From f70ce185687bbe4e2d7ff126a8c890631f5fc2af Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:11 +0100 Subject: [PATCH 1/9] sysfs: add sysfs_file_change_owner() Add helpers to change the owner of a sysfs files. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- fs/sysfs/file.c | 47 +++++++++++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 10 +++++++++ 2 files changed, 57 insertions(+) diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 130fc6fbcc038..4ca936ca3ba44 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -558,3 +558,50 @@ void sysfs_remove_bin_file(struct kobject *kobj, kernfs_remove_by_name(kobj->sd, attr->attr.name); } EXPORT_SYMBOL_GPL(sysfs_remove_bin_file); + +static int internal_change_owner(struct kernfs_node *kn, kuid_t kuid, + kgid_t kgid) +{ + struct iattr newattrs = { + .ia_valid = ATTR_UID | ATTR_GID, + .ia_uid = kuid, + .ia_gid = kgid, + }; + return kernfs_setattr(kn, &newattrs); +} + +/** + * sysfs_file_change_owner - change owner of a sysfs file. + * @kobj: object. + * @name: name of the file to change. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * This function looks up the sysfs entry @name under @kobj and changes the + * ownership to @kuid/@kgid. + * + * Returns 0 on success or error code on failure. + */ +int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, + kgid_t kgid) +{ + struct kernfs_node *kn; + int error; + + if (!name) + return -EINVAL; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + kn = kernfs_find_and_get(kobj->sd, name); + if (!kn) + return -ENOENT; + + error = internal_change_owner(kn, kuid, kgid); + + kernfs_put(kn); + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_file_change_owner); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index fa7ee503fb763..a7884024a9118 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -310,6 +310,9 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) return kernfs_enable_ns(kn); } +int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, + kgid_t kgid); + #else /* CONFIG_SYSFS */ static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns) @@ -522,6 +525,13 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) { } +static inline int sysfs_file_change_owner(struct kobject *kobj, + const char *name, kuid_t kuid, + kgid_t kgid) +{ + return 0; +} + #endif /* CONFIG_SYSFS */ static inline int __must_check sysfs_create_file(struct kobject *kobj, From 0666a3aee762cd4f7981c2eed0fd8cab87533539 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:12 +0100 Subject: [PATCH 2/9] sysfs: add sysfs_link_change_owner() Add a helper to change the owner of a sysfs link. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- fs/sysfs/file.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 10 ++++++++++ 2 files changed, 51 insertions(+) diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 4ca936ca3ba44..332cd69b378c7 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -570,6 +570,47 @@ static int internal_change_owner(struct kernfs_node *kn, kuid_t kuid, return kernfs_setattr(kn, &newattrs); } +/** + * sysfs_link_change_owner - change owner of a sysfs file. + * @kobj: object of the kernfs_node the symlink is located in. + * @targ: object of the kernfs_node the symlink points to. + * @name: name of the link. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * This function looks up the sysfs symlink entry @name under @kobj and changes + * the ownership to @kuid/@kgid. The symlink is looked up in the namespace of + * @targ. + * + * Returns 0 on success or error code on failure. + */ +int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ, + const char *name, kuid_t kuid, kgid_t kgid) +{ + struct kernfs_node *kn = NULL; + int error; + + if (!name || !kobj->state_in_sysfs || !targ->state_in_sysfs) + return -EINVAL; + + error = -ENOENT; + kn = kernfs_find_and_get_ns(kobj->sd, name, targ->sd->ns); + if (!kn) + goto out; + + error = -EINVAL; + if (kernfs_type(kn) != KERNFS_LINK) + goto out; + if (kn->symlink.target_kn->priv != targ) + goto out; + + error = internal_change_owner(kn, kuid, kgid); + +out: + kernfs_put(kn); + return error; +} + /** * sysfs_file_change_owner - change owner of a sysfs file. * @kobj: object. diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index a7884024a9118..7e15ebfd750e5 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -312,6 +312,8 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, kgid_t kgid); +int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ, + const char *name, kuid_t kuid, kgid_t kgid); #else /* CONFIG_SYSFS */ @@ -532,6 +534,14 @@ static inline int sysfs_file_change_owner(struct kobject *kobj, return 0; } +static inline int sysfs_link_change_owner(struct kobject *kobj, + struct kobject *targ, + const char *name, kuid_t kuid, + kgid_t kgid) +{ + return 0; +} + #endif /* CONFIG_SYSFS */ static inline int __must_check sysfs_create_file(struct kobject *kobj, From 303a42769c4c4d8e5e3ad928df87eb36f8c1fa60 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:13 +0100 Subject: [PATCH 3/9] sysfs: add sysfs_group{s}_change_owner() Add helpers to change the owner of sysfs groups. