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809 lines
23 KiB
809 lines
23 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#include <linux/fanotify.h> |
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#include <linux/fdtable.h> |
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#include <linux/fsnotify_backend.h> |
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#include <linux/init.h> |
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#include <linux/jiffies.h> |
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#include <linux/kernel.h> /* UINT_MAX */ |
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#include <linux/mount.h> |
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#include <linux/sched.h> |
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#include <linux/sched/user.h> |
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#include <linux/sched/signal.h> |
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#include <linux/types.h> |
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#include <linux/wait.h> |
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#include <linux/audit.h> |
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#include <linux/sched/mm.h> |
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#include <linux/statfs.h> |
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|
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#include "fanotify.h" |
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|
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static bool fanotify_path_equal(struct path *p1, struct path *p2) |
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{ |
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return p1->mnt == p2->mnt && p1->dentry == p2->dentry; |
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} |
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|
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static inline bool fanotify_fsid_equal(__kernel_fsid_t *fsid1, |
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__kernel_fsid_t *fsid2) |
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{ |
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return fsid1->val[0] == fsid2->val[0] && fsid1->val[1] == fsid2->val[1]; |
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} |
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static bool fanotify_fh_equal(struct fanotify_fh *fh1, |
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struct fanotify_fh *fh2) |
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{ |
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if (fh1->type != fh2->type || fh1->len != fh2->len) |
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return false; |
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|
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return !fh1->len || |
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!memcmp(fanotify_fh_buf(fh1), fanotify_fh_buf(fh2), fh1->len); |
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} |
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static bool fanotify_fid_event_equal(struct fanotify_fid_event *ffe1, |
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struct fanotify_fid_event *ffe2) |
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{ |
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/* Do not merge fid events without object fh */ |
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if (!ffe1->object_fh.len) |
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return false; |
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return fanotify_fsid_equal(&ffe1->fsid, &ffe2->fsid) && |
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fanotify_fh_equal(&ffe1->object_fh, &ffe2->object_fh); |
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} |
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|
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static bool fanotify_info_equal(struct fanotify_info *info1, |
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struct fanotify_info *info2) |
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{ |
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if (info1->dir_fh_totlen != info2->dir_fh_totlen || |
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info1->file_fh_totlen != info2->file_fh_totlen || |
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info1->name_len != info2->name_len) |
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return false; |
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if (info1->dir_fh_totlen && |
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!fanotify_fh_equal(fanotify_info_dir_fh(info1), |
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fanotify_info_dir_fh(info2))) |
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return false; |
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if (info1->file_fh_totlen && |
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!fanotify_fh_equal(fanotify_info_file_fh(info1), |
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fanotify_info_file_fh(info2))) |
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return false; |
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return !info1->name_len || |
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!memcmp(fanotify_info_name(info1), fanotify_info_name(info2), |
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info1->name_len); |
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} |
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static bool fanotify_name_event_equal(struct fanotify_name_event *fne1, |
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struct fanotify_name_event *fne2) |
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{ |
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struct fanotify_info *info1 = &fne1->info; |
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struct fanotify_info *info2 = &fne2->info; |
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/* Do not merge name events without dir fh */ |
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if (!info1->dir_fh_totlen) |
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return false; |
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if (!fanotify_fsid_equal(&fne1->fsid, &fne2->fsid)) |
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return false; |
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return fanotify_info_equal(info1, info2); |
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} |
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static bool fanotify_should_merge(struct fsnotify_event *old_fsn, |
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struct fsnotify_event *new_fsn) |
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{ |
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struct fanotify_event *old, *new; |
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|
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pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn); |
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old = FANOTIFY_E(old_fsn); |
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new = FANOTIFY_E(new_fsn); |
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if (old_fsn->objectid != new_fsn->objectid || |
