[PATCH v3 2/2] tcp: md5: add TCP_MD5SIG_EXT socket option to set a key address prefix
From: Ivan Delalande
Date: Thu Jun 15 2017 - 21:07:29 EST
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 <gilligan@xxxxxxxxxx>
Signed-off-by: Eric Mowat <mowat@xxxxxxxxxx>
Signed-off-by: Ivan Delalande <colona@xxxxxxxxxx>
---
include/net/tcp.h | 1 +
include/uapi/linux/tcp.h | 9 +++++++--
net/ipv4/tcp.c | 3 ++-
net/ipv4/tcp_ipv4.c | 16 ++++++++++++----
net/ipv6/tcp_ipv6.c | 25 ++++++++++++++++++-------
5 files changed, 40 insertions(+), 14 deletions(-)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 2b68023ab095..575f95cb8275 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1802,6 +1802,7 @@ 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 38a2b07afdff..9870b7f08f4f 100644
--- a/include/uapi/linux/tcp.h
+++ b/include/uapi/linux/tcp.h
@@ -117,6 +117,7 @@ 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_MD5SIG_EXT 31 /* TCP MD5 Signature with extensions */
struct tcp_repair_opt {
__u32 opt_code;
@@ -234,11 +235,15 @@ 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 1e4c76d2b827..2a68221d2e55 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2666,8 +2666,9 @@ 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 51ca3bd5a8a3..81d6c16aecdc 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1064,11 +1064,12 @@ 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;
@@ -1079,15 +1080,22 @@ 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 5cf19dab60aa..ae36442786ec 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -514,11 +514,12 @@ 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;
@@ -529,12 +530,22 @@ 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)
@@ -542,12 +553,12 @@ 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,
--
2.13.1