From: Miklos Szeredi mszeredi@redhat.com
[ 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 mszeredi@redhat.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com --- fs/overlayfs/inode.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
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 {