fanotify: divorce fanotify_path_event and fanotify_fid_event (7088f357) · Commits · 戴 / test

fs/notify/fanotify/fanotify.c

+93 −33

Original line number	Diff line number	Diff line
		@@ -42,6 +42,17 @@ static bool fanotify_fh_equal(struct fanotify_fh *fh1,
		!memcmp(fanotify_fh_buf(fh1), fanotify_fh_buf(fh2), fh1->len);
		}

		static bool fanotify_fid_event_equal(struct fanotify_fid_event *ffe1,
		struct fanotify_fid_event *ffe2)
		{
		/* Do not merge fid events without object fh */
		if (!ffe1->object_fh.len)
		return false;

		return fanotify_fsid_equal(&ffe1->fsid, &ffe2->fsid) &&
		fanotify_fh_equal(&ffe1->object_fh, &ffe2->object_fh);
		}

		static bool should_merge(struct fsnotify_event *old_fsn,
		struct fsnotify_event *new_fsn)
		{
		@@ -51,14 +62,15 @@ static bool should_merge(struct fsnotify_event *old_fsn,
		old = FANOTIFY_E(old_fsn);
		new = FANOTIFY_E(new_fsn);

		if (old_fsn->objectid != new_fsn->objectid \|\| old->pid != new->pid \|\|
		old->fh.type != new->fh.type)
		if (old_fsn->objectid != new_fsn->objectid \|\|
		old->type != new->type \|\| old->pid != new->pid)
		return false;

		if (fanotify_event_has_path(old)) {
		switch (old->type) {
		case FANOTIFY_EVENT_TYPE_PATH:
		return fanotify_path_equal(fanotify_event_path(old),
		fanotify_event_path(new));
		} else if (fanotify_event_has_fid(old)) {
		case FANOTIFY_EVENT_TYPE_FID:
		/*
		* We want to merge many dirent events in the same dir (i.e.
		* creates/unlinks/renames), but we do not want to merge dirent
		@@ -70,11 +82,12 @@ static bool should_merge(struct fsnotify_event *old_fsn,
		if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR))
		return false;

		return fanotify_fsid_equal(&old->fsid, &new->fsid) &&
		fanotify_fh_equal(&old->fh, &new->fh);
		return fanotify_fid_event_equal(FANOTIFY_FE(old),
		FANOTIFY_FE(new));
		default:
		WARN_ON_ONCE(1);
		}

		/* Do not merge events if we failed to encode fid */
		return false;
		}

		@@ -310,6 +323,7 @@ struct fanotify_event fanotify_alloc_event(struct fsnotify_group group,
		__kernel_fsid_t *fsid)
		{
		struct fanotify_event *event = NULL;
		struct fanotify_fid_event *ffe = NULL;
		gfp_t gfp = GFP_KERNEL_ACCOUNT;
		struct inode *id = fanotify_fid_inode(inode, mask, data, data_type);
		const struct path *path = fsnotify_data_path(data, data_type);
		@@ -334,14 +348,32 @@ struct fanotify_event fanotify_alloc_event(struct fsnotify_group group,
		pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp);
		if (!pevent)
		goto out;

		event = &pevent->fae;
		event->type = FANOTIFY_EVENT_TYPE_PATH_PERM;
		pevent->response = 0;
		pevent->state = FAN_EVENT_INIT;
		goto init;
		}
		event = kmem_cache_alloc(fanotify_event_cachep, gfp);
		if (!event)

		if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
		ffe = kmem_cache_alloc(fanotify_fid_event_cachep, gfp);
		if (!ffe)
		goto out;

		event = &ffe->fae;
		event->type = FANOTIFY_EVENT_TYPE_FID;
		} else {
		struct fanotify_path_event *pevent;

		pevent = kmem_cache_alloc(fanotify_path_event_cachep, gfp);
		if (!pevent)
		goto out;

		event = &pevent->fae;
		event->type = FANOTIFY_EVENT_TYPE_PATH;
		}

		init: __maybe_unused
		/*
		* Use the victim inode instead of the watching inode as the id for
		@@ -354,19 +386,23 @@ init: __maybe_unused
		event->pid = get_pid(task_pid(current));
		else
		event->pid = get_pid(task_tgid(current));
		event->fh.len = 0;
		if (id && FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
		event->fsid = *fsid;

