Many of the use cases for fanotify events only use the event->fd
to resolve the path of the event target object.
Using O_PATH for this purpose is more efficient and prevents
exposing a readable fd of the object if that is not required.
To be able to distinguish a user opened O_PATH fd, from fanotify
provided O_PATH event->fd, do not explicitly set FMODE_NONOTIFY
on open of all O_PATH fds, do not override FMODE_NONOTIFY when setting
FMODE_PATH in do_dentry_open() and check explicitly for FMODE_PATH in
fsnotify_file() to suppress FAN_CLOSE events on close of O_PATH fds.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/notify/fanotify/fanotify_user.c | 2 +-
fs/open.c | 4 ++--
include/linux/fs.h | 10 ++++++----
include/linux/fsnotify.h | 2 +-
4 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 9d7b3a610b4a..fd2906a8a15e 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -105,7 +105,7 @@ static void __init fanotify_sysctls_init(void)
#define FANOTIFY_INIT_ALL_EVENT_F_BITS ( \
O_ACCMODE | O_APPEND | O_NONBLOCK | \
__O_SYNC | O_DSYNC | O_CLOEXEC | \
- O_LARGEFILE | O_NOATIME )
+ O_LARGEFILE | O_NOATIME | O_PATH)
extern const struct fsnotify_ops fanotify_fsnotify_ops;
diff --git a/fs/open.c b/fs/open.c
index 7828234a7caa..4664240f4c5e 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -913,8 +913,8 @@ static int do_dentry_open(struct file *f,
f->f_sb_err = file_sample_sb_err(f);
if (unlikely(f->f_flags & O_PATH)) {
- f->f_mode = FMODE_PATH | FMODE_OPENED;
- file_set_fsnotify_mode(f, FMODE_NONOTIFY);
+ f->f_mode = FMODE_PATH | FMODE_OPENED |
+ FMODE_FSNOTIFY(f->f_mode);
f->f_op = &empty_fops;
return 0;
}
diff --git a/include/linux/fs.h b/include/linux/fs.h
index aad2fb940a45..098456235cb5 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -210,14 +210,16 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
#define FMODE_FSNOTIFY_MASK \
(FMODE_NONOTIFY | FMODE_NONOTIFY_PERM)
+#define FMODE_FSNOTIFY(mode) \
+ (mode & FMODE_FSNOTIFY_MASK)
#define FMODE_FSNOTIFY_NONE(mode) \
- ((mode & FMODE_FSNOTIFY_MASK) == FMODE_NONOTIFY)
+ (FMODE_FSNOTIFY(mode) == FMODE_NONOTIFY)
#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
#define FMODE_FSNOTIFY_PERM(mode) \
- ((mode & FMODE_FSNOTIFY_MASK) == 0 || \
- (mode & FMODE_FSNOTIFY_MASK) == (FMODE_NONOTIFY | FMODE_NONOTIFY_PERM))
+ (FMODE_FSNOTIFY(mode) == 0 || \
+ FMODE_FSNOTIFY(mode) == (FMODE_NONOTIFY | FMODE_NONOTIFY_PERM))
#define FMODE_FSNOTIFY_HSM(mode) \
- ((mode & FMODE_FSNOTIFY_MASK) == 0)
+ (FMODE_FSNOTIFY(mode) == 0)
#else
#define FMODE_FSNOTIFY_PERM(mode) 0
#define FMODE_FSNOTIFY_HSM(mode) 0
diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
index 454d8e466958..175149167642 100644
--- a/include/linux/fsnotify.h
+++ b/include/linux/fsnotify.h
@@ -121,7 +121,7 @@ static inline int fsnotify_file(struct file *file, __u32 mask)
* FMODE_PATH fds (involves open & close events) as they are just
* handle creation / destruction events and not "real" file events.
*/
- if (FMODE_FSNOTIFY_NONE(file->f_mode))
+ if (FMODE_FSNOTIFY_NONE(file->f_mode) || (file->f_mode & FMODE_PATH))
return 0;
return fsnotify_path(&file->f_path, mask);
--
2.34.1
