| /* SPDX-License-Identifier: GPL-2.0 */ |
| #include <linux/fsnotify_backend.h> |
| #include <linux/path.h> |
| #include <linux/slab.h> |
| #include <linux/exportfs.h> |
| #include <linux/hashtable.h> |
| |
| extern struct kmem_cache *fanotify_mark_cache; |
| 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 */ |
| enum { |
| FAN_EVENT_INIT, |
| FAN_EVENT_REPORTED, |
| FAN_EVENT_ANSWERED, |
| FAN_EVENT_CANCELED, |
| }; |
| |
| /* |
| * 3 dwords are sufficient for most local fs (64bit ino, 32bit generation). |
| * fh buf should be dword aligned. On 64bit arch, the ext_buf pointer is |
| * stored in either the first or last 2 dwords. |
| */ |
| #define FANOTIFY_INLINE_FH_LEN (3 << 2) |
| #define FANOTIFY_FH_HDR_LEN offsetof(struct fanotify_fh, buf) |
| |
| /* Fixed size struct for file handle */ |
| struct fanotify_fh { |
| u8 type; |
| u8 len; |
| #define FANOTIFY_FH_FLAG_EXT_BUF 1 |
| u8 flags; |
| u8 pad; |
| unsigned char buf[]; |
| } __aligned(4); |
| |
| /* Variable size struct for dir file handle + child file handle + name */ |
| struct fanotify_info { |
| /* size of dir_fh/file_fh including fanotify_fh hdr size */ |
| u8 dir_fh_totlen; |
| u8 dir2_fh_totlen; |
| u8 file_fh_totlen; |
| u8 name_len; |
| u8 name2_len; |
| u8 pad[3]; |
| unsigned char buf[]; |
| /* |
| * (struct fanotify_fh) dir_fh starts at buf[0] |
| * (optional) dir2_fh starts at buf[dir_fh_totlen] |
| * (optional) file_fh starts at buf[dir_fh_totlen + dir2_fh_totlen] |
| * name starts at buf[dir_fh_totlen + dir2_fh_totlen + file_fh_totlen] |
| * ... |
| */ |
| #define FANOTIFY_DIR_FH_SIZE(info) ((info)->dir_fh_totlen) |
| #define FANOTIFY_DIR2_FH_SIZE(info) ((info)->dir2_fh_totlen) |
| #define FANOTIFY_FILE_FH_SIZE(info) ((info)->file_fh_totlen) |
| #define FANOTIFY_NAME_SIZE(info) ((info)->name_len + 1) |
| #define FANOTIFY_NAME2_SIZE(info) ((info)->name2_len + 1) |
| |
| #define FANOTIFY_DIR_FH_OFFSET(info) 0 |
| #define FANOTIFY_DIR2_FH_OFFSET(info) \ |
| (FANOTIFY_DIR_FH_OFFSET(info) + FANOTIFY_DIR_FH_SIZE(info)) |
| #define FANOTIFY_FILE_FH_OFFSET(info) \ |
| (FANOTIFY_DIR2_FH_OFFSET(info) + FANOTIFY_DIR2_FH_SIZE(info)) |
| #define FANOTIFY_NAME_OFFSET(info) \ |
| (FANOTIFY_FILE_FH_OFFSET(info) + FANOTIFY_FILE_FH_SIZE(info)) |
| #define FANOTIFY_NAME2_OFFSET(info) \ |
| (FANOTIFY_NAME_OFFSET(info) + FANOTIFY_NAME_SIZE(info)) |
| |
| #define FANOTIFY_DIR_FH_BUF(info) \ |
| ((info)->buf + FANOTIFY_DIR_FH_OFFSET(info)) |
| #define FANOTIFY_DIR2_FH_BUF(info) \ |
| ((info)->buf + FANOTIFY_DIR2_FH_OFFSET(info)) |
| #define FANOTIFY_FILE_FH_BUF(info) \ |
| ((info)->buf + FANOTIFY_FILE_FH_OFFSET(info)) |
| #define FANOTIFY_NAME_BUF(info) \ |
| ((info)->buf + FANOTIFY_NAME_OFFSET(info)) |
| #define FANOTIFY_NAME2_BUF(info) \ |
| ((info)->buf + FANOTIFY_NAME2_OFFSET(info)) |
| } __aligned(4); |
| |
| static inline bool fanotify_fh_has_ext_buf(struct fanotify_fh *fh) |
| { |
| return (fh->flags & FANOTIFY_FH_FLAG_EXT_BUF); |
| } |
| |
| static inline char **fanotify_fh_ext_buf_ptr(struct fanotify_fh *fh) |
| { |
| BUILD_BUG_ON(FANOTIFY_FH_HDR_LEN % 4); |
| BUILD_BUG_ON(__alignof__(char *) - 4 + sizeof(char *) > |
| FANOTIFY_INLINE_FH_LEN); |
| return (char **)ALIGN((unsigned long)(fh->buf), __alignof__(char *)); |
| } |
| |
| static inline void *fanotify_fh_ext_buf(struct fanotify_fh *fh) |
| { |
| return *fanotify_fh_ext_buf_ptr(fh); |
| } |
| |
| static inline void *fanotify_fh_buf(struct fanotify_fh *fh) |
| { |
| return fanotify_fh_has_ext_buf(fh) ? fanotify_fh_ext_buf(fh) : fh->buf; |
| } |
| |
| static inline int fanotify_info_dir_fh_len(struct fanotify_info *info) |