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- fs/sysfs/group.c | 115 ++++++++++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 20 ++++++++ 2 files changed, 135 insertions(+) diff --git a/fs/sysfs/group.c b/fs/sysfs/group.c index c4ab045926b7c..5afe0e7ff7cd1 100644 --- a/fs/sysfs/group.c +++ b/fs/sysfs/group.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "sysfs.h" @@ -457,3 +458,117 @@ int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj, return PTR_ERR_OR_ZERO(link); } EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj); + +static int sysfs_group_attrs_change_owner(struct kernfs_node *grp_kn, + const struct attribute_group *grp, + struct iattr *newattrs) +{ + struct kernfs_node *kn; + int error; + + if (grp->attrs) { + struct attribute *const *attr; + + for (attr = grp->attrs; *attr; attr++) { + kn = kernfs_find_and_get(grp_kn, (*attr)->name); + if (!kn) + return -ENOENT; + + error = kernfs_setattr(kn, newattrs); + kernfs_put(kn); + if (error) + return error; + } + } + + if (grp->bin_attrs) { + struct bin_attribute *const *bin_attr; + + for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) { + kn = kernfs_find_and_get(grp_kn, (*bin_attr)->attr.name); + if (!kn) + return -ENOENT; + + error = kernfs_setattr(kn, newattrs); + kernfs_put(kn); + if (error) + return error; + } + } + + return 0; +} + +/** + * sysfs_group_change_owner - change owner of an attribute group. + * @kobj: The kobject containing the group. + * @grp: The attribute group. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * Returns 0 on success or error code on failure. + */ +int sysfs_group_change_owner(struct kobject *kobj, + const struct attribute_group *grp, kuid_t kuid, + kgid_t kgid) +{ + struct kernfs_node *grp_kn; + int error; + struct iattr newattrs = { + .ia_valid = ATTR_UID | ATTR_GID, + .ia_uid = kuid, + .ia_gid = kgid, + }; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + if (grp->name) { + grp_kn = kernfs_find_and_get(kobj->sd, grp->name); + } else { + kernfs_get(kobj->sd); + grp_kn = kobj->sd; + } + if (!grp_kn) + return -ENOENT; + + error = kernfs_setattr(grp_kn, &newattrs); + if (!error) + error = sysfs_group_attrs_change_owner(grp_kn, grp, &newattrs); + + kernfs_put(grp_kn); + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_group_change_owner); + +/** + * sysfs_groups_change_owner - change owner of a set of attribute groups. + * @kobj: The kobject containing the groups. + * @groups: The attribute groups. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * Returns 0 on success or error code on failure. + */ +int sysfs_groups_change_owner(struct kobject *kobj, + const struct attribute_group **groups, + kuid_t kuid, kgid_t kgid) +{ + int error = 0, i; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + if (!groups) + return 0; + + for (i = 0; groups[i]; i++) { + error = sysfs_group_change_owner(kobj, groups[i], kuid, kgid); + if (error) + break; + } + + return error; +} +EXPORT_SYMBOL_GPL(sysfs_groups_change_owner); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 7e15ebfd750e5..3fcaabdb05ef7 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -314,6 +314,12 @@ int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, kgid_t kgid); int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ, const char *name, kuid_t kuid, kgid_t kgid); +int sysfs_groups_change_owner(struct kobject *kobj, + const struct attribute_group **groups, + kuid_t kuid, kgid_t kgid); +int sysfs_group_change_owner(struct kobject *kobj, + const struct attribute_group *groups, kuid_t kuid, + kgid_t kgid); #else /* CONFIG_SYSFS */ @@ -542,6 +548,20 @@ static inline int sysfs_link_change_owner(struct kobject *kobj, return 0; } +static inline int sysfs_groups_change_owner(struct kobject *kobj, + const struct attribute_group **groups, + kuid_t kuid, kgid_t kgid) +{ + return 0; +} + +static inline int sysfs_group_change_owner(struct kobject *kobj, + const struct attribute_group **groups, + kuid_t kuid, kgid_t kgid) +{ + return 0; +} + #endif /* CONFIG_SYSFS */ static inline int __must_check sysfs_create_file(struct kobject *kobj, From 2c4f9401ceb00167a3bfd322a28aa87b646a253f Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:14 +0100 Subject: [PATCH 4/9] sysfs: add sysfs_change_owner() Add a helper