 insertions, 4 deletions
diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 715168e..5db4f30 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -680,6 +680,10 @@ int qcow2_snapshot_load_tmp(BlockDriverState *bs,
sn = &s->snapshots[snapshot_index];
/* Allocate and read in the snapshot's L1 table */
+ if (sn->l1_size > QCOW_MAX_L1_SIZE) {
+ error_setg(errp, "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 be48a27..bb6000f 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -638,9 +638,7 @@ 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 3649465..f28e7d9 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 (1ULL << 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..f7a943c 100644
--- a/tests/qemu-iotests/080.out
+++ b/tests/qemu-iotests/080.out
@@ -74,4 +74,10 @@ 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: Failed to load snapshot: Snapshot L1 table too large
*** done