ipv6: route: Fix return value of ip6_neigh_lookup() on neigh_create() error
authorStefano Brivio <sbrivio@redhat.com>
Wed, 2 Jan 2019 12:29:27 +0000 (13:29 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 9 Jan 2019 16:38:35 +0000 (17:38 +0100)
commitccc8b37473276bf7552369ff86406f90d947c2f6
treef5c7b3c4b840b6ca4a46e078deacd0f0e87b8659
parent2210c2737e196a369e033de590d605247c2fb476
ipv6: route: Fix return value of ip6_neigh_lookup() on neigh_create() error

[ Upstream commit 7adf3246092f5e87ed0fa610e8088fae416c581f ]

In ip6_neigh_lookup(), we must not return errors coming from
neigh_create(): if creation of a neighbour entry fails, the lookup should
return NULL, in the same way as it's done in __neigh_lookup().

Otherwise, callers legitimately checking for a non-NULL return value of
the lookup function might dereference an invalid pointer.

For instance, on neighbour table overflow, ndisc_router_discovery()
crashes ndisc_update() by passing ERR_PTR(-ENOBUFS) as 'neigh' argument.

Reported-by: Jianlin Shi <jishi@redhat.com>
Fixes: f8a1b43b709d ("net/ipv6: Create a neigh_lookup for FIB entries")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/ipv6/route.c