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From: Amir Goldstein <amir73il@gmail.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org
Subject: [PATCH v3 4/8] fanotify: deprecate uapi FAN_ALL_* constants
Date: Thu,  4 Oct 2018 00:25:35 +0300	[thread overview]
Message-ID: <20181003212539.2384-5-amir73il@gmail.com> (raw)
In-Reply-To: <20181003212539.2384-1-amir73il@gmail.com>

We do not want to add new bits to the FAN_ALL_* uapi constants
because they have been exposed to userspace.  If there are programs
out there using these constants, those programs could break if
re-compiled with modified FAN_ALL_* constants and run on an old kernel.

We deprecate the uapi constants FAN_ALL_* and define new FANOTIFY_*
constants for internal use to replace them. New feature bits will be
added only to the new constants.

Cc: <linux-api@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
---
 fs/notify/fanotify/fanotify.c      |  6 ++--
 fs/notify/fanotify/fanotify.h      |  2 +-
 fs/notify/fanotify/fanotify_user.c | 22 +++++++-------
 include/linux/fanotify.h           | 47 ++++++++++++++++++++++++++++++
 include/uapi/linux/fanotify.h      | 18 ++++++------
 5 files changed, 71 insertions(+), 24 deletions(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 94b52157bf8d..03498eb995be 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -131,8 +131,8 @@ static bool fanotify_should_send_event(struct fsnotify_iter_info *iter_info,
 	    !(marks_mask & FS_ISDIR & ~marks_ignored_mask))
 		return false;
 
-	if (event_mask & FAN_ALL_OUTGOING_EVENTS & marks_mask &
-				 ~marks_ignored_mask)
+	if (event_mask & FANOTIFY_OUTGOING_EVENTS &
+	    marks_mask & ~marks_ignored_mask)
 		return true;
 
 	return false;
@@ -236,7 +236,7 @@ static int fanotify_handle_event(struct fsnotify_group *group,
 	ret = fsnotify_add_event(group, fsn_event, fanotify_merge);
 	if (ret) {
 		/* Permission events shouldn't be merged */
-		BUG_ON(ret == 1 && mask & FAN_ALL_PERM_EVENTS);
+		BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS);
 		/* Our event wasn't used in the end. Free it. */
 		fsnotify_destroy_event(group, fsn_event);
 
diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
index 8609ba06f474..88a8290a61cb 100644
--- a/fs/notify/fanotify/fanotify.h
+++ b/fs/notify/fanotify/fanotify.h
@@ -44,7 +44,7 @@ FANOTIFY_PE(struct fsnotify_event *fse)
 static inline bool fanotify_is_perm_event(u32 mask)
 {
 	return IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS) &&
-		mask & FAN_ALL_PERM_EVENTS;
+		mask & FANOTIFY_PERM_EVENTS;
 }
 
 static inline struct fanotify_event_info *FANOTIFY_E(struct fsnotify_event *fse)
diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 34b511407035..530e5e486105 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -131,7 +131,7 @@ static int fill_event_metadata(struct fsnotify_group *group,
 	metadata->metadata_len = FAN_EVENT_METADATA_LEN;
 	metadata->vers = FANOTIFY_METADATA_VERSION;
 	metadata->reserved = 0;
-	metadata->mask = fsn_event->mask & FAN_ALL_OUTGOING_EVENTS;
+	metadata->mask = fsn_event->mask & FANOTIFY_OUTGOING_EVENTS;
 	metadata->pid = pid_vnr(event->tgid);
 	if (unlikely(fsn_event->mask & FAN_Q_OVERFLOW))
 		metadata->fd = FAN_NOFD;
@@ -395,7 +395,7 @@ static int fanotify_release(struct inode *ignored, struct file *file)
 	 */
 	while (!fsnotify_notify_queue_is_empty(group)) {
 		fsn_event = fsnotify_remove_first_event(group);
-		if (!(fsn_event->mask & FAN_ALL_PERM_EVENTS)) {
+		if (!(fsn_event->mask & FANOTIFY_PERM_EVENTS)) {
 			spin_unlock(&group->notification_lock);
 			fsnotify_destroy_event(group, fsn_event);
 			spin_lock(&group->notification_lock);
@@ -691,9 +691,9 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int, flags, unsigned int, event_f_flags)
 		return -EPERM;
 
 #ifdef CONFIG_AUDITSYSCALL
-	if (flags & ~(FAN_ALL_INIT_FLAGS | FAN_ENABLE_AUDIT))
+	if (flags & ~(FANOTIFY_INIT_FLAGS | FAN_ENABLE_AUDIT))
 #else
-	if (flags & ~FAN_ALL_INIT_FLAGS)
+	if (flags & ~FANOTIFY_INIT_FLAGS)
 #endif
 		return -EINVAL;
 
