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Sat, 24 Jun 2023 19:10:03 -0400 (EDT) From: Demi Marie Obenour To: Alasdair Kergon , Mike Snitzer , dm-devel@redhat.com Date: Sat, 24 Jun 2023 19:09:46 -0400 Message-ID: <20230624230950.2272-4-demi@invisiblethingslab.com> In-Reply-To: <20230624230950.2272-1-demi@invisiblethingslab.com> References: <20230624230950.2272-1-demi@invisiblethingslab.com> MIME-Version: 1.0 X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 Subject: [dm-devel] [PATCH v2 3/4] dm ioctl: Allow userspace to suppress uevent generation X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Demi Marie Obenour , linux-kernel@vger.kernel.org Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: invisiblethingslab.com Userspace can use this to avoid spamming udev with events that udev should ignore. Signed-off-by: Demi Marie Obenour --- drivers/md/dm-core.h | 2 + drivers/md/dm-ioctl.c | 71 ++++++++++++++++++----------------- drivers/md/dm.c | 5 ++- include/linux/device-mapper.h | 2 +- include/uapi/linux/dm-ioctl.h | 14 +++++-- 5 files changed, 54 insertions(+), 40 deletions(-) diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index 0d93661f88d306e0d0aa3a1ac085880a8b63d9d6..5a4acdbf119f9b3f9a1c60de36d23f0658449701 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -115,6 +115,8 @@ struct mapped_device { /* for blk-mq request-based DM support */ bool init_tio_pdu:1; + /* If set, do not emit any uevents. */ + bool disable_uevents:1; struct blk_mq_tag_set *tag_set; struct dm_stats stats; diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c index 7abaeec33f1884d4588e8563fb02e9ea1a6782c8..7eab9a8c77ff3286346a1c44581d3b6370a731eb 100644 --- a/drivers/md/dm-ioctl.c +++ b/drivers/md/dm-ioctl.c @@ -821,6 +821,11 @@ static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md, dm_get_inactive_table(md, srcu_idx) : dm_get_live_table(md, srcu_idx); } +static inline bool sloppy_checks(const struct dm_ioctl *param) +{ + return param->version[0] < DM_VERSION_MAJOR_STRICT; +} + /* * Fills in a dm_ioctl structure, ready for sending back to * userland. @@ -879,7 +884,7 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param) dm_put_live_table(md, srcu_idx); } - if (param->version[0] >= DM_VERSION_MAJOR_STRICT) + if (!sloppy_checks(param)) dm_set_diskseq(param, disk->diskseq); } @@ -895,7 +900,7 @@ static int dev_create(struct file *filp, struct dm_ioctl *param, size_t param_si if (param->flags & DM_PERSISTENT_DEV_FLAG) m = MINOR(huge_decode_dev(param->dev)); - r = dm_create(m, &md); + r = dm_create(m, &md, param->flags & DM_DISABLE_UEVENTS_FLAG); if (r) return r; @@ -1463,11 +1468,6 @@ static int next_target(struct dm_target_spec *last, uint32_t next, const char *e return 0; } -static inline bool sloppy_checks(const struct dm_ioctl *param) -{ - return param->version[0] < DM_VERSION_MAJOR_STRICT; -} - static bool no_non_nul_after_nul(const char *untrusted_str, size_t size, unsigned int cmd, const char *msg) { @@ -1939,64 +1939,67 @@ static int target_message(struct file *filp, struct dm_ioctl *param, size_t para * Implementation of open/close/ioctl on the special char device. *--------------------------------------------------------------- */ -static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags, uint32_t *supported_flags) +static ioctl_fn lookup_ioctl(unsigned int cmd, bool strict, int *ioctl_flags, + uint32_t *supported_flags) { static const struct { int cmd; int flags; ioctl_fn fn; uint32_t supported_flags; + uint32_t strict_flags; } _ioctls[] = { /* Macro