From 662d0c5392a272aa0357aa7205e77fa3ca89c316 Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Sun, 19 Jul 2020 15:20:58 +0300 Subject: [PATCH 1/3] block/crypto: disallow write sharing by default My commit 'block/crypto: implement the encryption key management' accidently allowed raw luks images to be shared between different qemu processes without share-rw=on explicit override. Fix that. Fixes: bbfdae91fb ("block/crypto: implement the encryption key management") Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1857490 Signed-off-by: Maxim Levitsky Message-Id: <20200719122059.59843-2-mlevitsk@redhat.com> Signed-off-by: Max Reitz --- block/crypto.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/crypto.c b/block/crypto.c index 8725c1bc02..0807557763 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -881,7 +881,7 @@ block_crypto_child_perms(BlockDriverState *bs, BdrvChild *c, * For backward compatibility, manually share the write * and resize permission */ - *nshared |= (BLK_PERM_WRITE | BLK_PERM_RESIZE); + *nshared |= shared & (BLK_PERM_WRITE | BLK_PERM_RESIZE); /* * Since we are not fully a format driver, don't always request * the read/resize permission but only when explicitly From 0fca43de1b617a95f2472691ca1e740932ab2fea Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Sun, 19 Jul 2020 15:20:59 +0300 Subject: [PATCH 2/3] qemu-iotests: add testcase for bz #1857490 Test that we can't write-share raw luks images by default, but we still can with share-rw=on Signed-off-by: Maxim Levitsky Message-Id: <20200719122059.59843-3-mlevitsk@redhat.com> Signed-off-by: Max Reitz --- tests/qemu-iotests/296 | 44 +++++++++++++++++++++++++++++++++++++- tests/qemu-iotests/296.out | 12 +++++++++-- 2 files changed, 53 insertions(+), 3 deletions(-) diff --git a/tests/qemu-iotests/296 b/tests/qemu-iotests/296 index ec69ec8974..fb7dec88aa 100755 --- a/tests/qemu-iotests/296 +++ b/tests/qemu-iotests/296 @@ -133,6 +133,21 @@ class EncryptionSetupTestCase(iotests.QMPTestCase): ) self.assert_qmp(result, 'return', {}) + + ########################################################################### + # add virtio-blk consumer for a block device + def addImageUser(self, vm, id, disk_id, share_rw=False): + result = vm.qmp('device_add', ** + { + 'driver': 'virtio-blk', + 'id': id, + 'drive': disk_id, + 'share-rw' : share_rw + } + ) + + iotests.log(result) + # close the encrypted block device def closeImageQmp(self, vm, id): result = vm.qmp('blockdev-del', **{ 'node-name': id }) @@ -159,7 +174,7 @@ class EncryptionSetupTestCase(iotests.QMPTestCase): vm.run_job('job0') # test that when the image opened by two qemu processes, - # neither of them can update the image + # neither of them can update the encryption keys def test1(self): self.createImg(test_img, self.secrets[0]); @@ -193,6 +208,9 @@ class EncryptionSetupTestCase(iotests.QMPTestCase): os.remove(test_img) + # test that when the image opened by two qemu processes, + # even if first VM opens it read-only, the second can't update encryption + # keys def test2(self): self.createImg(test_img, self.secrets[0]); @@ -226,6 +244,30 @@ class EncryptionSetupTestCase(iotests.QMPTestCase): self.closeImageQmp(self.vm1, "testdev") os.remove(test_img) + # test that two VMs can't open the same luks image by default + # and attach it to a guest device + def test3(self): + self.createImg(test_img, self.secrets[0]); + + self.openImageQmp(self.vm1, "testdev", test_img, self.secrets[0]) + self.addImageUser(self.vm1, "testctrl", "testdev") + + self.openImageQmp(self.vm2, "testdev", test_img, self.secrets[0]) + self.addImageUser(self.vm2, "testctrl", "testdev") + + + # test that two VMs can attach the same luks image to a guest device, + # if both use share-rw=on + def test4(self): + self.createImg(test_img, self.secrets[0]); + + self.openImageQmp(self.vm1, "testdev", test_img, self.secrets[0]) + self.addImageUser(self.vm1, "testctrl", "testdev", share_rw=True) + + self.openImageQmp(self.vm2, "testdev", test_img, self.secrets[0]) + self.addImageUser(self.vm2, "testctrl", "testdev", share_rw=True) + + if __name__ == '__main__': # support only raw luks since luks encrypted qcow2 is a proper diff --git a/tests/qemu-iotests/296.out b/tests/qemu-iotests/296.out index afb6d2d09d..cb2859a15c 100644 --- a/tests/qemu-iotests/296.out +++ b/tests/qemu-iotests/296.out @@ -26,8 +26,16 @@ Job failed: Failed to get shared "consistent read" lock {"return": {}} {"execute": "job-dismiss", "arguments": {"id": "job0"}} {"return": {}} -.. +Formatting 'TEST_DIR/test.img', fmt=luks size=1048576 key-secret=keysec0 iter-time=10 + +{"return": {}} +{"error": {"class": "GenericError", "desc": "Failed to get \"write\" lock"}} +Formatting 'TEST_DIR/test.img', fmt=luks size=1048576 key-secret=keysec0 iter-time=10 + +{"return": {}} +{"return": {}} +.... ---------------------------------------------------------------------- -Ran 2 tests +Ran 4 tests OK From 1d719ddc35e9827b6e5df771555874df34301a0d Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Mon, 20 Jul 2020 11:01:41 +0100 Subject: [PATCH 3/3] block: fix bdrv_aio_cancel() for ENOMEDIUM requests MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit bdrv_aio_cancel() calls aio_poll() on the AioContext for the given I/O request until it has completed. ENOMEDIUM requests are special because there is no BlockDriverState when the drive has no medium! Define a .get_aio_context() function for BlkAioEmAIOCB requests so that bdrv_aio_cancel() can find the AioContext where the completion BH is pending. Without this function bdrv_aio_cancel() aborts on ENOMEDIUM requests! libFuzzer triggered the following assertion: cat << EOF | qemu-system-i386 -M pc-q35-5.0 \ -nographic -monitor none -serial none \ -qtest stdio -trace ide\* outl 0xcf8 0x8000fa24 outl 0xcfc 0xe106c000 outl 0xcf8 0x8000fa04 outw 0xcfc 0x7 outl 0xcf8 0x8000fb20 write 0x0 0x3 0x2780e7 write 0xe106c22c 0xd 0x1130c218021130c218021130c2 write 0xe106c218 0x15 0x110010110010110010110010110010110010110010 EOF ide_exec_cmd IDE exec cmd: bus 0x56170a77a2b8; state 0x56170a77a340; cmd 0xe7 ide_reset IDEstate 0x56170a77a340 Aborted (core dumped) (gdb) bt #1 0x00007ffff4f93895 in abort () at /lib64/libc.so.6 #2 0x0000555555dc6c00 in bdrv_aio_cancel (acb=0x555556765550) at block/io.c:2745 #3 0x0000555555dac202 in blk_aio_cancel (acb=0x555556765550) at block/block-backend.c:1546 #4 0x0000555555b1bd74 in ide_reset (s=0x555557213340) at hw/ide/core.c:1318 #5 0x0000555555b1e3a1 in ide_bus_reset (bus=0x5555572132b8) at hw/ide/core.c:2422 #6 0x0000555555b2aa27 in ahci_reset_port (s=0x55555720eb50, port=2) at hw/ide/ahci.c:650 #7 0x0000555555b29fd7 in ahci_port_write (s=0x55555720eb50, port=2, offset=44, val=16) at hw/ide/ahci.c:360 #8 0x0000555555b2a564 in ahci_mem_write (opaque=0x55555720eb50, addr=556, val=16, size=1) at hw/ide/ahci.c:513 #9 0x000055555598415b in memory_region_write_accessor (mr=0x55555720eb80, addr=556, value=0x7fffffffb838, size=1, shift=0, mask=255, attrs=...) at softmmu/memory.c:483 Looking at bdrv_aio_cancel: 2728 /* async I/Os */ 2729 2730 void bdrv_aio_cancel(BlockAIOCB *acb) 2731 { 2732 qemu_aio_ref(acb); 2733 bdrv_aio_cancel_async(acb); 2734 while (acb->refcnt > 1) { 2735 if (acb->aiocb_info->get_aio_context) { 2736 aio_poll(acb->aiocb_info->get_aio_context(acb), true); 2737 } else if (acb->bs) { 2738 /* qemu_aio_ref and qemu_aio_unref are not thread-safe, so 2739 * assert that we're not using an I/O thread. Thread-safe 2740 * code should use bdrv_aio_cancel_async exclusively. 2741 */ 2742 assert(bdrv_get_aio_context(acb->bs) == qemu_get_aio_context()); 2743 aio_poll(bdrv_get_aio_context(acb->bs), true); 2744 } else { 2745 abort(); <=============== 2746 } 2747 } 2748 qemu_aio_unref(acb); 2749 } Fixes: 02c50efe08736116048d5fc355043080f4d5859c ("block: Add bdrv_aio_cancel_async") Reported-by: Alexander Bulekov Buglink: https://bugs.launchpad.net/qemu/+bug/1878255 Originally-by: Philippe Mathieu-Daudé Signed-off-by: Stefan Hajnoczi Message-Id: <20200720100141.129739-1-stefanha@redhat.com> Signed-off-by: Max Reitz --- block/block-backend.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index 0bf0188133..3a13cb5f0b 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1394,8 +1394,16 @@ typedef struct BlkAioEmAIOCB { bool has_returned; } BlkAioEmAIOCB; +static AioContext *blk_aio_em_aiocb_get_aio_context(BlockAIOCB *acb_) +{ + BlkAioEmAIOCB *acb = container_of(acb_, BlkAioEmAIOCB, common); + + return blk_get_aio_context(acb->rwco.blk); +} + static const AIOCBInfo blk_aio_em_aiocb_info = { .aiocb_size = sizeof(BlkAioEmAIOCB), + .get_aio_context = blk_aio_em_aiocb_get_aio_context, }; static void blk_aio_complete(BlkAioEmAIOCB *acb)