From 2bdb80165c2e095b169c59ef18607b30f8758ec7 Mon Sep 17 00:00:00 2001
From: Sebastian Harl <sh@tokkee.org>
Date: Wed, 14 Jan 2015 22:36:38 +0100
Subject: [PATCH] frontend: Make peer detection more flexible.

It's now a property of a listener implementation.

Moved the unixsock implementation over from frontend/connection to
frontend/sock.
---
 src/frontend/connection.c | 52 +---------------------------------
 src/frontend/sock.c       | 59 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 59 insertions(+), 52 deletions(-)

diff --git a/src/frontend/connection.c b/src/frontend/connection.c
index c35d2d2..700c84a 100644
--- a/src/frontend/connection.c
+++ b/src/frontend/connection.c
@@ -47,19 +47,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-#include <sys/socket.h>
-#include <sys/types.h>
-#include <sys/param.h>
-
-#ifdef HAVE_UCRED_H
-#	include <ucred.h>
-#endif
-#ifdef HAVE_SYS_UCRED_H
-#	include <sys/ucred.h>
-#endif
-
-#include <pwd.h>
-
 #include <pthread.h>
 
 /*
@@ -77,36 +64,6 @@ static bool          conn_ctx_key_initialized = 0;
 #define CONN_FD_PREFIX "conn#"
 #define CONN_FD_PLACEHOLDER "XXXXXXX"
 
-/* XXX: only supports UNIX sockets so far */
-static char *
-peer(int sockfd)
-{
-	uid_t uid;
-
-	struct passwd pw_entry;
-	struct passwd *result = NULL;
-	char buf[1024];
-
-#ifdef SO_PEERCRED
-	struct ucred cred;
-	socklen_t len = sizeof(cred);
-
-	if (getsockopt(sockfd, SOL_SOCKET, SO_PEERCRED, &cred, &len)
-			|| (len != sizeof(cred)))
-		return NULL;
-	uid = cred.uid;
-#else /* SO_PEERCRED */
-	errno = ENOSYS;
-	return NULL;
-#endif
-
-	memset(&pw_entry, 0, sizeof(pw_entry));
-	if (getpwuid_r(uid, &pw_entry, buf, sizeof(buf), &result)
-			|| (! result))
-		return NULL;
-	return strdup(result->pw_name);
-} /* peer */
-
 static ssize_t
 conn_read(sdb_conn_t *conn, size_t len)
 {
@@ -181,14 +138,7 @@ connection_init(sdb_object_t *obj, va_list ap)
 		return -1;
 	}
 
-	conn->username = peer(conn->fd);
-	if (! conn->username) {
-		char buf[1024];
-		sdb_log(SDB_LOG_ERR, "frontend: Failed to retrieve peer for "
-				"connection conn#%i: %s", conn->fd,
-				sdb_strerror(errno, buf, sizeof(buf)));
-		return -1;
-	}
+	conn->username = NULL;
 	conn->ready = 0;
 
 	sdb_log(SDB_LOG_DEBUG, "frontend: Accepted connection on fd=%i",
diff --git a/src/frontend/sock.c b/src/frontend/sock.c
index 860fb8e..2def8da 100644
--- a/src/frontend/sock.c
+++ b/src/frontend/sock.c
@@ -53,10 +53,19 @@
 #include <sys/types.h>
 #include <sys/select.h>
 #include <sys/socket.h>
+#include <sys/param.h>
 #include <sys/un.h>
 
-#include <libgen.h>
+#ifdef HAVE_UCRED_H
+#	include <ucred.h>
+#endif
+#ifdef HAVE_SYS_UCRED_H
+#	include <sys/ucred.h>
+#endif
+
+#include <pwd.h>
 
+#include <libgen.h>
 #include <pthread.h>
 
 /*
@@ -69,6 +78,7 @@ typedef struct {
 
 	int sock_fd;
 	int (*accept)(sdb_conn_t *);
+	int (*peer)(sdb_conn_t *);
 } listener_t;
 
 typedef struct {
@@ -94,6 +104,46 @@ struct sdb_fe_socket {
  * connection management functions
  */
 
+static int
+unixsock_peer(sdb_conn_t *conn)
+{
+	uid_t uid;
+
+	struct passwd pw_entry;
+	struct passwd *result = NULL;
+	char buf[1024];
+
+#ifdef SO_PEERCRED
+	struct ucred cred;
+	socklen_t len = sizeof(cred);
+
+	if (getsockopt(conn->fd, SOL_SOCKET, SO_PEERCRED, &cred, &len)
+			|| (len != sizeof(cred))) {
+		char errbuf[1024];
+		sdb_log(SDB_LOG_ERR, "frontend: Failed to determine peer for "
+				"connection conn#%i: %s", conn->fd,
+				sdb_strerror(errno, errbuf, sizeof(errbuf)));
+		return -1;
+	}
+	uid = cred.uid;
+#else /* SO_PEERCRED */
+	sdb_log(SDB_LOG_ERR, "frontend: Failed to determine peer for "
+			"connection conn#%i: operation not supported", conn->fd);
+	return -1;
+#endif
+
+	memset(&pw_entry, 0, sizeof(pw_entry));
+	if (getpwuid_r(uid, &pw_entry, buf, sizeof(buf), &result) || (! result)
+			|| (! (conn->username = strdup(result->pw_name)))) {
+		char errbuf[1024];
+		sdb_log(SDB_LOG_ERR, "frontend: Failed to determine peer for "
+				"connection conn#%i: %s", conn->fd,
+				sdb_strerror(errno, errbuf, sizeof(errbuf)));
+		return -1;
+	}
+	return 0;
+} /* unixsock_peer */
+
 static int
 open_unixsock(listener_t *listener)
 {
@@ -147,6 +197,8 @@ open_unixsock(listener_t *listener)
 				listener->address, sdb_strerror(errno, buf, sizeof(buf)));
 		return -1;
 	}
+
+	listener->peer = unixsock_peer;
 	return 0;
 } /* open_unixsock */
 
@@ -397,6 +449,11 @@ connection_accept(sdb_fe_socket_t *sock, listener_t *listener)
 		sdb_object_deref(obj);
 		return -1;
 	}
+	if (listener->peer && listener->peer(CONN(obj))) {
+		/* peer() is expected to log an error */
+		sdb_object_deref(obj);
+		return -1;
+	}
 
 	status = sdb_llist_append(sock->open_connections, obj);
 	if (status)
-- 
2.30.2