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high7.0Public exploit code

CVE-2017-1000112

Linux kernel: Exploitable memory corruption due to UFO to non-UFO path switch.

Public exploit code

Working exploit or proof of concept code has been published for this vulnerability. Treat unpatched systems as at risk.

Impact

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.

Affected products

VendorProductAffected versions
LinuxLinux Kernel
from 2.6.15 before 3.10.108
from 3.11 before 3.16.47
from 3.17 before 3.18.65
from 3.19 before 4.4.82
from 4.5 before 4.9.43
from 4.10 before 4.12.7

Weakness classification

CWE-362

References