| { |
| if (!info->dir_fh_totlen || |
| WARN_ON_ONCE(info->dir_fh_totlen < FANOTIFY_FH_HDR_LEN)) |
| return 0; |
| |
| return info->dir_fh_totlen - FANOTIFY_FH_HDR_LEN; |
| } |
| |
| static inline struct fanotify_fh *fanotify_info_dir_fh(struct fanotify_info *info) |
| { |
| BUILD_BUG_ON(offsetof(struct fanotify_info, buf) % 4); |
| |
| return (struct fanotify_fh *)FANOTIFY_DIR_FH_BUF(info); |
| } |
| |
| static inline int fanotify_info_dir2_fh_len(struct fanotify_info *info) |
| { |
| if (!info->dir2_fh_totlen || |
| WARN_ON_ONCE(info->dir2_fh_totlen < FANOTIFY_FH_HDR_LEN)) |
| return 0; |
| |
| return info->dir2_fh_totlen - FANOTIFY_FH_HDR_LEN; |
| } |
| |
| static inline struct fanotify_fh *fanotify_info_dir2_fh(struct fanotify_info *info) |
| { |
| return (struct fanotify_fh *)FANOTIFY_DIR2_FH_BUF(info); |
| } |
| |
| static inline int fanotify_info_file_fh_len(struct fanotify_info *info) |
| { |
| if (!info->file_fh_totlen || |
| WARN_ON_ONCE(info->file_fh_totlen < FANOTIFY_FH_HDR_LEN)) |
| return 0; |
| |
| return info->file_fh_totlen - FANOTIFY_FH_HDR_LEN; |
| } |
| |
| static inline struct fanotify_fh *fanotify_info_file_fh(struct fanotify_info *info) |
| { |
| return (struct fanotify_fh *)FANOTIFY_FILE_FH_BUF(info); |
| } |
| |
| static inline char *fanotify_info_name(struct fanotify_info *info) |
| { |
| if (!info->name_len) |
| return NULL; |
| |
| return FANOTIFY_NAME_BUF(info); |
| } |
| |
| static inline char *fanotify_info_name2(struct fanotify_info *info) |
| { |
| if (!info->name2_len) |
| return NULL; |
| |
| return FANOTIFY_NAME2_BUF(info); |
| } |
| |
| static inline void fanotify_info_init(struct fanotify_info *info) |
| { |
| BUILD_BUG_ON(FANOTIFY_FH_HDR_LEN + MAX_HANDLE_SZ > U8_MAX); |
| BUILD_BUG_ON(NAME_MAX > U8_MAX); |
| |
| info->dir_fh_totlen = 0; |
| info->dir2_fh_totlen = 0; |
| info->file_fh_totlen = 0; |
| info->name_len = 0; |
| info->name2_len = 0; |
| } |
| |
| /* These set/copy helpers MUST be called by order */ |
| static inline void fanotify_info_set_dir_fh(struct fanotify_info *info, |
| unsigned int totlen) |
| { |
| if (WARN_ON_ONCE(info->dir2_fh_totlen > 0) || |
| WARN_ON_ONCE(info->file_fh_totlen > 0) || |
| WARN_ON_ONCE(info->name_len > 0) || |
| WARN_ON_ONCE(info->name2_len > 0)) |
| return; |
| |
| info->dir_fh_totlen = totlen; |
| } |
| |
| static inline void fanotify_info_set_dir2_fh(struct fanotify_info *info, |
| unsigned int totlen) |
| { |
| if (WARN_ON_ONCE(info->file_fh_totlen > 0) || |
| WARN_ON_ONCE(info->name_len > 0) || |
| WARN_ON_ONCE(info->name2_len > 0)) |
| return; |
| |
| info->dir2_fh_totlen = totlen; |
| } |
| |
| static inline void fanotify_info_set_file_fh(struct fanotify_info *info, |
| unsigned int totlen) |
| { |
| if (WARN_ON_ONCE(info->name_len > 0) || |
| WARN_ON_ONCE(info->name2_len > 0)) |
| return; |
| |
| info->file_fh_totlen = totlen; |
| } |
| |
| static inline void fanotify_info_copy_name(struct fanotify_info *info, |
| const struct qstr *name) |
| { |
| if (WARN_ON_ONCE(name->len > NAME_MAX) || |
| WARN_ON_ONCE(info->name2_len > 0)) |
| return; |
| |
| info->name_len = name->len; |
| strcpy(fanotify_info_name(info), name->name); |
| } |
| |
| static inline void fanotify_info_copy_name2(struct fanotify_info *info, |
| const struct qstr *name) |
| { |
| if (WARN_ON_ONCE(name->len > NAME_MAX)) |
| return; |
| |
| info->name2_len = name->len; |
| strcpy(fanotify_info_name2(info), name->name); |
| } |
| |
| /* |
| * Common structure for fanotify events. Concrete structs are allocated in |
