mpls: fix out-of-bounds access when via address not specified
When a via address isn't specified, the via table is left initialised to 0 (NEIGH_ARP_TABLE), and the via address length also left initialised to 0. This results in a via address array of length 0 being allocated (contiguous with route and nexthop array), meaning that when a packet is sent using neigh_xmit the neighbour lookup and creation will cause an out-of-bounds access when accessing the 4 bytes of the IPv4 address it assumes it has been given a pointer to. This could be fixed by allocating the 4 bytes of via address necessary and leaving it as all zeroes. However, it seems wrong to me to use an ipv4 nexthop (including possibly ARPing for 0.0.0.0) when the user didn't specify to do so. Instead, set the via address table to NEIGH_NR_TABLES to signify it hasn't been specified and use this at forwarding time to signify a neigh_xmit using an L2 address consisting of the device address. This mechanism is the same as that used for both ARP and ND for loopback interfaces and those flagged as no-arp, which are all we can really support in this case. Fixes: cf4b24f0 ("mpls: reduce memory usage of routes") Signed-off-by: NRobert Shearman <rshearma@brocade.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Showing
想要评论请 注册 或 登录