Hi, On Mon, Dec 4, 2023 at 3:57 AM Miquel Raynal <miquel.raynal@xxxxxxxxxxx> wrote: > > Hi Zhang, > > zhang_shurong@xxxxxxxxxxx wrote on Sat, 2 Dec 2023 22:58:52 +0800: > > > The syzkaller reported an issue: > > Subject should start with [PATCH wpan] > > > > > BUG: KMSAN: uninit-value in ieee802154_hdr_push_sechdr net/ieee802154/header_ops.c:54 [inline] > > BUG: KMSAN: uninit-value in ieee802154_hdr_push+0x971/0xb90 net/ieee802154/header_ops.c:108 > > ieee802154_hdr_push_sechdr net/ieee802154/header_ops.c:54 [inline] > > ieee802154_hdr_push+0x971/0xb90 net/ieee802154/header_ops.c:108 > > ieee802154_header_create+0x9c0/0xc00 net/mac802154/iface.c:396 > > wpan_dev_hard_header include/net/cfg802154.h:494 [inline] > > dgram_sendmsg+0xd1d/0x1500 net/ieee802154/socket.c:677 > > ieee802154_sock_sendmsg+0x91/0xc0 net/ieee802154/socket.c:96 > > sock_sendmsg_nosec net/socket.c:725 [inline] > > sock_sendmsg net/socket.c:748 [inline] > > ____sys_sendmsg+0x9c2/0xd60 net/socket.c:2494 > > ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2548 > > __sys_sendmsg+0x225/0x3c0 net/socket.c:2577 > > __compat_sys_sendmsg net/compat.c:346 [inline] > > __do_compat_sys_sendmsg net/compat.c:353 [inline] > > __se_compat_sys_sendmsg net/compat.c:350 [inline] > > > > We found hdr->key_id_mode is uninitialized in mac802154_set_header_security() > > which indicates hdr.fc.security_enabled should be 0. However, it is set to be cb->secen before. > > Later, ieee802154_hdr_push_sechdr is invoked, causing KMSAN complains uninit-value issue. > > I am not too deeply involved in the security header but for me it feels > like your patch does the opposite of what's needed. We should maybe > initialize hdr->key_id_mode based on the value in cb->secen, no? (maybe > Alexander will have a better understanding than I have). I can't help yet with a better answer why syzkaller reports it but it will break things as we using skb->cb to pass additional parameters through header_ops->create()... in this case it is some sockopts of af802154, I guess. side note: we should stop doing that with skb->cb and introduce some 802.15.4 specific header_ops callback structure and not depend on such generic callback which does not fit here (and maybe somebody does a wrapper around that and reuse skb->cb for their needs, etc.) - Alex
