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Diffstat (limited to 'fs/notify/fanotify/fanotify.c')
-rw-r--r--fs/notify/fanotify/fanotify.c267
1 files changed, 225 insertions, 42 deletions
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 3723f3d18d20..6b9c27548997 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -13,22 +13,40 @@
#include <linux/wait.h>
#include <linux/audit.h>
#include <linux/sched/mm.h>
+#include <linux/statfs.h>
#include "fanotify.h"
static bool should_merge(struct fsnotify_event *old_fsn,
struct fsnotify_event *new_fsn)
{
- struct fanotify_event_info *old, *new;
+ struct fanotify_event *old, *new;
pr_debug("%s: old=%p new=%p\n", __func__, old_fsn, new_fsn);
old = FANOTIFY_E(old_fsn);
new = FANOTIFY_E(new_fsn);
- if (old_fsn->inode == new_fsn->inode && old->pid == new->pid &&
- old->path.mnt == new->path.mnt &&
- old->path.dentry == new->path.dentry)
- return true;
+ if (old_fsn->inode != new_fsn->inode || old->pid != new->pid ||
+ old->fh_type != new->fh_type || old->fh_len != new->fh_len)
+ return false;
+
+ if (fanotify_event_has_path(old)) {
+ return old->path.mnt == new->path.mnt &&
+ old->path.dentry == new->path.dentry;
+ } else if (fanotify_event_has_fid(old)) {
+ /*
+ * We want to merge many dirent events in the same dir (i.e.
+ * creates/unlinks/renames), but we do not want to merge dirent
+ * events referring to subdirs with dirent events referring to
+ * non subdirs, otherwise, user won't be able to tell from a
+ * mask FAN_CREATE|FAN_DELETE|FAN_ONDIR if it describes mkdir+
+ * unlink pair or rmdir+create pair of events.
+ */
+ return (old->mask & FS_ISDIR) == (new->mask & FS_ISDIR) &&
+ fanotify_fid_equal(&old->fid, &new->fid, old->fh_len);
+ }
+
+ /* Do not merge events if we failed to encode fid */
return false;
}
@@ -36,20 +54,22 @@ static bool should_merge(struct fsnotify_event *old_fsn,
static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
{
struct fsnotify_event *test_event;
+ struct fanotify_event *new;
pr_debug("%s: list=%p event=%p\n", __func__, list, event);
+ new = FANOTIFY_E(event);
/*
* Don't merge a permission event with any other event so that we know
* the event structure we have created in fanotify_handle_event() is the
* one we should check for permission response.
*/
- if (fanotify_is_perm_event(event->mask))
+ if (fanotify_is_perm_event(new->mask))
return 0;
list_for_each_entry_reverse(test_event, list, list) {
if (should_merge(test_event, event)) {
- test_event->mask |= event->mask;
+ FANOTIFY_E(test_event)->mask |= new->mask;
return 1;
}
}
@@ -57,15 +77,44 @@ static int fanotify_merge(struct list_head *list, struct fsnotify_event *event)
return 0;
}
+/*
+ * Wait for response to permission event. The function also takes care of
+ * freeing the permission event (or offloads that in case the wait is canceled
+ * by a signal). The function returns 0 in case access got allowed by userspace,
+ * -EPERM in case userspace disallowed the access, and -ERESTARTSYS in case
+ * the wait got interrupted by a signal.
+ */
static int fanotify_get_response(struct fsnotify_group *group,
- struct fanotify_perm_event_info *event,
+ struct fanotify_perm_event *event,
struct fsnotify_iter_info *iter_info)
{
int ret;
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
- wait_event(group->fanotify_data.access_waitq, event->response);
+ ret = wait_event_killable(group->fanotify_data.access_waitq,
+ event->state == FAN_EVENT_ANSWERED);
+ /* Signal pending? */
+ if (ret < 0) {
+ spin_lock(&group->notification_lock);
+ /* Event reported to userspace and no answer yet? */
+ if (event->state == FAN_EVENT_REPORTED) {
+ /* Event will get freed once userspace answers to it */
+ event->state = FAN_EVENT_CANCELED;
+ spin_unlock(&group->notification_lock);
+ return ret;
+ }
+ /* Event not yet reported? Just remove it. */
+ if (event->state == FAN_EVENT_INIT)
+ fsnotify_remove_queued_event(group, &event->fae.fse);
+ /*
+ * Event may be also answered in case signal delivery raced
+ * with wakeup. In that case we have nothing to do besides
+ * freeing the event and reporting error.
+ */
+ spin_unlock(&group->notification_lock);
+ goto out;
+ }
/* userspace responded, convert to something usable */
switch (event->response & ~FAN_AUDIT) {
@@ -81,11 +130,11 @@ static int fanotify_get_response(struct fsnotify_group *group,
if (event->response & FAN_AUDIT)
audit_fanotify(event->response & ~FAN_AUDIT);
- event->response = 0;
-
pr_debug("%s: group=%p event=%p about to return ret=%d\n", __func__,
group, event, ret);
-
+out:
+ fsnotify_destroy_event(group, &event->fae.fse);
+
return ret;
}
@@ -95,11 +144,13 @@ static int fanotify_get_response(struct fsnotify_group *group,
* been included within the event mask, but have not been explicitly
* requested by the user, will not be present in the returned mask.
