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authorOndrej Zajicek <santiago@crfreenet.org>2008-10-26 22:42:39 +0100
committerOndrej Zajicek <santiago@crfreenet.org>2008-10-26 22:42:39 +0100
commitd51aa2819005a03e4cfb6f62333be6ccadfb3c06 (patch)
tree2a76b826cfdac4cf1a94a305f9fe416a2df45840
parent11cb620266035ffbe17b21c4a174380cb8b6a521 (diff)
downloadbird-d51aa2819005a03e4cfb6f62333be6ccadfb3c06.tar
bird-d51aa2819005a03e4cfb6f62333be6ccadfb3c06.zip
Implementation of MD5 authentication of BGP sessions.
-rw-r--r--lib/socket.h2
-rw-r--r--proto/bgp/bgp.c19
-rw-r--r--proto/bgp/bgp.h1
-rw-r--r--proto/bgp/config.Y4
-rw-r--r--sysdep/linux/sysio.h21
-rw-r--r--sysdep/unix/io.c75
6 files changed, 120 insertions, 2 deletions
diff --git a/lib/socket.h b/lib/socket.h
index ab932b3..4aa521d 100644
--- a/lib/socket.h
+++ b/lib/socket.h
@@ -39,6 +39,7 @@ typedef struct birdsock {
int fd; /* System-dependent data */
node n;
void *rbuf_alloc, *tbuf_alloc;
+ char *password; /* Password for MD5 authentication */
} sock;
sock *sk_new(pool *); /* Allocate new socket */
@@ -47,6 +48,7 @@ int sk_send(sock *, unsigned len); /* Send data, <0=err, >0=ok, 0=sleep */
int sk_send_to(sock *, unsigned len, ip_addr to, unsigned port); /* sk_send to given destination */
void sk_reallocate(sock *); /* Free and allocate tbuf & rbuf */
void sk_dump_all(void);
+int sk_set_md5_auth(sock *s, ip_addr a, char *passwd); /* Add or remove security associations for given passive socket */
static inline int
sk_send_buffer_empty(sock *sk)
diff --git a/proto/bgp/bgp.c b/proto/bgp/bgp.c
index ed2524c..e1f5ec0 100644
--- a/proto/bgp/bgp.c
+++ b/proto/bgp/bgp.c
@@ -78,10 +78,14 @@ static void bgp_setup_listen_sk(void);
static void
-bgp_close(struct bgp_proto *p UNUSED)
+bgp_close(struct bgp_proto *p)
{
ASSERT(bgp_counter);
bgp_counter--;
+
+ if (p->cf->password)
+ sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, NULL);
+
if (!bgp_counter)
{
rfree(bgp_listen_sk);
@@ -330,6 +334,7 @@ bgp_connect(struct bgp_proto *p) /* Enter Connect state and start establishing c
bgp_setup_conn(p, conn);
bgp_setup_sk(p, conn, s);
s->tx_hook = bgp_connected;
+ s->password = p->cf->password;
conn->state = BS_CONNECT;
if (sk_open(s))
{
@@ -506,6 +511,7 @@ bgp_start(struct proto *P)
bgp_counter++;
bgp_setup_listen_sk();
+
if (!bgp_linpool)
bgp_linpool = lp_new(&root_pool, 4080);
@@ -523,6 +529,17 @@ bgp_start(struct proto *P)
lock->hook = bgp_start_locked;
lock->data = p;
olock_acquire(lock);
+
+ /* We should create security association after we get a lock not to
+ * break existing connections.
+ */
+ if (p->cf->password)
+ {
+ int rv = sk_set_md5_auth(bgp_listen_sk, p->cf->remote_ip, p->cf->password);
+ if (rv < 0)
+ return PS_STOP;
+ }
+
return PS_START;
}
diff --git a/proto/bgp/bgp.h b/proto/bgp/bgp.h
index aa1bd10..9338324 100644
--- a/proto/bgp/bgp.h
+++ b/proto/bgp/bgp.h
@@ -33,6 +33,7 @@ struct bgp_config {
unsigned error_delay_time_min; /* Time to wait after an error is detected */
unsigned error_delay_time_max;
unsigned disable_after_error; /* Disable the protocol when error is detected */
+ char *password; /* Password used for MD5 authentication */
};
struct bgp_conn {
diff --git a/proto/bgp/config.Y b/proto/bgp/config.Y
index 63dfb61..580c008 100644
--- a/proto/bgp/config.Y
+++ b/proto/bgp/config.Y
@@ -20,7 +20,7 @@ CF_KEYWORDS(BGP, LOCAL, NEIGHBOR, AS, HOLD, TIME, CONNECT, RETRY, KEEPALIVE,
MULTIHOP, STARTUP, VIA, NEXT, HOP, SELF, DEFAULT, PATH, METRIC,
ERROR, START, DELAY, FORGET, WAIT, DISABLE, AFTER,
BGP_PATH, BGP_LOCAL_PREF, BGP_MED, BGP_ORIGIN, BGP_NEXT_HOP,
- BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY, SOURCE, ADDRESS)
