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authorAmir Goldstein <amir73il@gmail.com>2020-07-16 11:42:26 +0300
committerJan Kara <jack@suse.cz>2020-07-28 00:24:00 +0300
commit83b7a59896dd24015a34b7f00027f0ff3747972f (patch)
treef908cc9e64fdfdb4618933989b45b7ecd72d69d3 /fs/notify
parent79cb299c7e181fad683bf6191edb8224b2412512 (diff)
downloadlinux-83b7a59896dd24015a34b7f00027f0ff3747972f.tar.xz
fanotify: add basic support for FAN_REPORT_DIR_FID
For now, the flag is mutually exclusive with FAN_REPORT_FID. Events include a single info record of type FAN_EVENT_INFO_TYPE_DFID with a directory file handle. For now, events are only reported for: - Directory modification events - Events on children of a watching directory - Events on directory objects Soon, we will add support for reporting the parent directory fid for events on non-directories with filesystem/mount mark and support for reporting both parent directory fid and child fid. Link: https://lore.kernel.org/r/20200716084230.30611-19-amir73il@gmail.com Signed-off-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify')
-rw-r--r--fs/notify/fanotify/fanotify.c34
-rw-r--r--fs/notify/fanotify/fanotify_user.c71
2 files changed, 93 insertions, 12 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 3baf93e998c1..fc2e1fab34af 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -223,7 +223,7 @@ out:
static u32 fanotify_group_event_mask(struct fsnotify_group *group,
struct fsnotify_iter_info *iter_info,
u32 event_mask, const void *data,
- int data_type)
+ int data_type, struct inode *dir)
{
__u32 marks_mask = 0, marks_ignored_mask = 0;
__u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS |
@@ -243,6 +243,10 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
/* Path type events are only relevant for files and dirs */
if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry))
return 0;
+ } else if (!(fid_mode & FAN_REPORT_FID)) {
+ /* Do we have a directory inode to report? */
+ if (!dir && !(event_mask & FS_ISDIR))
+ return 0;
}
fsnotify_foreach_obj_type(type) {
@@ -396,6 +400,28 @@ static struct inode *fanotify_fid_inode(u32 event_mask, const void *data,
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 (S_ISDIR(inode->i_mode))
+ return inode;
+
+ return dir;
+}
+
static struct fanotify_event *fanotify_alloc_path_event(const struct path *path,
gfp_t gfp)
{
@@ -491,10 +517,14 @@ static struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
struct fanotify_event *event = NULL;
gfp_t gfp = GFP_KERNEL_ACCOUNT;
struct inode *id = fanotify_fid_inode(mask, data, data_type, dir);
+ struct inode *dirid = fanotify_dfid_inode(mask, data, data_type, dir);
const struct path *path = fsnotify_data_path(data, data_type);
unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
bool name_event = false;
+ if ((fid_mode & FAN_REPORT_DIR_FID) && dirid)
+ id = dirid;
+
/*
* For queues with unlimited length lost events are not expected and
* can possibly have security implications. Avoid losing events when
@@ -605,7 +635,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
mask = fanotify_group_event_mask(group, iter_info, mask, data,
- data_type);
+ data_type, dir);
if (!mask)
return 0;
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 3842ef00b52e..e494400711c9 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -216,7 +216,7 @@ static int process_access_response(struct fsnotify_group *group,
}
static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
- const char *name, size_t name_len,
+ int info_type, const char *name, size_t name_len,
char __user *buf, size_t count)
{
struct fanotify_event_info_fid info = { };
@@ -229,7 +229,7 @@ static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
pr_debug("%s: fh_len=%zu name_len=%zu, info_len=%zu, count=%zu\n",
__func__, fh_len, name_len, info_len, count);
- if (!fh_len || (name && !name_len))
+ if (!fh_len)
return 0;
if (WARN_ON_ONCE(len < sizeof(info) || len > count))
@@ -239,8 +239,21 @@ static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
* Copy event info fid header followed by variable sized file handle
* and optionally followed by variable sized filename.