to make the structure initializers somewhat readable */ -#define I(cmd, flags, fn, supported_flags) ((typeof(_ioctls[0])) { \ +#define I(cmd, flags, fn, supported_flags, strict_flags) ((typeof(_ioctls[0])) { \ (cmd), \ (flags), \ (fn), \ /* * Supported flags in sloppy mode must not include anything in DM_STRICT_ONLY_FLAGS. - * Use BUILD_BUG_ON_ZERO to check for that. Currently there are no strict-only flags - * defined. + * Use BUILD_BUG_ON_ZERO to check for that. */ \ (supported_flags) | BUILD_BUG_ON_ZERO((supported_flags) & DM_STRICT_ONLY_FLAGS), \ + (strict_flags) | (supported_flags) | \ + BUILD_BUG_ON_ZERO((supported_flags) & (strict_flags)), \ }) - I(DM_VERSION_CMD, 0, NULL, 0), /* version is dealt with elsewhere */ + I(DM_VERSION_CMD, 0, NULL, 0, 0), /* version is dealt with elsewhere */ I(DM_REMOVE_ALL_CMD, IOCTL_FLAGS_NO_PARAMS | IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, - remove_all, DM_DEFERRED_REMOVE), - I(DM_LIST_DEVICES_CMD, 0, list_devices, DM_UUID_FLAG), + remove_all, DM_DEFERRED_REMOVE, 0), + I(DM_LIST_DEVICES_CMD, 0, list_devices, DM_UUID_FLAG, 0), I(DM_DEV_CREATE_CMD, IOCTL_FLAGS_NO_PARAMS | IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, - dev_create, DM_PERSISTENT_DEV_FLAG), + dev_create, DM_PERSISTENT_DEV_FLAG, DM_DISABLE_UEVENTS_FLAG), I(DM_DEV_REMOVE_CMD, IOCTL_FLAGS_NO_PARAMS | IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, - dev_remove, DM_DEFERRED_REMOVE), + dev_remove, DM_DEFERRED_REMOVE, 0), I(DM_DEV_RENAME_CMD, IOCTL_FLAGS_ISSUE_GLOBAL_EVENT, dev_rename, - DM_QUERY_INACTIVE_TABLE_FLAG | DM_UUID_FLAG), + DM_QUERY_INACTIVE_TABLE_FLAG | DM_UUID_FLAG, 0), I(DM_DEV_SUSPEND_CMD, IOCTL_FLAGS_NO_PARAMS, dev_suspend, - DM_QUERY_INACTIVE_TABLE_FLAG | DM_SUSPEND_FLAG | DM_SKIP_LOCKFS_FLAG | - DM_NOFLUSH_FLAG), + DM_QUERY_INACTIVE_TABLE_FLAG | DM_SUSPEND_FLAG | + DM_SKIP_LOCKFS_FLAG | DM_NOFLUSH_FLAG, 0), I(DM_DEV_STATUS_CMD, IOCTL_FLAGS_NO_PARAMS, dev_status, - DM_QUERY_INACTIVE_TABLE_FLAG), + DM_QUERY_INACTIVE_TABLE_FLAG, 0), I(DM_DEV_WAIT_CMD, IOCTL_FLAGS_TAKES_EVENT_NR, dev_wait, - DM_QUERY_INACTIVE_TABLE_FLAG | DM_STATUS_TABLE_FLAG | DM_NOFLUSH_FLAG), - I(DM_TABLE_LOAD_CMD, 0, table_load, DM_QUERY_INACTIVE_TABLE_FLAG | - DM_READONLY_FLAG), + DM_QUERY_INACTIVE_TABLE_FLAG | DM_STATUS_TABLE_FLAG | DM_NOFLUSH_FLAG, 0), + I(DM_TABLE_LOAD_CMD, 0, table_load, + DM_QUERY_INACTIVE_TABLE_FLAG | DM_READONLY_FLAG, 0), I(DM_TABLE_CLEAR_CMD, IOCTL_FLAGS_NO_PARAMS, table_clear, - DM_QUERY_INACTIVE_TABLE_FLAG), - I(DM_TABLE_DEPS_CMD, 0, table_deps, DM_QUERY_INACTIVE_TABLE_FLAG), + DM_QUERY_INACTIVE_TABLE_FLAG, 0), + I(DM_TABLE_DEPS_CMD, 0, table_deps, DM_QUERY_INACTIVE_TABLE_FLAG, 0), I(DM_TABLE_STATUS_CMD, 0, table_status, - DM_QUERY_INACTIVE_TABLE_FLAG | DM_STATUS_TABLE_FLAG | DM_NOFLUSH_FLAG), + DM_QUERY_INACTIVE_TABLE_FLAG | DM_STATUS_TABLE_FLAG | DM_NOFLUSH_FLAG, 0), - I(DM_LIST_VERSIONS_CMD, 0, list_versions, 0), + I(DM_LIST_VERSIONS_CMD, 0, list_versions, 0, 0), - I(DM_TARGET_MSG_CMD, 0, target_message, DM_QUERY_INACTIVE_TABLE_FLAG), - I(DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry, 0), - I(DM_DEV_ARM_POLL_CMD, IOCTL_FLAGS_NO_PARAMS, dev_arm_poll, 0), - I(DM_GET_TARGET_VERSION_CMD, 0, get_target_version, 0), + I(DM_TARGET_MSG_CMD, 0, target_message, DM_QUERY_INACTIVE_TABLE_FLAG, 0), + I(DM_DEV_SET_GEOMETRY_CMD, 0, dev_set_geometry, 0, 0), + I(DM_DEV_ARM_POLL_CMD, IOCTL_FLAGS_NO_PARAMS, dev_arm_poll, 0, 0), + I(DM_GET_TARGET_VERSION_CMD, 0, get_target_version, 0, 0), }; if (unlikely(cmd >= ARRAY_SIZE(_ioctls))) return