linux-ext4 - [PATCH v5 15/23] fanotify: Require fid

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Message-Id: <20210804160612.3575505-16-krisman@collabora.com>
Date:   Wed,  4 Aug 2021 12:06:04 -0400
From:   Gabriel Krisman Bertazi <krisman@...labora.com>
To:     jack@...e.com, amir73il@...il.com
Cc:     djwong@...nel.org, tytso@....edu, david@...morbit.com,
        dhowells@...hat.com, khazhy@...gle.com,
        linux-fsdevel@...r.kernel.org, linux-ext4@...r.kernel.org,
        linux-api@...r.kernel.org,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        kernel@...labora.com
Subject: [PATCH v5 15/23] fanotify: Require fid_mode for any non-fd event

Like inode events, FAN_FS_ERROR will require fid mode.  Therefore,
convert the verification during fanotify_mark(2) to require fid for any
non-fd event.  This means fid_mode will not only be required for inode
events, but for any event that doesn't provide a descriptor.

Suggested-by: Amir Goldstein <amir73il@...il.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>

---
changes since v5:
  - Fix condition to include FANOTIFY_EVENT_FLAGS. (me)
---
 fs/notify/fanotify/fanotify_user.c | 14 +++++++-------
 include/linux/fanotify.h           |  3 +++
 2 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index 0696f2121781..6dad2a00e337 100644
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -1382,14 +1382,14 @@ static int do_fanotify_mark(int fanotify_fd, unsigned int flags, __u64 mask,
 		goto fput_and_out;
 
 	/*
-	 * Events with data type inode do not carry enough information to report
-	 * event->fd, so we do not allow setting a mask for inode events unless
-	 * group supports reporting fid.
-	 * inode events are not supported on a mount mark, because they do not
-	 * carry enough information (i.e. path) to be filtered by mount point.
-	 */
+	* Events that do not carry enough information to report
+	* event->fd require a group that supports reporting fid.  Those
+	* events are not supported on a mount mark, because they do not
+	* carry enough information (i.e. path) to be filtered by mount
+	* point.
+	*/
 	fid_mode = FAN_GROUP_FLAG(group, FANOTIFY_FID_BITS);
-	if (mask & FANOTIFY_INODE_EVENTS &&
+	if (mask & ~(FANOTIFY_FD_EVENTS|FANOTIFY_EVENT_FLAGS) &&
 	    (!fid_mode || mark_type == FAN_MARK_MOUNT))
 		goto fput_and_out;
 
diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h
index a16dbeced152..c05d45bde8b8 100644
--- a/include/linux/fanotify.h
+++ b/include/linux/fanotify.h
@@ -81,6 +81,9 @@ extern struct ctl_table fanotify_table[]; /* for sysctl */
  */
 #define FANOTIFY_DIRENT_EVENTS	(FAN_MOVE | FAN_CREATE | FAN_DELETE)
 
+/* Events that can be reported with event->fd */
+#define FANOTIFY_FD_EVENTS (FANOTIFY_PATH_EVENTS | FANOTIFY_PERM_EVENTS)
+
 /* Events that can only be reported with data type FSNOTIFY_EVENT_INODE */
 #define FANOTIFY_INODE_EVENTS	(FANOTIFY_DIRENT_EVENTS | \
 				 FAN_ATTRIB | FAN_MOVE_SELF | FAN_DELETE_SELF)
-- 
2.32.0