From: Cong Wang xiyou.wangcong@gmail.com
[ Upstream commit 47733f9daf4fe4f7e0eb9e273f21ad3a19130487 ]
__tipc_nl_compat_dumpit() has two callers, and it expects them to pass a valid nlmsghdr via arg->data. This header is artificial and crafted just for __tipc_nl_compat_dumpit().
tipc_nl_compat_publ_dump() does so by putting a genlmsghdr as well as some nested attribute, TIPC_NLA_SOCK. But the other caller tipc_nl_compat_dumpit() does not, this leaves arg->data uninitialized on this call path.
Fix this by just adding a similar nlmsghdr without any payload in tipc_nl_compat_dumpit().
This bug exists since day 1, but the recent commit 6ea67769ff33 ("net: tipc: prepare attrs in __tipc_nl_compat_dumpit()") makes it easier to appear.
Reported-and-tested-by: syzbot+0e7181deafa7e0b79923@syzkaller.appspotmail.com Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat") Cc: Jon Maloy jmaloy@redhat.com Cc: Ying Xue ying.xue@windriver.com Cc: Richard Alpe richard.alpe@ericsson.com Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Acked-by: Ying Xue ying.xue@windriver.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/tipc/netlink_compat.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
--- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -275,8 +275,9 @@ err_out: static int tipc_nl_compat_dumpit(struct tipc_nl_compat_cmd_dump *cmd, struct tipc_nl_compat_msg *msg) { - int err; + struct nlmsghdr *nlh; struct sk_buff *arg; + int err;
if (msg->req_type && (!msg->req_size || !TLV_CHECK_TYPE(msg->req, msg->req_type))) @@ -305,6 +306,15 @@ static int tipc_nl_compat_dumpit(struct return -ENOMEM; }
+ nlh = nlmsg_put(arg, 0, 0, tipc_genl_family.id, 0, NLM_F_MULTI); + if (!nlh) { + kfree_skb(arg); + kfree_skb(msg->rep); + msg->rep = NULL; + return -EMSGSIZE; + } + nlmsg_end(arg, nlh); + err = __tipc_nl_compat_dumpit(cmd, msg, arg); if (err) { kfree_skb(msg->rep);