@@ -745,7 +745,7 @@ 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 & FAN_ALL_CLASS_BITS) {
+	switch (flags & FANOTIFY_CLASS_BITS) {
 	case FAN_CLASS_NOTIF:
 		group->priority = FS_PRIO_0;
 		break;
@@ -803,8 +803,8 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	struct fsnotify_group *group;
 	struct fd f;
 	struct path path;
-	u32 valid_mask = FAN_ALL_EVENTS | FAN_EVENT_ON_CHILD | FAN_ONDIR;
-	unsigned int mark_type = flags & FAN_MARK_TYPE_MASK;
+	u32 valid_mask = FANOTIFY_EVENTS | FAN_EVENT_ON_CHILD | FAN_ONDIR;
+	unsigned int mark_type = flags & FANOTIFY_MARK_TYPE_BITS;
 	int ret;
 
 	pr_debug("%s: fanotify_fd=%d flags=%x dfd=%d pathname=%p mask=%llx\n",
@@ -814,7 +814,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	if (mask & ((__u64)0xffffffff << 32))
 		return -EINVAL;
 
-	if (flags & ~FAN_ALL_MARK_FLAGS)
+	if (flags & ~FANOTIFY_MARK_FLAGS)
 		return -EINVAL;
 
 	switch (mark_type) {
@@ -833,7 +833,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 			return -EINVAL;
 		break;
 	case FAN_MARK_FLUSH:
-		if (flags & ~(FAN_MARK_TYPE_MASK | FAN_MARK_FLUSH))
+		if (flags & ~(FANOTIFY_MARK_TYPE_BITS | FAN_MARK_FLUSH))
 			return -EINVAL;
 		break;
 	default:
@@ -841,7 +841,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	}
 
 	if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS))
-		valid_mask |= FAN_ALL_PERM_EVENTS;
+		valid_mask |= FANOTIFY_PERM_EVENTS;
 
 	if (mask & ~valid_mask)
 		return -EINVAL;
@@ -861,7 +861,7 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 	 * allowed to set permissions events.
 	 */
 	ret = -EINVAL;
-	if (mask & FAN_ALL_PERM_EVENTS &&
+	if (mask & FANOTIFY_PERM_EVENTS &&
 	    group->priority == FS_PRIO_0)
 		goto fput_and_out;
 
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index a8c3fc54276d..4519b0988afe 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -7,4 +7,51 @@
 #define FAN_GROUP_FLAG(group, flag) \
 	((group)->fanotify_data.flags & (flag))
 
+/*
+ * Flags allowed to be passed from/to userspace.
+ *
+ * We intentionally do not add new bits to the old FAN_ALL_* constants, because
+ * they are uapi exposed constants. If there are programs out there using
+ * these constant, the programs may break if re-compiled with new uapi headers
+ * and then run on an old kernel.
+ */
+#define FANOTIFY_CLASS_BITS	(FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
+				 FAN_CLASS_PRE_CONTENT)
+
+#define FANOTIFY_INIT_FLAGS	(FANOTIFY_CLASS_BITS | \
+				 FAN_CLOEXEC | FAN_NONBLOCK | \
+				 FAN_UNLIMITED_QUEUE | FAN_UNLIMITED_MARKS)
+
+#define FANOTIFY_MARK_TYPE_BITS	(FAN_MARK_INODE | FAN_MARK_MOUNT | \
+				 FAN_MARK_FILESYSTEM)
+
+#define FANOTIFY_MARK_FLAGS	(FANOTIFY_MARK_TYPE_BITS | \
+				 FAN_MARK_ADD | \
+				 FAN_MARK_REMOVE | \
+				 FAN_MARK_DONT_FOLLOW | \
+				 FAN_MARK_ONLYDIR | \
+				 FAN_MARK_IGNORED_MASK | \
+				 FAN_MARK_IGNORED_SURV_MODIFY | \
+				 FAN_MARK_FLUSH)
+
+/* Events that user can request to be notified on */
+#define FANOTIFY_EVENTS		(FAN_ACCESS | FAN_MODIFY | \
+				 FAN_CLOSE | FAN_OPEN)
+
+/* Events that require a permission response from user */
+#define FANOTIFY_PERM_EVENTS	(FAN_OPEN_PERM | FAN_ACCESS_PERM)
+
+/* Events that may be reported to user */
+#define FANOTIFY_OUTGOING_EVENTS	(FANOTIFY_EVENTS | \
+					 FANOTIFY_PERM_EVENTS | \
+					 FAN_Q_OVERFLOW)
+
+/* Do not use these old uapi constants internally */
+#undef FAN_ALL_CLASS_BITS
+#undef FAN_ALL_INIT_FLAGS
+#undef FAN_ALL_MARK_FLAGS
+#undef FAN_ALL_EVENTS
+#undef FAN_ALL_PERM_EVENTS
+#undef FAN_ALL_OUTGOING_EVENTS
+
 #endif /* _LINUX_FANOTIFY_H */
diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h
index ad81234d1919..d0c05de670ef 100644
--- a/include/uapi/linux/fanotify.h
+++ b/include/uapi/linux/fanotify.h
@@ -31,6 +31,8 @@
 #define FAN_CLASS_NOTIF		0x00000000
 #define FAN_CLASS_CONTENT	0x00000004
 #define FAN_CLASS_PRE_CONTENT	0x00000008
+
+/* Deprecated - do not use this in programs and do not add new flags here! */
 #define FAN_ALL_CLASS_BITS	(FAN_CLASS_NOTIF | FAN_CLASS_CONTENT | \
 				 FAN_CLASS_PRE_CONTENT)
 
