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![Amir Goldstein](/assets/img/avatar_default.png)
The logic for handling events on child in groups that have a mark on
the parent inode, but without FS_EVENT_ON_CHILD flag in the mask is
duplicated in several places and inconsistent.
Move the logic into the preparation of mark type iterator, so that the
parent mark type will be excluded from all mark type iterations in that
case.
This results in several subtle changes of behavior, hopefully all
desired changes of behavior, for example:
- Group A has a mount mark with FS_MODIFY in mask
- Group A has a mark with ignore mask that does not survive FS_MODIFY
and does not watch children on directory D.
- Group B has a mark with FS_MODIFY in mask that does watch children
on directory D.
- FS_MODIFY event on file D/foo should not clear the ignore mask of
group A, but before this change it does
And if group A ignore mask was set to survive FS_MODIFY:
- FS_MODIFY event on file D/foo should be reported to group A on account
of the mount mark, but before this change it is wrongly ignored
Fixes: 2f02fd3fa1
("fanotify: fix ignore mask logic for events on child and on dir")
Reported-by: Jan Kara <jack@suse.com>
Link: https://lore.kernel.org/linux-fsdevel/20220314113337.j7slrb5srxukztje@quack3.lan/
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220511190213.831646-3-amir73il@gmail.com
1073 lines
30 KiB
C
1073 lines
30 KiB
C
// 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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#include <linux/stringhash.h>
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#include "fanotify.h"
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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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static unsigned int fanotify_hash_path(const struct path *path)
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{
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return hash_ptr(path->dentry, FANOTIFY_EVENT_HASH_BITS) ^
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hash_ptr(path->mnt, FANOTIFY_EVENT_HASH_BITS);
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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 unsigned int fanotify_hash_fsid(__kernel_fsid_t *fsid)
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{
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return hash_32(fsid->val[0], FANOTIFY_EVENT_HASH_BITS) ^
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hash_32(fsid->val[1], FANOTIFY_EVENT_HASH_BITS);
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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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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 unsigned int fanotify_hash_fh(struct fanotify_fh *fh)
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{
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long salt = (long)fh->type | (long)fh->len << 8;
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/*
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* full_name_hash() works long by long, so it handles fh buf optimally.
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*/
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return full_name_hash((void *)salt, fanotify_fh_buf(fh), fh->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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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->dir2_fh_totlen != info2->dir2_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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info1->name2_len != info2->name2_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->dir2_fh_totlen &&
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!fanotify_fh_equal(fanotify_info_dir2_fh(info1),
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fanotify_info_dir2_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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if (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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return false;
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return !info1->name2_len ||
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!memcmp(fanotify_info_name2(info1), fanotify_info_name2(info2),
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info1->name2_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_error_event_equal(struct fanotify_error_event *fee1,
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struct fanotify_error_event *fee2)
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{
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/* Error events against the same file system are always merged. */
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if (!fanotify_fsid_equal(&fee1->fsid, &fee2->fsid))
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return false;
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return true;
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}
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static bool fanotify_should_merge(struct fanotify_event *old,
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struct fanotify_event *new)
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{
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pr_debug("%s: old=%p new=%p\n", __func__, old, new);
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if (old->hash != new->hash ||
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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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/*
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* FAN_RENAME event is reported with special info record types,
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* so we cannot merge it with other events.
