fanotify: fix copy_event_to_user() fid error clean up

Ensure that clean up is performed on the allocated file descriptor and
struct file object in the event that an error is encountered while copying
fid info objects. Currently, we return directly to the caller when an error
is experienced in the fid info copying helper, which isn't ideal given that
the listener process could be left with a dangling file descriptor in their
fdtable.

Fixes: 36f05ebd99c9 ("fanotify: copy event fid info to user")
Fixes: fc9aabc0d0c9 ("fanotify: report name info for FAN_DIR_MODIFY event")
Link: https://lore.kernel.org/linux-fsdevel/YMKv1U7tNPK955ho@google.com/T/#m15361cd6399dad4396aad650de25dbf6b312288e
Link: https://lore.kernel.org/r/1ef8ae9100101eb1a91763c516c2e9a3a3b112bd.1623376346.git.repnop@google.com
Signed-off-by: Matthew Bobrowski <repnop@google.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/notify/fanotify/fanotify_user.c b/fs/notify/fanotify/fanotify_user.c
index be5b6d2c01e7ac5e65a70b7ed893082f1fdf05d5..64864fb40b401184550ec3114cf4e34b7b839dd6 100644 (file)
--- a/fs/notify/fanotify/fanotify_user.c
+++ b/fs/notify/fanotify/fanotify_user.c
@@ -471,7 +471,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
                                        info_type, fanotify_info_name(info),
                                        info->name_len, buf, count);
                if (ret < 0)
-                       return ret;
+                       goto out_close_fd;
 
                buf += ret;
                count -= ret;
@@ -519,7 +519,7 @@ static ssize_t copy_event_to_user(struct fsnotify_group *group,
                                        fanotify_event_object_fh(event),
                                        info_type, dot, dot_len, buf, count);
                if (ret < 0)
-                       return ret;
+                       goto out_close_fd;
 
                buf += ret;
                count -= ret;