to change the owner of sysfs objects. This function will be used to correctly account for kobject ownership changes, e.g. when moving network devices between network namespaces. This mirrors how a kobject is added through driver core which in its guts is done via kobject_add_internal() which in summary creates the main directory via create_dir(), populates that directory with the groups associated with the ktype of the kobject (if any) and populates the directory with the basic attributes associated with the ktype of the kobject (if any). These are the basic steps that are associated with adding a kobject in sysfs. Any additional properties are added by the specific subsystem itself (not by driver core) after it has registered the device. So for the example of network devices, a network device will e.g. register a queue subdirectory under the basic sysfs directory for the network device and than further subdirectories within that queues subdirectory. But that is all specific to network devices and they call the corresponding sysfs functions to do that directly when they create those queue objects. So anything that a subsystem adds outside of what driver core does must also be changed by it (That's already true for removal of files it created outside of driver core.) and it's the same for ownership changes. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- fs/sysfs/file.c | 60 +++++++++++++++++++++++++++++++++++++++++++ include/linux/sysfs.h | 6 +++++ 2 files changed, 66 insertions(+) diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 332cd69b378c7..26bbf960e2a2e 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -646,3 +646,63 @@ int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, return error; } EXPORT_SYMBOL_GPL(sysfs_file_change_owner); + +/** + * sysfs_change_owner - change owner of the given object. + * @kobj: object. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * Change the owner of the default directory, files, groups, and attributes of + * @kobj to @kuid/@kgid. Note that sysfs_change_owner mirrors how the sysfs + * entries for a kobject are added by driver core. In summary, + * sysfs_change_owner() takes care of the default directory entry for @kobj, + * the default attributes associated with the ktype of @kobj and the default + * attributes associated with the ktype of @kobj. + * Additional properties not added by driver core have to be changed by the + * driver or subsystem which created them. This is similar to how + * driver/subsystem specific entries are removed. + * + * Returns 0 on success or error code on failure. + */ +int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid) +{ + int error; + const struct kobj_type *ktype; + + if (!kobj->state_in_sysfs) + return -EINVAL; + + /* Change the owner of the kobject itself. */ + error = internal_change_owner(kobj->sd, kuid, kgid); + if (error) + return error; + + ktype = get_ktype(kobj); + if (ktype) { + struct attribute **kattr; + + /* + * Change owner of the default attributes associated with the + * ktype of @kobj. + */ + for (kattr = ktype->default_attrs; kattr && *kattr; kattr++) { + error = sysfs_file_change_owner(kobj, (*kattr)->name, + kuid, kgid); + if (error) + return error; + } + + /* + * Change owner of the default groups associated with the + * ktype of @kobj. + */ + error = sysfs_groups_change_owner(kobj, ktype->default_groups, + kuid, kgid); + if (error) + return error; + } + + return 0; +} +EXPORT_SYMBOL_GPL(sysfs_change_owner); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index 3fcaabdb05ef7..9e531ec762741 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -312,6 +312,7 @@ static inline void sysfs_enable_ns(struct kernfs_node *kn) int sysfs_file_change_owner(struct kobject *kobj, const char *name, kuid_t kuid, kgid_t kgid); +int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid); int sysfs_link_change_owner(struct kobject *kobj, struct kobject *targ, const char *name, kuid_t kuid, kgid_t kgid); int sysfs_groups_change_owner(struct kobject *kobj, @@ -548,6 +549,11 @@ static inline int sysfs_link_change_owner(struct kobject *kobj, return 0; } +static inline int sysfs_change_owner(struct kobject *kobj, kuid_t kuid, kgid_t kgid) +{ + return 0; +} + static inline int sysfs_groups_change_owner(struct kobject *kobj, const struct attribute_group **groups, kuid_t kuid, kgid_t kgid) From b8f33e5d76a7a1b87e0cc760d05bf2477b4e91d6 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:15 +0100 Subject: [PATCH 5/9] device: add device_change_owner() Add a helper to change the owner of a device's sysfs entries. This needs to happen when the ownership of a device is changed, e.g. when moving network devices between