[PATCH v2 2/4] treewide: Improve robustness against sockaddrs of unexpected family

[David Gibson <david@gibson.dropbear.id.au>]

inany_from_sockaddr() expects a socket address of family AF_INET or
AF_INET6 and ASSERT()s if it gets anything else.  In many of the callers we
can handle an unexpected family more gracefully, though, e.g. by failing
a single flow rather than killing passt.

Change inany_from_sockaddr() to return an error instead of ASSERT()ing,
and handle those errors in the callers.  Improve the reporting of any such
errors while we're at it.

With this greater robustness, allow inany_from_sockaddr() to take a void *
rather than specifically a union sockaddr_inany *.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 flow.c     | 16 ++++++++++++++--
 inany.h    | 28 +++++++++++++++++-----------
 tcp.c      | 10 ++++------
 udp_flow.c |  6 +++---
 4 files changed, 38 insertions(+), 22 deletions(-)

diff --git a/flow.c b/flow.c
index 3c81cb42..447c0211 100644
--- a/flow.c
+++ b/flow.c
@@ -408,7 +408,12 @@ struct flowside *flow_initiate_sa(union flow *flow, uint8_t pif,
 {
 	struct flowside *ini = &flow->f.side[INISIDE];
 
-	inany_from_sockaddr(&ini->eaddr, &ini->eport, ssa);
+	if (inany_from_sockaddr(&ini->eaddr, &ini->eport, ssa) < 0) {
+		char str[SOCKADDR_STRLEN];
+
+		ASSERT_WITH_MSG(0, "Bad socket address %s",
+				sockaddr_ntop(ssa, str, sizeof(str)));
+	}
 	if (daddr)
 		ini->oaddr = *daddr;
 	else if (inany_v4(&ini->eaddr))
@@ -768,7 +773,14 @@ flow_sidx_t flow_lookup_sa(const struct ctx *c, uint8_t proto, uint8_t pif,
 		.oport = oport,
 	};
 
-	inany_from_sockaddr(&side.eaddr, &side.eport, esa);
+	if (inany_from_sockaddr(&side.eaddr, &side.eport, esa) < 0) {
+		char str[SOCKADDR_STRLEN];
+
+		warn("Flow lookup on bad socket address %s",
+		     sockaddr_ntop(esa, str, sizeof(str)));
+		return FLOW_SIDX_NONE;
+	}
+
 	if (oaddr)
 		side.oaddr = *oaddr;
 	else if (inany_v4(&side.eaddr))
diff --git a/inany.h b/inany.h
index 1c247e1e..7ca5cbd3 100644
--- a/inany.h
+++ b/inany.h
@@ -237,24 +237,30 @@ static inline void inany_from_af(union inany_addr *aa,
 }
 
 /** inany_from_sockaddr - Extract IPv[46] address and port number from sockaddr
- * @aa:		Pointer to store IPv[46] address
+ * @dst:	Pointer to store IPv[46] address (output)
  * @port:	Pointer to store port number, host order
- * @addr:	AF_INET or AF_INET6 socket address
+ * @addr:	Socket address
+ *
+ * Return: 0 on success, -1 on error (bad address family)
  */
-static inline void inany_from_sockaddr(union inany_addr *aa, in_port_t *port,
-				       const union sockaddr_inany *sa)
+static inline int inany_from_sockaddr(union inany_addr *dst, in_port_t *port,
+				      const void *addr)
 {
+	const union sockaddr_inany *sa = (const union sockaddr_inany *)addr;
+
 	if (sa->sa_family == AF_INET6) {
-		inany_from_af(aa, AF_INET6, &sa->sa6.sin6_addr);
+		inany_from_af(dst, AF_INET6, &sa->sa6.sin6_addr);
 		*port = ntohs(sa->sa6.sin6_port);
-	} else if (sa->sa_family == AF_INET) {
-		inany_from_af(aa, AF_INET, &sa->sa4.sin_addr);
+		return 0;
+	}
+
+	if (sa->sa_family == AF_INET) {
+		inany_from_af(dst, AF_INET, &sa->sa4.sin_addr);
 		*port = ntohs(sa->sa4.sin_port);
-	} else {
-		/* Not valid to call with other address families */
-		ASSERT_WITH_MSG(0, "Unexpected sockaddr family: %u",
-				sa->sa_family);
+		return 0;
 	}
+
+	return -1;
 }
 
