// SPDX-License-Identifier: GPL-2.0
#include <linux/fanotify.h>
#include <linux/fcntl.h>
+#include <linux/fdtable.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/anon_inodes.h>
struct kmem_cache *fanotify_perm_event_cachep __read_mostly;
#define FANOTIFY_EVENT_ALIGN 4
-#define FANOTIFY_INFO_HDR_LEN \
+#define FANOTIFY_FID_INFO_HDR_LEN \
(sizeof(struct fanotify_event_info_fid) + sizeof(struct file_handle))
+#define FANOTIFY_PIDFD_INFO_HDR_LEN \
+ sizeof(struct fanotify_event_info_pidfd)
static int fanotify_fid_info_len(int fh_len, int name_len)
{
if (name_len)
info_len += name_len + 1;
- return roundup(FANOTIFY_INFO_HDR_LEN + info_len, FANOTIFY_EVENT_ALIGN);
+ return roundup(FANOTIFY_FID_INFO_HDR_LEN + info_len,
+ FANOTIFY_EVENT_ALIGN);
}
-static int fanotify_event_info_len(unsigned int fid_mode,
+static int fanotify_event_info_len(unsigned int info_mode,
struct fanotify_event *event)
{
struct fanotify_info *info = fanotify_event_info(event);
if (dir_fh_len) {
info_len += fanotify_fid_info_len(dir_fh_len, info->name_len);
- } else if ((fid_mode & FAN_REPORT_NAME) && (event->mask & FAN_ONDIR)) {
+ } else if ((info_mode & FAN_REPORT_NAME) &&
+ (event->mask & FAN_ONDIR)) {
/*
* With group flag FAN_REPORT_NAME, if name was not recorded in
* event on a directory, we will report the name ".".
dot_len = 1;
}
+ if (info_mode & FAN_REPORT_PIDFD)
+ info_len += FANOTIFY_PIDFD_INFO_HDR_LEN;
+
if (fh_len)
info_len += fanotify_fid_info_len(fh_len, dot_len);
size_t event_size = FAN_EVENT_METADATA_LEN;
struct fanotify_event *event = NULL;
struct fsnotify_event *fsn_event;
- unsigned int fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
+ unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
pr_debug("%s: group=%p count=%zd\n", __func__, group, count);
goto out;
event = FANOTIFY_E(fsn_event);
- if (fid_mode)
- event_size += fanotify_event_info_len(fid_mode, event);
+ if (info_mode)
+ event_size += fanotify_event_info_len(info_mode, event);
if (event_size > count) {
event = ERR_PTR(-EINVAL);
return -ENOENT;
}
-static int copy_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
- int info_type, const char *name, size_t name_len,
- char __user *buf, size_t count)
+static int copy_fid_info_to_user(__kernel_fsid_t *fsid, struct fanotify_fh *fh,
+ int info_type, const char *name,
+ size_t name_len,
+ char __user *buf, size_t count)
{
struct fanotify_event_info_fid info = { };
struct file_handle handle = { };
return info_len;
}
+static int copy_pidfd_info_to_user(int pidfd,
+ char __user *buf,
+ size_t count)
+{
+ struct fanotify_event_info_pidfd info = { };
+ size_t info_len = FANOTIFY_PIDFD_INFO_HDR_LEN;
+
+ if (WARN_ON_ONCE(info_len > count))
+ return -EFAULT;
+
+ info.hdr.info_type = FAN_EVENT_INFO_TYPE_PIDFD;
+ info.hdr.len = info_len;
+ info.pidfd = pidfd;
+
+ if (copy_to_user(buf, &info, info_len))
+ return -EFAULT;
+
+ return info_len;
+}
+
+static int copy_info_records_to_user(struct fanotify_event *event,
+ struct fanotify_info *info,
+ unsigned int info_mode, int pidfd,
+ char __user *buf, size_t count)
+{
+ int ret, total_bytes = 0, info_type = 0;
+ unsigned int fid_mode = info_mode & FANOTIFY_FID_BITS;
+ unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
+
+ /*
+ * Event info records order is as follows: dir fid + name, child fid.
+ */
+ if (fanotify_event_dir_fh_len(event)) {
+ info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
+ FAN_EVENT_INFO_TYPE_DFID;
+ ret = copy_fid_info_to_user(fanotify_event_fsid(event),
+ fanotify_info_dir_fh(info),
+ info_type,
+ fanotify_info_name(info),
+ info->name_len, buf, count);
+ if (ret < 0)
+ return ret;
+
+ buf += ret;
+ count -= ret;
+ total_bytes += ret;
+ }
+
+ if (fanotify_event_object_fh_len(event)) {
+ const char *dot = NULL;
+ int dot_len = 0;
+
+ 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 ((fid_mode & FAN_REPORT_NAME) &&
+ (event->mask & FAN_ONDIR)) {
+ /*
+ * With group flag FAN_REPORT_NAME, if name was not
+ * recorded in an event on a directory, report the name
+ * "." with info type DFID_NAME.