network namespaces. This function will be used to correctly account for ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- drivers/base/core.c | 116 +++++++++++++++++++++++++++++++++++++++++ include/linux/device.h | 1 + 2 files changed, 117 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index 42a6724564323..988f34ce2eb04 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3458,6 +3458,122 @@ int device_move(struct device *dev, struct device *new_parent, } EXPORT_SYMBOL_GPL(device_move); +static int device_attrs_change_owner(struct device *dev, kuid_t kuid, + kgid_t kgid) +{ + struct kobject *kobj = &dev->kobj; + struct class *class = dev->class; + const struct device_type *type = dev->type; + int error; + + if (class) { + /* + * Change the device groups of the device class for @dev to + * @kuid/@kgid. + */ + error = sysfs_groups_change_owner(kobj, class->dev_groups, kuid, + kgid); + if (error) + return error; + } + + if (type) { + /* + * Change the device groups of the device type for @dev to + * @kuid/@kgid. + */ + error = sysfs_groups_change_owner(kobj, type->groups, kuid, + kgid); + if (error) + return error; + } + + /* Change the device groups of @dev to @kuid/@kgid. */ + error = sysfs_groups_change_owner(kobj, dev->groups, kuid, kgid); + if (error) + return error; + + if (device_supports_offline(dev) && !dev->offline_disabled) { + /* Change online device attributes of @dev to @kuid/@kgid. */ + error = sysfs_file_change_owner(kobj, dev_attr_online.attr.name, + kuid, kgid); + if (error) + return error; + } + + return 0; +} + +/** + * device_change_owner - change the owner of an existing device. + * @dev: device. + * @kuid: new owner's kuid + * @kgid: new owner's kgid + * + * This changes the owner of @dev and its corresponding sysfs entries to + * @kuid/@kgid. This function closely mirrors how @dev was added via driver + * core. + * + * Returns 0 on success or error code on failure. + */ +int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) +{ + int error; + struct kobject *kobj = &dev->kobj; + + dev = get_device(dev); + if (!dev) + return -EINVAL; + + /* + * Change the kobject and the default attributes and groups of the + * ktype associated with it to @kuid/@kgid. + */ + error = sysfs_change_owner(kobj, kuid, kgid); + if (error) + goto out; + + /* + * Change the uevent file for @dev to the new owner. The uevent file + * was created in a separate step when @dev got added and we mirror + * that step here. + */ + error = sysfs_file_change_owner(kobj, dev_attr_uevent.attr.name, kuid, + kgid); + if (error) + goto out; + + /* + * Change the device groups, the device groups associated with the + * device class, and the groups associated with the device type of @dev + * to @kuid/@kgid. + */ + error = device_attrs_change_owner(dev, kuid, kgid); + if (error) + goto out; + +#ifdef CONFIG_BLOCK + if (sysfs_deprecated && dev->class == &block_class) + goto out; +#endif + + /* + * Change the owner of the symlink located in the class directory of + * the device class associated with @dev which points to the actual + * directory entry for @dev to @kuid/@kgid. This ensures that the + * symlink shows the same permissions as its target. + */ + error = sysfs_link_change_owner(&dev->class->p->subsys.kobj, &dev->kobj, + dev_name(dev), kuid, kgid); + if (error) + goto out; + +out: + put_device(dev); + return error; +} +EXPORT_SYMBOL_GPL(device_change_owner); + /** * device_shutdown - call ->shutdown() on each device to shutdown. */ diff --git a/include/linux/device.h b/include/linux/device.h index 0cd7c647c16c6..3e40533d20376 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -817,6 +817,7 @@ extern struct device *device_find_child_by_name(struct device *parent, extern int device_rename(struct device *dev, const char *new_name); extern int device_move(struct device *dev, struct device *new_parent, enum dpm_order dpm_order); +extern int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid); extern const char *device_get_devnode(struct device *dev, umode_t *mode, kuid_t *uid, kgid_t *gid, const char **tmp); From 3b52fc5d7876a312e6a964d7e626ba05ab1ea6b2 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:16 +0100 Subject: [PATCH 6/9] drivers/base/power: add dpm_sysfs_change_owner() Add a helper to change the owner of a device's power entries. This needs to happen when the ownership of a device is changed, e.g. when moving network devices between network namespaces. This function will be used to correctly account for ownership changes, e.g. when moving network devices between network namespaces. Reviewed-by: Greg Kroah-Hartman Reviewed-by: "Rafael J. Wysocki" Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- drivers/base/core.c | 4 +++ drivers/base/power/power.h | 3 +++ drivers/base/power/sysfs.c | 55 +++++++++++++++++++++++++++++++++++++- 3 files changed, 61 insertions(+), 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index 988f34ce2eb04..fb8b7990f6fd7 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3552,6 +3552,10 @@ int device_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) if (error) goto out; + error = dpm_sysfs_change_owner(dev, kuid, kgid); + if (error) + goto out; + #ifdef CONFIG_BLOCK if (sysfs_deprecated && dev->class == &block_class) goto out; diff --git a/drivers/base/power/power.h b/drivers/base/power/power.h index 444f5c169a0b9..54292cdd7808b 100644 --- a/drivers/base/power/power.h +++ b/drivers/base/power/power.h @@ -74,6 +74,7 @@ extern int pm_qos_sysfs_add_flags(struct device *dev); extern void pm_qos_sysfs_remove_flags(struct device *dev); extern int pm_qos_sysfs_add_latency_tolerance(struct device *dev); extern void pm_qos_sysfs_remove_latency_tolerance(struct device *dev); +extern int dpm_sysfs_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid); #else /* CONFIG_PM */ @@ -88,6 +89,8 @@ static inline void pm_runtime_remove(struct device *dev) {} static inline int dpm_sysfs_add(struct device *dev) { return 0; } static inline void dpm_sysfs_remove(struct device *dev) {} +static inline int dpm_sysfs_change_owner(struct device *dev, kuid_t kuid, + kgid_t kgid) { return 0; } #endif diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c index d7d82db2e4bc4..2b99fe1eb207d 100644 --- a/drivers/base/power/sysfs.c +++ b/drivers/base/power/sysfs.c @@ -480,6 +480,14 @@ static ssize_t wakeup_last_time_ms_show(struct device *dev, return enabled ? sprintf(buf, "%lld\n", msec) : sprintf(buf, "\n"); } +static inline int dpm_sysfs_wakeup_change_owner(struct device *dev, kuid_t kuid, + kgid_t kgid) +{ + if (dev->power.wakeup && dev->power.wakeup->dev) + return device_change_owner(dev->power.wakeup->dev, kuid, kgid); + return 0; +} + static DEVICE_ATTR_RO(wakeup_last_time_ms); #ifdef CONFIG_PM_AUTOSLEEP @@ -501,7 +509,13 @@ static ssize_t wakeup_prevent_sleep_time_ms_show(struct device *dev, static DEVICE_ATTR_RO(wakeup_prevent_sleep_time_ms); #endif /* CONFIG_PM_AUTOSLEEP */ -#endif /* CONFIG_PM_SLEEP */ +#else /* CONFIG_PM_SLEEP */ +static inline int dpm_sysfs_wakeup_change_owner(struct device *dev, kuid_t kuid, + kgid_t kgid) +{ + return 0; +} +#endif #ifdef CONFIG_PM_ADVANCED_DEBUG static ssize_t runtime_usage_show(struct device *dev, @@ -684,6 +698,45 @@ int dpm_sysfs_add(struct device *dev) return rc; } +int dpm_sysfs_change_owner(struct device *dev, kuid_t kuid, kgid_t kgid) +{ + int rc; + + if (device_pm_not_required(dev)) + return 0; + + rc = sysfs_group_change_owner(&dev->kobj, &pm_attr_group, kuid, kgid); + if (rc) + return rc; + + if (pm_runtime_callbacks_present(dev)) { + rc = sysfs_group_change_owner( + &dev->kobj, &pm_runtime_attr_group, kuid, kgid); + if (rc) + return rc; + } + + if (device_can_wakeup(dev)) { + rc = sysfs_group_change_owner(&dev->kobj, &pm_wakeup_attr_group, + kuid, kgid); + if (rc) + return rc; + + rc = dpm_sysfs_wakeup_change_owner(dev, kuid, kgid); + if (rc) + return rc; + } + + if (dev->power.set_latency_tolerance) { + rc = sysfs_group_change_owner( + &dev->kobj, &pm_qos_latency_tolerance_attr_group, kuid, + kgid); + if (rc) + return rc; + } + return 0; +} + int wakeup_sysfs_add(struct device *dev) { return sysfs_merge_group(&dev->kobj, &pm_wakeup_attr_group); From e6dee9f3893c823dff9c7f33fe0a598ee25c78f7 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:17 +0100 Subject: [PATCH 7/9] net-sysfs: add netdev_change_owner() Add a function to change the owner of a network device when it is moved between network namespaces. Currently, when moving network devices between network namespaces the ownership of the corresponding sysfs entries is not changed. This leads to problems when tools try to operate on the corresponding sysfs files. This leads to a bug whereby a network device that is created in a network namespaces owned by a user namespace will have its corresponding sysfs entry owned by the root user of the corresponding user namespace. If such a network device has to be moved back to the host network namespace the permissions will still be set to the user namespaces. This means unprivileged users can e.g. trigger uevents for such incorrectly owned devices. They can also modify the settings of the device itself. Both of these things are unwanted. For example, workloads will create network devices in the host network namespace. Other tools will then proceed to move such devices between network namespaces owner by other user namespaces. While the ownership of the device