diff options
author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2024-05-23 01:14:28 -0400 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-06-21 14:40:11 +0200 |
commit | 99b86d85f7c73d676c50e8c35748f94dd41389da (patch) | |
tree | d3e96e82acc35d5b4747e9c085d6a6a7974d2229 /fs | |
parent | d74ac0ab8cfeea347c59b39dba5805d0e1811955 (diff) |
eventfs: Update all the eventfs_inodes from the events descriptor
[ Upstream commit 340f0c7067a95281ad13734f8225f49c6cf52067 ]
The change to update the permissions of the eventfs_inode had the
misconception that using the tracefs_inode would find all the
eventfs_inodes that have been updated and reset them on remount.
The problem with this approach is that the eventfs_inodes are freed when
they are no longer used (basically the reason the eventfs system exists).
When they are freed, the updated eventfs_inodes are not reset on a remount
because their tracefs_inodes have been freed.
Instead, since the events directory eventfs_inode always has a
tracefs_inode pointing to it (it is not freed when finished), and the
events directory has a link to all its children, have the
eventfs_remount() function only operate on the events eventfs_inode and
have it descend into its children updating their uid and gids.
Link: https://lore.kernel.org/all/CAK7LNARXgaWw3kH9JgrnH4vK6fr8LDkNKf3wq8NhMWJrVwJyVQ@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240523051539.754424703@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: baa23a8d4360d ("tracefs: Reset permissions on remount if permissions are options")
Reported-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/tracefs/event_inode.c | 51 |
1 files changed, 39 insertions, 12 deletions
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 55a40a730b10..129d0f54ba62 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -305,33 +305,60 @@ static const struct file_operations eventfs_file_operations = { .llseek = generic_file_llseek, }; -/* - * On a remount of tracefs, if UID or GID options are set, then - * the mount point inode permissions should be used. - * Reset the saved permission flags appropriately. - */ -void eventfs_remount(struct tracefs_inode *ti, bool update_uid, bool update_gid) +static void eventfs_set_attrs(struct eventfs_inode *ei, bool update_uid, kuid_t uid, + bool update_gid, kgid_t gid, int level) { - struct eventfs_inode *ei = ti->private; + struct eventfs_inode *ei_child; - if (!ei) + /* Update events/<system>/<event> */ + if (WARN_ON_ONCE(level > 3)) return; - if (update_uid) + if (update_uid) { ei->attr.mode &= ~EVENTFS_SAVE_UID; + ei->attr.uid = uid; + } - if (update_gid) + if (update_gid) { ei->attr.mode &= ~EVENTFS_SAVE_GID; + ei->attr.gid = gid; + } + + list_for_each_entry(ei_child, &ei->children, list) { + eventfs_set_attrs(ei_child, update_uid, uid, update_gid, gid, level + 1); + } if (!ei->entry_attrs) return; for (int i = 0; i < ei->nr_entries; i++) { - if (update_uid) + if (update_uid) { ei->entry_attrs[i].mode &= ~EVENTFS_SAVE_UID; - if (update_gid) + ei->entry_attrs[i].uid = uid; + } + if (update_gid) { ei->entry_attrs[i].mode &= ~EVENTFS_SAVE_GID; + ei->entry_attrs[i].gid = gid; + } } + +} + +/* + * On a remount of tracefs, if UID or GID options are set, then + * the mount point inode permissions should be used. + * Reset the saved permission flags appropriately. + */ +void eventfs_remount(struct tracefs_inode *ti, bool update_uid, bool update_gid) +{ + struct eventfs_inode *ei = ti->private; + + /* Only the events directory does the updates */ + if (!ei || !ei->is_events || ei->is_freed) + return; + + eventfs_set_attrs(ei, update_uid, ti->vfs_inode.i_uid, + update_gid, ti->vfs_inode.i_gid, 0); } /* Return the evenfs_inode of the "events" directory */ |