From: Xin Long lucien.xin@gmail.com
commit 2ac695d1d602ce00b12170242f58c3d3a8e36d04 upstream.
Syzbot found a crash:
BUG: KMSAN: uninit-value in tipc_nl_compat_name_table_dump+0x54f/0xcd0 net/tipc/netlink_compat.c:872 Call Trace: tipc_nl_compat_name_table_dump+0x54f/0xcd0 net/tipc/netlink_compat.c:872 __tipc_nl_compat_dumpit+0x59e/0xda0 net/tipc/netlink_compat.c:215 tipc_nl_compat_dumpit+0x63a/0x820 net/tipc/netlink_compat.c:280 tipc_nl_compat_handle net/tipc/netlink_compat.c:1226 [inline] tipc_nl_compat_recv+0x1b5f/0x2750 net/tipc/netlink_compat.c:1265 genl_family_rcv_msg net/netlink/genetlink.c:601 [inline] genl_rcv_msg+0x185f/0x1a60 net/netlink/genetlink.c:626 netlink_rcv_skb+0x431/0x620 net/netlink/af_netlink.c:2477 genl_rcv+0x63/0x80 net/netlink/genetlink.c:637 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline] netlink_unicast+0xf3e/0x1020 net/netlink/af_netlink.c:1336 netlink_sendmsg+0x127f/0x1300 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg net/socket.c:632 [inline]
Uninit was created at: __alloc_skb+0x309/0xa20 net/core/skbuff.c:208 alloc_skb include/linux/skbuff.h:1012 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1182 [inline] netlink_sendmsg+0xb82/0x1300 net/netlink/af_netlink.c:1892 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg net/socket.c:632 [inline]
It was supposed to be fixed on commit 974cb0e3e7c9 ("tipc: fix uninit-value in tipc_nl_compat_name_table_dump") by checking TLV_GET_DATA_LEN(msg->req) in cmd->header()/tipc_nl_compat_name_table_dump_header(), which is called ahead of tipc_nl_compat_name_table_dump().
However, tipc_nl_compat_dumpit() doesn't handle the error returned from cmd header function. It means even when the check added in that fix fails, it won't stop calling tipc_nl_compat_name_table_dump(), and the issue will be triggered again.
So this patch is to add the process for the err returned from cmd header function in tipc_nl_compat_dumpit().
Reported-by: syzbot+3ce8520484b0d4e260a5@syzkaller.appspotmail.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/tipc/netlink_compat.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
--- a/net/tipc/netlink_compat.c +++ b/net/tipc/netlink_compat.c @@ -267,8 +267,14 @@ static int tipc_nl_compat_dumpit(struct if (msg->rep_type) tipc_tlv_init(msg->rep, msg->rep_type);
- if (cmd->header) - (*cmd->header)(msg); + if (cmd->header) { + err = (*cmd->header)(msg); + if (err) { + kfree_skb(msg->rep); + msg->rep = NULL; + return err; + } + }
arg = nlmsg_new(0, GFP_KERNEL); if (!arg) {