itself is updated in net/core/net-sysfs.c:dev_change_net_namespace() the corresponding sysfs entry for the device is not: drwxr-xr-x 5 nobody nobody 0 Jan 25 18:08 . drwxr-xr-x 9 nobody nobody 0 Jan 25 18:08 .. -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 addr_assign_type -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 addr_len -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 address -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 broadcast -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 carrier -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 carrier_changes -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 carrier_down_count -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 carrier_up_count -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 dev_id -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 dev_port -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 dormant -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 duplex -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 flags -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 gro_flush_timeout -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 ifalias -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 ifindex -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 iflink -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 link_mode -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 mtu -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 name_assign_type -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 netdev_group -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 operstate -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 phys_port_id -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 phys_port_name -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 phys_switch_id drwxr-xr-x 2 nobody nobody 0 Jan 25 18:09 power -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 proto_down drwxr-xr-x 4 nobody nobody 0 Jan 25 18:09 queues -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 speed drwxr-xr-x 2 nobody nobody 0 Jan 25 18:09 statistics lrwxrwxrwx 1 nobody nobody 0 Jan 25 18:08 subsystem -> ../../../../class/net -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:09 tx_queue_len -r--r--r-- 1 nobody nobody 4096 Jan 25 18:09 type -rw-r--r-- 1 nobody nobody 4096 Jan 25 18:08 uevent However, if a device is created directly in the network namespace then the device's sysfs permissions will be correctly updated: drwxr-xr-x 5 root root 0 Jan 25 18:12 . drwxr-xr-x 9 nobody nobody 0 Jan 25 18:08 .. -r--r--r-- 1 root root 4096 Jan 25 18:12 addr_assign_type -r--r--r-- 1 root root 4096 Jan 25 18:12 addr_len -r--r--r-- 1 root root 4096 Jan 25 18:12 address -r--r--r-- 1 root root 4096 Jan 25 18:12 broadcast -rw-r--r-- 1 root root 4096 Jan 25 18:12 carrier -r--r--r-- 1 root root 4096 Jan 25 18:12 carrier_changes -r--r--r-- 1 root root 4096 Jan 25 18:12 carrier_down_count -r--r--r-- 1 root root 4096 Jan 25 18:12 carrier_up_count -r--r--r-- 1 root root 4096 Jan 25 18:12 dev_id -r--r--r-- 1 root root 4096 Jan 25 18:12 dev_port -r--r--r-- 1 root root 4096 Jan 25 18:12 dormant -r--r--r-- 1 root root 4096 Jan 25 18:12 duplex -rw-r--r-- 1 root root 4096 Jan 25 18:12 flags -rw-r--r-- 1 root root 4096 Jan 25 18:12 gro_flush_timeout -rw-r--r-- 1 root root 4096 Jan 25 18:12 ifalias -r--r--r-- 1 root root 4096 Jan 25 18:12 ifindex -r--r--r-- 1 root root 4096 Jan 25 18:12 iflink -r--r--r-- 1 root root 4096 Jan 25 18:12 link_mode -rw-r--r-- 1 root root 4096 Jan 25 18:12 mtu -r--r--r-- 1 root root 4096 Jan 25 18:12 name_assign_type -rw-r--r-- 1 root root 4096 Jan 25 18:12 netdev_group -r--r--r-- 1 root root 4096 Jan 25 18:12 operstate -r--r--r-- 1 root root 4096 Jan 25 18:12 phys_port_id -r--r--r-- 1 root root 4096 Jan 25 18:12 phys_port_name -r--r--r-- 1 root root 4096 Jan 25 18:12 phys_switch_id drwxr-xr-x 2 root root 0 Jan 25 18:12 power -rw-r--r-- 1 root root 4096 Jan 25 18:12 proto_down drwxr-xr-x 4 root root 0 Jan 25 18:12 queues -r--r--r-- 1 root root 4096 Jan 25 18:12 speed drwxr-xr-x 2 root root 0 Jan 25 18:12 statistics lrwxrwxrwx 1 nobody nobody 0 Jan 25 18:12 subsystem -> ../../../../class/net -rw-r--r-- 1 root root 4096 Jan 25 18:12 tx_queue_len -r--r--r-- 1 root root 4096 Jan 25 18:12 type -rw-r--r-- 1 root root 4096 Jan 25 18:12 uevent Now, when creating a network device in a network namespace owned by a user namespace and moving it to the host the permissions will be set to the id that the user namespace root user has been mapped to on the host leading to all sorts of permission issues: 458752 drwxr-xr-x 5 458752 458752 0 Jan 25 18:12 . drwxr-xr-x 9 root root 0 Jan 