From 8917a777be3ba566377be05117f71b93a5fd909d Mon Sep 17 00:00:00 2001 From: Ivan Delalande Date: Thu, 15 Jun 2017 18:07:07 -0700 Subject: [PATCH] tcp: md5: add TCP_MD5SIG_EXT socket option to set a key address prefix Replace first padding in the tcp_md5sig structure with a new flag field and address prefix length so it can be specified when configuring a new key for TCP MD5 signature. The tcpm_flags field will only be used if the socket option is TCP_MD5SIG_EXT to avoid breaking existing programs, and tcpm_prefixlen only when the TCP_MD5SIG_FLAG_PREFIX flag is set. Signed-off-by: Bob Gilligan Signed-off-by: Eric Mowat Signed-off-by: Ivan Delalande Signed-off-by: David S. Miller --- include/net/tcp.h | 1 + include/uapi/linux/tcp.h | 11 ++++++++--- net/ipv4/tcp.c | 3 ++- net/ipv4/tcp_ipv4.c | 16 ++++++++++++---- net/ipv6/tcp_ipv6.c | 25 ++++++++++++++++++------- 5 files changed, 41 insertions(+), 15 deletions(-) diff --git a/include/net/tcp.h b/include/net/tcp.h index 8f4076d31669..d0751b79d99c 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -1848,6 +1848,7 @@ struct tcp_sock_af_ops { const struct sock *sk, const struct sk_buff *skb); int (*md5_parse)(struct sock *sk, + int optname, char __user *optval, int optlen); #endif diff --git a/include/uapi/linux/tcp.h b/include/uapi/linux/tcp.h index 8204dcebc6f3..a5507c977497 100644 --- a/include/uapi/linux/tcp.h +++ b/include/uapi/linux/tcp.h @@ -117,7 +117,8 @@ enum { #define TCP_SAVED_SYN 28 /* Get SYN headers recorded for connection */ #define TCP_REPAIR_WINDOW 29 /* Get/set window parameters */ #define TCP_FASTOPEN_CONNECT 30 /* Attempt FastOpen with connect */ -#define TCP_ULP 31 /* Attach a ULP to a TCP connection */ +#define TCP_ULP 31 /* Attach a ULP to a TCP connection */ +#define TCP_MD5SIG_EXT 32 /* TCP MD5 Signature with extensions */ struct tcp_repair_opt { __u32 opt_code; @@ -235,11 +236,15 @@ enum { /* for TCP_MD5SIG socket option */ #define TCP_MD5SIG_MAXKEYLEN 80 +/* tcp_md5sig extension flags for TCP_MD5SIG_EXT */ +#define TCP_MD5SIG_FLAG_PREFIX 1 /* address prefix length */ + struct tcp_md5sig { struct __kernel_sockaddr_storage tcpm_addr; /* address associated */ - __u16 __tcpm_pad1; /* zero */ + __u8 tcpm_flags; /* extension flags */ + __u8 tcpm_prefixlen; /* address prefix */ __u16 tcpm_keylen; /* key length */ - __u32 __tcpm_pad2; /* zero */ + __u32 __tcpm_pad; /* zero */ __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */ }; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 11e4ee281aa0..058f509ca98e 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2714,8 +2714,9 @@ static int do_tcp_setsockopt(struct sock *sk, int level, #ifdef CONFIG_TCP_MD5SIG case TCP_MD5SIG: + case TCP_MD5SIG_EXT: /* Read the IP->Key mappings from userspace */ - err = tp->af_specific->md5_parse(sk, optval, optlen); + err = tp->af_specific->md5_parse(sk, optname, optval, optlen); break; #endif case TCP_USER_TIMEOUT: diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index a3c67866b780..bf407f3e20dd 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1066,11 +1066,12 @@ static void tcp_clear_md5_list(struct sock *sk) } } -static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval, - int optlen) +static int tcp_v4_parse_md5_keys(struct sock *sk, int optname, + char __user *optval, int optlen) { struct tcp_md5sig cmd; struct sockaddr_in *sin = (struct sockaddr_in *)&cmd.tcpm_addr; + u8 prefixlen = 32; if (optlen < sizeof(cmd)) return -EINVAL; @@ -1081,15 +1082,22 @@ static int tcp_v4_parse_md5_keys(struct sock *sk, char __user *optval, if (sin->sin_family != AF_INET) return -EINVAL; + if (optname == TCP_MD5SIG_EXT && + cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { + prefixlen = cmd.tcpm_prefixlen; + if (prefixlen > 32) + return -EINVAL; + } + if (!cmd.tcpm_keylen) return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, - AF_INET, 32); + AF_INET, prefixlen); if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) return -EINVAL; return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin->sin_addr.s_addr, - AF_INET, 32, cmd.tcpm_key, cmd.tcpm_keylen, + AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL); } diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index 261689310408..68dc7472b44d 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -515,11 +515,12 @@ static struct tcp_md5sig_key *tcp_v6_md5_lookup(const struct sock *sk, return tcp_v6_md5_do_lookup(sk, &addr_sk->sk_v6_daddr); } -static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval, - int optlen) +static int tcp_v6_parse_md5_keys(struct sock *sk, int optname, + char __user *optval, int optlen) { struct tcp_md5sig cmd; struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&cmd.tcpm_addr; + u8 prefixlen; if (optlen < sizeof(cmd)) return -EINVAL; @@ -530,12 +531,22 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval, if (sin6->sin6_family != AF_INET6) return -EINVAL; + if (optname == TCP_MD5SIG_EXT && + cmd.tcpm_flags & TCP_MD5SIG_FLAG_PREFIX) { + prefixlen = cmd.tcpm_prefixlen; + if (prefixlen > 128 || (ipv6_addr_v4mapped(&sin6->sin6_addr) && + prefixlen > 32)) + return -EINVAL; + } else { + prefixlen = ipv6_addr_v4mapped(&sin6->sin6_addr) ? 32 : 128; + } + 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, 32); + AF_INET, prefixlen); return tcp_md5_do_del(sk, (union tcp_md5_addr *)&sin6->sin6_addr, - AF_INET6, 128); + AF_INET6, prefixlen); } if (cmd.tcpm_keylen > TCP_MD5SIG_MAXKEYLEN) @@ -543,12 +554,12 @@ static int tcp_v6_parse_md5_keys(struct sock *sk, char __user *optval, if (ipv6_addr_v4mapped(&sin6->sin6_addr)) return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr.s6_addr32[3], - AF_INET, 32, cmd.tcpm_key, + AF_INET, prefixlen, cmd.tcpm_key, cmd.tcpm_keylen, GFP_KERNEL); return tcp_md5_do_add(sk, (union tcp_md5_addr *)&sin6->sin6_addr, - AF_INET6, 128, cmd.tcpm_key, cmd.tcpm_keylen, - GFP_KERNEL); + AF_INET6, prefixlen, cmd.tcpm_key, + cmd.tcpm_keylen, GFP_KERNEL); } static int tcp_v6_md5_hash_headers(struct tcp_md5sig_pool *hp, -- 2.20.1