Entreprise française de cybersécurité depuis 2004
☎ 03 60 47 09 81 - info@securiteinfo.com
☎ 03 60 47 09 81 - info@securiteinfo.com
In the Linux kernel, the following vulnerability has been resolved:netlink: Fix wraparounds of sk->sk_rmem_alloc.Netlink has this pattern in some places if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf) atomic_add(skb->truesize, &sk->sk_rmem_alloc);, which has the same problem fixed by commit 5a465a0da13e ("udp:Fix multiple wraparounds of sk->sk_rmem_alloc.").For example, if we set INT_MAX to SO_RCVBUFFORCE, the conditionis always false as the two operands are of int.Then, a single socket can eat as many skb as possible until OOMhappens, and we can see multiple wraparounds of sk->sk_rmem_alloc.Let's fix it by using atomic_add_return() and comparing the twovariables as unsigned int.Before: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port -1668710080 0 rtnl:nl_wraparound/293 *After: [root@fedora ~]# ss -f netlink Recv-Q Send-Q Local Address:Port Peer Address:Port 2147483072 0 rtnl:nl_wraparound/290 * ^ `--- INT_MAX - 576
No PoCs from references.
- https://github.com/w4zu/Debian_security