*/
-static u32 fanotify_group_event_mask(struct fsnotify_iter_info *iter_info,
- u32 event_mask, const void *data,
- int data_type)
+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)
{
__u32 marks_mask = 0, marks_ignored_mask = 0;
+ __u32 test_mask, user_mask = FANOTIFY_OUTGOING_EVENTS;
const struct path *path = data;
struct fsnotify_mark *mark;
int type;
@@ -107,14 +158,14 @@ static u32 fanotify_group_event_mask(struct fsnotify_iter_info *iter_info,
pr_debug("%s: report_mask=%x mask=%x data=%p data_type=%d\n",
__func__, iter_info->report_mask, event_mask, data, data_type);
- /* If we don't have enough info to send an event to userspace say no */
- if (data_type != FSNOTIFY_EVENT_PATH)
- return 0;
-
- /* Sorry, fanotify only gives a damn about files and dirs */
- if (!d_is_reg(path->dentry) &&
- !d_can_lookup(path->dentry))
- return 0;
+ if (!FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+ /* Do we have path to open a file descriptor? */
+ if (data_type != FSNOTIFY_EVENT_PATH)
+ return 0;
+ /* Path type events are only relevant for files and dirs */
+ if (!d_is_reg(path->dentry) && !d_can_lookup(path->dentry))
+ return 0;
+ }
fsnotify_foreach_obj_type(type) {
if (!fsnotify_iter_should_report_type(iter_info, type))
@@ -133,20 +184,106 @@ static u32 fanotify_group_event_mask(struct fsnotify_iter_info *iter_info,
marks_ignored_mask |= mark->ignored_mask;
}
- if (d_is_dir(path->dentry) &&
+ test_mask = event_mask & marks_mask & ~marks_ignored_mask;
+
+ /*
+ * dirent modification events (create/delete/move) do not carry the
+ * child entry name/inode information. Instead, we report FAN_ONDIR
+ * for mkdir/rmdir so user can differentiate them from creat/unlink.
+ *
+ * For backward compatibility and consistency, do not report FAN_ONDIR
+ * to user in legacy fanotify mode (reporting fd) and report FAN_ONDIR
+ * to user in FAN_REPORT_FID mode for all event types.
+ */
+ if (FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+ /* Do not report FAN_ONDIR without any event */
+ if (!(test_mask & ~FAN_ONDIR))
+ return 0;
+ } else {
+ user_mask &= ~FAN_ONDIR;
+ }
+
+ if (event_mask & FS_ISDIR &&
!(marks_mask & FS_ISDIR & ~marks_ignored_mask))
return 0;
- return event_mask & FANOTIFY_OUTGOING_EVENTS & marks_mask &
- ~marks_ignored_mask;
+ return test_mask & user_mask;
+}
+
+static int fanotify_encode_fid(struct fanotify_event *event,
+ struct inode *inode, gfp_t gfp,
+ __kernel_fsid_t *fsid)
+{
+ struct fanotify_fid *fid = &event->fid;
+ int dwords, bytes = 0;
+ int err, type;
+
+ fid->ext_fh = NULL;
+ dwords = 0;
+ err = -ENOENT;
+ type = exportfs_encode_inode_fh(inode, NULL, &dwords, NULL);
+ if (!dwords)
+ goto out_err;
+
+ bytes = dwords << 2;
+ if (bytes > FANOTIFY_INLINE_FH_LEN) {
+ /* Treat failure to allocate fh as failure to allocate event */
+ err = -ENOMEM;
+ fid->ext_fh = kmalloc(bytes, gfp);
+ if (!fid->ext_fh)
+ goto out_err;
+ }
+
+ type = exportfs_encode_inode_fh(inode, fanotify_fid_fh(fid, bytes),
+ &dwords, NULL);
+ err = -EINVAL;
+ if (!type || type == FILEID_INVALID || bytes != dwords << 2)
+ goto out_err;
+
+ fid->fsid = *fsid;
+ event->fh_len = bytes;
+
+ return type;
+
+out_err:
+ pr_warn_ratelimited("fanotify: failed to encode fid (fsid=%x.%x, "
+ "type=%d, bytes=%d, err=%i)\n",
+ fsid->val[0], fsid->val[1], type, bytes, err);
+ kfree(fid->ext_fh);
+ fid->ext_fh = NULL;
+ event->fh_len = 0;
+
+ return FILEID_INVALID;
}
-struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group,
- struct inode *inode, u32 mask,
- const struct path *path)
+/*
+ * The inode to use as identifier when reporting fid depends on the event.
+ * Report the modified directory inode on dirent modification events.
+ * Report the "victim" inode otherwise.
+ * For example:
+ * FS_ATTRIB reports the child inode even if reported on a watched parent.
+ * FS_CREATE reports the modified dir inode and not the created inode.