+ */
+ info_type = FAN_EVENT_INFO_TYPE_DFID_NAME;
+ dot = ".";
+ dot_len = 1;
+ } 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_fid_info_to_user(fanotify_event_fsid(event),
+ fanotify_event_object_fh(event),
+ info_type, dot, dot_len,
+ buf, count);
+ if (ret < 0)
+ return ret;
+
+ buf += ret;
+ count -= ret;
+ total_bytes += ret;
+ }
+
+ if (pidfd_mode) {
+ ret = copy_pidfd_info_to_user(pidfd, buf, count);
+ if (ret < 0)
+ return ret;
+
+ buf += ret;
+ count -= ret;
+ total_bytes += ret;
+ }
+
+ return total_bytes;
+}
+
static ssize_t copy_event_to_user(struct fsnotify_group *group,
struct fanotify_event *event,
char __user *buf, size_t count)
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);
+ unsigned int info_mode = FAN_GROUP_FLAG(group, FANOTIFY_INFO_MODES);
+ unsigned int pidfd_mode = info_mode & FAN_REPORT_PIDFD;
struct file *f = NULL;
- int ret, fd = FAN_NOFD;
- int info_type = 0;
+ int ret, pidfd = FAN_NOPIDFD, fd = FAN_NOFD;
pr_debug("%s: group=%p event=%p\n", __func__, group, event);
metadata.event_len = FAN_EVENT_METADATA_LEN +
- fanotify_event_info_len(fid_mode, event);
+ fanotify_event_info_len(info_mode, event);
metadata.metadata_len = FAN_EVENT_METADATA_LEN;
metadata.vers = FANOTIFY_METADATA_VERSION;
metadata.reserved = 0;
}
metadata.fd = fd;
+ if (pidfd_mode) {
+ /*
+ * Complain if the FAN_REPORT_PIDFD and FAN_REPORT_TID mutual
+ * exclusion is ever lifted. At the time of incoporating pidfd
+ * support within fanotify, the pidfd API only supported the
+ * creation of pidfds for thread-group leaders.
+ */
+ WARN_ON_ONCE(FAN_GROUP_FLAG(group, FAN_REPORT_TID));
+
+ /*
+ * The PIDTYPE_TGID check for an event->pid is performed
+ * preemptively in an attempt to catch out cases where the event
+ * listener reads events after the event generating process has
+ * already terminated. Report FAN_NOPIDFD to the event listener
+ * in those cases, with all other pidfd creation errors being
+ * reported as FAN_EPIDFD.
+ */
+ if (metadata.pid == 0 ||
+ !pid_has_task(event->pid, PIDTYPE_TGID)) {
+ pidfd = FAN_NOPIDFD;
+ } else {
+ pidfd = pidfd_create(event->pid, 0);
+ if (pidfd < 0)
+ pidfd = FAN_EPIDFD;
+ }
+ }
+
ret = -EFAULT;
/*
* Sanity check copy size in case get_one_event() and
if (f)
fd_install(fd, f);
- /* Event info records order is: dir fid + name, child fid */
- if (fanotify_event_dir_fh_len(event)) {
- info_type = info->name_len ? FAN_EVENT_INFO_TYPE_DFID_NAME :
- FAN_EVENT_INFO_TYPE_DFID;
- ret = copy_info_to_user(fanotify_event_fsid(event),
- fanotify_info_dir_fh(info),
- info_type, fanotify_info_name(info),
- info->name_len, buf, count);
+ if (info_mode) {
+ ret = copy_info_records_to_user(event, info, info_mode, pidfd,
+ buf, count);
if (ret < 0)
goto out_close_fd;
-
- buf += ret;
- count -= ret;
- }
-
- if (fanotify_event_object_fh_len(event)) {
- const char *dot = NULL;
- int dot_len = 0;
-
- 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 ((fid_mode & FAN_REPORT_NAME) &&
- (event->mask & FAN_ONDIR)) {
- /*
- * With group flag FAN_REPORT_NAME, if name was not
- * recorded in an event on a directory, report the
- * name "." with info type DFID_NAME.
