CVE-2017-1000112

Name	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.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-3981-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
linux (PTS)	jessie, jessie (lts)	3.16.84-1	fixed
	stretch (security)	4.9.320-2	fixed
	stretch (lts), stretch	4.9.320-3	fixed
	buster	4.19.249-2	fixed
	buster (security)	4.19.304-1	fixed
	bullseye	5.10.209-2	fixed
	bullseye (security)	5.10.205-2	fixed
	bookworm	6.1.76-1	fixed
	bookworm (security)	6.1.85-1	fixed
	trixie	6.6.15-2	fixed
	sid	6.7.12-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin
linux	source	jessie	3.16.43-2+deb8u5		DSA-3981-1
linux	source	stretch	4.9.30-2+deb9u5		DSA-3981-1
linux	source	(unstable)	4.12.6-1	low

Notes

[wheezy] - linux <ignored> (Low severity and difficult to backport)
Introduced by: https://git.kernel.org/linus/e89e9cf539a28df7d0eb1d0a545368e9920b34ac (2.6.15-rc1)
Fixed by: https://git.kernel.org/linus/85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa