--- zzzz-none-000/linux-5.4.213/fs/notify/fanotify/fanotify.c 2022-09-15 10:04:56.000000000 +0000 +++ miami-7690-761/linux-5.4.213/fs/notify/fanotify/fanotify.c 2024-05-29 11:20:02.000000000 +0000 @@ -17,8 +17,79 @@ #include "fanotify.h" -static bool should_merge(struct fsnotify_event *old_fsn, - struct fsnotify_event *new_fsn) +static bool fanotify_path_equal(struct path *p1, struct path *p2) +{ + return p1->mnt == p2->mnt && p1->dentry == p2->dentry; +} + +static inline bool fanotify_fsid_equal(__kernel_fsid_t *fsid1, + __kernel_fsid_t *fsid2) +{ + return fsid1->val[0] == fsid2->val[0] && fsid1->val[1] == fsid2->val[1]; +} + +static bool fanotify_fh_equal(struct fanotify_fh *fh1, + struct fanotify_fh *fh2) +{ + if (fh1->type != fh2->type || fh1->len != fh2->len) + return false; + + return !fh1->len || + !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 fanotify_info_equal(struct fanotify_info *info1, + struct fanotify_info *info2) +{ + if (info1->dir_fh_totlen != info2->dir_fh_totlen || + info1->file_fh_totlen != info2->file_fh_totlen || + info1->name_len != info2->name_len) + return false; + + if (info1->dir_fh_totlen && + !fanotify_fh_equal(fanotify_info_dir_fh(info1), + fanotify_info_dir_fh(info2))) + return false; + + if (info1->file_fh_totlen && + !fanotify_fh_equal(fanotify_info_file_fh(info1), + fanotify_info_file_fh(info2))) + return false; + + return !info1->name_len || + !memcmp(fanotify_info_name(info1), fanotify_info_name(info2), + info1->name_len); +} + +static bool fanotify_name_event_equal(struct fanotify_name_event *fne1, + struct fanotify_name_event *fne2) +{ + struct fanotify_info *info1 = &fne1->info; + struct fanotify_info *info2 = &fne2->info; + + /* Do not merge name events without dir fh */ + if (!info1->dir_fh_totlen) + return false; + + if (!fanotify_fsid_equal(&fne1->fsid, &fne2->fsid)) + return false; + + return fanotify_info_equal(info1, info2); +} + +static bool fanotify_should_merge(struct fsnotify_event *old_fsn, + struct fsnotify_event *new_fsn) { struct fanotify_event *old, *new; @@ -26,27 +97,35 @@ 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 || old->fh_len != new->fh_len) + if (old_fsn->objectid != new_fsn->objectid || + old->type != new->type || old->pid != new->pid) return false; - if (fanotify_event_has_path(old)) { - return old->path.mnt == new->path.mnt && - old->path.dentry == new->path.dentry; - } else if (fanotify_event_has_fid(old)) { - /* - * We want to merge many dirent events in the same dir (i.e. - * creates/unlinks/renames), but we do not want to merge dirent - * events referring to subdirs with dirent events referring to - * non subdirs, otherwise, user won't be able to tell from a - * mask FAN_CREATE|FAN_DELETE|FAN_ONDIR if it describes mkdir+ - * unlink pair or rmdir+create pair of events. - */ - return (old->mask & FS_ISDIR) == (new->mask & FS_ISDIR) && - fanotify_fid_equal(&old->fid, &new->fid, old->fh_len); + /* + * We want to merge many dirent events in the same dir (i.e. + * creates/unlinks/renames), but we do not want to merge dirent + * events referring to subdirs with dirent events referring to + * non subdirs, otherwise, user won't be able to tell from a + * mask FAN_CREATE|FAN_DELETE|FAN_ONDIR if it describes mkdir+ + * unlink pair or rmdir+create pair of events. + */ + if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR)) + return false; + + switch (old->type) { + case FANOTIFY_EVENT_TYPE_PATH: + return fanotify_path_equal(fanotify_event_path(old), + fanotify_event_path(new)); + case FANOTIFY_EVENT_TYPE_FID: + return fanotify_fid_event_equal(FANOTIFY_FE(old), + FANOTIFY_FE(new)); + case FANOTIFY_EVENT_TYPE_FID_NAME: + return fanotify_name_event_equal(FANOTIFY_NE(old), + FANOTIFY_NE(new)); + default: + WARN_ON_ONCE(1); } - /* Do not merge events if we failed to encode fid */ return false; } @@ -68,7 +147,7 @@ return 0; list_for_each_entry_reverse(test_event, list, list) { - if (should_merge(test_event, event)) { + if (fanotify_should_merge(test_event, event)) { FANOTIFY_E(test_event)->mask |= new->mask; return 1; } @@ -147,24 +226,30 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, struct fsnotify_iter_info *iter_info, u32 event_mask, const void *data, - int data_type) + int data_type, struct inode *dir) { __u32 marks_mask = 0, marks_ignored_mask = 0; - __u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS; - const struct path *path = data; + __u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS | + FANOTIFY_EVENT_FLAGS; + const struct path *path = fsnotify_data_path(data, data_type); + unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); struct fsnotify_mark *mark; int type; pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n", __func__, iter_info->report_mask, event_mask, data, data_type); - if (!FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { + if (!fid_mode) { /* Do we have path to open a file descriptor? */ - if (data_type != FSNOTIFY_EVENT_PATH) + if (!path) return 0; /* Path type events are only relevant for files and dirs */ if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry)) return 0; + } else if (!(fid_mode & FAN_REPORT_FID)) { + /* Do we have a directory inode to report? */ + if (!dir && !(event_mask & FS_ISDIR)) + return 0; } fsnotify_foreach_obj_type(type) { @@ -183,12 +268,12 @@ continue; /* - * If the event is for a child and this mark doesn't care about - * events on a child, don't send it! + * If the event is for a child and this mark is on a parent not + * watching children, don't send it! */ if (event_mask & FS_EVENT_ON_CHILD && - (type != FSNOTIFY_OBJ_TYPE_INODE || - !(mark->mask & FS_EVENT_ON_CHILD))) + type == FSNOTIFY_OBJ_TYPE_INODE && + !(mark->mask & FS_EVENT_ON_CHILD)) continue; marks_mask |= mark->mask; @@ -197,69 +282,108 @@ test_mask = event_mask & marks_mask & ~marks_ignored_mask; /* - * dirent modification events (create/delete/move) do not carry the - * child entry name/inode information. Instead, we report FAN_ONDIR - * for mkdir/rmdir so user can differentiate them from creat/unlink. + * For dirent modification events (create/delete/move) that do not carry + * the child entry name information, we report FAN_ONDIR for mkdir/rmdir + * so user can differentiate them from creat/unlink. * * For backward compatibility and consistency, do not report FAN_ONDIR * to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR - * to user in FAN_REPORT_FID mode for all event types. + * to user in fid mode for all event types. + * + * We never report FAN_EVENT_ON_CHILD to user, but we do pass it in to + * fanotify_alloc_event() when group is reporting fid as indication + * that event happened on child. */ - if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { - /* Do not report FAN_ONDIR without any event */ - if (!(test_mask & ~FAN_ONDIR)) + if (fid_mode) { + /* Do not report event flags without any event */ + if (!(test_mask & ~FANOTIFY_EVENT_FLAGS)) return 0; } else { - user_mask &= ~FAN_ONDIR; + user_mask &= ~FANOTIFY_EVENT_FLAGS; } return test_mask & user_mask; } -static int fanotify_encode_fid(struct fanotify_event *event, - struct inode *inode, gfp_t gfp, - __kernel_fsid_t *fsid) -{ - struct fanotify_fid *fid = &event->fid; - int dwords, bytes = 0; - int err, type; +/* + * Check size needed to encode fanotify_fh. + * + * Return size of encoded fh without fanotify_fh header. + * Return 0 on failure to encode. + */ +static int fanotify_encode_fh_len(struct inode *inode) +{ + int dwords = 0; + + if (!inode) + return 0; + + exportfs_encode_fid(inode, NULL, &dwords); + + return dwords << 2; +} - fid->ext_fh = NULL; - dwords = 0; +/* + * Encode fanotify_fh. + * + * Return