| * fanotify_handle_event() and freed when the information is retrieved by |
| * 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, /* fixed length */ |
| FANOTIFY_EVENT_TYPE_FID_NAME, /* variable length */ |
| FANOTIFY_EVENT_TYPE_PATH, |
| FANOTIFY_EVENT_TYPE_PATH_PERM, |
| FANOTIFY_EVENT_TYPE_OVERFLOW, /* struct fanotify_event */ |
| FANOTIFY_EVENT_TYPE_FS_ERROR, /* struct fanotify_error_event */ |
| __FANOTIFY_EVENT_TYPE_NUM |
| }; |
| |
| #define FANOTIFY_EVENT_TYPE_BITS \ |
| (ilog2(__FANOTIFY_EVENT_TYPE_NUM - 1) + 1) |
| #define FANOTIFY_EVENT_HASH_BITS \ |
| (32 - FANOTIFY_EVENT_TYPE_BITS) |
| |
| struct fanotify_event { |
| struct fsnotify_event fse; |
| struct hlist_node merge_list; /* List for hashed merge */ |
| u32 mask; |
| struct { |
| unsigned int type : FANOTIFY_EVENT_TYPE_BITS; |
| unsigned int hash : FANOTIFY_EVENT_HASH_BITS; |
| }; |
| struct pid *pid; |
| }; |
| |
| static inline void fanotify_init_event(struct fanotify_event *event, |
| unsigned int hash, u32 mask) |
| { |
| fsnotify_init_event(&event->fse); |
| INIT_HLIST_NODE(&event->merge_list); |
| event->hash = hash; |
| event->mask = mask; |
| event->pid = NULL; |
| } |
| |
| #define FANOTIFY_INLINE_FH(name, size) \ |
| struct { \ |
| struct fanotify_fh (name); \ |
| /* Space for object_fh.buf[] - access with fanotify_fh_buf() */ \ |
| unsigned char _inline_fh_buf[(size)]; \ |
| } |
| |
| struct fanotify_fid_event { |
| struct fanotify_event fae; |
| __kernel_fsid_t fsid; |
| |
| FANOTIFY_INLINE_FH(object_fh, FANOTIFY_INLINE_FH_LEN); |
| }; |
| |
| static inline struct fanotify_fid_event * |
| FANOTIFY_FE(struct fanotify_event *event) |
| { |
| return container_of(event, struct fanotify_fid_event, fae); |
| } |
| |
| struct fanotify_name_event { |
| struct fanotify_event fae; |
| __kernel_fsid_t fsid; |
| struct fanotify_info info; |
| }; |
| |
| static inline struct fanotify_name_event * |
| FANOTIFY_NE(struct fanotify_event *event) |
| { |
| return container_of(event, struct fanotify_name_event, fae); |
| } |
| |
| struct fanotify_error_event { |
| struct fanotify_event fae; |
| s32 error; /* Error reported by the Filesystem. */ |
| u32 err_count; /* Suppressed errors count */ |
| |
| __kernel_fsid_t fsid; /* FSID this error refers to. */ |
| |
| FANOTIFY_INLINE_FH(object_fh, MAX_HANDLE_SZ); |
| }; |
| |
| static inline struct fanotify_error_event * |
| FANOTIFY_EE(struct fanotify_event *event) |
| { |
| return container_of(event, struct fanotify_error_event, fae); |
| } |
| |
| static inline __kernel_fsid_t *fanotify_event_fsid(struct fanotify_event *event) |
| { |
| if (event->type == FANOTIFY_EVENT_TYPE_FID) |
| return &FANOTIFY_FE(event)->fsid; |
| else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME) |
| return &FANOTIFY_NE(event)->fsid; |
| else if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR) |
| return &FANOTIFY_EE(event)->fsid; |
| else |
| return NULL; |
| } |
| |
| static inline struct fanotify_fh *fanotify_event_object_fh( |
| struct fanotify_event *event) |
| { |
| if (event->type == FANOTIFY_EVENT_TYPE_FID) |
| return &FANOTIFY_FE(event)->object_fh; |
| else if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME) |
| return fanotify_info_file_fh(&FANOTIFY_NE(event)->info); |
| else if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR) |
| return &FANOTIFY_EE(event)->object_fh; |
| else |
| return NULL; |
| } |
| |
| static inline struct fanotify_info *fanotify_event_info( |
| struct fanotify_event *event) |
| { |
| if (event->type == FANOTIFY_EVENT_TYPE_FID_NAME) |
| return &FANOTIFY_NE(event)->info; |
| else |
| return NULL; |