		if (fanotify_event_has_fid(event)) {
		ffe->object_fh.len = 0;
		if (fsid)
		ffe->fsid = *fsid;
		if (id)
		fanotify_encode_fh(&event->fh, id, gfp);
		} else if (path) {
		event->fh.type = FILEID_ROOT;
		event->path = *path;
		fanotify_encode_fh(&ffe->object_fh, id, gfp);
		} else if (fanotify_event_has_path(event)) {
		struct path *p = fanotify_event_path(event);

		if (path) {
		p = path;
		path_get(path);
		} else {
		event->fh.type = FILEID_INVALID;
		event->path.mnt = NULL;
		event->path.dentry = NULL;
		p->mnt = NULL;
		p->dentry = NULL;
		}
		}
		out:
		memalloc_unuse_memcg();
		@@ -486,7 +522,7 @@ static int fanotify_handle_event(struct fsnotify_group *group,

		ret = 0;
		} else if (fanotify_is_perm_event(mask)) {
		ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event),
		ret = fanotify_get_response(group, FANOTIFY_PERM(event),
		iter_info);
		}
		finish:
		@@ -505,22 +541,46 @@ static void fanotify_free_group_priv(struct fsnotify_group *group)
		free_uid(user);
		}

		static void fanotify_free_path_event(struct fanotify_event *event)
		{
		path_put(fanotify_event_path(event));
		kmem_cache_free(fanotify_path_event_cachep, FANOTIFY_PE(event));
		}

		static void fanotify_free_perm_event(struct fanotify_event *event)
		{
		path_put(fanotify_event_path(event));
		kmem_cache_free(fanotify_perm_event_cachep, FANOTIFY_PERM(event));
		}

		static void fanotify_free_fid_event(struct fanotify_event *event)
		{
		struct fanotify_fid_event *ffe = FANOTIFY_FE(event);

		if (fanotify_fh_has_ext_buf(&ffe->object_fh))
		kfree(fanotify_fh_ext_buf(&ffe->object_fh));
		kmem_cache_free(fanotify_fid_event_cachep, ffe);
		}

		static void fanotify_free_event(struct fsnotify_event *fsn_event)
		{
		struct fanotify_event *event;

		event = FANOTIFY_E(fsn_event);
		if (fanotify_event_has_path(event))
		path_put(&event->path);
		else if (fanotify_fh_has_ext_buf(&event->fh))
		kfree(fanotify_fh_ext_buf(&event->fh));
		put_pid(event->pid);
		if (fanotify_is_perm_event(event->mask)) {
		kmem_cache_free(fanotify_perm_event_cachep,
		FANOTIFY_PE(fsn_event));
		return;
		switch (event->type) {
		case FANOTIFY_EVENT_TYPE_PATH:
		fanotify_free_path_event(event);
		break;
		case FANOTIFY_EVENT_TYPE_PATH_PERM:
		fanotify_free_perm_event(event);
		break;
		case FANOTIFY_EVENT_TYPE_FID:
		fanotify_free_fid_event(event);
		break;
		default:
		WARN_ON_ONCE(1);
		}
		kmem_cache_free(fanotify_event_cachep, event);
		}

		static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)

fs/notify/fanotify/fanotify.h

+50 −27

Original line number	Diff line number	Diff line
		@@ -5,7 +5,8 @@
		#include <linux/exportfs.h>

		extern struct kmem_cache *fanotify_mark_cache;
		extern struct kmem_cache *fanotify_event_cachep;
		extern struct kmem_cache *fanotify_fid_event_cachep;
		extern struct kmem_cache *fanotify_path_event_cachep;
		extern struct kmem_cache *fanotify_perm_event_cachep;

		/* Possible states of the permission event */
		@@ -52,43 +53,45 @@ static inline void fanotify_fh_buf(struct fanotify_fh fh)
		}