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old->type != new->type || old->pid != new->pid) |
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return false; |
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/* |
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* We want to merge many dirent events in the same dir (i.e. |
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* creates/unlinks/renames), but we do not want to merge dirent |
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* events referring to subdirs with dirent events referring to |
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* non subdirs, otherwise, user won't be able to tell from a |
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* mask FAN_CREATE|FAN_DELETE|FAN_ONDIR if it describes mkdir+ |
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* unlink pair or rmdir+create pair of events. |
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*/ |
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if ((old->mask & FS_ISDIR) != (new->mask & FS_ISDIR)) |
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return false; |
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switch (old->type) { |
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case FANOTIFY_EVENT_TYPE_PATH: |
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return fanotify_path_equal(fanotify_event_path(old), |
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fanotify_event_path(new)); |
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case FANOTIFY_EVENT_TYPE_FID: |
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return fanotify_fid_event_equal(FANOTIFY_FE(old), |
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FANOTIFY_FE(new)); |
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case FANOTIFY_EVENT_TYPE_FID_NAME: |
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return fanotify_name_event_equal(FANOTIFY_NE(old), |
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FANOTIFY_NE(new)); |
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default: |
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WARN_ON_ONCE(1); |
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} |
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return false; |
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} |
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/* and the list better be locked by something too! */ |
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static int fanotify_merge(struct list_head *list, struct fsnotify_event *event) |
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{ |
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struct fsnotify_event *test_event; |
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struct fanotify_event *new; |
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pr_debug("%s: list=%p event=%p\n", __func__, list, event); |
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new = FANOTIFY_E(event); |
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/* |
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* Don't merge a permission event with any other event so that we know |
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* the event structure we have created in fanotify_handle_event() is the |
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* one we should check for permission response. |
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*/ |
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if (fanotify_is_perm_event(new->mask)) |
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return 0; |
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list_for_each_entry_reverse(test_event, list, list) { |
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if (fanotify_should_merge(test_event, event)) { |
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FANOTIFY_E(test_event)->mask |= new->mask; |
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return 1; |
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} |
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} |
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return 0; |
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} |
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/* |
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* Wait for response to permission event. The function also takes care of |
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* freeing the permission event (or offloads that in case the wait is canceled |
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* by a signal). The function returns 0 in case access got allowed by userspace, |
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* -EPERM in case userspace disallowed the access, and -ERESTARTSYS in case |
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* the wait got interrupted by a signal. |
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*/ |
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static int fanotify_get_response(struct fsnotify_group *group, |
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struct fanotify_perm_event *event, |
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struct fsnotify_iter_info *iter_info) |
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{ |
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int ret; |
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pr_debug("%s: group=%p event=%p\n", __func__, group, event); |
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ret = wait_event_killable(group->fanotify_data.access_waitq, |
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event->state == FAN_EVENT_ANSWERED); |
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/* Signal pending? */ |
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if (ret < 0) { |
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spin_lock(&group->notification_lock); |
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/* Event reported to userspace and no answer yet? */ |
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if (event->state == FAN_EVENT_REPORTED) { |
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/* Event will get freed once userspace answers to it */ |
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event->state = FAN_EVENT_CANCELED; |
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spin_unlock(&group->notification_lock); |
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return ret; |
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} |
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/* Event not yet reported? Just remove it. */ |
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if (event->state == FAN_EVENT_INIT) |
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fsnotify_remove_queued_event(group, &event->fae.fse); |
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/* |
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* Event may be also answered in case signal delivery raced |
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* with wakeup. In that case we have nothing to do besides |
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* freeing the event and reporting error. |
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*/ |
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spin_unlock(&group->notification_lock); |