NULL; cmd = array_index_nospec(cmd, ARRAY_SIZE(_ioctls)); - *supported_flags = _ioctls[cmd].supported_flags; + *supported_flags = strict ? _ioctls[cmd].strict_flags : _ioctls[cmd].supported_flags; *ioctl_flags = _ioctls[cmd].flags; return _ioctls[cmd].fn; } @@ -2260,7 +2263,7 @@ static int ctl_ioctl(struct file *file, uint command, struct dm_ioctl __user *us if (cmd == DM_VERSION_CMD) return 0; - fn = lookup_ioctl(cmd, &ioctl_flags, &supported_flags); + fn = lookup_ioctl(cmd, !sloppy_checks(¶m_kernel), &ioctl_flags, &supported_flags); if (!fn) { DMERR("dm_ctl_ioctl: unknown command 0x%x", command); return -ENOTTY; @@ -2480,7 +2483,7 @@ int __init dm_early_create(struct dm_ioctl *dmi, m = MINOR(huge_decode_dev(dmi->dev)); /* alloc dm device */ - r = dm_create(m, &md); + r = dm_create(m, &md, false); if (r) return r; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index ea1671c39ba131ab2e49b93289d1094cda5cfb25..b7817b4aea52033afeeea9f2b93b9215de682e9c 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2281,13 +2281,14 @@ static struct dm_table *__unbind(struct mapped_device *md) /* * Constructor for a new device. */ -int dm_create(int minor, struct mapped_device **result) +int dm_create(int minor, struct mapped_device **result, bool disable_uevents) { struct mapped_device *md; md = alloc_dev(minor); if (!md) return -ENXIO; + md->disable_uevents = disable_uevents; dm_ima_reset_data(md); @@ -3005,6 +3006,8 @@ int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action, char udev_cookie[DM_COOKIE_LENGTH]; char *envp[3] = { NULL, NULL, NULL }; char **envpp = envp; + if (md->disable_uevents) + return 0; if (cookie) { snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u", DM_COOKIE_ENV_VAR_NAME, cookie); diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h index 69d0435c7ebb0d7b712e2b8bf32d9ba34c54e09e..2be940c2c6f42ed8e13b97ea8b07d0895566f3e2 100644 --- a/include/linux/device-mapper.h +++ b/include/linux/device-mapper.h @@ -461,7 +461,7 @@ void dm_consume_args(struct dm_arg_set *as, unsigned int num_args); * DM_ANY_MINOR chooses the next available minor number. */ #define DM_ANY_MINOR (-1) -int dm_create(int minor, struct mapped_device **md); +int dm_create(int minor, struct mapped_device **md, bool disable_uevents); /* * Reference counting for md. diff --git a/include/uapi/linux/dm-ioctl.h b/include/uapi/linux/dm-ioctl.h index 1d33109aece2ff9854e752066baa96fdf7d85857..b338a4f9a299acda9430995d63fbb490e70c8cd8 100644 --- a/include/uapi/linux/dm-ioctl.h +++ b/include/uapi/linux/dm-ioctl.h @@ -369,8 +369,16 @@ enum { #define DM_BUFFER_FULL_FLAG (1 << 8) /* Out */ /* - * This flag is now ignored if DM_VERSION_MAJOR is used, and causes - * -EINVAL if DM_VERSION_MAJOR_STRICT is used. + * This flag is only recognized when DM_VERSION_MAJOR_STRICT is used. + * It tells the kernel to not generate any uevents for the newly-created + * device. Using it outside of DM_DEV_CREATE results in -EINVAL. When + * DM_VERSION_MAJOR is used this flag is ignored. + */ +#define DM_DISABLE_UEVENTS_FLAG (1 << 9) /* In */ + +/* + * This flag is now ignored if DM_VERSION_MAJOR is used. When + * DM_VERSION_MAJOR_STRICT is used it is an alias for DM_DISABLE_UEVENT_FLAG. */ #define DM_SKIP_BDGET_FLAG (1 << 9) /* In */ @@ -439,8 +447,6 @@ enum { /* * If DM_VERSION_MAJOR is used, these flags are ignored by the kernel. - * If DM_VERSION_MAJOR_STRICT is used, these flags are reserved and - * must be zeroed. */ #define DM_STRICT_ONLY_FLAGS \ (DM_ACTIVE_PRESENT_FLAG | DM_INACTIVE_PRESENT_FLAG | \