CVE-2017-1000112

MEDIUM

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.

References

http://seclists.org/oss-sec/2017/q3/277

http://www.debian.org/security/2017/dsa-3981

http://www.securityfocus.com/bid/100262

http://www.securitytracker.com/id/1039162

https://access.redhat.com/errata/RHSA-2017:2918

https://access.redhat.com/errata/RHSA-2017:2930

https://access.redhat.com/errata/RHSA-2017:2931

https://access.redhat.com/errata/RHSA-2017:3200

https://github.com/xairy/kernel-exploits/tree/master/CVE-2017-1000112

https://www.exploit-db.com/exploits/45147/

Details

Source: MITRE

Published: 2017-10-05

Updated: 2018-08-06

Type: CWE-362

Risk Information

CVSS v2.0

Base Score: 6.9

Vector: (AV:L/AC:M/Au:N/C:C/I:C/A:C)

Impact Score: 10

Exploitability Score: 3.4

Severity: MEDIUM

CVSS v3.0

Base Score: 7

Vector: CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Impact Score: 5.9

Exploitability Score: 1

Severity: HIGH