blockdev: Refuse to open encrypted image unless paused

Opening an encrypted image takes an additional step: setting the key.
Between open and the key set, the image must not be used.

We have some protection against accidental use in place: you can't
unpause a guest while we're missing keys.  You can, however, hot-plug
block devices lacking keys into a running guest just fine, or insert
media lacking keys.  In the latter case, notifying the guest of the
insert is delayed until the key is set, which may suffice to protect
at least some guests in common usage.

This patch makes the protection apply in more cases, in a rather
heavy-handed way: it doesn't let you open encrypted images unless
we're in a paused state.

It doesn't extend the protection to users other than the guest (block
jobs?).  Use of runstate_check() from block.c is disgusting.  Best I
can do right now.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/block.c b/block.c
index fae50c95b5e27b58316f4e47282470e7f73d549b..53f5b44fbb632d7bf69271952ec2acf0ccbca299 100644 (file)
--- a/block.c
+++ b/block.c
@@ -1388,12 +1388,19 @@ done:
         ret = -EINVAL;
         goto close_and_fail;
     }
-    QDECREF(options);
 
     if (!bdrv_key_required(bs)) {
         bdrv_dev_change_media_cb(bs, true);
+    } else if (!runstate_check(RUN_STATE_PRELAUNCH)
+               && !runstate_check(RUN_STATE_INMIGRATE)
+               && !runstate_check(RUN_STATE_PAUSED)) { /* HACK */
+        error_setg(errp,
+                   "Guest must be stopped for opening of encrypted image");
+        ret = -EBUSY;
+        goto close_and_fail;
     }
 
+    QDECREF(options);
     *pbs = bs;
     return 0;
 

diff --git a/stubs/Makefile.objs b/stubs/Makefile.objs
index 59c5a542394e8f84040c2c3d99d1a1897e0dfef0..5ed1d38d70d6a961eed62b486aa16d8758de93ee 100644 (file)
--- a/stubs/Makefile.objs
+++ b/stubs/Makefile.objs
@@ -20,6 +20,7 @@ stub-obj-y += mon-set-error.o
 stub-obj-y += pci-drive-hot-add.o
 stub-obj-y += qtest.o
 stub-obj-y += reset.o
+stub-obj-y += runstate-check.o
 stub-obj-y += set-fd-handler.o
 stub-obj-y += slirp.o
 stub-obj-y += sysbus.o

diff --git a/stubs/runstate-check.c b/stubs/runstate-check.c
new file mode 100644 (file)
index 0000000..bd2e375
--- /dev/null
+++ b/stubs/runstate-check.c
@@ -0,0 +1,6 @@
+#include "sysemu/sysemu.h"
+
+bool runstate_check(RunState state)
+{
+    return state == RUN_STATE_PRELAUNCH;
+}

diff --git a/tests/qemu-iotests/087 b/tests/qemu-iotests/087
index 53b6c43bffd56386c5d1687641f48b2884656c79..a38bb702b332a6e5c3a8af14944e8ce456d24a8f 100755 (executable)
--- a/tests/qemu-iotests/087
+++ b/tests/qemu-iotests/087
@@ -99,6 +99,23 @@ echo === Encrypted image ===
 echo
 
 _make_test_img -o encryption=on $size
+run_qemu -S <<EOF
+{ "execute": "qmp_capabilities" }
+{ "execute": "blockdev-add",
+  "arguments": {
+      "options": {
+        "driver": "$IMGFMT",
+        "id": "disk",
+        "file": {
+            "driver": "file",
+            "filename": "$TEST_IMG"
+        }
+      }
+    }
+  }
+{ "execute": "quit" }
+EOF
+
 run_qemu <<EOF
 { "execute": "qmp_capabilities" }
 { "execute": "blockdev-add",

diff --git a/tests/qemu-iotests/087.out b/tests/qemu-iotests/087.out
index b87103252eeac541f2dd45e9570cd7c4ecb59481..e65dcdfbb36d473e5db61e9abdd359815ceb678c 100644 (file)
--- a/tests/qemu-iotests/087.out
+++ b/tests/qemu-iotests/087.out
@@ -28,7 +28,7 @@ QMP_VERSION
 === Encrypted image ===
 
 Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728 encryption=on 
-Testing:
+Testing: -S
 QMP_VERSION
 {"return": {}}
 {"error": {"class": "GenericError", "desc": "blockdev-add doesn't support encrypted devices"}}
@@ -37,4 +37,13 @@ QMP_VERSION
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "ide1-cd0", "tray-open": true}}
 {"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "floppy0", "tray-open": true}}
 
+Testing:
+QMP_VERSION
+{"return": {}}
+{"error": {"class": "GenericError", "desc": "could not open disk image disk: Guest must be stopped for opening of encrypted image"}}
+{"return": {}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "SHUTDOWN"}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "ide1-cd0", "tray-open": true}}
+{"timestamp": {"seconds":  TIMESTAMP, "microseconds":  TIMESTAMP}, "event": "DEVICE_TRAY_MOVED", "data": {"device": "floppy0", "tray-open": true}}
+
 *** done