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*/
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if ((old->mask & FAN_RENAME) != (new->mask & FAN_RENAME))
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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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case FANOTIFY_EVENT_TYPE_FS_ERROR:
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return fanotify_error_event_equal(FANOTIFY_EE(old),
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FANOTIFY_EE(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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/* Limit event merges to limit CPU overhead per event */
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#define FANOTIFY_MAX_MERGE_EVENTS 128
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/* and the list better be locked by something too! */
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static int fanotify_merge(struct fsnotify_group *group,
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struct fsnotify_event *event)
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{
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struct fanotify_event *old, *new = FANOTIFY_E(event);
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unsigned int bucket = fanotify_event_hash_bucket(group, new);
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struct hlist_head *hlist = &group->fanotify_data.merge_hash[bucket];
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int i = 0;
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pr_debug("%s: group=%p event=%p bucket=%u\n", __func__,
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group, event, bucket);
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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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hlist_for_each_entry(old, hlist, merge_list) {
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if (++i > FANOTIFY_MAX_MERGE_EVENTS)
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break;
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if (fanotify_should_merge(old, new)) {
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old->mask |= new->mask;
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if (fanotify_is_error_event(old->mask))
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FANOTIFY_EE(old)->err_count++;
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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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/* Permission events are not supposed to be hashed */
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WARN_ON_ONCE(!hlist_unhashed(&event->fae.merge_list));
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}
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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 *match_mask, u32 event_mask,
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const void *data, int data_type,
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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_iter_mark_type(iter_info, mark, type) {
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/* Apply ignore mask regardless of mark's ISDIR flag */
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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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marks_mask |= mark->mask;
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/* Record the mark types of this group that matched the event */
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*match_mask |= 1U << type;
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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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int fh_len;
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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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fh_len = dwords << 2;
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/*
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* struct fanotify_error_event might be preallocated and is
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* limited to MAX_HANDLE_SZ. This should never happen, but
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* safeguard by forcing an invalid file handle.
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*/
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if (WARN_ON_ONCE(fh_len > MAX_HANDLE_SZ))
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return 0;
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return fh_len;
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}
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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, unsigned int *hash,
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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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/*
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* Invalid FHs are used by FAN_FS_ERROR for errors not
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* linked to any inode. The f_handle won't be reported
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* back to userspace.
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*/
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if (!inode)
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goto out;
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|
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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) || fh_len > MAX_HANDLE_SZ)
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goto out_err;
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|
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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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|
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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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|
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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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|
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fh->type = type;
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fh->len = fh_len;
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|
|
out:
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/*
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* Mix fh into event merge key. Hash might be NULL in case of
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* unhashed FID events (i.e. FAN_FS_ERROR).
|
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*/
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if (hash)
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*hash ^= fanotify_hash_fh(fh);
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|
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return FANOTIFY_FH_HDR_LEN + fh_len;
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|
|
out_err:
|
|
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;
|
|
}
|
|
|
|
/*
|
|
* FAN_REPORT_FID is ambiguous in that it reports the fid of the child for
|
|
* some events and the fid of the parent for create/delete/move events.
|
|
*
|
|
* With the FAN_REPORT_TARGET_FID flag, the fid of the child is reported
|
|
* also in create/delete/move events in addition to the fid of the parent
|
|
* and the name of the child.
|
|
*/
|
|
static inline bool fanotify_report_child_fid(unsigned int fid_mode, u32 mask)
|
|
{
|
|
if (mask & ALL_FSNOTIFY_DIRENT_EVENTS)
|
|
return (fid_mode & FAN_REPORT_TARGET_FID);
|
|
|
|
return (fid_mode & FAN_REPORT_FID) && !(mask & FAN_ONDIR);
|
|
}
|
|
|
|
/*
|
|
* The inode to use as identifier when reporting fid depends on the event
|
|
* and the group flags.
|
|
*
|
|
* With the group flag FAN_REPORT_TARGET_FID, always report the child fid.
|
|
*
|
|
* Without the group flag FAN_REPORT_TARGET_FID, report the modified directory
|
|
* fid on dirent events and the child fid otherwise.
|
|
*
|
|
* For example:
|
|
* FS_ATTRIB reports the child fid even if reported on a watched parent.
|
|
* FS_CREATE reports the modified dir fid without FAN_REPORT_TARGET_FID.
|
|
* and reports the created child fid with FAN_REPORT_TARGET_FID.