 /** inany_siphash_feed- Fold IPv[46] address into an in-progress siphash
diff --git a/tcp.c b/tcp.c
index 9c6bc529..0ac298a7 100644
--- a/tcp.c
+++ b/tcp.c
@@ -1546,9 +1546,8 @@ static void tcp_conn_from_tap(const struct ctx *c, sa_family_t af,
 
 	if (c->mode == MODE_VU) { /* To rebind to same oport after migration */
 		sl = sizeof(sa);
-		if (!getsockname(s, &sa.sa, &sl))
-			inany_from_sockaddr(&tgt->oaddr, &tgt->oport, &sa);
-		else
+		if (getsockname(s, &sa.sa, &sl) ||
+		    inany_from_sockaddr(&tgt->oaddr, &tgt->oport, &sa) < 0)
 			err_perror("Can't get local address for socket %i", s);
 	}
 
@@ -2204,9 +2203,8 @@ void tcp_listen_handler(const struct ctx *c, union epoll_ref ref,
 			       NULL, ref.tcp_listen.port);
 
 	if (c->mode == MODE_VU) { /* Rebind to same address after migration */
-		if (!getsockname(s, &sa.sa, &sl))
-			inany_from_sockaddr(&ini->oaddr, &ini->oport, &sa);
-		else
+		if (getsockname(s, &sa.sa, &sl) ||
+		    inany_from_sockaddr(&ini->oaddr, &ini->oport, &sa) < 0)
 			err_perror("Can't get local address for socket %i", s);
 	}
 
diff --git a/udp_flow.c b/udp_flow.c
index ef2cbb06..fea1cf3c 100644
--- a/udp_flow.c
+++ b/udp_flow.c
@@ -158,12 +158,12 @@ static flow_sidx_t udp_flow_new(const struct ctx *c, union flow *flow,
 		socklen_t sl = sizeof(sa);
 		in_port_t port;
 
-		if (getsockname(uflow->s[TGTSIDE], &sa.sa, &sl) < 0) {
+		if (getsockname(uflow->s[TGTSIDE], &sa.sa, &sl) < 0 ||
+		    inany_from_sockaddr(&uflow->f.side[TGTSIDE].oaddr,
+					&port, &sa) < 0) {
 			flow_perror(uflow, "Unable to determine local address");
 			goto cancel;
 		}
-		inany_from_sockaddr(&uflow->f.side[TGTSIDE].oaddr,
-				    &port, &sa);
 		if (port != tgt->oport) {
 			flow_err(uflow, "Unexpected local port");
 			goto cancel;
-- 
@@ -158,12 +158,12 @@ static flow_sidx_t udp_flow_new(const struct ctx *c, union flow *flow,
 		socklen_t sl = sizeof(sa);
 		in_port_t port;
 
-		if (getsockname(uflow->s[TGTSIDE], &sa.sa, &sl) < 0) {
+		if (getsockname(uflow->s[TGTSIDE], &sa.sa, &sl) < 0 ||
+		    inany_from_sockaddr(&uflow->f.side[TGTSIDE].oaddr,
+					&port, &sa) < 0) {
 			flow_perror(uflow, "Unable to determine local address");
 			goto cancel;
 		}
-		inany_from_sockaddr(&uflow->f.side[TGTSIDE].oaddr,
-				    &port, &sa);
 		if (port != tgt->oport) {
 			flow_err(uflow, "Unexpected local port");
 			goto cancel;
-- 
2.49.0