diff options
Diffstat (limited to 'fs/notify/fanotify/fanotify.c')
-rw-r--r-- | fs/notify/fanotify/fanotify.c | 302 |
1 files changed, 228 insertions, 74 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c index 5778d1347b35..5435a40f82be 100644 --- a/fs/notify/fanotify/fanotify.c +++ b/fs/notify/fanotify/fanotify.c @@ -17,6 +17,59 @@ #include "fanotify.h" +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; + + /* Do not merge events if we failed to encode fh */ + if (fh1->type == FILEID_INVALID) + 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_name_event_equal(struct fanotify_name_event *fne1, + struct fanotify_name_event *fne2) +{ + /* + * Do not merge name events without dir fh. + * FAN_DIR_MODIFY does not encode object fh, so it may be empty. + */ + if (!fne1->dir_fh.len) + return false; + + if (fne1->name_len != fne2->name_len || + !fanotify_fh_equal(&fne1->dir_fh, &fne2->dir_fh)) + return false; + + return !memcmp(fne1->name, fne2->name, fne1->name_len); +} + static bool should_merge(struct fsnotify_event *old_fsn, struct fsnotify_event *new_fsn) { @@ -26,14 +79,15 @@ static bool should_merge(struct fsnotify_event *old_fsn, old = FANOTIFY_E(old_fsn); new = FANOTIFY_E(new_fsn); - if (old_fsn->inode != new_fsn->inode || 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)) { + 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: /* * We want to merge many dirent events in the same dir (i.e. * creates/unlinks/renames), but we do not want to merge dirent @@ -42,11 +96,18 @@ static bool should_merge(struct fsnotify_event *old_fsn, * 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); + if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR)) + return false; + + 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; } @@ -151,7 +212,7 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, { __u32 marks_mask = 0, marks_ignored_mask = 0; __u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS; - const struct path *path = data; + const struct path *path = fsnotify_data_path(data, data_type); struct fsnotify_mark *mark; int type; @@ -160,7 +221,7 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, if (!FAN_GROUP_FLAG(group, FAN_REPORT_FID)) { /* 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)) @@ -172,6 +233,13 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, continue; mark = iter_info->marks[type]; /* + * If the event is on dir and this mark doesn't care about + * events on dir, don't send it! + */ + if (event_mask & FS_ISDIR && !(mark->mask & FS_ISDIR)) + continue; + + /* * If the event is for a child and this mark doesn't care about * events on a child, don't send it! */ @@ -187,9 +255,9 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, 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 @@ -203,22 +271,20 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group, user_mask &= ~FAN_ONDIR; } - if (event_mask & FS_ISDIR && - !(marks_mask & FS_ISDIR & ~marks_ignored_mask)) - return 0; - return test_mask & user_mask; } -static int fanotify_encode_fid(struct fanotify_event *event, - struct inode *inode, gfp_t gfp, - __kernel_fsid_t *fsid) +static void fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, + gfp_t gfp) { - struct fanotify_fid *fid = &event->fid; - int dwords, bytes = 0; - int err, type; + int dwords, type, bytes = 0; + char *ext_buf = NULL; + void *buf = fh->buf; + int err; + + if (!inode) + goto out; - fid->ext_fh = NULL; dwords = 0; err = -ENOENT; type = exportfs_encode_inode_fh(inode, NULL, &dwords, NULL); @@ -229,31 +295,33 @@ static int fanotify_encode_fid(struct fanotify_event *event, if (bytes > FANOTIFY_INLINE_FH_LEN) { /* Treat failure to allocate fh as failure to allocate event */ err = -ENOMEM; - fid->ext_fh = kmalloc(bytes, gfp); - if (!fid->ext_fh) + ext_buf = kmalloc(bytes, gfp); + if (!ext_buf) goto out_err; + + *fanotify_fh_ext_buf_ptr(fh) = ext_buf; + buf = ext_buf; } - type = exportfs_encode_inode_fh(inode, fanotify_fid_fh(fid, bytes), - &dwords, NULL); + type = exportfs_encode_inode_fh(inode, buf, &dwords, NULL); err = -EINVAL; if (!type || type == FILEID_INVALID || bytes != dwords << 2) goto out_err; - fid->fsid = *fsid; - event->fh_len = bytes; + fh->type = type; + fh->len = bytes; - return type; + return; 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, bytes, err); + kfree(ext_buf); + *fanotify_fh_ext_buf_ptr(fh) = NULL; +out: + /* Report the event without a file identifier on encode error */ + fh->type = FILEID_INVALID; + fh->len = 0; } /* @@ -269,21 +337,22 @@ static struct inode *fanotify_fid_inode(struct inode *to_tell, u32 event_mask, { 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 (struct inode *)fsnotify_data_inode(data, data_type); } struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, struct inode *inode, u32 mask, const void *data, int data_type, + const struct qstr *file_name, __kernel_fsid_t *fsid) { struct fanotify_event *event = NULL; + struct fanotify_fid_event *ffe = NULL; + struct fanotify_name_event *fne = 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); /* * For queues with unlimited length lost events are not expected and @@ -305,33 +374,81 @@ 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) - goto out; -init: __maybe_unused - fsnotify_init_event(&event->fse, inode); + + /* + * For FAN_DIR_MODIFY event, we report the fid of the directory and + * the name of the modified entry. + * Allocate an fanotify_name_event struct and copy the name. + */ + if (mask & FAN_DIR_MODIFY && !(WARN_ON_ONCE(!file_name))) { + fne = kmalloc(sizeof(*fne) + file_name->len + 1, gfp); + if (!fne) + goto out; + + event = &fne->fae; + event->type = FANOTIFY_EVENT_TYPE_FID_NAME; + fne->name_len = file_name->len; + strcpy(fne->name, file_name->name); + goto init; + } + + 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: + /* + * 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; 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; + + if (fsid && fanotify_event_fsid(event)) + *fanotify_event_fsid(event) = *fsid; + + if (fanotify_event_object_fh(event)) + fanotify_encode_fh(fanotify_event_object_fh(event), id, gfp); + + if (fanotify_event_dir_fh(event)) + fanotify_encode_fh(fanotify_event_dir_fh(event), id, gfp); + + if (fanotify_event_has_path(event)) { + struct path *p = fanotify_event_path(event); + + if (path) { + *p = *path; + path_get(path); + } else { + p->mnt = NULL; + p->dentry = NULL; + } } out: memalloc_unuse_memcg(); @@ -392,6 +509,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, BUILD_BUG_ON(FAN_MOVED_FROM != FS_MOVED_FROM); BUILD_BUG_ON(FAN_CREATE != FS_CREATE); BUILD_BUG_ON(FAN_DELETE != FS_DELETE); + BUILD_BUG_ON(FAN_DIR_MODIFY != FS_DIR_MODIFY); BUILD_BUG_ON(FAN_DELETE_SELF != FS_DELETE_SELF); BUILD_BUG_ON(FAN_MOVE_SELF != FS_MOVE_SELF); BUILD_BUG_ON(FAN_EVENT_ON_CHILD != FS_EVENT_ON_CHILD); @@ -402,7 +520,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC); BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM); - BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19); + BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 20); mask = fanotify_group_event_mask(group, iter_info, mask, data, data_type); @@ -429,7 +547,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, } event = fanotify_alloc_event(group, inode, mask, data, data_type, - &fsid); + file_name, &fsid); ret = -ENOMEM; if (unlikely(!event)) { /* @@ -451,7 +569,7 @@ 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: @@ -470,22 +588,58 @@ 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_name_event(struct fanotify_event *event) +{ + struct fanotify_name_event *fne = FANOTIFY_NE(event); + + if (fanotify_fh_has_ext_buf(&fne->dir_fh)) + kfree(fanotify_fh_ext_buf(&fne->dir_fh)); + kfree(fne); +} + 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; + default: + WARN_ON_ONCE(1); } - kmem_cache_free(fanotify_event_cachep, event); } static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |