[PATCH 4.9 18/28] net: Only honor ifindex in IP_PKTINFO if non-0

Greg Kroah-Hartman
2018-03-29T18:06:38Z

From: David Ahern <dsahern@gmail.com>

[ 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@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
@@ -242,7 +242,8 @@ int ip_cmsg_send(struct sock *sk, 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;
}
@@ -272,7 +273,8 @@ int ip_cmsg_send(struct sock *sk, 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;
}