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goto out; |
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} |
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/* userspace responded, convert to something usable */ |
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switch (event->response & ~FAN_AUDIT) { |
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case FAN_ALLOW: |
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ret = 0; |
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break; |
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case FAN_DENY: |
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default: |
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ret = -EPERM; |
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} |
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/* Check if the response should be audited */ |
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if (event->response & FAN_AUDIT) |
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audit_fanotify(event->response & ~FAN_AUDIT); |
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pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__, |
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group, event, ret); |
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out: |
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fsnotify_destroy_event(group, &event->fae.fse); |
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return ret; |
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} |
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/* |
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* This function returns a mask for an event that only contains the flags |
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* that have been specifically requested by the user. Flags that may have |
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* been included within the event mask, but have not been explicitly |
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* requested by the user, will not be present in the returned mask. |
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*/ |
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static u32 fanotify_group_event_mask(struct fsnotify_group *group, |
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struct fsnotify_iter_info *iter_info, |
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u32 event_mask, const void *data, |
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int data_type, struct inode *dir) |
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{ |
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__u32 marks_mask = 0, marks_ignored_mask = 0; |
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__u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS | |
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FANOTIFY_EVENT_FLAGS; |
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const struct path *path = fsnotify_data_path(data, data_type); |
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unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); |
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struct fsnotify_mark *mark; |
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int type; |
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pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n", |
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__func__, iter_info->report_mask, event_mask, data, data_type); |
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if (!fid_mode) { |
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/* Do we have path to open a file descriptor? */ |
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if (!path) |
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return 0; |
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/* Path type events are only relevant for files and dirs */ |
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if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry)) |
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return 0; |
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} else if (!(fid_mode & FAN_REPORT_FID)) { |
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/* Do we have a directory inode to report? */ |
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if (!dir && !(event_mask & FS_ISDIR)) |
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return 0; |
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} |
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fsnotify_foreach_obj_type(type) { |
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if (!fsnotify_iter_should_report_type(iter_info, type)) |
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continue; |
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mark = iter_info->marks[type]; |
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/* Apply ignore mask regardless of ISDIR and ON_CHILD flags */ |
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marks_ignored_mask |= mark->ignored_mask; |
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/* |
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* If the event is on dir and this mark doesn't care about |
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* events on dir, don't send it! |
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*/ |
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if (event_mask & FS_ISDIR && !(mark->mask & FS_ISDIR)) |
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continue; |
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/* |
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* If the event is on a child and this mark is on a parent not |
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* watching children, don't send it! |
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*/ |
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if (type == FSNOTIFY_OBJ_TYPE_PARENT && |
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!(mark->mask & FS_EVENT_ON_CHILD)) |
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continue; |
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marks_mask |= mark->mask; |
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} |
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test_mask = event_mask & marks_mask & ~marks_ignored_mask; |
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/* |
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* For dirent modification events (create/delete/move) that do not carry |
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* the child entry name information, we report FAN_ONDIR for mkdir/rmdir |
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* so user can differentiate them from creat/unlink. |
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* |
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* For backward compatibility and consistency, do not report FAN_ONDIR |
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* to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR |
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* to user in fid mode for all event types. |
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* |
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* We never report FAN_EVENT_ON_CHILD to user, but we do pass it in to |
