CVE-2017-1000112

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.

• linux linux kernel (>= 2.6.15 < 3.10.108) • linux linux kernel (>= 3.11 < 3.16.47) • linux linux kernel (>= 3.17 < 3.18.65) • linux linux kernel (>= 3.19 < 4.4.82) • linux linux kernel (>= 4.5 < 4.9.43) • linux linux kernel (>= 4.10 < 4.12.7)