		/*
		* Structure for normal fanotify events. It gets allocated in
		* Common structure for fanotify events. Concrete structs are allocated in
		* fanotify_handle_event() and freed when the information is retrieved by
		* userspace
		* userspace. The type of event determines how it was allocated, how it will
		* be freed and which concrete struct it may be cast to.
		*/
		enum fanotify_event_type {
		FANOTIFY_EVENT_TYPE_FID,
		FANOTIFY_EVENT_TYPE_PATH,
		FANOTIFY_EVENT_TYPE_PATH_PERM,
		};

		struct fanotify_event {
		struct fsnotify_event fse;
		u32 mask;
		/*
		* With FAN_REPORT_FID, we do not hold any reference on the
		* victim object. Instead we store its NFS file handle and its
		* filesystem's fsid as a unique identifier.
		*/
		__kernel_fsid_t fsid;
		struct fanotify_fh fh;
		/*
		* We hold ref to this path so it may be dereferenced at any
		* point during this object's lifetime
		*/
		struct path path;
		enum fanotify_event_type type;
		struct pid *pid;
		};

		static inline bool fanotify_event_has_path(struct fanotify_event *event)
		struct fanotify_fid_event {
		struct fanotify_event fae;
		__kernel_fsid_t fsid;
		struct fanotify_fh object_fh;
		};

		static inline struct fanotify_fid_event *
		FANOTIFY_FE(struct fanotify_event *event)
		{
		return event->fh.type == FILEID_ROOT;
		return container_of(event, struct fanotify_fid_event, fae);
		}

		static inline bool fanotify_event_has_fid(struct fanotify_event *event)
		{
		return event->fh.type != FILEID_ROOT &&
		event->fh.type != FILEID_INVALID;
		return event->type == FANOTIFY_EVENT_TYPE_FID;
		}

		static inline __kernel_fsid_t fanotify_event_fsid(struct fanotify_event event)
		{
		if (fanotify_event_has_fid(event))
		return &event->fsid;
		if (event->type == FANOTIFY_EVENT_TYPE_FID)
		return &FANOTIFY_FE(event)->fsid;
		else
		return NULL;
		}
		@@ -96,8 +99,8 @@ static inline __kernel_fsid_t fanotify_event_fsid(struct fanotify_event event)
		static inline struct fanotify_fh *fanotify_event_object_fh(
		struct fanotify_event *event)
		{
		if (fanotify_event_has_fid(event))
		return &event->fh;
		if (event->type == FANOTIFY_EVENT_TYPE_FID)
		return &FANOTIFY_FE(event)->object_fh;
		else
		return NULL;
		}
		@@ -109,6 +112,17 @@ static inline int fanotify_event_object_fh_len(struct fanotify_event *event)
		return fh ? fh->len : 0;
		}

		struct fanotify_path_event {
		struct fanotify_event fae;
		struct path path;
		};

		static inline struct fanotify_path_event *
		FANOTIFY_PE(struct fanotify_event *event)
		{
		return container_of(event, struct fanotify_path_event, fae);
		}

		/*
		* Structure for permission fanotify events. It gets allocated and freed in
		* fanotify_handle_event() since we wait there for user response. When the
		@@ -118,15 +132,16 @@ static inline int fanotify_event_object_fh_len(struct fanotify_event *event)
		*/
		struct fanotify_perm_event {
		struct fanotify_event fae;
		struct path path;
		unsigned short response; /* userspace answer to the event */
		unsigned short state; /* state of the event */
		int fd; /* fd we passed to userspace for this event */
		};

		static inline struct fanotify_perm_event *
		FANOTIFY_PE(struct fsnotify_event *fse)
		FANOTIFY_PERM(struct fanotify_event *event)
		{
		return container_of(fse, struct fanotify_perm_event, fae.fse);
		return container_of(event, struct fanotify_perm_event, fae);
		}

		static inline bool fanotify_is_perm_event(u32 mask)
		@@ -140,10 +155,18 @@ static inline struct fanotify_event FANOTIFY_E(struct fsnotify_event fse)
		return container_of(fse, struct fanotify_event, fse);
		}

		static inline bool fanotify_event_has_path(struct fanotify_event *event)
		{
		return event->type == FANOTIFY_EVENT_TYPE_PATH \|\|
		event->type == FANOTIFY_EVENT_TYPE_PATH_PERM;
		}

		static inline struct path fanotify_event_path(struct fanotify_event event)
		{
		if (fanotify_event_has_path(event))
		return &event->path;
		if (event->type == FANOTIFY_EVENT_TYPE_PATH)
		return &FANOTIFY_PE(event)->path;
		else if (event->type == FANOTIFY_EVENT_TYPE_PATH_PERM)
		return &FANOTIFY_PERM(event)->path;
		else
		return NULL;
		}

fs/notify/fanotify/fanotify_user.c

+37 −34

Original line number	Diff line number	Diff line
		@@ -46,7 +46,8 @@
		extern const struct fsnotify_ops fanotify_fsnotify_ops;

		struct kmem_cache *fanotify_mark_cache __read_mostly;
		struct kmem_cache *fanotify_event_cachep __read_mostly;
		struct kmem_cache *fanotify_fid_event_cachep __read_mostly;
		struct kmem_cache *fanotify_path_event_cachep __read_mostly;
		struct kmem_cache *fanotify_perm_event_cachep __read_mostly;

		#define FANOTIFY_EVENT_ALIGN 4
		@@ -64,16 +65,16 @@ static int fanotify_event_info_len(struct fanotify_event *event)
		}

		/*
		* Get an fsnotify notification event if one exists and is small
		* Get an fanotify notification event if one exists and is small
		* enough to fit in "count". Return an error pointer if the count
		* is not large enough. When permission event is dequeued, its state is
		* updated accordingly.
		*/
		static struct fsnotify_event get_one_event(struct fsnotify_group group,
		static struct fanotify_event get_one_event(struct fsnotify_group group,
		size_t count)
		{
		size_t event_size = FAN_EVENT_METADATA_LEN;
		struct fsnotify_event *fsn_event = NULL;
		struct fanotify_event *event = NULL;

		pr_debug("%s: group=%p count=%zd\n", __func__, group, count);

		@@ -87,15 +88,15 @@ static struct fsnotify_event get_one_event(struct fsnotify_group group,
		}

		if (event_size > count) {
		fsn_event = ERR_PTR(-EINVAL);
		event = ERR_PTR(-EINVAL);
		goto out;
		}
		fsn_event = fsnotify_remove_first_event(group);
		if (fanotify_is_perm_event(FANOTIFY_E(fsn_event)->mask))
		FANOTIFY_PE(fsn_event)->state = FAN_EVENT_REPORTED;
		event = FANOTIFY_E(fsnotify_remove_first_event(group));
		if (fanotify_is_perm_event(event->mask))
		FANOTIFY_PERM(event)->state = FAN_EVENT_REPORTED;
		out:
		spin_unlock(&group->notification_lock);
		return fsn_event;
		return event;
		}

		static int create_fd(struct fsnotify_group group, struct path path,
		@@ -252,19 +253,16 @@ static int copy_fid_to_user(struct fanotify_event event, char __user buf)
		}

		static ssize_t copy_event_to_user(struct fsnotify_group *group,
		struct fsnotify_event *fsn_event,
		struct fanotify_event *event,
		char __user *buf, size_t count)
		{
		struct fanotify_event_metadata metadata;
		struct fanotify_event *event;
		struct path *path;
		struct path *path = fanotify_event_path(event);
		struct file *f = NULL;
		int ret, fd = FAN_NOFD;

		pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event);
		pr_debug("%s: group=%p event=%p\n", __func__, group, event);

		event = container_of(fsn_event, struct fanotify_event, fse);
		path = fanotify_event_path(event);
		metadata.event_len = FAN_EVENT_METADATA_LEN;
		metadata.metadata_len = FAN_EVENT_METADATA_LEN;
		metadata.vers = FANOTIFY_METADATA_VERSION;
		@@ -293,9 +291,9 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
		goto out_close_fd;

		if (fanotify_is_perm_event(event->mask))
		FANOTIFY_PE(fsn_event)->fd = fd;
		FANOTIFY_PERM(event)->fd = fd;

		if (fanotify_event_has_path(event)) {
		if (f) {
		fd_install(fd, f);
		} else if (fanotify_event_has_fid(event)) {
		ret = copy_fid_to_user(event, buf + FAN_EVENT_METADATA_LEN);
		@@ -332,7 +330,7 @@ static ssize_t fanotify_read(struct file file, char __user buf,
		size_t count, loff_t *pos)
		{
		struct fsnotify_group *group;
		struct fsnotify_event *kevent;
		struct fanotify_event *event;
		char __user *start;
		int ret;
		DEFINE_WAIT_FUNC(wait, woken_wake_function);
		@@ -344,13 +342,13 @@ static ssize_t fanotify_read(struct file file, char __user buf,