25 18:08 .. -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 addr_assign_type -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 addr_len -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 address -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 broadcast -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 carrier -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 carrier_changes -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 carrier_down_count -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 carrier_up_count -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 dev_id -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 dev_port -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 dormant -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 duplex -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 flags -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 gro_flush_timeout -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 ifalias -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 ifindex -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 iflink -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 link_mode -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 mtu -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 name_assign_type -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 netdev_group -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 operstate -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 phys_port_id -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 phys_port_name -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 phys_switch_id drwxr-xr-x 2 458752 458752 0 Jan 25 18:12 power -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 proto_down drwxr-xr-x 4 458752 458752 0 Jan 25 18:12 queues -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 speed drwxr-xr-x 2 458752 458752 0 Jan 25 18:12 statistics lrwxrwxrwx 1 root root 0 Jan 25 18:12 subsystem -> ../../../../class/net -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 tx_queue_len -r--r--r-- 1 458752 458752 4096 Jan 25 18:12 type -rw-r--r-- 1 458752 458752 4096 Jan 25 18:12 uevent Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- net/core/net-sysfs.c | 27 +++++++++++++++++++++++++++ net/core/net-sysfs.h | 2 ++ 2 files changed, 29 insertions(+) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index 4c826b8bf9b1e..e19967665cb00 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -1767,6 +1767,33 @@ int netdev_register_kobject(struct net_device *ndev) return error; } +/* Change owner for sysfs entries when moving network devices across network + * namespaces owned by different user namespaces. + */ +int netdev_change_owner(struct net_device *ndev, const struct net *net_old, + const struct net *net_new) +{ + struct device *dev = &ndev->dev; + kuid_t old_uid, new_uid; + kgid_t old_gid, new_gid; + int error; + + net_ns_get_ownership(net_old, &old_uid, &old_gid); + net_ns_get_ownership(net_new, &new_uid, &new_gid); + + /* The network namespace was changed but the owning user namespace is + * identical so there's no need to change the owner of sysfs entries. + */ + if (uid_eq(old_uid, new_uid) && gid_eq(old_gid, new_gid)) + return 0; + + error = device_change_owner(dev, new_uid, new_gid); + if (error) + return error; + + return 0; +} + int netdev_class_create_file_ns(const struct class_attribute *class_attr, const void *ns) { diff --git a/net/core/net-sysfs.h b/net/core/net-sysfs.h index 006876c7b78da..8a5b04c2699aa 100644 --- a/net/core/net-sysfs.h +++ b/net/core/net-sysfs.h @@ -8,5 +8,7 @@ void netdev_unregister_kobject(struct net_device *); int net_rx_queue_update_kobjects(struct net_device *, int old_num, int new_num); int netdev_queue_update_kobjects(struct net_device *net, int old_num, int new_num); +int netdev_change_owner(struct net_device *, const struct net *net_old, + const struct net *net_new); #endif From d755407d4444c3e0fbd7d7c3aa666d595e9ab217 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:18 +0100 Subject: [PATCH 8/9] net-sysfs: add queue_change_owner() Add a function to change the owner of the queue entries for a network device when it is moved between network namespaces. Currently, when moving network devices between network namespaces the ownership of the corresponding queue sysfs entries are not changed. This leads to problems when tools try to operate on the corresponding sysfs files. Fix this. Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- net/core/net-sysfs.c | 106 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c index e19967665cb00..cf0215734ceb0 100644 --- a/net/core/net-sysfs.c +++ b/net/core/net-sysfs.c @@ -944,6 +944,24 @@ static int rx_queue_add_kobject(struct net_device *dev, int index) kobject_put(kobj); return error; } + +static int rx_queue_change_owner(struct net_device *dev, int index, kuid_t kuid, + kgid_t kgid) +{ + struct netdev_rx_queue *queue = dev->_rx + index; + struct kobject *kobj = &queue->kobj; + int error; + + error = sysfs_change_owner(kobj, kuid, kgid); + if (error) + return error; + + if (dev->sysfs_rx_queue_group) + error = sysfs_group_change_owner( + kobj, dev->sysfs_rx_queue_group, kuid, kgid); + + return error; +} #endif /* CONFIG_SYSFS */ int @@ -981,6 +999,29 @@ net_rx_queue_update_kobjects(struct net_device *dev, int old_num, int new_num) #endif } +static int net_rx_queue_change_owner(struct net_device *dev, int num, + kuid_t kuid, kgid_t kgid) +{ +#ifdef CONFIG_SYSFS + int error = 0; + int i; + +#ifndef CONFIG_RPS + if (!dev->sysfs_rx_queue_group) + return 0; +#endif + for (i = 0; i < num; i++) { + error = rx_queue_change_owner(dev, i, kuid, kgid); + if (error) + break; + } + + return error; +#else + return 0; +#endif +} + #ifdef CONFIG_SYSFS /* * netdev_queue sysfs structures and functions. @@ -1486,6 +1527,23 @@ static int netdev_queue_add_kobject(struct net_device *dev, int index) kobject_put(kobj); return error; } + +static int tx_queue_change_owner(struct net_device *ndev, int index, + kuid_t kuid, kgid_t kgid) +{ + struct netdev_queue *queue = ndev->_tx + index; + struct kobject *kobj = &queue->kobj; + int error; + + error = sysfs_change_owner(kobj, kuid, kgid); + if (error) + return error; + +#ifdef CONFIG_BQL + error = sysfs_group_change_owner(kobj, &dql_group, kuid, kgid); +#endif + return error; +} #endif /* CONFIG_SYSFS */ int @@ -1520,6 +1578,25 @@ netdev_queue_update_kobjects(struct net_device *dev, int old_num, int new_num) #endif /* CONFIG_SYSFS */ } +static int net_tx_queue_change_owner(struct net_device *dev, int num, + kuid_t kuid, kgid_t kgid) +{ +#ifdef CONFIG_SYSFS + int error = 0; + int i; + + for (i = 0; i < num; i++) { + error = tx_queue_change_owner(dev, i, kuid, kgid); + if (error) + break; + } + + return error; +#else + return 0; +#endif /* CONFIG_SYSFS */ +} + static int register_queue_kobjects(struct net_device *dev) { int error = 0, txq = 0, rxq = 0, real_rx = 0, real_tx = 0; @@ -1554,6 +1631,31 @@ static int register_queue_kobjects(struct net_device *dev) return error; } +static int queue_change_owner(struct net_device *ndev, kuid_t kuid, kgid_t kgid) +{ + int error = 0, real_rx = 0, real_tx = 0; + +#ifdef CONFIG_SYSFS + if (ndev->queues_kset) { + error = sysfs_change_owner(&ndev->queues_kset->kobj, kuid, kgid); + if (error) + return error; + } + real_rx = ndev->real_num_rx_queues; +#endif + real_tx = ndev->real_num_tx_queues; + + error = net_rx_queue_change_owner(ndev, real_rx, kuid, kgid); + if (error) + return error; + + error = net_tx_queue_change_owner(ndev, real_tx, kuid, kgid); + if (error) + return error; + + return 0; +} + static void remove_queue_kobjects(struct net_device *dev) { int real_rx = 0, real_tx = 0; @@ -1791,6 +1893,10 @@ int netdev_change_owner(struct net_device *ndev, const struct net *net_old, if (error) return error; + error = queue_change_owner(ndev, new_uid, new_gid); + if (error) + return error; + return 0; } From ef6a4c88e9e11bc32cd02b052d04745af9691412 Mon Sep 17 00:00:00 2001 From: Christian Brauner Date: Thu, 27 Feb 2020 04:37:19 +0100 Subject: [PATCH 9/9] net: fix sysfs permssions when device changes network namespace Now that we moved all the helpers in place and make use netdev_change_owner() to fixup the permissions when moving network devices between network namespaces. Signed-off-by: Christian Brauner Signed-off-by: David S. Miller --- net/core/dev.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 4770dde3448d4..dbbfff123196a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -10003,6 +10003,7 @@ EXPORT_SYMBOL(unregister_netdev); int dev_change_net_namespace(struct net_device *dev, struct net *net, const char *pat) { + struct net *net_old = dev_net(dev); int err, new_nsid, new_ifindex; ASSERT_RTNL(); @@ -10018,7 +10019,7 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char /* Get out if there is nothing todo */ err = 0; - if (net_eq(dev_net(dev), net)) + if (net_eq(net_old, net)) goto out; /* Pick the destination device name, and ensure @@ -10094,6 +10095,12 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char err = device_rename(&dev->dev, dev->name); WARN_ON(err); + /* Adapt owner in case owning user namespace of target network + * namespace is different from the original one. + */ + err = netdev_change_owner(dev, net_old, net); + WARN_ON(err); + /* Add the device back in the hashes */ list_netdevice(dev);