|
|
*/
|
|
static struct inode *fanotify_fid_inode(u32 event_mask, const void *data,
|
|
int data_type, struct inode *dir,
|
|
unsigned int fid_mode)
|
|
{
|
|
if ((event_mask & ALL_FSNOTIFY_DIRENT_EVENTS) &&
|
|
!(fid_mode & FAN_REPORT_TARGET_FID))
|
|
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 dir;
|
|
|
|
if (inode && S_ISDIR(inode->i_mode))
|
|
return inode;
|
|
|
|
return dir;
|
|
}
|
|
|
|
static struct fanotify_event *fanotify_alloc_path_event(const struct path *path,
|
|
unsigned int *hash,
|
|
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;
|
|
*hash ^= fanotify_hash_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;
|
|
}
|
|
|
|
static struct fanotify_event *fanotify_alloc_fid_event(struct inode *id,
|
|
__kernel_fsid_t *fsid,
|
|
unsigned int *hash,
|
|
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;
|
|
*hash ^= fanotify_hash_fsid(fsid);
|
|
fanotify_encode_fh(&ffe->object_fh, id, fanotify_encode_fh_len(id),
|
|
hash, gfp);
|
|
|
|
return &ffe->fae;
|
|
}
|
|
|
|
static struct fanotify_event *fanotify_alloc_name_event(struct inode *dir,
|
|
__kernel_fsid_t *fsid,
|
|
const struct qstr *name,
|
|
struct inode *child,
|
|
struct dentry *moved,
|
|
unsigned int *hash,
|
|
gfp_t gfp)
|
|
{
|
|
struct fanotify_name_event *fne;
|
|
struct fanotify_info *info;
|
|
struct fanotify_fh *dfh, *ffh;
|
|
struct inode *dir2 = moved ? d_inode(moved->d_parent) : NULL;
|
|
const struct qstr *name2 = moved ? &moved->d_name : NULL;
|
|
unsigned int dir_fh_len = fanotify_encode_fh_len(dir);
|
|
unsigned int dir2_fh_len = fanotify_encode_fh_len(dir2);
|
|
unsigned int child_fh_len = fanotify_encode_fh_len(child);
|
|
unsigned long name_len = name ? name->len : 0;
|
|
unsigned long name2_len = name2 ? name2->len : 0;
|
|
unsigned int len, size;
|
|
|
|
/* Reserve terminating null byte even for empty name */
|
|
size = sizeof(*fne) + name_len + name2_len + 2;
|
|
if (dir_fh_len)
|
|
size += FANOTIFY_FH_HDR_LEN + dir_fh_len;
|
|
if (dir2_fh_len)
|
|
size += FANOTIFY_FH_HDR_LEN + dir2_fh_len;
|
|
if (child_fh_len)
|
|
size += FANOTIFY_FH_HDR_LEN + child_fh_len;
|
|
fne = kmalloc(size, gfp);
|
|
if (!fne)
|
|
return NULL;
|
|
|
|
fne->fae.type = FANOTIFY_EVENT_TYPE_FID_NAME;
|
|
fne->fsid = *fsid;
|
|
*hash ^= fanotify_hash_fsid(fsid);
|
|
info = &fne->info;
|
|
fanotify_info_init(info);
|
|
if (dir_fh_len) {
|
|
dfh = fanotify_info_dir_fh(info);
|
|
len = fanotify_encode_fh(dfh, dir, dir_fh_len, hash, 0);
|
|
fanotify_info_set_dir_fh(info, len);
|
|
}
|
|
if (dir2_fh_len) {
|
|
dfh = fanotify_info_dir2_fh(info);
|
|
len = fanotify_encode_fh(dfh, dir2, dir2_fh_len, hash, 0);
|
|
fanotify_info_set_dir2_fh(info, len);
|
|
}
|
|
if (child_fh_len) {
|
|
ffh = fanotify_info_file_fh(info);
|
|
len = fanotify_encode_fh(ffh, child, child_fh_len, hash, 0);
|
|
fanotify_info_set_file_fh(info, len);
|
|
}
|
|
if (name_len) {
|
|
fanotify_info_copy_name(info, name);
|
|
*hash ^= full_name_hash((void *)name_len, name->name, name_len);
|
|
}
|
|
if (name2_len) {
|
|
fanotify_info_copy_name2(info, name2);
|
|
*hash ^= full_name_hash((void *)name2_len, name2->name,
|
|
name2_len);
|
|
}
|
|
|
|
pr_debug("%s: size=%u dir_fh_len=%u child_fh_len=%u name_len=%u name='%.*s'\n",
|
|
__func__, size, dir_fh_len, child_fh_len,
|
|
info->name_len, info->name_len, fanotify_info_name(info));
|
|
|
|
if (dir2_fh_len) {
|
|
pr_debug("%s: dir2_fh_len=%u name2_len=%u name2='%.*s'\n",
|
|
__func__, dir2_fh_len, info->name2_len,
|
|
info->name2_len, fanotify_info_name2(info));
|
|
}
|
|
|
|
return &fne->fae;
|
|
}
|
|
|
|
static struct fanotify_event *fanotify_alloc_error_event(
|
|
struct fsnotify_group *group,
|
|
__kernel_fsid_t *fsid,
|
|
const void *data, int data_type,
|
|
unsigned int *hash)
|
|
{
|
|
struct fs_error_report *report =
|
|
fsnotify_data_error_report(data, data_type);
|
|
struct inode *inode;
|
|