+ BGP_ATOMIC_AGGR, BGP_AGGREGATOR, BGP_COMMUNITY, SOURCE, ADDRESS, PASSWORD)
CF_GRAMMAR
@@ -38,6 +38,7 @@ bgp_proto_start: proto_start BGP {
BGP_CFG->error_amnesia_time = 300;
BGP_CFG->error_delay_time_min = 60;
BGP_CFG->error_delay_time_max = 300;
+ BGP_CFG->password = NULL;
}
;
@@ -65,6 +66,7 @@ bgp_proto:
| bgp_proto ERROR FORGET TIME expr ';' { BGP_CFG->error_amnesia_time = $5; }
| bgp_proto ERROR WAIT TIME expr ',' expr ';' { BGP_CFG->error_delay_time_min = $5; BGP_CFG->error_delay_time_max = $7; }
| bgp_proto DISABLE AFTER ERROR bool ';' { BGP_CFG->disable_after_error = $5; }
+ | bgp_proto PASSWORD TEXT ';' { BGP_CFG->password = $3; }
;
CF_ADDTO(dynamic_attr, BGP_PATH
diff --git a/sysdep/linux/sysio.h b/sysdep/linux/sysio.h
index 3a29cdc..b0aff71 100644
--- a/sysdep/linux/sysio.h
+++ b/sysdep/linux/sysio.h
@@ -139,3 +139,24 @@ static inline char *sysio_mcast_join(sock *s)
#endif
#endif
+
+#include <linux/socket.h>
+#include <linux/tcp.h>
+
+/* For the case that we have older kernel headers */
+/* Copied from Linux kernel file include/linux/tcp.h */
+
+#ifndef TCP_MD5SIG
+
+#define TCP_MD5SIG 14
+#define TCP_MD5SIG_MAXKEYLEN 80
+
+struct tcp_md5sig {
+ struct __kernel_sockaddr_storage tcpm_addr; /* address associated */
+ __u16 __tcpm_pad1; /* zero */
+ __u16 tcpm_keylen; /* key length */
+ __u32 __tcpm_pad2; /* zero */
+ __u8 tcpm_key[TCP_MD5SIG_MAXKEYLEN]; /* key (binary) */
+};
+
+#endif
diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 7dcca21..6faa176 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -546,6 +546,7 @@ sk_new(pool *p)
s->err_hook = NULL;
s->fd = -1;
s->rbuf_alloc = s->tbuf_alloc = NULL;
+ s->password = NULL;
return s;
}
@@ -642,6 +643,71 @@ bad:
return err;
}
+
+/* FIXME: check portability */
+
+static int
+sk_set_md5_auth_int(sock *s, sockaddr *sa, char *passwd)
+{
+ struct tcp_md5sig md5;
+
+ memset(&md5, 0, sizeof(md5));
+ memcpy(&md5.tcpm_addr, (struct sockaddr *) sa, sizeof(*sa));
+
+ if (passwd)
+ {
+ int len = strlen(passwd);
+
+ if (len > TCP_MD5SIG_MAXKEYLEN)
+ {
+ log(L_ERR "MD5 password too long");
+ return -1;
+ }
+
+ md5.tcpm_keylen = len;
+ memcpy(&md5.tcpm_key, passwd, len);
+ }
+
+ int rv = setsockopt(s->fd, IPPROTO_TCP, TCP_MD5SIG, &md5, sizeof(md5));
+
+ if (rv < 0)
+ {
+ if (errno == ENOPROTOOPT)
+ log(L_ERR "Kernel does not support TCP MD5 signatures");
+ else
+ log(L_ERR "sk_set_md5_auth_int: setsockopt: %m");
+ }
+
+ return rv;
+}
+
+/**
+ * sk_set_md5_auth - add / remove MD5 security association for given socket.
+ * @s: socket
+ * @a: IP address of the other side
+ * @passwd: password used for MD5 authentication
+ *
+ * In TCP MD5 handling code in kernel, there is a set of pairs
+ * (address, password) used to choose password according to
+ * address of the other side. This function is useful for
+ * listening socket, for active sockets it is enough to set
+ * s->password field.
+ *
+ * When called with passwd != NULL, the new pair is added,
+ * When called with passwd == NULL, the existing pair is removed.
+ *
+ * Result: 0 for success, -1 for an error.
+ */
+
+int
+sk_set_md5_auth(sock *s, ip_addr a, char *passwd)
+{
+ sockaddr sa;
+ fill_in_sockaddr(&sa, a, 0);
+ return sk_set_md5_auth_int(s, &sa, passwd);
+}
+
+
static void
sk_tcp_connected(sock *s)
{
@@ -805,6 +871,14 @@ sk_open(sock *s)
ERR("bind");
}
fill_in_sockaddr(&sa, s->daddr, s->dport);
+
+ if (s->password)
+ {
+ int rv = sk_set_md5_auth_int(s, &sa, s->password);
+ if (rv < 0)
+ goto bad_no_log;
+ }
+
switch (type)
{
case SK_TCP_ACTIVE:
@@ -846,6 +920,7 @@ sk_open(sock *s)
bad:
log(L_ERR "sk_open: %s: %m", err);
+bad_no_log:
close(fd);
s->fd = -1;
return -1;