[PATCH] selinux: disable setxattr on mountpoint labeled filesystems

This patch disables the setting of SELinux xattrs on files created in
filesystems labeled via mountpoint labeling (mounted with the context=
option).  selinux_inode_setxattr already prevents explicit setxattr from
userspace on such filesystems, so this provides consistent behavior for
file creation.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 45c41490d521..fc774436a264 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1986,6 +1986,9 @@ static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
 
         inode_security_set_sid(inode, newsid);
 
+        if (sbsec->behavior == SECURITY_FS_USE_MNTPOINT)
+                return -EOPNOTSUPP;
+
         if (name) {
                 namep = kstrdup(XATTR_SELINUX_SUFFIX, GFP_KERNEL);
                 if (!namep)