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* fanotify_alloc_event() when group is reporting fid as indication |
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* that event happened on child. |
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*/ |
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if (fid_mode) { |
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/* Do not report event flags without any event */ |
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if (!(test_mask & ~FANOTIFY_EVENT_FLAGS)) |
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return 0; |
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} else { |
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user_mask &= ~FANOTIFY_EVENT_FLAGS; |
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} |
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return test_mask & user_mask; |
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} |
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/* |
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* Check size needed to encode fanotify_fh. |
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* |
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* Return size of encoded fh without fanotify_fh header. |
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* Return 0 on failure to encode. |
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*/ |
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static int fanotify_encode_fh_len(struct inode *inode) |
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{ |
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int dwords = 0; |
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if (!inode) |
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return 0; |
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exportfs_encode_inode_fh(inode, NULL, &dwords, NULL); |
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return dwords << 2; |
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} |
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/* |
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* Encode fanotify_fh. |
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* |
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* Return total size of encoded fh including fanotify_fh header. |
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* Return 0 on failure to encode. |
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*/ |
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static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode, |
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unsigned int fh_len, gfp_t gfp) |
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{ |
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int dwords, type = 0; |
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char *ext_buf = NULL; |
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void *buf = fh->buf; |
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int err; |
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fh->type = FILEID_ROOT; |
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fh->len = 0; |
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fh->flags = 0; |
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if (!inode) |
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return 0; |
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/* |
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* !gpf means preallocated variable size fh, but fh_len could |
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* be zero in that case if encoding fh len failed. |
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*/ |
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err = -ENOENT; |
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if (fh_len < 4 || WARN_ON_ONCE(fh_len % 4)) |
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goto out_err; |
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/* No external buffer in a variable size allocated fh */ |
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if (gfp && fh_len > FANOTIFY_INLINE_FH_LEN) { |
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/* Treat failure to allocate fh as failure to encode fh */ |
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err = -ENOMEM; |
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ext_buf = kmalloc(fh_len, gfp); |
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if (!ext_buf) |
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goto out_err; |
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*fanotify_fh_ext_buf_ptr(fh) = ext_buf; |
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buf = ext_buf; |
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fh->flags |= FANOTIFY_FH_FLAG_EXT_BUF; |
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} |
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dwords = fh_len >> 2; |
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type = exportfs_encode_inode_fh(inode, buf, &dwords, NULL); |
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err = -EINVAL; |
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if (!type || type == FILEID_INVALID || fh_len != dwords << 2) |
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goto out_err; |
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fh->type = type; |
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fh->len = fh_len; |
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return FANOTIFY_FH_HDR_LEN + fh_len; |
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out_err: |
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pr_warn_ratelimited("fanotify: failed to encode fid (type=%d, len=%d, err=%i)\n", |
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type, fh_len, err); |
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kfree(ext_buf); |
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*fanotify_fh_ext_buf_ptr(fh) = NULL; |
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/* Report the event without a file identifier on encode error */ |
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fh->type = FILEID_INVALID; |
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fh->len = 0; |
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return 0; |
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} |
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/* |
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* The inode to use as identifier when reporting fid depends on the event. |
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* Report the modified directory inode on dirent modification events. |
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* Report the "victim" inode otherwise. |
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* For example: |
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* FS_ATTRIB reports the child inode even if reported on a watched parent. |
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* FS_CREATE reports the modified dir inode and not the created inode. |
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*/ |
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static struct inode *fanotify_fid_inode(u32 event_mask, const void *data, |
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int data_type, struct inode *dir) |
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{ |
