From: Xin Long <lucien.xin@xxxxxxxxx> commit 8c63bf9ab4be8b83bd8c34aacfd2f1d2c8901c8a upstream. A similar issue as fixed by Patch "tipc: check bearer name with right length in tipc_nl_compat_bearer_enable" was also found by syzbot in tipc_nl_compat_link_set(). The length to check with should be 'TLV_GET_DATA_LEN(msg->req) - offsetof(struct tipc_link_config, name)'. Reported-by: syzbot+de00a87b8644a582ae79@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/tipc/netlink_compat.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -768,7 +768,12 @@ static int tipc_nl_compat_link_set(struc lc = (struct tipc_link_config *)TLV_DATA(msg->req); - len = min_t(int, TLV_GET_DATA_LEN(msg->req), TIPC_MAX_LINK_NAME); + len = TLV_GET_DATA_LEN(msg->req); + len -= offsetof(struct tipc_link_config, name); + if (len <= 0) + return -EINVAL; + + len = min_t(int, len, TIPC_MAX_LINK_NAME); if (!string_is_valid(lc->name, len)) return -EINVAL;
