Oracle Linux 6 : kernel (ELSA-2017-3200)


The remote Oracle Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the ELSA-2017-3200 advisory. - Linux kernel: heap out-of-bounds in AF_PACKET sockets. This new issue is analogous to previously disclosed CVE-2016-8655. In both cases, a socket option that changes socket state may race with safety checks in packet_set_ring. Previously with PACKET_VERSION. This time with PACKET_RESERVE. The solution is similar: lock the socket for the update. This issue may be exploitable, we did not investigate further. As this issue affects PF_PACKET sockets, it requires CAP_NET_RAW in the process namespace. But note that with user namespaces enabled, any process can create a namespace in which it has CAP_NET_RAW. (CVE-2017-1000111) - The tcp_disconnect function in net/ipv4/tcp.c in the Linux kernel before 4.12 allows local users to cause a denial of service (__tcp_select_window divide-by-zero error and system crash) by triggering a disconnect within a certain tcp_recvmsg code path. (CVE-2017-14106) - Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch. When building a UFO packet with MSG_MORE __ip_append_data() calls ip_ufo_append_data() to append. However in between two send() calls, the append path can be switched from UFO to non-UFO one, which leads to a memory corruption. In case UFO packet lengths exceeds MTU, copy = maxfraglen - skb->len becomes negative on the non-UFO path and the branch to allocate new skb is taken. This triggers fragmentation and computation of fraggap = skb_prev->len - maxfraglen. Fraggap can exceed MTU, causing copy = datalen - transhdrlen - fraggap to become negative. Subsequently skb_copy_and_csum_bits() writes out-of-bounds. A similar issue is present in IPv6 code. The bug was introduced in e89e9cf539a2 ([IPv4/IPv6]: UFO Scatter-gather approach) on Oct 18 2005. (CVE-2017-1000112) Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.