From 6b102db50cdde3ba2f78631ed21222edf3a5fb51 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 30 Dec 2019 14:14:29 -0800 Subject: [PATCH] net: Add device index to tcp_md5sig Add support for userspace to specify a device index to limit the scope of an entry via the TCP_MD5SIG_EXT setsockopt. The existing __tcpm_pad is renamed to tcpm_ifindex and the new field is only checked if the new TCP_MD5SIG_FLAG_IFINDEX is set in tcpm_flags. For now, the device index must point to an L3 master device (e.g., VRF). The API and error handling are setup to allow the constraint to be relaxed in the future to any device index. Signed-off-by: David Ahern Signed-off-by: David S. Miller --- include/uapi/linux/tcp.h | 5 +++-- net/ipv4/tcp_ipv4.c | 18 ++++++++++++++++++ net/ipv6/tcp_ipv6.c | 20 +++++++++++++++++++- 3 files changed, 40 insertions(+), 3 deletions(-) diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 74af1f759cee..d87184e673ca 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -317,14 +317,15 @@ enum { #define TCP_MD5SIG_MAXKEYLEN 80 /* tcp_md5sig extension flags for TCP_MD5SIG_EXT */ -#define TCP_MD5SIG_FLAG_PREFIX 1 /* address prefix length */ +#define TCP_MD5SIG_FLAG_PREFIX 0x1 /* address prefix length */ +#define TCP_MD5SIG_FLAG_IFINDEX 0x2 /* ifindex set */ struct tcp_md5sig { struct __kernel_sockaddr_storage tcpm_addr; /* address associated */ __u8 tcpm_flags; /* extension flags */ __u8 tcpm_prefixlen; /* address prefix */ __u16 tcpm_keylen; /* key length */ - __u32 __tcpm_pad; /* zero */ + int tcpm_ifindex; /* device index for scope */ __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */ }; diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 30b3f19d6301..4adac9c75343 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1196,6 +1196,24 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, return -EINVAL; } + if (optname == TCP_MD5SIG_EXT && + cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) { + struct net_device *dev; + + rcu_read_lock(); + dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex); + if (dev && netif_is_l3_master(dev)) + l3index = dev->ifindex; + + rcu_read_unlock(); + + /* ok to reference set/not set outside of rcu; + * right now device MUST be an L3 master + */ + if (!dev || !l3index) + return -EINVAL; + } + addr = (union tcp_md5_addr *)&sin->sin_addr.s_addr; if (!cmd.tcpm_keylen) diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 71ad7d89be0f..95e4e1e95db2 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -578,10 +578,28 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, int optname, prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128; } + if (optname == TCP_MD5SIG_EXT && + cmd.tcpm_flags & TCP_MD5SIG_FLAG_IFINDEX) { + struct net_device *dev; + + rcu_read_lock(); + dev = dev_get_by_index_rcu(sock_net(sk), cmd.tcpm_ifindex); + if (dev && netif_is_l3_master(dev)) + l3index = dev->ifindex; + rcu_read_unlock(); + + /* ok to reference set/not set outside of rcu; + * right now device MUST be an L3 master + */ + if (!dev || !l3index) + return -EINVAL; + } + if (!cmd.tcpm_keylen) { if (ipv6_addr_v4mapped(&sin6->sin6_addr)) return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3], - AF_INET, prefixlen, l3index); + AF_INET, prefixlen, + l3index); return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr, AF_INET6, prefixlen, l3index); } -- 2.30.2