1 files changed, 243 insertions, 0 deletions
diff --git a/src/daemon/agent_priv.c b/src/daemon/agent_priv.c
new file mode 100644
index 0000000..b5cf72a
--- /dev/null
+++ b/src/daemon/agent_priv.c
@@ -0,0 +1,243 @@
+/* -*- mode: c; c-file-style: "openbsd" -*- */
+/*
+ * Copyright (c) 2008 Vincent Bernat <bernat@luffy.cx>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+/* Some of the code here (agent_priv_unix_*) has been adapted from code from
+ * Net-SNMP project (snmplib/snmpUnixDomain.c). Net-SNMP project is licensed
+ * using BSD and BSD-like licenses. I don't know the exact license of the file
+ * snmplib/snmpUnixDomain.c. */
+
+#include "lldpd.h"
+
+#include <unistd.h>
+#include <errno.h>
+#include <poll.h>
+
+#ifdef ENABLE_PRIVSEP
+#  include <net-snmp/net-snmp-config.h>
+#  include <net-snmp/net-snmp-includes.h>
+#  include <net-snmp/agent/net-snmp-agent-includes.h>
+#  include <net-snmp/agent/snmp_vars.h>
+#  include <net-snmp/library/snmpUnixDomain.h>
+
+#  ifdef ASN_PRIV_STOP
+/* NetSNMP 5.8+ */
+#    define F_SEND_SIGNATURE \
+      netsnmp_transport *t, const void *buf, int size, void **opaque, int *olength
+#    define F_FMTADDR_SIGNATURE netsnmp_transport *t, const void *data, int len
+#    define F_FROM_OSTRING_SIGNATURE const void *o, size_t o_len, int local
+#  else
+#    define F_SEND_SIGNATURE \
+      netsnmp_transport *t, void *buf, int size, void **opaque, int *olength
+#    define F_FMTADDR_SIGNATURE netsnmp_transport *t, void *data, int len
+#    define F_FROM_OSTRING_SIGNATURE const u_char *o, size_t o_len, int local
+#  endif
+
+static oid netsnmp_unix[] = { TRANSPORT_DOMAIN_LOCAL };
+static netsnmp_tdomain unixDomain;
+
+static char *
+agent_priv_unix_fmtaddr(F_FMTADDR_SIGNATURE)
+{
+	/* We don't bother to implement the full function */
+	return strdup("Local Unix socket with privilege separation: unknown");
+}
+
+static int
+agent_priv_unix_recv(netsnmp_transport *t, void *buf, int size, void **opaque,
+    int *olength)
+{
+	int rc = -1;
+	socklen_t tolen = sizeof(struct sockaddr_un);
+	struct sockaddr *to = NULL;
+
+	if (t == NULL || t->sock < 0) goto recv_error;
+	to = (struct sockaddr *)calloc(1, sizeof(struct sockaddr_un));
+	if (to == NULL) goto recv_error;
+	if (getsockname(t->sock, to, &tolen) != 0) goto recv_error;
+	while (rc < 0) {
+		rc = recv(t->sock, buf, size, 0);
+		/* TODO: handle the (unlikely) case where we get EAGAIN or EWOULDBLOCK
+		 */
+		if (rc < 0 && errno != EINTR) {
+			log_warn("snmp", "unable to receive from fd %d", t->sock);
+			goto recv_error;
+		}
+	}
+	*opaque = (void *)to;
+	*olength = sizeof(struct sockaddr_un);
+	return rc;
+
+recv_error:
+	free(to);
+	*opaque = NULL;
+	*olength = 0;
+	return -1;
+}
+
+#  define AGENT_WRITE_TIMEOUT 2000
+static int
+agent_priv_unix_send(F_SEND_SIGNATURE)
+{
+	int rc = -1;
+
+	if (t != NULL && t->sock >= 0) {
+		struct pollfd sagentx = { .fd = t->sock,
+			.events = POLLOUT | POLLERR | POLLHUP };
+		while (rc < 0) {
+			rc = poll(&sagentx, 1, AGENT_WRITE_TIMEOUT);
+			if (rc == 0) {
+				log_warnx("snmp",
+				    "timeout while communicating with the master agent");
+				rc = -1;
+				break;
+			}
+			if (rc > 0) {
+				/* We can either write or have an error somewhere */
+				rc = send(t->sock, buf, size, 0);
+				if (rc < 0) {
+					if (errno == EAGAIN || errno == EWOULDBLOCK ||
+					    errno == EINTR)
