The patch below does not apply to the 3.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 5c2e9f346b815841f9bed6029ebcb06415caf640 Mon Sep 17 00:00:00 2001

From: Mark Salyzyn salyzyn@android.com Date: Thu, 29 Aug 2019 11:30:14 -0700 Subject: [PATCH] ovl: filter of trusted xattr results in audit

When filtering xattr list for reading, presence of trusted xattr results in a security audit log. However, if there is other content no errno will be set, and if there isn't, the errno will be -ENODATA and not -EPERM as is usually associated with a lack of capability. The check does not block the request to list the xattrs present.

Switch to ns_capable_noaudit to reflect a more appropriate check.

Signed-off-by: Mark Salyzyn salyzyn@android.com Cc: linux-security-module@vger.kernel.org Cc: kernel-team@android.com Cc: stable@vger.kernel.org # v3.18+ Fixes: a082c6f680da ("ovl: filter trusted xattr for non-admin") Signed-off-by: Miklos Szeredi mszeredi@redhat.com

diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 7663aeb85fa3..bc14781886bf 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -383,7 +383,8 @@ static bool ovl_can_list(const char *s) return true;

/* Never list trusted.overlay, list other trusted for superuser only */ - return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN); + return !ovl_is_private_xattr(s) && + ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN); }

ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)