+ */
+static struct inode *fanotify_fid_inode(struct inode *to_tell, u32 event_mask,
+ const void *data, int data_type)
{
- struct fanotify_event_info *event = NULL;
+ if (event_mask & ALL_FSNOTIFY_DIRENT_EVENTS)
+ return to_tell;
+ else if (data_type == FSNOTIFY_EVENT_INODE)
+ return (struct inode *)data;
+ else if (data_type == FSNOTIFY_EVENT_PATH)
+ return d_inode(((struct path *)data)->dentry);
+ return NULL;
+}
+
+struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
+ struct inode *inode, u32 mask,
+ const void *data, int data_type,
+ __kernel_fsid_t *fsid)
+{
+ struct fanotify_event *event = NULL;
gfp_t gfp = GFP_KERNEL_ACCOUNT;
+ struct inode *id = fanotify_fid_inode(inode, mask, data, data_type);
/*
* For queues with unlimited length lost events are not expected and
@@ -160,28 +297,36 @@ struct fanotify_event_info *fanotify_alloc_event(struct fsnotify_group *group,
memalloc_use_memcg(group->memcg);
if (fanotify_is_perm_event(mask)) {
- struct fanotify_perm_event_info *pevent;
+ struct fanotify_perm_event *pevent;
pevent = kmem_cache_alloc(fanotify_perm_event_cachep, gfp);
if (!pevent)
goto out;
event = &pevent->fae;
pevent->response = 0;
+ pevent->state = FAN_EVENT_INIT;
goto init;
}
event = kmem_cache_alloc(fanotify_event_cachep, gfp);
if (!event)
goto out;
init: __maybe_unused
- fsnotify_init_event(&event->fse, inode, mask);
+ fsnotify_init_event(&event->fse, inode);
+ event->mask = mask;
if (FAN_GROUP_FLAG(group, FAN_REPORT_TID))
event->pid = get_pid(task_pid(current));
else
event->pid = get_pid(task_tgid(current));
- if (path) {
- event->path = *path;
+ event->fh_len = 0;
+ if (id && FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+ /* Report the event without a file identifier on encode error */
+ event->fh_type = fanotify_encode_fid(event, id, gfp, fsid);
+ } else if (data_type == FSNOTIFY_EVENT_PATH) {
+ event->fh_type = FILEID_ROOT;
+ event->path = *((struct path *)data);
path_get(&event->path);
} else {
+ event->fh_type = FILEID_INVALID;
event->path.mnt = NULL;
event->path.dentry = NULL;
}
@@ -190,6 +335,29 @@ out:
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) {
+ if (!fsnotify_iter_should_report_type(iter_info, type))
+ continue;
+
+ fsid = iter_info->marks[type]->connector->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,
struct inode *inode,
u32 mask, const void *data, int data_type,
@@ -197,14 +365,22 @@ static int fanotify_handle_event(struct fsnotify_group *group,
struct fsnotify_iter_info *iter_info)
{
int ret = 0;
- struct fanotify_event_info *event;
+ 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);
@@ -213,9 +389,10 @@ static int fanotify_handle_event(struct fsnotify_group *group,
BUILD_BUG_ON(FAN_OPEN_EXEC != FS_OPEN_EXEC);
BUILD_BUG_ON(FAN_OPEN_EXEC_PERM != FS_OPEN_EXEC_PERM);
- BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 12);
+ BUILD_BUG_ON(HWEIGHT32(ALL_FANOTIFY_EVENT_BITS) != 19);
- mask = fanotify_group_event_mask(iter_info, mask, data, data_type);
+ mask = fanotify_group_event_mask(group, iter_info, mask, data,
+ data_type);
if (!mask)
return 0;
@@ -231,7 +408,11 @@ static int fanotify_handle_event(struct fsnotify_group *group,
return 0;
}
- event = fanotify_alloc_event(group, inode, mask, data);
+ if (FAN_GROUP_FLAG(group, FAN_REPORT_FID))
+ fsid = fanotify_get_fsid(iter_info);
+
+ event = fanotify_alloc_event(group, inode, mask, data, data_type,
+ &fsid);
ret = -ENOMEM;
if (unlikely(!event)) {
/*
@@ -255,7 +436,6 @@ static int fanotify_handle_event(struct fsnotify_group *group,
} else if (fanotify_is_perm_event(mask)) {
ret = fanotify_get_response(group, FANOTIFY_PE(fsn_event),
iter_info);
- fsnotify_destroy_event(group, fsn_event);
}
finish:
if (fanotify_is_perm_event(mask))
@@ -275,12 +455,15 @@ static void fanotify_free_group_priv(struct fsnotify_group *group)
static void fanotify_free_event(struct fsnotify_event *fsn_event)
{
- struct fanotify_event_info *event;
+ struct fanotify_event *event;
event = FANOTIFY_E(fsn_event);
- path_put(&event->path);
+ if (fanotify_event_has_path(event))
+ path_put(&event->path);
+ else if (fanotify_event_has_ext_fh(event))
+ kfree(event->fid.ext_fh);
put_pid(event->pid);
- if (fanotify_is_perm_event(fsn_event->mask)) {
+ if (fanotify_is_perm_event(event->mask)) {
kmem_cache_free(fanotify_perm_event_cachep,
FANOTIFY_PE(fsn_event));
return;