total size of encoded fh including fanotify_fh header. + * Return 0 on failure to encode. + */ +static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, + unsigned int fh_len, gfp_t gfp) +{ + int dwords, type = 0; + char *ext_buf = NULL; + void *buf = fh->buf; + int err; + + fh->type = FILEID_ROOT; + fh->len = 0; + fh->flags = 0; + if (!inode) + return 0; + + /* + * !gpf means preallocated variable size fh, but fh_len could + * be zero in that case if encoding fh len failed. + */ err = -ENOENT; - type = exportfs_encode_inode_fh(inode, NULL, &dwords, NULL); - if (!dwords) + if (fh_len < 4 || WARN_ON_ONCE(fh_len % 4)) goto out_err; - bytes = dwords << 2; - if (bytes > FANOTIFY_INLINE_FH_LEN) { - /* Treat failure to allocate fh as failure to allocate event */ + /* No external buffer in a variable size allocated fh */ + if (gfp && fh_len > FANOTIFY_INLINE_FH_LEN) { + /* Treat failure to allocate fh as failure to encode fh */ err = -ENOMEM; - fid->ext_fh = kmalloc(bytes, gfp); - if (!fid->ext_fh) + ext_buf = kmalloc(fh_len, gfp); + if (!ext_buf) goto out_err; + + *fanotify_fh_ext_buf_ptr(fh) = ext_buf; + buf = ext_buf; + fh->flags |= FANOTIFY_FH_FLAG_EXT_BUF; } - type = exportfs_encode_inode_fh(inode, fanotify_fid_fh(fid, bytes), - &dwords, NULL); + dwords = fh_len >> 2; + type = exportfs_encode_fid(inode, buf, &dwords); err = -EINVAL; - if (!type || type == FILEID_INVALID || bytes != dwords << 2) + if (!type || type == FILEID_INVALID || fh_len != dwords << 2) goto out_err; - fid->fsid = *fsid; - event->fh_len = bytes; + fh->type = type; + fh->len = fh_len; - return type; + return FANOTIFY_FH_HDR_LEN + fh_len; out_err: - pr_warn_ratelimited("fanotify: failed to encode fid (fsid=%x.%x, " - "type=%d, bytes=%d, err=%i)\n", - fsid->val[0], fsid->val[1], type, bytes, err); - kfree(fid->ext_fh); - fid->ext_fh = NULL; - event->fh_len = 0; - - return FILEID_INVALID; + pr_warn_ratelimited("fanotify: failed to encode fid (type=%d, len=%d, err=%i)\n", + type, fh_len, err); + kfree(ext_buf); + *fanotify_fh_ext_buf_ptr(fh) = NULL; + /* Report the event without a file identifier on encode error */ + fh->type = FILEID_INVALID; + fh->len = 0; + return 0; } /* @@ -270,26 +394,179 @@ * FS_ATTRIB reports the child inode even if reported on a watched parent. * FS_CREATE reports the modified dir inode and not the created inode. */ -static struct inode *fanotify_fid_inode(struct inode *to_tell, u32 event_mask, - const void *data, int data_type) +static struct inode *fanotify_fid_inode(u32 event_mask, const void *data, + int data_type, struct inode *dir) +{ + if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) + return dir; + + return fsnotify_data_inode(data, data_type); +} + +/* + * The inode to use as identifier when reporting dir fid depends on the event. + * Report the modified directory inode on dirent modification events. + * Report the "victim" inode if "victim" is a directory. + * Report the parent inode if "victim" is not a directory and event is + * reported to parent. + * Otherwise, do not report dir fid. + */ +static struct inode *fanotify_dfid_inode(u32 event_mask, const void *data, + int data_type, struct inode *dir) { + struct inode *inode = fsnotify_data_inode(data, data_type); + if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) - return to_tell; - else if (data_type == FSNOTIFY_EVENT_INODE) - return (struct inode *)data; - else if (data_type == FSNOTIFY_EVENT_PATH) - return d_inode(((struct path *)data)->dentry); - return NULL; + return dir; + + if (S_ISDIR(inode->i_mode)) + return inode; + + return dir; +} + +static struct fanotify_event *fanotify_alloc_path_event(const struct path *path, + gfp_t gfp) +{ + struct fanotify_path_event *pevent; + + pevent = kmem_cache_alloc(fanotify_path_event_cachep, gfp); + if (!pevent) + return