CVE ID:	CVE-2017-1000112
Description:	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.
Test IDs:	1.3.6.1.4.1.25623.1.1.4.2017.2509.1   1.3.6.1.4.1.25623.1.1.4.2017.2500.1   1.3.6.1.4.1.25623.1.1.4.2017.2511.1   1.3.6.1.4.1.25623.1.1.4.2017.2510.1   1.3.6.1.4.1.25623.1.1.4.2017.2440.1   1.3.6.1.4.1.25623.1.1.4.2017.2442.1   1.3.6.1.4.1.25623.1.1.4.2017.2506.1   1.3.6.1.4.1.25623.1.1.4.2017.2439.1   1.3.6.1.4.1.25623.1.1.4.2017.2437.1   1.3.6.1.4.1.25623.1.1.4.2017.2498.1   1.3.6.1.4.1.25623.1.1.4.2017.2438.1   1.3.6.1.4.1.25623.1.1.4.2017.2508.1   1.3.6.1.4.1.25623.1.1.4.2017.2441.1   1.3.6.1.4.1.25623.1.1.4.2017.2499.1   1.3.6.1.4.1.25623.1.1.4.2017.2436.1   1.3.6.1.4.1.25623.1.1.4.2017.2424.1   1.3.6.1.4.1.25623.1.1.2.2017.1256   1.3.6.1.4.1.25623.1.1.4.2017.2423.1   1.3.6.1.4.1.25623.1.1.4.2017.2443.1
Cross References:	Common Vulnerability Exposure (CVE) ID: CVE-2017-1000112 BugTraq ID: 100262 http://www.securityfocus.com/bid/100262 Debian Security Information: DSA-3981 (Google Search) http://www.debian.org/security/2017/dsa-3981 https://www.exploit-db.com/exploits/45147/ https://github.com/xairy/kernel-exploits/tree/master/CVE-2017-1000112 http://seclists.org/oss-sec/2017/q3/277 RedHat Security Advisories: RHSA-2017:2918 https://access.redhat.com/errata/RHSA-2017:2918 RedHat Security Advisories: RHSA-2017:2930 https://access.redhat.com/errata/RHSA-2017:2930 RedHat Security Advisories: RHSA-2017:2931 https://access.redhat.com/errata/RHSA-2017:2931 RedHat Security Advisories: RHSA-2017:3200 https://access.redhat.com/errata/RHSA-2017:3200 RedHat Security Advisories: RHSA-2019:1931 https://access.redhat.com/errata/RHSA-2019:1931 RedHat Security Advisories: RHSA-2019:1932 https://access.redhat.com/errata/RHSA-2019:1932 RedHat Security Advisories: RHSA-2019:4159 https://access.redhat.com/errata/RHSA-2019:4159 http://www.securitytracker.com/id/1039162