ceph: return -ERANGE if virtual xattr value didn't fit in buffer

[ Upstream commit 3b421018f48c482bdc9650f894aa1747cf90e51d ]

The getxattr manpage states that we should return ERANGE if the
destination buffer size is too small to hold the value.
ceph_vxattrcb_layout does this internally, but we should be doing
this for all vxattrs.

Fix the only caller of getxattr_cb to check the returned size
against the buffer length and return -ERANGE if it doesn't fit.
Drop the same check in ceph_vxattrcb_layout and just rely on the
caller to handle it.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: "Yan, Zheng" <zyan@redhat.com>
Acked-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 5cc8b94..0a2d489 100644 (file)
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -79,7 +79,7 @@ static size_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
        const char *ns_field = " pool_namespace=";
        char buf[128];
        size_t len, total_len = 0;
-       int ret;
+       ssize_t ret;
 
        pool_ns = ceph_try_get_string(ci->i_layout.pool_ns);
 
@@ -103,11 +103,8 @@ static size_t ceph_vxattrcb_layout(struct ceph_inode_info *ci, char *val,
        if (pool_ns)
                total_len += strlen(ns_field) + pool_ns->len;
 
-       if (!size) {
-               ret = total_len;
-       } else if (total_len > size) {
-               ret = -ERANGE;
-       } else {
+       ret = total_len;
+       if (size >= total_len) {
                memcpy(val, buf, len);
                ret = len;
                if (pool_name) {
@@ -817,8 +814,11 @@ ssize_t __ceph_getxattr(struct inode *inode, const char *name, void *value,
                if (err)
                        return err;
                err = -ENODATA;
-               if (!(vxattr->exists_cb && !vxattr->exists_cb(ci)))
+               if (!(vxattr->exists_cb && !vxattr->exists_cb(ci))) {
                        err = vxattr->getxattr_cb(ci, value, size);
+                       if (size && size < err)
+                               err = -ERANGE;
+               }
                return err;
        }