NULL; + + pevent->fae.type = FANOTIFY_EVENT_TYPE_PATH; + pevent->path = *path; + path_get(path); + + return &pevent->fae; +} + +static struct fanotify_event *fanotify_alloc_perm_event(const struct path *path, + gfp_t gfp) +{ + struct fanotify_perm_event *pevent; + + pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp); + if (!pevent) + return NULL; + + pevent->fae.type = FANOTIFY_EVENT_TYPE_PATH_PERM; + pevent->response = 0; + pevent->state = FAN_EVENT_INIT; + pevent->path = *path; + path_get(path); + + return &pevent->fae; } -struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, - struct inode *inode, u32 mask, - const void *data, int data_type, - __kernel_fsid_t *fsid) +static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id, + __kernel_fsid_t *fsid, + gfp_t gfp) +{ + struct fanotify_fid_event *ffe; + + ffe = kmem_cache_alloc(fanotify_fid_event_cachep, gfp); + if (!ffe) + return NULL; + + ffe->fae.type = FANOTIFY_EVENT_TYPE_FID; + ffe->fsid = *fsid; + fanotify_encode_fh(&ffe->object_fh, id, fanotify_encode_fh_len(id), + gfp); + + return &ffe->fae; +} + +static struct fanotify_event *fanotify_alloc_name_event(struct inode *id, + __kernel_fsid_t *fsid, + const struct qstr *file_name, + struct inode *child, + gfp_t gfp) +{ + struct fanotify_name_event *fne; + struct fanotify_info *info; + struct fanotify_fh *dfh, *ffh; + unsigned int dir_fh_len = fanotify_encode_fh_len(id); + unsigned int child_fh_len = fanotify_encode_fh_len(child); + unsigned int size; + + size = sizeof(*fne) + FANOTIFY_FH_HDR_LEN + dir_fh_len; + if (child_fh_len) + size += FANOTIFY_FH_HDR_LEN + child_fh_len; + if (file_name) + size += file_name->len + 1; + fne = kmalloc(size, gfp); + if (!fne) + return NULL; + + fne->fae.type = FANOTIFY_EVENT_TYPE_FID_NAME; + fne->fsid = *fsid; + info = &fne->info; + fanotify_info_init(info); + dfh = fanotify_info_dir_fh(info); + info->dir_fh_totlen = fanotify_encode_fh(dfh, id, dir_fh_len, 0); + if (child_fh_len) { + ffh = fanotify_info_file_fh(info); + info->file_fh_totlen = fanotify_encode_fh(ffh, child, child_fh_len, 0); + } + if (file_name) + fanotify_info_copy_name(info, file_name); + + pr_debug("%s: ino=%lu size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n", + __func__, id->i_ino, size, dir_fh_len, child_fh_len, + info->name_len, info->name_len, fanotify_info_name(info)); + + return &fne->fae; +} + +static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, + u32 mask, const void *data, + int data_type, struct inode *dir, + const struct qstr *file_name, + __kernel_fsid_t *fsid) { struct fanotify_event *event = NULL; gfp_t gfp = GFP_KERNEL_ACCOUNT; - struct inode *id = fanotify_fid_inode(inode, mask, data, data_type); + struct inode *id = fanotify_fid_inode(mask, data, data_type, dir); + struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir); + const struct path *path = fsnotify_data_path(data, data_type); + unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); + struct inode *child = NULL; + bool name_event = false; + + if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) { + /* + * With both flags FAN_REPORT_DIR_FID and FAN_REPORT_FID, we + * report the child fid for events reported on a non-dir child + * in addition to reporting the parent fid and maybe child name. + */ + if ((fid_mode & FAN_REPORT_FID) && + id != dirid && !(mask & FAN_ONDIR)) + child = id; + + id = dirid; + + /* + * We record file name only in a group with FAN_REPORT_NAME + * and when we have a directory inode to report. + * + * For directory entry modification event, we record the fid of + * the directory and the name of the modified entry. + * + * For event on non-directory that is reported to parent, we + * record the fid of the parent and the name of the child. + * + * Even if not reporting name, we need a variable length + * fanotify_name_event if reporting both parent and child fids. + */ + if (!