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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /fs/notify/fanotify/fanotify.h | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/notify/fanotify/fanotify.h')
-rw-r--r-- | fs/notify/fanotify/fanotify.h | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h new file mode 100644 index 000000000..57f51a9a3 --- /dev/null +++ b/fs/notify/fanotify/fanotify.h @@ -0,0 +1,500 @@ +/* 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 const 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; +} |