*/
- info.hdr.info_type = name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
- FAN_EVENT_INFO_TYPE_FID;
+ switch (info_type) {
+ case FAN_EVENT_INFO_TYPE_FID:
+ case FAN_EVENT_INFO_TYPE_DFID:
+ if (WARN_ON_ONCE(name_len))
+ return -EFAULT;
+ break;
+ case FAN_EVENT_INFO_TYPE_DFID_NAME:
+ if (WARN_ON_ONCE(!name || !name_len))
+ return -EFAULT;
+ break;
+ default:
+ return -EFAULT;
+ }
+
+ info.hdr.info_type = info_type;
info.hdr.len = len;
info.fsid = *fsid;
if (copy_to_user(buf, &info, sizeof(info)))
@@ -304,8 +317,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
struct fanotify_event_metadata metadata;
struct path *path = fanotify_event_path(event);
struct fanotify_info *info = fanotify_event_info(event);
+ unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
struct file *f = NULL;
int ret, fd = FAN_NOFD;
+ int info_type = 0;
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
@@ -346,9 +361,10 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
/* Event info records order is: dir fid + name, child fid */
if (fanotify_event_dir_fh_len(event)) {
+ info_type = FAN_EVENT_INFO_TYPE_DFID_NAME;
ret = copy_info_to_user(fanotify_event_fsid(event),
fanotify_info_dir_fh(info),
- fanotify_info_name(info),
+ info_type, fanotify_info_name(info),
info->name_len, buf, count);
if (ret < 0)
return ret;
@@ -358,9 +374,33 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
}
if (fanotify_event_object_fh_len(event)) {
+ if (fid_mode == FAN_REPORT_FID || info_type) {
+ /*
+ * With only group flag FAN_REPORT_FID only type FID is
+ * reported. Second info record type is always FID.
+ */
+ info_type = FAN_EVENT_INFO_TYPE_FID;
+ } else if ((event->mask & ALL_FSNOTIFY_DIRENT_EVENTS) ||
+ (event->mask & FAN_ONDIR)) {
+ /*
+ * With group flag FAN_REPORT_DIR_FID, a single info
+ * record has type DFID for directory entry modification
+ * event and for event on a directory.
+ */
+ info_type = FAN_EVENT_INFO_TYPE_DFID;
+ } else {
+ /*
+ * With group flags FAN_REPORT_DIR_FID|FAN_REPORT_FID,
+ * a single info record has type FID for event on a
+ * non-directory, when there is no directory to report.
+ * For example, on FAN_DELETE_SELF event.
+ */
+ info_type = FAN_EVENT_INFO_TYPE_FID;
+ }
+
ret = copy_info_to_user(fanotify_event_fsid(event),
fanotify_event_object_fh(event),
- NULL, 0, buf, count);
+ info_type, NULL, 0, buf, count);
if (ret < 0)
return ret;
@@ -861,6 +901,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
struct fsnotify_group *group;
int f_flags, fd;
struct user_struct *user;
+ unsigned int fid_mode = flags & FANOTIFY_FID_BITS;
+ unsigned int class = flags & FANOTIFY_CLASS_BITS;
pr_debug("%s: flags=%x event_f_flags=%x\n",
__func__, flags, event_f_flags);
@@ -887,10 +929,19 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
return -EINVAL;
}
- if ((flags & FANOTIFY_FID_BITS) &&
- (flags & FANOTIFY_CLASS_BITS) != FAN_CLASS_NOTIF)
+ if (fid_mode && class != FAN_CLASS_NOTIF)
return -EINVAL;
+ /* Reporting either object fid or dir fid */
+ switch (fid_mode) {
+ case 0:
+ case FAN_REPORT_FID:
+ case FAN_REPORT_DIR_FID:
+ break;
+ default:
+ return -EINVAL;
+ }
+
user = get_current_user();
if (atomic_read(&user->fanotify_listeners) > FANOTIFY_DEFAULT_MAX_LISTENERS) {
free_uid(user);
@@ -926,7 +977,7 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
group->fanotify_data.f_flags = event_f_flags;
init_waitqueue_head(&group->fanotify_data.access_waitq);
INIT_LIST_HEAD(&group->fanotify_data.access_list);
- switch (flags & FANOTIFY_CLASS_BITS) {
+ switch (class) {
case FAN_CLASS_NOTIF:
group->priority = FS_PRIO_0;
break;
@@ -1236,7 +1287,7 @@ COMPAT_SYSCALL_DEFINE6(fanotify_mark,
*/
static int __init fanotify_user_setup(void)
{
- BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 8);
+ BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 9);
BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,