+						/* Let's retry */
+						continue;
+					log_warn("snmp",
+					    "error while sending to master agent");
+					break;
+				}
+			} else {
+				if (errno != EINTR) {
+					log_warn("snmp",
+					    "error while attempting to send to master agent");
+					break;
+				}
+				continue;
+			}
+		}
+	}
+	return rc;
+}
+
+static int
+agent_priv_unix_close(netsnmp_transport *t)
+{
+	int rc = 0;
+
+	if (t->sock >= 0) {
+		rc = close(t->sock);
+		t->sock = -1;
+		return rc;
+	}
+	return -1;
+}
+
+static int
+agent_priv_unix_accept(netsnmp_transport *t)
+{
+	log_warnx("snmp", "should not have been called");
+	return -1;
+}
+
+static netsnmp_transport *
+agent_priv_unix_transport(const char *string, int len, int local)
+{
+	struct sockaddr_un addr = { .sun_family = AF_UNIX };
+	netsnmp_transport *t = NULL;
+
+	if (local) {
+		log_warnx("snmp", "should not have been called for local transport");
+		return NULL;
+	}
+	if (!string) return NULL;
+	if (len >= sizeof(addr.sun_path) ||
+	    strlcpy(addr.sun_path, string, sizeof(addr.sun_path)) >=
+		sizeof(addr.sun_path)) {
+		log_warnx("snmp", "path too long for Unix domain transport");
+		return NULL;
+	}
+
+	if ((t = (netsnmp_transport *)calloc(1, sizeof(netsnmp_transport))) == NULL)
+		return NULL;
+
+	t->domain = netsnmp_unix;
+	t->domain_length = sizeof(netsnmp_unix) / sizeof(netsnmp_unix[0]);
+
+	if ((t->sock = priv_snmp_socket(&addr)) < 0) {
+		netsnmp_transport_free(t);
+		return NULL;
+	}
+
+	t->flags = NETSNMP_TRANSPORT_FLAG_STREAM;
+
+	if ((t->remote = (u_char *)calloc(1, strlen(addr.sun_path) + 1)) == NULL) {
+		agent_priv_unix_close(t);
+		netsnmp_transport_free(t);
+		return NULL;
+	}
+	memcpy(t->remote, addr.sun_path, strlen(addr.sun_path));
+	t->remote_length = strlen(addr.sun_path);
+
+	t->msgMaxSize = 0x7fffffff;
+	t->f_recv = agent_priv_unix_recv;
+	t->f_send = agent_priv_unix_send;
+	t->f_close = agent_priv_unix_close;
+	t->f_accept = agent_priv_unix_accept;
+	t->f_fmtaddr = agent_priv_unix_fmtaddr;
+
+	return t;
+}
+
+#  if HAVE_NETSNMP_TDOMAIN_F_CREATE_FROM_TSTRING_NEW
+static netsnmp_transport *
+agent_priv_unix_create_tstring_new(const char *string, int local,
+    const char *default_target)
+{
+	if ((!string || *string == '\0') && default_target && *default_target != '\0') {
+		string = default_target;
+	}
+	if (!string) return NULL;
+	return agent_priv_unix_transport(string, strlen(string), local);
+}
+#  else
+static netsnmp_transport *
+agent_priv_unix_create_tstring(const char *string, int local)
+{
+	if (!string) return NULL;
+	return agent_priv_unix_transport(string, strlen(string), local);
+}
+#  endif
+
+static netsnmp_transport *
+agent_priv_unix_create_ostring(F_FROM_OSTRING_SIGNATURE)
+{
+	return agent_priv_unix_transport((char *)o, o_len, local);
+}
+
+void
+agent_priv_register_domain()
+{
+	unixDomain.name = netsnmp_unix;
+	unixDomain.name_length = sizeof(netsnmp_unix) / sizeof(oid);
+	unixDomain.prefix = (const char **)calloc(2, sizeof(char *));
+	unixDomain.prefix[0] = "unix";
+#  if HAVE_NETSNMP_TDOMAIN_F_CREATE_FROM_TSTRING_NEW
+	unixDomain.f_create_from_tstring_new = agent_priv_unix_create_tstring_new;
+#  else
+	unixDomain.f_create_from_tstring = agent_priv_unix_create_tstring;
+#  endif
+	unixDomain.f_create_from_ostring = agent_priv_unix_create_ostring;
+	netsnmp_tdomain_register(&unixDomain);
+}
+#endif