diff mbox

[v2,6/7] qcow2: Check snapshot L1 table in qcow2_snapshot_delete()

Message ID d201591c15c093103cab425efa70a345983cad51.1520352600.git.berto@igalia.com (mailing list archive)
State New, archived
Headers show

Commit Message

Alberto Garcia March 6, 2018, 4:14 p.m. UTC 
This function deletes a snapshot from disk, removing its entry from
the snapshot table, freeing its L1 table and decreasing the refcounts
of all clusters.

The L1 table offset and size are however not validated. If we use
invalid values in this function we'll probably corrupt the image even
more, so we should return an error instead.

We now have a function to take care of this, so let's use it.

Signed-off-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 block/qcow2-snapshot.c     | 7 +++++++
 tests/qemu-iotests/080     | 2 ++
 tests/qemu-iotests/080.out | 2 ++
 3 files changed, 11 insertions(+)
diff mbox

Patch

diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c
index 0faf728dc4..74293be470 100644
--- a/block/qcow2-snapshot.c
+++ b/block/qcow2-snapshot.c
@@ -611,6 +611,13 @@  int qcow2_snapshot_delete(BlockDriverState *bs,
     }
     sn = s->snapshots[snapshot_index];
 
+    ret = qcow2_validate_table(bs, sn.l1_table_offset, sn.l1_size,
+                               sizeof(uint64_t), QCOW_MAX_L1_SIZE,
+                               "Snapshot L1 table", errp);
+    if (ret < 0) {
+        return ret;
+    }
+
     /* Remove it from the snapshot list */
     memmove(s->snapshots + snapshot_index,
             s->snapshots + snapshot_index + 1,
diff --git a/tests/qemu-iotests/080 b/tests/qemu-iotests/080
index 538857310f..f8e7d6f4df 100755
--- a/tests/qemu-iotests/080
+++ b/tests/qemu-iotests/080
@@ -181,6 +181,7 @@  poke_file "$TEST_IMG" "$offset_snap1_l1_offset" "\x00\x00\x00\x00\x00\x40\x02\x0
 { $QEMU_IO -c "open -o overlap-check.inactive-l2=on $TEST_IMG" \
            -c 'write 0 4k'; } 2>&1 | _filter_qemu_io | _filter_testdir
 { $QEMU_IMG snapshot -a test $TEST_IMG; } 2>&1 | _filter_testdir
+{ $QEMU_IMG snapshot -d test $TEST_IMG; } 2>&1 | _filter_testdir
 
 echo
 echo "== Invalid snapshot L1 table size =="
@@ -193,6 +194,7 @@  poke_file "$TEST_IMG" "$offset_snap1_l1_size" "\x10\x00\x00\x00"
 { $QEMU_IO -c "open -o overlap-check.inactive-l2=on $TEST_IMG" \
            -c 'write 0 4k'; } 2>&1 | _filter_qemu_io | _filter_testdir
 { $QEMU_IMG snapshot -a test $TEST_IMG; } 2>&1 | _filter_testdir
+{ $QEMU_IMG snapshot -d test $TEST_IMG; } 2>&1 | _filter_testdir
 
 # success, all done
 echo "*** done"
diff --git a/tests/qemu-iotests/080.out b/tests/qemu-iotests/080.out
index 1525e1b087..89bcd27172 100644
--- a/tests/qemu-iotests/080.out
+++ b/tests/qemu-iotests/080.out
@@ -70,6 +70,7 @@  Failed to flush the refcount block cache: Invalid argument
 write failed: Invalid argument
 qemu-img: Snapshot L1 table offset invalid
 qemu-img: Could not apply snapshot 'test': Failed to load snapshot: Invalid argument
+qemu-img: Could not delete snapshot 'test': Snapshot L1 table offset invalid
 
 == Invalid snapshot L1 table size ==
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
@@ -82,4 +83,5 @@  Failed to flush the refcount block cache: File too large
 write failed: File too large
 qemu-img: Snapshot L1 table too large
 qemu-img: Could not apply snapshot 'test': Failed to load snapshot: File too large
+qemu-img: Could not delete snapshot 'test': Snapshot L1 table too large
 *** done