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if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) |
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return dir; |
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return fsnotify_data_inode(data, data_type); |
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} |
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/* |
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* The inode to use as identifier when reporting dir fid depends on the event. |
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* Report the modified directory inode on dirent modification events. |
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* Report the "victim" inode if "victim" is a directory. |
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* Report the parent inode if "victim" is not a directory and event is |
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* reported to parent. |
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* Otherwise, do not report dir fid. |
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*/ |
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static struct inode *fanotify_dfid_inode(u32 event_mask, const void *data, |
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int data_type, struct inode *dir) |
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{ |
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struct inode *inode = fsnotify_data_inode(data, data_type); |
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if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) |
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return dir; |
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if (S_ISDIR(inode->i_mode)) |
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return inode; |
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return dir; |
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} |
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static struct fanotify_event *fanotify_alloc_path_event(const struct path *path, |
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gfp_t gfp) |
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{ |
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struct fanotify_path_event *pevent; |
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pevent = kmem_cache_alloc(fanotify_path_event_cachep, gfp); |
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if (!pevent) |
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return NULL; |
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pevent->fae.type = FANOTIFY_EVENT_TYPE_PATH; |
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pevent->path = *path; |
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path_get(path); |
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return &pevent->fae; |
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} |
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static struct fanotify_event *fanotify_alloc_perm_event(const struct path *path, |
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gfp_t gfp) |
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{ |
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struct fanotify_perm_event *pevent; |
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pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp); |
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if (!pevent) |
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return NULL; |
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pevent->fae.type = FANOTIFY_EVENT_TYPE_PATH_PERM; |
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pevent->response = 0; |
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pevent->state = FAN_EVENT_INIT; |
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pevent->path = *path; |
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path_get(path); |
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return &pevent->fae; |
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} |
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static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id, |
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__kernel_fsid_t *fsid, |
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gfp_t gfp) |
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{ |
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struct fanotify_fid_event *ffe; |
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ffe = kmem_cache_alloc(fanotify_fid_event_cachep, gfp); |
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if (!ffe) |
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return NULL; |
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ffe->fae.type = FANOTIFY_EVENT_TYPE_FID; |
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ffe->fsid = *fsid; |
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fanotify_encode_fh(&ffe->object_fh, id, fanotify_encode_fh_len(id), |
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gfp); |
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return &ffe->fae; |
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} |
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static struct fanotify_event *fanotify_alloc_name_event(struct inode *id, |
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__kernel_fsid_t *fsid, |
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const struct qstr *file_name, |
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struct inode *child, |
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gfp_t gfp) |
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{ |
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struct fanotify_name_event *fne; |
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struct fanotify_info *info; |
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struct fanotify_fh *dfh, *ffh; |
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unsigned int dir_fh_len = fanotify_encode_fh_len(id); |
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unsigned int child_fh_len = fanotify_encode_fh_len(child); |
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unsigned int size; |
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size = sizeof(*fne) + FANOTIFY_FH_HDR_LEN + dir_fh_len; |
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if (child_fh_len) |
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size += FANOTIFY_FH_HDR_LEN + child_fh_len; |
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if (file_name) |
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size += file_name->len + 1; |
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fne = kmalloc(size, gfp); |
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if (!fne) |
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return NULL; |
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fne->fae.type = FANOTIFY_EVENT_TYPE_FID_NAME; |
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fne->fsid = *fsid; |
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info = &fne->info; |
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fanotify_info_init(info); |
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dfh = fanotify_info_dir_fh(info); |
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info->dir_fh_totlen = fanotify_encode_fh(dfh, id, dir_fh_len, 0); |