| } |
| |
| static inline int fanotify_event_object_fh_len(struct fanotify_event *event) |
| { |
| struct fanotify_info *info = fanotify_event_info(event); |
| struct fanotify_fh *fh = fanotify_event_object_fh(event); |
| |
| if (info) |
| return info->file_fh_totlen ? fh->len : 0; |
| else |
| return fh ? fh->len : 0; |
| } |
| |
| static inline int fanotify_event_dir_fh_len(struct fanotify_event *event) |
| { |
| struct fanotify_info *info = fanotify_event_info(event); |
| |
| return info ? fanotify_info_dir_fh_len(info) : 0; |
| } |
| |
| static inline int fanotify_event_dir2_fh_len(struct fanotify_event *event) |
| { |
| struct fanotify_info *info = fanotify_event_info(event); |
| |
| return info ? fanotify_info_dir2_fh_len(info) : 0; |
| } |
| |
| static inline bool fanotify_event_has_object_fh(struct fanotify_event *event) |
| { |
| /* For error events, even zeroed fh are reported. */ |
| if (event->type == FANOTIFY_EVENT_TYPE_FS_ERROR) |
| return true; |
| return fanotify_event_object_fh_len(event) > 0; |
| } |
| |
| static inline bool fanotify_event_has_dir_fh(struct fanotify_event *event) |
| { |
| return fanotify_event_dir_fh_len(event) > 0; |
| } |
| |
| static inline bool fanotify_event_has_dir2_fh(struct fanotify_event *event) |
| { |
| return fanotify_event_dir2_fh_len(event) > 0; |
| } |
| |
| static inline bool fanotify_event_has_any_dir_fh(struct fanotify_event *event) |
| { |
| return fanotify_event_has_dir_fh(event) || |
| fanotify_event_has_dir2_fh(event); |
| } |
| |
| 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 |
| * information is retrieved by userspace the structure is moved from |
| * group->notification_list to group->fanotify_data.access_list to wait for |
| * user response. |
| */ |
| 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_PERM(struct fanotify_event *event) |
| { |
| return container_of(event, struct fanotify_perm_event, fae); |
| } |
| |
| static inline bool fanotify_is_perm_event(u32 mask) |
| { |
| return IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS) && |
| mask & FANOTIFY_PERM_EVENTS; |
| } |
| |
| static inline struct fanotify_event *FANOTIFY_E(struct fsnotify_event *fse) |
| { |
| return container_of(fse, struct fanotify_event, fse); |
| } |
| |
| static inline bool fanotify_is_error_event(u32 mask) |
| { |
| return mask & FAN_FS_ERROR; |
| } |
| |
| 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 (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; |
| } |
| |
| /* |
| * Use 128 size hash table to speed up events merge. |
| */ |
| #define FANOTIFY_HTABLE_BITS (7) |
| #define FANOTIFY_HTABLE_SIZE (1 << FANOTIFY_HTABLE_BITS) |
| #define FANOTIFY_HTABLE_MASK (FANOTIFY_HTABLE_SIZE - 1) |
| |
| /* |
| * Permission events and overflow event do not get merged - don't hash them. |
| */ |
| static inline bool fanotify_is_hashed_event(u32 mask) |
| { |
| return !(fanotify_is_perm_event(mask) || |
| fsnotify_is_overflow_event(mask)); |
| } |
| |
| static inline unsigned int fanotify_event_hash_bucket( |
| struct fsnotify_group *group, |
| struct fanotify_event *event) |
| { |
| return event->hash & FANOTIFY_HTABLE_MASK; |
| } |
| |
| static inline unsigned int fanotify_mark_user_flags(struct fsnotify_mark *mark) |
| { |
| unsigned int mflags = 0; |
| |
| if (mark->flags & FSNOTIFY_MARK_FLAG_IGNORED_SURV_MODIFY) |
| mflags |= FAN_MARK_IGNORED_SURV_MODIFY; |
| if (mark->flags & FSNOTIFY_MARK_FLAG_NO_IREF) |
| mflags |= FAN_MARK_EVICTABLE; |
| if (mark->flags & FSNOTIFY_MARK_FLAG_HAS_IGNORE_FLAGS) |
| mflags |= FAN_MARK_IGNORE; |
| |
| return mflags; |
| } |