From d88cbbe7ba0c9d75846d82e0ad6d7d82ef246e31 Mon Sep 17 00:00:00 2001 From: Miklos Szeredi Date: Mon, 29 May 2017 15:15:27 +0200 Subject: ovl: filter trusted xattr for non-admin [ Upstream commit a082c6f680da298cf075886ff032f32ccb7c5e1a ] Filesystems filter out extended attributes in the "trusted." domain for unprivlieged callers. Overlay calls underlying filesystem's method with elevated privs, so need to do the filtering in overlayfs too. Signed-off-by: Miklos Szeredi Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- fs/overlayfs/inode.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'fs/overlayfs/inode.c') diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 220b04f04523..985a4cdae06d 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -272,6 +272,16 @@ ssize_t ovl_getxattr(struct dentry *dentry, const char *name, return vfs_getxattr(realpath.dentry, name, value, size); } +static bool ovl_can_list(const char *s) +{ + /* List all non-trusted xatts */ + if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) + return true; + + /* Never list trusted.overlay, list other trusted for superuser only */ + return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN); +} + ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) { struct path realpath; @@ -296,7 +306,7 @@ ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) return -EIO; len -= slen; - if (ovl_is_private_xattr(s)) { + if (!ovl_can_list(s)) { res -= slen; memmove(s, s + slen, len); } else { -- cgit v1.2.3