		add_wait_queue(&group->notification_waitq, &wait);
		while (1) {
		kevent = get_one_event(group, count);
		if (IS_ERR(kevent)) {
		ret = PTR_ERR(kevent);
		event = get_one_event(group, count);
		if (IS_ERR(event)) {
		ret = PTR_ERR(event);
		break;
		}

		if (!kevent) {
		if (!event) {
		ret = -EAGAIN;
		if (file->f_flags & O_NONBLOCK)
		break;
		@@ -366,7 +364,7 @@ static ssize_t fanotify_read(struct file file, char __user buf,
		continue;
		}

		ret = copy_event_to_user(group, kevent, buf, count);
		ret = copy_event_to_user(group, event, buf, count);
		if (unlikely(ret == -EOPENSTALE)) {
		/*
		* We cannot report events with stale fd so drop it.
		@@ -381,17 +379,17 @@ static ssize_t fanotify_read(struct file file, char __user buf,
		* Permission events get queued to wait for response. Other
		* events can be destroyed now.
		*/
		if (!fanotify_is_perm_event(FANOTIFY_E(kevent)->mask)) {
		fsnotify_destroy_event(group, kevent);
		if (!fanotify_is_perm_event(event->mask)) {
		fsnotify_destroy_event(group, &event->fse);
		} else {
		if (ret <= 0) {
		spin_lock(&group->notification_lock);
		finish_permission_event(group,
		FANOTIFY_PE(kevent), FAN_DENY);
		FANOTIFY_PERM(event), FAN_DENY);
		wake_up(&group->fanotify_data.access_waitq);
		} else {
		spin_lock(&group->notification_lock);
		list_add_tail(&kevent->list,
		list_add_tail(&event->fse.list,
		&group->fanotify_data.access_list);
		spin_unlock(&group->notification_lock);
		}
		@@ -437,8 +435,6 @@ static ssize_t fanotify_write(struct file file, const char __user buf, size_t
		static int fanotify_release(struct inode ignored, struct file file)
		{
		struct fsnotify_group *group = file->private_data;
		struct fanotify_perm_event *event;
		struct fsnotify_event *fsn_event;

		/*
		* Stop new events from arriving in the notification queue. since
		@@ -453,6 +449,8 @@ static int fanotify_release(struct inode ignored, struct file file)
		*/
		spin_lock(&group->notification_lock);
		while (!list_empty(&group->fanotify_data.access_list)) {
		struct fanotify_perm_event *event;

		event = list_first_entry(&group->fanotify_data.access_list,
		struct fanotify_perm_event, fae.fse.list);
		list_del_init(&event->fae.fse.list);
		@@ -466,12 +464,14 @@ static int fanotify_release(struct inode ignored, struct file file)
		* response is consumed and fanotify_get_response() returns.
		*/
		while (!fsnotify_notify_queue_is_empty(group)) {
		fsn_event = fsnotify_remove_first_event(group);
		if (!(FANOTIFY_E(fsn_event)->mask & FANOTIFY_PERM_EVENTS)) {
		struct fanotify_event *event;

		event = FANOTIFY_E(fsnotify_remove_first_event(group));
		if (!(event->mask & FANOTIFY_PERM_EVENTS)) {
		spin_unlock(&group->notification_lock);
		fsnotify_destroy_event(group, fsn_event);
		fsnotify_destroy_event(group, &event->fse);
		} else {
		finish_permission_event(group, FANOTIFY_PE(fsn_event),
		finish_permission_event(group, FANOTIFY_PERM(event),
		FAN_ALLOW);
		}
		spin_lock(&group->notification_lock);
		@@ -1136,7 +1136,10 @@ static int __init fanotify_user_setup(void)

		fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
		SLAB_PANIC\|SLAB_ACCOUNT);
		fanotify_event_cachep = KMEM_CACHE(fanotify_event, SLAB_PANIC);
		fanotify_fid_event_cachep = KMEM_CACHE(fanotify_fid_event,
		SLAB_PANIC);
		fanotify_path_event_cachep = KMEM_CACHE(fanotify_path_event,
		SLAB_PANIC);
		if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
		fanotify_perm_event_cachep =
		KMEM_CACHE(fanotify_perm_event, SLAB_PANIC);

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