tipc: improve size validations for received domain records

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@appgate.com>
Reported-by: Eric Dumazet <edumazet@google.com>
Fixes: 35c55c9877f8 ("tipc: add neighbor monitoring framework")
Signed-off-by: Jon Maloy <jmaloy@redhat.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Samuel Page <samuel.page@appgate.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/tipc/link.c b/net/tipc/link.c
index 0b44427e29ec591417b73525a7c623174ccd1701..d3017811b67a62578fab13f393fdd4cdd3f7d34d 100644 (file)
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1462,12 +1462,15 @@ static int tipc_link_proto_rcv(struct tipc_link *l, struct sk_buff *skb,
        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;
 

diff --git a/net/tipc/monitor.c b/net/tipc/monitor.c
index 254ddc2c39146135e0206d44c928a249349e1296..c6496da9392d716a58ff66e6e0ef92525e981198 100644 (file)
--- a/net/tipc/monitor.c
+++ b/net/tipc/monitor.c
@@ -457,6 +457,8 @@ void tipc_mon_rcv(struct net *net, void *data, u16 dlen, u32 addr,
        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))