CVE-2017-1000112

NameCVE-2017-1000112
DescriptionLinux 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SuSE, Mageia, GitHub code/issues, web search, more)
ReferencesDSA-3981-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)wheezy3.2.78-1vulnerable
wheezy (security)3.2.93-1vulnerable
jessie3.16.43-2+deb8u2vulnerable
jessie (security)3.16.43-2+deb8u5fixed
stretch4.9.51-1fixed
stretch (security)4.9.30-2+deb9u5fixed
buster, sid4.13.4-2fixed

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

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsource(unstable)4.12.6-1low
linuxsourcejessie3.16.43-2+deb8u5DSA-3981-1
linuxsourcestretch4.9.30-2+deb9u5DSA-3981-1

Notes

Introduced by: https://git.kernel.org/linus/e89e9cf539a28df7d0eb1d0a545368e9920b34ac (2.6.15-rc1)
Fixed by: https://git.kernel.org/linus/85f1bd9a7b5a79d5baa8bf44af19658f7bf77bfa

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