From: Emanuele Giuseppe Esposito Date: Wed, 9 Feb 2022 10:54:48 +0000 (-0500) Subject: crypto: perform permission checks under BQL X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c1019d1687fb767afb6f6b09394975845763f830;p=qemu.git crypto: perform permission checks under BQL Move the permission API calls into driver-specific callbacks that always run under BQL. In this case, bdrv_crypto_luks needs to perform permission checks before and after qcrypto_block_amend_options(). The problem is that the caller, block_crypto_amend_options_generic_luks(), can also run in I/O from .bdrv_co_amend(). This does not comply with Global State-I/O API split, as permissions API must always run under BQL. Firstly, introduce .bdrv_amend_pre_run() and .bdrv_amend_clean() callbacks. These two callbacks are guaranteed to be invoked under BQL, respectively before and after .bdrv_co_amend(). They take care of performing the permission checks in the same way as they are currently done before and after qcrypto_block_amend_options(). These callbacks are in preparation for next patch, where we delete the original permission check. Right now they just add redundant control. Then, call .bdrv_amend_pre_run() before job_start in qmp_x_blockdev_amend(), so that it will be run before the job coroutine is created and stay in the main loop. As a cleanup, use JobDriver's .clean() callback to call .bdrv_amend_clean(), and run amend-specific cleanup callbacks under BQL. After this patch, permission failures occur early in the blockdev-amend job to update a LUKS volume's keys. iotest 296 must now expect them in x-blockdev-amend's QMP reply instead of waiting for the actual job to fail later. Signed-off-by: Emanuele Giuseppe Esposito Message-Id: <20220209105452.1694545-2-eesposit@redhat.com> Signed-off-by: Hanna Reitz Message-Id: <20220304153729.711387-6-hreitz@redhat.com> Signed-off-by: Kevin Wolf --- diff --git a/block/amend.c b/block/amend.c index 392df9ef83..f465738665 100644 --- a/block/amend.c +++ b/block/amend.c @@ -53,10 +53,29 @@ static int coroutine_fn blockdev_amend_run(Job *job, Error **errp) return ret; } +static int blockdev_amend_pre_run(BlockdevAmendJob *s, Error **errp) +{ + if (s->bs->drv->bdrv_amend_pre_run) { + return s->bs->drv->bdrv_amend_pre_run(s->bs, errp); + } + + return 0; +} + +static void blockdev_amend_clean(Job *job) +{ + BlockdevAmendJob *s = container_of(job, BlockdevAmendJob, common); + + if (s->bs->drv->bdrv_amend_clean) { + s->bs->drv->bdrv_amend_clean(s->bs); + } +} + static const JobDriver blockdev_amend_job_driver = { .instance_size = sizeof(BlockdevAmendJob), .job_type = JOB_TYPE_AMEND, .run = blockdev_amend_run, + .clean = blockdev_amend_clean, }; void qmp_x_blockdev_amend(const char *job_id, @@ -113,5 +132,11 @@ void qmp_x_blockdev_amend(const char *job_id, s->bs = bs, s->opts = QAPI_CLONE(BlockdevAmendOptions, options), s->force = has_force ? force : false; + + if (blockdev_amend_pre_run(s, errp)) { + job_early_fail(&s->common); + return; + } + job_start(&s->common); } diff --git a/block/crypto.c b/block/crypto.c index c8ba4681e2..70b2f07351 100644 --- a/block/crypto.c +++ b/block/crypto.c @@ -777,6 +777,37 @@ block_crypto_get_specific_info_luks(BlockDriverState *bs, Error **errp) return spec_info; } +static int +block_crypto_amend_prepare(BlockDriverState *bs, Error **errp) +{ + BlockCrypto *crypto = bs->opaque; + int ret; + + /* apply for exclusive read/write permissions to the underlying file */ + crypto->updating_keys = true; + ret = bdrv_child_refresh_perms(bs, bs->file, errp); + if (ret < 0) { + /* Well, in this case we will not be updating any keys */ + crypto->updating_keys = false; + } + return ret; +} + +static void +block_crypto_amend_cleanup(BlockDriverState *bs) +{ + BlockCrypto *crypto = bs->opaque; + Error *errp = NULL; + + /* release exclusive read/write permissions to the underlying file */ + crypto->updating_keys = false; + bdrv_child_refresh_perms(bs, bs->file, &errp); + + if (errp) { + error_report_err(errp); + } +} + static int block_crypto_amend_options_generic_luks(BlockDriverState *bs, QCryptoBlockAmendOptions *amend_options, @@ -931,6 +962,8 @@ static BlockDriver bdrv_crypto_luks = { .bdrv_get_specific_info = block_crypto_get_specific_info_luks, .bdrv_amend_options = block_crypto_amend_options_luks, .bdrv_co_amend = block_crypto_co_amend_luks, + .bdrv_amend_pre_run = block_crypto_amend_prepare, + .bdrv_amend_clean = block_crypto_amend_cleanup, .is_format = true, diff --git a/include/block/block_int.h b/include/block/block_int.h index 27008cfb22..31bd788919 100644 --- a/include/block/block_int.h +++ b/include/block/block_int.h @@ -124,6 +124,20 @@ struct BlockDriver { * on those children. */ bool is_format; + + /* + * This function is invoked under BQL before .bdrv_co_amend() + * (which in contrast does not necessarily run under the BQL) + * to allow driver-specific initialization code that requires + * the BQL, like setting up specific permission flags. + */ + int (*bdrv_amend_pre_run)(BlockDriverState *bs, Error **errp); + /* + * This function is invoked under BQL after .bdrv_co_amend() + * to allow cleaning up what was done in .bdrv_amend_pre_run(). + */ + void (*bdrv_amend_clean)(BlockDriverState *bs); + /* * Return true if @to_replace can be replaced by a BDS with the * same data as @bs without it affecting @bs's behavior (that is, diff --git a/tests/qemu-iotests/296 b/tests/qemu-iotests/296 index 099a3eeaa5..f80ef3434a 100755 --- a/tests/qemu-iotests/296 +++ b/tests/qemu-iotests/296 @@ -174,8 +174,12 @@ class EncryptionSetupTestCase(iotests.QMPTestCase): } result = vm.qmp('x-blockdev-amend', **args) - assert result['return'] == {} - vm.run_job('job0') + iotests.log(result) + # Run the job only if it was created + event = ('JOB_STATUS_CHANGE', + {'data': {'id': 'job0', 'status': 'created'}}) + if vm.events_wait([event], timeout=0.0) is not None: + vm.run_job('job0') # test that when the image opened by two qemu processes, # neither of them can update the encryption keys diff --git a/tests/qemu-iotests/296.out b/tests/qemu-iotests/296.out index 42205cc981..609826eaa0 100644 --- a/tests/qemu-iotests/296.out +++ b/tests/qemu-iotests/296.out @@ -1,11 +1,9 @@ -{"execute": "job-dismiss", "arguments": {"id": "job0"}} {"return": {}} -Job failed: Failed to get shared "consistent read" lock {"execute": "job-dismiss", "arguments": {"id": "job0"}} {"return": {}} -Job failed: Failed to get shared "consistent read" lock -{"execute": "job-dismiss", "arguments": {"id": "job0"}} +{"error": {"class": "GenericError", "desc": "Failed to get shared \"consistent read\" lock"}} +{"error": {"class": "GenericError", "desc": "Failed to get shared \"consistent read\" lock"}} {"return": {}} {"execute": "job-dismiss", "arguments": {"id": "job0"}} {"return": {}} @@ -13,14 +11,9 @@ qemu-img: Failed to get shared "consistent read" lock Is another process using the image [TEST_DIR/test.img]? . -Job failed: Block node is read-only -{"execute": "job-dismiss", "arguments": {"id": "job0"}} -{"return": {}} -Job failed: Failed to get shared "consistent read" lock -{"execute": "job-dismiss", "arguments": {"id": "job0"}} -{"return": {}} -Job failed: Failed to get shared "consistent read" lock -{"execute": "job-dismiss", "arguments": {"id": "job0"}} +{"error": {"class": "GenericError", "desc": "Block node is read-only"}} +{"error": {"class": "GenericError", "desc": "Failed to get shared \"consistent read\" lock"}} +{"error": {"class": "GenericError", "desc": "Failed to get shared \"consistent read\" lock"}} {"return": {}} {"execute": "job-dismiss", "arguments": {"id": "job0"}} {"return": {}}