struct fanotify_error_event *fee;
|
|
int fh_len;
|
|
|
|
if (WARN_ON_ONCE(!report))
|
|
return NULL;
|
|
|
|
fee = mempool_alloc(&group->fanotify_data.error_events_pool, GFP_NOFS);
|
|
if (!fee)
|
|
return NULL;
|
|
|
|
fee->fae.type = FANOTIFY_EVENT_TYPE_FS_ERROR;
|
|
fee->error = report->error;
|
|
fee->err_count = 1;
|
|
fee->fsid = *fsid;
|
|
|
|
inode = report->inode;
|
|
fh_len = fanotify_encode_fh_len(inode);
|
|
|
|
/* Bad fh_len. Fallback to using an invalid fh. Should never happen. */
|
|
if (!fh_len && inode)
|
|
inode = NULL;
|
|
|
|
fanotify_encode_fh(&fee->object_fh, inode, fh_len, NULL, 0);
|
|
|
|
*hash ^= fanotify_hash_fsid(fsid);
|
|
|
|
return &fee->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, u32 match_mask)
|
|
{
|
|
struct fanotify_event *event = NULL;
|
|
gfp_t gfp = GFP_KERNEL_ACCOUNT;
|
|
unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
|
|
struct inode *id = fanotify_fid_inode(mask, data, data_type, dir,
|
|
fid_mode);
|
|
struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir);
|
|
const struct path *path = fsnotify_data_path(data, data_type);
|
|
struct mem_cgroup *old_memcg;
|
|
struct dentry *moved = NULL;
|
|
struct inode *child = NULL;
|
|
bool name_event = false;
|
|
unsigned int hash = 0;
|
|
bool ondir = mask & FAN_ONDIR;
|
|
struct pid *pid;
|
|
|
|
if ((fid_mode & FAN_REPORT_DIR_FID) && dirid) {
|
|
/*
|
|
* For certain events and group flags, report the child fid
|
|
* in addition to reporting the parent fid and maybe child name.
|
|
*/
|
|
if (fanotify_report_child_fid(fid_mode, mask) && id != dirid)
|
|
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) || !ondir) {
|
|
name_event = true;
|
|
}
|
|
|
|
/*
|
|
* In the special case of FAN_RENAME event, use the match_mask
|
|
* to determine if we need to report only the old parent+name,
|
|
* only the new parent+name or both.
|
|
* 'dirid' and 'file_name' are the old parent+name and
|
|
* 'moved' has the new parent+name.
|
|
*/
|
|
if (mask & FAN_RENAME) {
|
|
bool report_old, report_new;
|
|
|
|
if (WARN_ON_ONCE(!match_mask))
|
|
return NULL;
|
|
|
|
/* Report both old and new parent+name if sb watching */
|
|
report_old = report_new =
|
|
match_mask & (1U << FSNOTIFY_ITER_TYPE_SB);
|
|
report_old |=
|
|
match_mask & (1U << FSNOTIFY_ITER_TYPE_INODE);
|
|
report_new |=
|
|
match_mask & (1U << FSNOTIFY_ITER_TYPE_INODE2);
|
|
|
|
if (!report_old) {
|
|
/* Do not report old parent+name */
|
|
dirid = NULL;
|
|
file_name = NULL;
|
|
}
|
|
if (report_new) {
|
|
/* Report new parent+name */
|
|
moved = fsnotify_data_dentry(data, data_type);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 (fanotify_is_error_event(mask)) {
|
|
event = fanotify_alloc_error_event(group, fsid, data,
|
|
data_type, &hash);
|
|
} else if (name_event && (file_name || moved || child)) {
|
|
event = fanotify_alloc_name_event(dirid, fsid, file_name, child,
|
|
moved, &hash, gfp);
|
|
} else if (fid_mode) {
|
|
event = fanotify_alloc_fid_event(id, fsid, &hash, gfp);
|
|
} else {
|
|
event = fanotify_alloc_path_event(path, &hash, gfp);
|
|
}
|
|
|
|
if (!event)
|
|
goto out;
|
|
|
|
if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))
|
|
pid = get_pid(task_pid(current));
|
|
else
|
|
pid = get_pid(task_tgid(current));
|
|
|
|
/* Mix event info, FAN_ONDIR flag and pid into event merge key */
|
|
hash ^= hash_long((unsigned long)pid | ondir, FANOTIFY_EVENT_HASH_BITS);
|
|
fanotify_init_event(event, hash, mask);
|
|
event->pid = pid;
|
|
|
|
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)
|
|
{
|
|
struct fsnotify_mark *mark;
|
|
int type;
|
|
__kernel_fsid_t fsid = {};
|
|
|
|
fsnotify_foreach_iter_mark_type(iter_info, mark, type) {
|
|
struct fsnotify_mark_connector *conn;
|
|
|
|
conn = READ_ONCE(mark->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;
|
|
}
|
|
|
|
/*
|
|
* Add an event to hash table for faster merge.