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if (child_fh_len) { |
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ffh = fanotify_info_file_fh(info); |
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info->file_fh_totlen = fanotify_encode_fh(ffh, child, child_fh_len, 0); |
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} |
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if (file_name) |
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fanotify_info_copy_name(info, file_name); |
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pr_debug("%s: ino=%lu size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n", |
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__func__, id->i_ino, size, dir_fh_len, child_fh_len, |
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info->name_len, info->name_len, fanotify_info_name(info)); |
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|
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return &fne->fae; |
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} |
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|
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static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group, |
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u32 mask, const void *data, |
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int data_type, struct inode *dir, |
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const struct qstr *file_name, |
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__kernel_fsid_t *fsid) |
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{ |
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struct fanotify_event *event = NULL; |
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gfp_t gfp = GFP_KERNEL_ACCOUNT; |
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struct inode *id = fanotify_fid_inode(mask, data, data_type, dir); |
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struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir); |
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const struct path *path = fsnotify_data_path(data, data_type); |
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unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS); |
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struct mem_cgroup *old_memcg; |
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struct inode *child = NULL; |
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bool name_event = false; |
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|
|
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 |
|
* can possibly have security implications. Avoid losing events when |
|
* memory is short. For the limited size queues, avoid OOM killer in the |
|
* target monitoring memcg as it may have security repercussion. |
|
*/ |
|
if (group->max_events == UINT_MAX) |
|
gfp |= __GFP_NOFAIL; |
|
else |
|
gfp |= __GFP_RETRY_MAYFAIL; |
|
|
|
/* Whoever is interested in the event, pays for the allocation. */ |
|
old_memcg = set_active_memcg(group->memcg); |
|
|
|
if (fanotify_is_perm_event(mask)) { |
|
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); |
|
} |
|
|
|
if (!event) |
|
goto out; |
|
|
|
/* |
|
* 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. |
|
*/ |
|
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)); |
|
|
|
out: |
|
set_active_memcg(old_memcg); |
|
return event; |
|
} |
|
|
|
/* |
|
* Get cached fsid of the filesystem containing the object from any connector. |
|
* All connectors are supposed to have the same fsid, but we do not verify that |
|
* here. |
|
*/ |
|
static __kernel_fsid_t fanotify_get_fsid(struct fsnotify_iter_info *iter_info) |
|
{ |
|
int type; |
|
__kernel_fsid_t fsid = {}; |
|
|
|
fsnotify_foreach_obj_type(type) { |
|
struct fsnotify_mark_connector *conn; |
|
|
|
if (!fsnotify_iter_should_report_type(iter_info, type)) |
|
continue; |
|
|
|
conn = READ_ONCE(iter_info->marks[type]->connector); |
|
/* Mark is just getting destroyed or created? */ |
|
if (!conn) |
|
continue; |
|
if (!(conn->flags & FSNOTIFY_CONN_FLAG_HAS_FSID)) |
|
continue; |
|
/* Pairs with smp_wmb() in fsnotify_add_mark_list() */ |
|
smp_rmb(); |
|
fsid = conn->fsid; |
|
if (WARN_ON_ONCE(!fsid.val[0] && !fsid.val[1])) |
|
continue; |
|
return fsid; |
|
} |
|
|
|
return fsid; |
|
} |
|
|
|
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) |
|
{ |
|
int ret = 0; |
|
struct fanotify_event *event; |
|
struct fsnotify_event *fsn_event; |
|
__kernel_fsid_t fsid = {}; |
|
|
|
BUILD_BUG_ON(FAN_ACCESS != FS_ACCESS); |
|
BUILD_BUG_ON(FAN_MODIFY != FS_MODIFY); |
|
BUILD_BUG_ON(FAN_ATTRIB != FS_ATTRIB); |
|
BUILD_BUG_ON(FAN_CLOSE_NOWRITE != FS_CLOSE_NOWRITE); |
|
BUILD_BUG_ON(FAN_CLOSE_WRITE != FS_CLOSE_WRITE); |
|
BUILD_BUG_ON(FAN_OPEN != FS_OPEN); |
|
BUILD_BUG_ON(FAN_MOVED_TO != FS_MOVED_TO); |
|
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_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); |
|
BUILD_BUG_ON(FAN_Q_OVERFLOW != FS_Q_OVERFLOW); |
|
BUILD_BUG_ON(FAN_OPEN_PERM != FS_OPEN_PERM); |
|
BUILD_BUG_ON(FAN_ACCESS_PERM != FS_ACCESS_PERM); |
|
BUILD_BUG_ON(FAN_ONDIR != FS_ISDIR); |
|
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); |
|
|
|
mask = fanotify_group_event_mask(group, iter_info, mask, data, |
|
data_type, dir); |
|
if (!mask) |
|
return 0; |
|
|
|
pr_debug("%s: group=%p mask=%x\n", __func__, group, mask); |
|
|
|
if (fanotify_is_perm_event(mask)) { |
|
/* |
|
* fsnotify_prepare_user_wait() fails if we race with mark |
|
* deletion. Just let the operation pass in that case. |
|
*/ |
|
if (!fsnotify_prepare_user_wait(iter_info)) |
|
return 0; |
|
} |
|
|
|
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, mask, data, data_type, dir, |
|
file_name, &fsid); |
|
ret = -ENOMEM; |
|
if (unlikely(!event)) { |
|
/* |
|
* We don't queue overflow events for permission events as |
|
* there the access is denied and so no event is in fact lost. |
|
*/ |
|
if (!fanotify_is_perm_event(mask)) |
|
fsnotify_queue_overflow(group); |
|
goto finish; |
|
} |
|
|
|
fsn_event = &event->fse; |
|
ret = fsnotify_add_event(group, fsn_event, fanotify_merge); |
|
if (ret) { |
|
/* Permission events shouldn't be merged */ |
|
BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS); |
|
/* Our event wasn't used in the end. Free it. */ |
|
fsnotify_destroy_event(group, fsn_event); |
|
|
|
ret = 0; |
|
} else if (fanotify_is_perm_event(mask)) { |
|
ret = fanotify_get_response(group, FANOTIFY_PERM(event), |
|
iter_info); |
|
} |
|
finish: |
|
if (fanotify_is_perm_event(mask)) |
|
fsnotify_finish_user_wait(iter_info); |
|
|
|
return ret; |
|
} |
|
|
|
static void fanotify_free_group_priv(struct fsnotify_group *group) |
|
{ |
|
struct user_struct *user; |
|
|
|
user = group->fanotify_data.user; |
|
atomic_dec(&user->fanotify_listeners); |
|
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); |
|
put_pid(event->pid); |
|
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); |
|
} |
|
} |
|
|
|
static void fanotify_free_mark(struct fsnotify_mark *fsn_mark) |
|
{ |
|
kmem_cache_free(fanotify_mark_cache, fsn_mark); |
|
} |
|
|
|
const struct fsnotify_ops fanotify_fsnotify_ops = { |
|
.handle_event = fanotify_handle_event, |
|
.free_group_priv = fanotify_free_group_priv, |
|
.free_event = fanotify_free_event, |
|
.free_mark = fanotify_free_mark, |
|
};
|
|
|