#include <linux/wait.h>
#include <linux/audit.h>
#include <linux/sched/mm.h>
+#include <linux/statfs.h>
#include "fanotify.h"
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)) {
+ return fanotify_fid_equal(&old->fid, &new->fid, old->fh_len);
+ }
+
+ /* Do not merge events if we failed to encode fid */
return false;
}
~marks_ignored_mask;
}
+static int fanotify_encode_fid(struct fanotify_event *event,
+ const struct path *path, gfp_t gfp)
+{
+ struct fanotify_fid *fid = &event->fid;
+ int dwords, bytes = 0;
+ struct kstatfs stat;
+ int err, type;
+
+ stat.f_fsid.val[0] = stat.f_fsid.val[1] = 0;
+ fid->ext_fh = NULL;
+ dwords = 0;
+ err = -ENOENT;
+ type = exportfs_encode_inode_fh(d_inode(path->dentry), NULL, &dwords,
+ NULL);
+ if (!dwords)
+ goto out_err;
+
+ err = vfs_statfs(path, &stat);
+ if (err)
+ 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(d_inode(path->dentry),
+ fanotify_fid_fh(fid, bytes), &dwords,
+ NULL);
+ err = -EINVAL;
+ if (!type || type == FILEID_INVALID || bytes != dwords << 2)
+ goto out_err;
+
+ fid->fsid = stat.f_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",
+ stat.f_fsid.val[0], stat.f_fsid.val[1],
+ type, bytes, err);
+ kfree(fid->ext_fh);
+ fid->ext_fh = NULL;
+ event->fh_len = 0;
+
+ return FILEID_INVALID;
+}
+
struct fanotify_event *fanotify_alloc_event(struct fsnotify_group *group,
struct inode *inode, u32 mask,
const struct path *path)
event->pid = get_pid(task_pid(current));
else
event->pid = get_pid(task_tgid(current));
- if (path) {
+ event->fh_len = 0;
+ if (path && FAN_GROUP_FLAG(group, FAN_REPORT_FID)) {
+ /* Report the event without a file identifier on encode error */
+ event->fh_type = fanotify_encode_fid(event, path, gfp);
+ } else if (path) {
+ event->fh_type = FILEID_ROOT;
event->path = *path;
path_get(&event->path);
} else {
+ event->fh_type = FILEID_INVALID;
event->path.mnt = NULL;
event->path.dentry = NULL;
}
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(event->mask)) {
kmem_cache_free(fanotify_perm_event_cachep,
#include <linux/fsnotify_backend.h>
#include <linux/path.h>
#include <linux/slab.h>
+#include <linux/exportfs.h>
extern struct kmem_cache *fanotify_mark_cache;
extern struct kmem_cache *fanotify_event_cachep;
extern struct kmem_cache *fanotify_perm_event_cachep;
/*
+ * 3 dwords are sufficient for most local fs (64bit ino, 32bit generation).
+ * For 32bit arch, fid increases the size of fanotify_event by 12 bytes and
+ * fh_* fields increase the size of fanotify_event by another 4 bytes.
+ * For 64bit arch, fid increases the size of fanotify_fid by 8 bytes and
+ * fh_* fields are packed in a hole after mask.
+ */
+#if BITS_PER_LONG == 32
+#define FANOTIFY_INLINE_FH_LEN (3 << 2)
+#else
+#define FANOTIFY_INLINE_FH_LEN (4 << 2)
+#endif
+
+struct fanotify_fid {
+ __kernel_fsid_t fsid;
+ union {
+ unsigned char fh[FANOTIFY_INLINE_FH_LEN];
+ unsigned char *ext_fh;
+ };
+};
+
+static inline void *fanotify_fid_fh(struct fanotify_fid *fid,
+ unsigned int fh_len)
+{
+ return fh_len <= FANOTIFY_INLINE_FH_LEN ? fid->fh : fid->ext_fh;
+}
+
+static inline bool fanotify_fid_equal(struct fanotify_fid *fid1,
+ struct fanotify_fid *fid2,
+ unsigned int fh_len)
+{
+ return fid1->fsid.val[0] == fid2->fsid.val[0] &&
+ fid1->fsid.val[1] == fid2->fsid.val[1] &&
+ !memcmp(fanotify_fid_fh(fid1, fh_len),
+ fanotify_fid_fh(fid2, fh_len), fh_len);
+}
+
+/*
* Structure for normal fanotify events. It gets allocated in
* fanotify_handle_event() and freed when the information is retrieved by
* userspace
struct fsnotify_event fse;
u32 mask;
/*
- * We hold ref to this path so it may be dereferenced at any point
- * during this object's lifetime
+ * Those fields are outside fanotify_fid to pack fanotify_event nicely
+ * on 64bit arch and to use fh_type as an indication of whether path
+ * or fid are used in the union:
+ * FILEID_ROOT (0) for path, > 0 for fid, FILEID_INVALID for neither.
*/
- struct path path;
+ u8 fh_type;
+ u8 fh_len;
+ u16 pad;
+ union {
+ /*
+ * We hold ref to this path so it may be dereferenced at any
+ * point during this object's lifetime
+ */
+ struct path path;
+ /*
+ * With FAN_REPORT_FID, we do not hold any reference on the
+ * victim object. Instead we store its NFS file handle and its
+ * filesystem's fsid as a unique identifier.
+ */
+ struct fanotify_fid fid;
+ };
struct pid *pid;
};
+static inline bool fanotify_event_has_path(struct fanotify_event *event)
+{
+ return event->fh_type == FILEID_ROOT;
+}
+
+static inline bool fanotify_event_has_fid(struct fanotify_event *event)
+{
+ return event->fh_type != FILEID_ROOT &&
+ event->fh_type != FILEID_INVALID;
+}
+
+static inline bool fanotify_event_has_ext_fh(struct fanotify_event *event)
+{
+ return fanotify_event_has_fid(event) &&
+ event->fh_len > FANOTIFY_INLINE_FH_LEN;
+}
+
/*
* Structure for permission fanotify events. It gets allocated and freed in
* fanotify_handle_event() since we wait there for user response. When the
struct fanotify_event_metadata metadata;
struct fanotify_event *event;
struct file *f = NULL;
- int fd, ret;
+ int ret, fd = FAN_NOFD;
pr_debug("%s: group=%p event=%p\n", __func__, group, fsn_event);
metadata.mask = event->mask & FANOTIFY_OUTGOING_EVENTS;
metadata.pid = pid_vnr(event->pid);
- if (unlikely(event->mask & FAN_Q_OVERFLOW)) {
- fd = FAN_NOFD;
- } else {
+ if (fanotify_event_has_path(event)) {
fd = create_fd(group, event, &f);
if (fd < 0)
return fd;
/* Flags to determine fanotify event format */
#define FAN_REPORT_TID 0x00000100 /* event->pid is thread id */
+#define FAN_REPORT_FID 0x00000200 /* Report unique file id */
/* Deprecated - do not use this in programs and do not add new flags here! */
#define FAN_ALL_INIT_FLAGS (FAN_CLOEXEC | FAN_NONBLOCK | \
projects / platform / kernel / linux-rpi.git / commitdiff