- */
- info_type = FAN_EVENT_INFO_TYPE_DFID_NAME;
- dot = ".";
- dot_len = 1;
- } 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),
- info_type, dot, dot_len, buf, count);
- if (ret < 0)
- goto out_close_fd;
-
- buf += ret;
- count -= ret;
}
return metadata.event_len;
put_unused_fd(fd);
fput(f);
}
+
+ if (pidfd >= 0)
+ close_fd(pidfd);
+
return ret;
}
#endif
return -EINVAL;
+ /*
+ * A pidfd can only be returned for a thread-group leader; thus
+ * FAN_REPORT_PIDFD and FAN_REPORT_TID need to remain mutually
+ * exclusive.
+ */
+ if ((flags & FAN_REPORT_PIDFD) && (flags & FAN_REPORT_TID))
+ return -EINVAL;
+
if (event_f_flags & ~FANOTIFY_INIT_ALL_EVENT_F_BITS)
return -EINVAL;
FANOTIFY_DEFAULT_MAX_USER_MARKS);
BUILD_BUG_ON(FANOTIFY_INIT_FLAGS & FANOTIFY_INTERNAL_GROUP_FLAGS);
- BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 10);
+ BUILD_BUG_ON(HWEIGHT32(FANOTIFY_INIT_FLAGS) != 11);
BUILD_BUG_ON(HWEIGHT32(FANOTIFY_MARK_FLAGS) != 9);
fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
}
}
+static void fsnotify_get_inode_ref(struct inode *inode)
+{
+ ihold(inode);
+ atomic_long_inc(&inode->i_sb->s_fsnotify_connectors);
+}
+
+static void fsnotify_put_inode_ref(struct inode *inode)
+{
+ struct super_block *sb = inode->i_sb;
+
+ iput(inode);
+ if (atomic_long_dec_and_test(&sb->s_fsnotify_connectors))
+ wake_up_var(&sb->s_fsnotify_connectors);
+}
+
+static void fsnotify_get_sb_connectors(struct fsnotify_mark_connector *conn)
+{
+ struct super_block *sb = fsnotify_connector_sb(conn);
+
+ if (sb)
+ atomic_long_inc(&sb->s_fsnotify_connectors);
+}
+
+static void fsnotify_put_sb_connectors(struct fsnotify_mark_connector *conn)
+{
+ struct super_block *sb = fsnotify_connector_sb(conn);
+
+ if (sb && atomic_long_dec_and_test(&sb->s_fsnotify_connectors))
+ wake_up_var(&sb->s_fsnotify_connectors);
+}
+
static void *fsnotify_detach_connector_from_object(
struct fsnotify_mark_connector *conn,
unsigned int *type)
if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) {
inode = fsnotify_conn_inode(conn);
inode->i_fsnotify_mask = 0;
- atomic_long_inc(&inode->i_sb->s_fsnotify_inode_refs);
} else if (conn->type == FSNOTIFY_OBJ_TYPE_VFSMOUNT) {
fsnotify_conn_mount(conn)->mnt_fsnotify_mask = 0;
} else if (conn->type == FSNOTIFY_OBJ_TYPE_SB) {
fsnotify_conn_sb(conn)->s_fsnotify_mask = 0;
}
+ fsnotify_put_sb_connectors(conn);
rcu_assign_pointer(*(conn->obj), NULL);
conn->obj = NULL;
conn->type = FSNOTIFY_OBJ_TYPE_DETACHED;
/* Drop object reference originally held by a connector */
static void fsnotify_drop_object(unsigned int type, void *objp)
{
- struct inode *inode;
- struct super_block *sb;
-
if (!objp)
return;
/* Currently only inode references are passed to be dropped */
if (WARN_ON_ONCE(type != FSNOTIFY_OBJ_TYPE_INODE))
return;
- inode = objp;
- sb = inode->i_sb;
- iput(inode);
- if (atomic_long_dec_and_test(&sb->s_fsnotify_inode_refs))
- wake_up_var(&sb->s_fsnotify_inode_refs);
+ fsnotify_put_inode_ref(objp);
}
void fsnotify_put_mark(struct fsnotify_mark *mark)
conn->fsid.val[0] = conn->fsid.val[1] = 0;
conn->flags = 0;
}
- if (conn->type == FSNOTIFY_OBJ_TYPE_INODE)
- inode = igrab(fsnotify_conn_inode(conn));
+ if (conn->type == FSNOTIFY_OBJ_TYPE_INODE) {
+ inode = fsnotify_conn_inode(conn);
+ fsnotify_get_inode_ref(inode);
+ }
+ fsnotify_get_sb_connectors(conn);
+
/*
* cmpxchg() provides the barrier so that readers of *connp can see
* only initialized structure
if (cmpxchg(connp, NULL, conn)) {
/* Someone else created list structure for us */
if (inode)
- iput(inode);
+ fsnotify_put_inode_ref(inode);
kmem_cache_free(fsnotify_mark_connector_cachep, conn);
}
projects / linux-2.6-microblaze.git / commitdiff