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 <gilligan@arista.com>
Signed-off-by: Eric Mowat <mowat@arista.com>
Signed-off-by: Ivan Delalande <colona@arista.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 11e4ee2..058f509 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 a3c6786..bf407f3 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);
}