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authorJeff Layton <jeff.layton@primarydata.com>2015-11-16 09:49:34 -0500
committerJeff Layton <jeff.layton@primarydata.com>2015-11-16 09:49:34 -0500
commit9e8925b67a809bb27ce4b7d352d67f25cf1d7fc5 (patch)
tree3a349e8389f85f87c9c559f5e1860855694e6bae /fs/namespace.c
parent8005c49d9aea74d382f474ce11afbbc7d7130bec (diff)
downloadlinux-9e8925b67a809bb27ce4b7d352d67f25cf1d7fc5.tar.bz2
locks: Allow disabling mandatory locking at compile time
Mandatory locking appears to be almost unused and buggy and there appears no real interest in doing anything with it. Since effectively no one uses the code and since the code is buggy let's allow it to be disabled at compile time. I would just suggest removing the code but undoubtedly that will break some piece of userspace code somewhere. For the distributions that don't care about this piece of code this gives a nice starting point to make mandatory locking go away. Cc: Benjamin Coddington <bcodding@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jeff Layton <jeff.layton@primarydata.com> Cc: J. Bruce Fields <bfields@fieldses.org> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Diffstat (limited to 'fs/namespace.c')
-rw-r--r--fs/namespace.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index 0570729c87fd..4219885e9681 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1584,6 +1584,14 @@ static inline bool may_mount(void)
return ns_capable(current->nsproxy->mnt_ns->user_ns, CAP_SYS_ADMIN);
}
+static inline bool may_mandlock(void)
+{
+#ifndef CONFIG_MANDATORY_FILE_LOCKING
+ return false;
+#endif
+ return true;
+}
+
/*
* Now umount can handle mount points as well as block devices.
* This is important for filesystems which use unnamed block devices.
@@ -2677,6 +2685,8 @@ long do_mount(const char *dev_name, const char __user *dir_name,
type_page, flags, data_page);
if (!retval && !may_mount())
retval = -EPERM;
+ if (!retval && (flags & MS_MANDLOCK) && !may_mandlock())
+ retval = -EPERM;
if (retval)
goto dput_out;