From: Jon Maloy <jmaloy@xxxxxxxxxx> commit 9aa422ad326634b76309e8ff342c246800621216 upstream. The function tipc_mon_rcv() allows a node to receive and process domain_record structs from peer nodes to track their views of the network topology. This patch verifies that the number of members in a received domain record does not exceed the limit defined by MAX_MON_DOMAIN, something that may otherwise lead to a stack overflow. tipc_mon_rcv() is called from the function tipc_link_proto_rcv(), where we are reading a 32 bit message data length field into a uint16. To avert any risk of bit overflow, we add an extra sanity check for this in that function. We cannot see that happen with the current code, but future designers being unaware of this risk, may introduce it by allowing delivery of very large (> 64k) sk buffers from the bearer layer. This potential problem was identified by Eric Dumazet. This fixes CVE-2022-0435 Reported-by: Samuel Page <samuel.page@xxxxxxxxxxx> Reported-by: Eric Dumazet <edumazet@xxxxxxxxxx> Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework") Signed-off-by: Jon Maloy <jmaloy@xxxxxxxxxx> Reviewed-by: Xin Long <lucien.xin@xxxxxxxxx> Reviewed-by: Samuel Page <samuel.page@xxxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/tipc/link.c | 5 ++++- net/tipc/monitor.c | 2 ++ 2 files changed, 6 insertions(+), 1 deletion(-) --- a/net/tipc/link.c +++ b/net/tipc/link.c @@ -1441,12 +1441,15 @@ static int tipc_link_proto_rcv(struct ti u16 peers_tol = msg_link_tolerance(hdr); u16 peers_prio = msg_linkprio(hdr); u16 rcv_nxt = l->rcv_nxt; - u16 dlen = msg_data_sz(hdr); + u32 dlen = msg_data_sz(hdr); int mtyp = msg_type(hdr); void *data; char *if_name; int rc = 0; + if (dlen > U16_MAX) + goto exit; + if (tipc_link_is_blocked(l) || !xmitq) goto exit; --- a/net/tipc/monitor.c +++ b/net/tipc/monitor.c @@ -457,6 +457,8 @@ void tipc_mon_rcv(struct net *net, void state->probing = false; /* Sanity check received domain record */ + if (new_member_cnt > MAX_MON_DOMAIN) + return; if (dlen < dom_rec_len(arrv_dom, 0)) return; if (dlen != dom_rec_len(arrv_dom, new_member_cnt)) Patches currently in stable-queue which might be from jmaloy@xxxxxxxxxx are queue-4.9/tipc-improve-size-validations-for-received-domain-records.patch