(fid_mode & FAN_REPORT_NAME)) { + name_event = !!child; + file_name = NULL; + } else if ((mask & ALL_FSNOTIFY_DIRENT_EVENTS) || + !(mask & FAN_ONDIR)) { + name_event = true; + } + } /* * For queues with unlimited length lost events are not expected and @@ -306,44 +583,30 @@ memalloc_use_memcg(group->memcg); if (fanotify_is_perm_event(mask)) { - struct fanotify_perm_event *pevent; - - pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp); - if (!pevent) - goto out; - event = &pevent->fae; - pevent->response = 0; - pevent->state = FAN_EVENT_INIT; - goto init; + event = fanotify_alloc_perm_event(path, gfp); + } else if (name_event && (file_name || child)) { + event = fanotify_alloc_name_event(id, fsid, file_name, child, + gfp); + } else if (fid_mode) { + event = fanotify_alloc_fid_event(id, fsid, gfp); + } else { + event = fanotify_alloc_path_event(path, gfp); } - event = kmem_cache_alloc(fanotify_event_cachep, gfp); + if (!event) goto out; -init: __maybe_unused + /* * Use the victim inode instead of the watching inode as the id for * event queue, so event reported on parent is merged with event * reported on child when both directory and child watches exist. */ - fsnotify_init_event(&event->fse, (unsigned long)id); - event->mask = mask; + fanotify_init_event(event, (unsigned long)id, mask); if (FAN_GROUP_FLAG(group, FAN_REPORT_TID)) 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)) { - /* Report the event without a file identifier on encode error */ - event->fh_type = fanotify_encode_fid(event, id, gfp, fsid); - } else if (data_type == FSNOTIFY_EVENT_PATH) { - event->fh_type = FILEID_ROOT; - event->path = *((struct path *)data); - path_get(&event->path); - } else { - event->fh_type = FILEID_INVALID; - event->path.mnt = NULL; - event->path.dentry = NULL; - } + out: memalloc_unuse_memcg(); return event; @@ -382,9 +645,9 @@ return fsid; } -static int fanotify_handle_event(struct fsnotify_group *group, - struct inode *inode, - u32 mask, const void *data, int data_type, +static int fanotify_handle_event(struct fsnotify_group *group, u32 mask, + const void *data, int data_type, + struct inode *dir, const struct qstr *file_name, u32 cookie, struct fsnotify_iter_info *iter_info) { @@ -416,12 +679,11 @@ BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19); mask = fanotify_group_event_mask(group, iter_info, mask, data, - data_type); + data_type, dir); if (!mask) return 0; - pr_debug("%s: group=%p inode=%p mask=%x\n", __func__, group, inode, - mask); + pr_debug("%s: group=%p mask=%x\n", __func__, group, mask); if (fanotify_is_perm_event(mask)) { /* @@ -432,15 +694,15 @@ return 0; } - if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { + if (FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS)) { fsid = fanotify_get_fsid(iter_info); /* Racing with mark destruction or creation? */ if (!fsid.val[0] && !fsid.val[1]) return 0; } - event = fanotify_alloc_event(group, inode, mask, data, data_type, - &fsid); + event = fanotify_alloc_event(group, mask, data, data_type, dir, + file_name, &fsid); ret = -ENOMEM; if (unlikely(!event)) { /* @@ -462,7 +724,7 @@ 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: @@ -481,22 +743,57 @@ 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_name_event(struct fanotify_event *event) +{ + kfree(FANOTIFY_NE(event)); +} + 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_event_has_ext_fh(event)) - kfree(event->fid.ext_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; + case FANOTIFY_EVENT_TYPE_FID_NAME: + fanotify_free_name_event(event); + break; + case FANOTIFY_EVENT_TYPE_OVERFLOW: + kfree(event); + break; + default: + WARN_ON_ONCE(1); } - kmem_cache_free(fanotify_event_cachep, event); } static void fanotify_free_mark(struct fsnotify_mark *fsn_mark)