This is a note to let you know that I've just added the patch titled net: Only honor ifindex in IP_PKTINFO if non-0 to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-only-honor-ifindex-in-ip_pktinfo-if-non-0.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Mar 29 08:33:08 CEST 2018 From: David Ahern <dsahern@xxxxxxxxx> Date: Fri, 16 Feb 2018 11:03:03 -0800 Subject: net: Only honor ifindex in IP_PKTINFO if non-0 From: David Ahern <dsahern@xxxxxxxxx> [ Upstream commit 2cbb4ea7de167b02ffa63e9cdfdb07a7e7094615 ] Only allow ifindex from IP_PKTINFO to override SO_BINDTODEVICE settings if the index is actually set in the message. Signed-off-by: David Ahern <dsahern@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/ip_sockglue.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -241,7 +241,8 @@ int ip_cmsg_send(struct net *net, struct src_info = (struct in6_pktinfo *)CMSG_DATA(cmsg); if (!ipv6_addr_v4mapped(&src_info->ipi6_addr)) return -EINVAL; - ipc->oif = src_info->ipi6_ifindex; + if (src_info->ipi6_ifindex) + ipc->oif = src_info->ipi6_ifindex; ipc->addr = src_info->ipi6_addr.s6_addr32[3]; continue; } @@ -264,7 +265,8 @@ int ip_cmsg_send(struct net *net, struct if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct in_pktinfo))) return -EINVAL; info = (struct in_pktinfo *)CMSG_DATA(cmsg); - ipc->oif = info->ipi_ifindex; + if (info->ipi_ifindex) + ipc->oif = info->ipi_ifindex; ipc->addr = info->ipi_spec_dst.s_addr; break; } Patches currently in stable-queue which might be from dsahern@xxxxxxxxx are queue-4.4/net-only-honor-ifindex-in-ip_pktinfo-if-non-0.patch