Commit 75422726 authored by Eric W. Biederman's avatar Eric W. Biederman

libfs: Modify mount_pseudo_xattr to be clear it is not a userspace mount

Add MS_KERNMOUNT to the flags that are passed.
Use sget_userns and force &init_user_ns instead of calling sget so that
even if called from a weird context the internal filesystem will be
considered to be in the intial user namespace.

Luis Ressel reported that the the failure to pass MS_KERNMOUNT into
mount_pseudo broke his in development graphics driver that uses the
generic drm infrastructure.  I am not certain the deriver was bug
free in it's usage of that infrastructure but since
mount_pseudo_xattr can never be triggered by userspace it is clearer
and less error prone, and less problematic for the code to be explicit.
Reported-by: default avatarLuis Ressel <aranea@aixah.de>
Tested-by: default avatarLuis Ressel <aranea@aixah.de>
Acked-by: default avatarAl Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent 3895dbf8
......@@ -245,7 +245,8 @@ struct dentry *mount_pseudo_xattr(struct file_system_type *fs_type, char *name,
struct inode *root;
struct qstr d_name = QSTR_INIT(name, strlen(name));
s = sget(fs_type, NULL, set_anon_super, MS_NOUSER, NULL);
s = sget_userns(fs_type, NULL, set_anon_super, MS_KERNMOUNT|MS_NOUSER,
&init_user_ns, NULL);
if (IS_ERR(s))
return ERR_CAST(s);
......
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