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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
Exploits
Public proof-of-concept code below. AS-IS, for defenders and authorised testing only.
Metasploit modules
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| arch | fixed | 4.13-1 | |
| debian | bookworm | fixed | 4.12.6-1 |
| debian | bullseye | fixed | 4.12.6-1 |
| debian | forky | fixed | 4.12.6-1 |
| debian | sid | fixed | 4.12.6-1 |
| debian | trixie | fixed | 4.12.6-1 |
| linux-kernel | affected | 3.10.108 |
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://access.redhat.com/errata/RHSA-2019:1931
- https://access.redhat.com/errata/RHSA-2019:1932
- https://access.redhat.com/errata/RHSA-2019:4159
- https://github.com/xairy/kernel-exploits/tree/master/CVE-2017-1000112
- https://www.exploit-db.com/exploits/45147/
- https://www.suse.com/security/cve/CVE-2017-1000112.html
- https://security-tracker.debian.org/tracker/CVE-2017-1000112
CWEs
CWE-362
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.