|
|
*/
|
|
static void fanotify_insert_event(struct fsnotify_group *group,
|
|
struct fsnotify_event *fsn_event)
|
|
{
|
|
struct fanotify_event *event = FANOTIFY_E(fsn_event);
|
|
unsigned int bucket = fanotify_event_hash_bucket(group, event);
|
|
struct hlist_head *hlist = &group->fanotify_data.merge_hash[bucket];
|
|
|
|
assert_spin_locked(&group->notification_lock);
|
|
|
|
if (!fanotify_is_hashed_event(event->mask))
|
|
return;
|
|
|
|
pr_debug("%s: group=%p event=%p bucket=%u\n", __func__,
|
|
group, event, bucket);
|
|
|
|
hlist_add_head(&event->merge_list, hlist);
|
|
}
|
|
|
|
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 = {};
|
|
u32 match_mask = 0;
|
|
|
|
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(FAN_FS_ERROR != FS_ERROR);
|
|
BUILD_BUG_ON(FAN_RENAME != FS_RENAME);
|
|
|
|
BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 21);
|
|
|
|
mask = fanotify_group_event_mask(group, iter_info, &match_mask,
|
|
mask, data, data_type, dir);
|
|
if (!mask)
|
|
return 0;
|
|
|
|
pr_debug("%s: group=%p mask=%x report_mask=%x\n", __func__,
|
|
group, mask, match_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, match_mask);
|
|
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_insert_event(group, fsn_event, fanotify_merge,
|
|
fanotify_insert_event);
|
|
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)
|
|
{
|
|
kfree(group->fanotify_data.merge_hash);
|
|
if (group->fanotify_data.ucounts)
|
|
dec_ucount(group->fanotify_data.ucounts,
|
|
UCOUNT_FANOTIFY_GROUPS);
|
|
|
|
if (mempool_initialized(&group->fanotify_data.error_events_pool))
|
|
mempool_exit(&group->fanotify_data.error_events_pool);
|
|
}
|
|
|
|
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_error_event(struct fsnotify_group *group,
|
|
struct fanotify_event *event)
|
|
{
|
|
struct fanotify_error_event *fee = FANOTIFY_EE(event);
|
|
|
|
mempool_free(fee, &group->fanotify_data.error_events_pool);
|
|
}
|
|
|
|
static void fanotify_free_event(struct fsnotify_group *group,
|
|
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;
|
|
case FANOTIFY_EVENT_TYPE_FS_ERROR:
|
|
fanotify_free_error_event(group, event);
|
|
break;
|
|
default:
|
|
WARN_ON_ONCE(1);
|
|
}
|
|
}
|
|
|
|
static void fanotify_freeing_mark(struct fsnotify_mark *mark,
|
|
struct fsnotify_group *group)
|
|
{
|
|
if (!FAN_GROUP_FLAG(group, FAN_UNLIMITED_MARKS))
|
|
dec_ucount(group->fanotify_data.ucounts, UCOUNT_FANOTIFY_MARKS);
|
|
}
|
|
|
|
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,
|
|
.freeing_mark = fanotify_freeing_mark,
|
|
.free_mark = fanotify_free_mark,
|
|
};
|