@@ -38,6 +40,7 @@
 #define FAN_UNLIMITED_MARKS	0x00000020
 #define FAN_ENABLE_AUDIT	0x00000040
 
+/* Deprecated - do not use this in programs and do not add new flags here! */
 #define FAN_ALL_INIT_FLAGS	(FAN_CLOEXEC | FAN_NONBLOCK | \
 				 FAN_ALL_CLASS_BITS | FAN_UNLIMITED_QUEUE |\
 				 FAN_UNLIMITED_MARKS)
@@ -57,23 +60,18 @@
 #define FAN_MARK_INODE		0x00000000
 #define FAN_MARK_MOUNT		0x00000010
 #define FAN_MARK_FILESYSTEM	0x00000100
-#define FAN_MARK_TYPE_MASK	(FAN_MARK_INODE | FAN_MARK_MOUNT | \
-				 FAN_MARK_FILESYSTEM)
 
+/* Deprecated - do not use this in programs and do not add new flags here! */
 #define FAN_ALL_MARK_FLAGS	(FAN_MARK_ADD |\
 				 FAN_MARK_REMOVE |\
 				 FAN_MARK_DONT_FOLLOW |\
 				 FAN_MARK_ONLYDIR |\
+				 FAN_MARK_MOUNT |\
 				 FAN_MARK_IGNORED_MASK |\
 				 FAN_MARK_IGNORED_SURV_MODIFY |\
-				 FAN_MARK_FLUSH|\
-				 FAN_MARK_TYPE_MASK)
+				 FAN_MARK_FLUSH)
 
-/*
- * All of the events - we build the list by hand so that we can add flags in
- * the future and not break backward compatibility.  Apps will get only the
- * events that they originally wanted.  Be sure to add new events here!
- */
+/* Deprecated - do not use this in programs and do not add new flags here! */
 #define FAN_ALL_EVENTS (FAN_ACCESS |\
 			FAN_MODIFY |\
 			FAN_CLOSE |\
@@ -82,9 +80,11 @@
 /*
  * All events which require a permission response from userspace
  */
+/* Deprecated - do not use this in programs and do not add new flags here! */
 #define FAN_ALL_PERM_EVENTS (FAN_OPEN_PERM |\
 			     FAN_ACCESS_PERM)
 
+/* Deprecated - do not use this in programs and do not add new flags here! */
 #define FAN_ALL_OUTGOING_EVENTS	(FAN_ALL_EVENTS |\
 				 FAN_ALL_PERM_EVENTS |\
 				 FAN_Q_OVERFLOW)
-- 
2.17.1

  parent reply	other threads:[~2018-10-04  4:16 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-03 21:25 [PATCH v3 0/8] New fanotify event info API Amir Goldstein
2018-10-03 21:25 ` [PATCH v3 1/8] fanotify: fix collision of internal and uapi mark flags Amir Goldstein
2018-10-03 21:25 ` [PATCH v3 2/8] fsnotify: generalize handling of extra event flags Amir Goldstein
2018-10-03 21:25 ` [PATCH v3 3/8] fanotify: simplify handling of FAN_ONDIR Amir Goldstein
2018-10-03 21:25 ` Amir Goldstein [this message]
2018-10-03 21:25 ` [PATCH v3 5/8] fsnotify: convert runtime BUG_ON() to BUILD_BUG_ON() Amir Goldstein
2018-10-03 21:25 ` [PATCH v3 6/8] fanotify: add BUILD_BUG_ON() to count the bits of fanotify constants Amir Goldstein
2018-10-04  8:41   ` Jan Kara
2018-10-04 10:24     ` Amir Goldstein
2018-10-03 21:25 ` [PATCH v3 7/8] fanotify: support reporting thread id instead of process id Amir Goldstein
2018-10-04  8:46   ` Jan Kara
2018-10-04 10:27     ` Amir Goldstein
2018-10-11 10:16   ` Jan Kara
2018-10-12  2:43     ` Nixiaoming
2018-10-16 12:06       ` Jan Kara
2018-10-03 21:25 ` [PATCH v3 8/8] fsnotify: optimize away srcu_read_lock() for events on directories Amir Goldstein
2018-10-04  9:09   ` Jan Kara
2018-10-04 10:30     ` Amir Goldstein
2018-10-04 11:26       ` Jan Kara
2018-10-04 22:05         ` Amir Goldstein

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