From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Thu, 12 Sep 2019 15:51:52 +0000 (-0400)
Subject: inet: fix: possible unaligned access in packed structure (inet/inet6)
X-Git-Tag: v2.9.13~4
X-Git-Url: https://git.liburcu.org/?p=lttng-tools.git;a=commitdiff_plain;h=e909777bf000d0fd8f0116569b3fb31676b228be

inet: fix: possible unaligned access in packed structure (inet/inet6)

Fix the warnings that unaligned pointers can be passed as parameters
emitted when building inet.c and inet6.c.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/common/macros.h b/src/common/macros.h
index 9637a3830..e2d0fcf3e 100644
--- a/src/common/macros.h
+++ b/src/common/macros.h
@@ -87,6 +87,13 @@ void *zmalloc(size_t len)
 
 #define member_sizeof(type, field)	sizeof(((type *) 0)->field)
 
+/*
+ * Get an aligned pointer to a value. This is meant
+ * as a helper to pass an aligned pointer to a member in a packed structure
+ * to a function.
+ */
+#define ALIGNED_CONST_PTR(value) (((const typeof(value) []) { value }))
+
 /*
  * lttng_strncpy returns 0 on success, or nonzero on failure.
  * It checks that the @src string fits into @dst_len before performing
diff --git a/src/common/sessiond-comm/inet.c b/src/common/sessiond-comm/inet.c
index 6b7a894ad..22d9181ee 100644
--- a/src/common/sessiond-comm/inet.c
+++ b/src/common/sessiond-comm/inet.c
@@ -102,7 +102,8 @@ int lttcomm_bind_inet_sock(struct lttcomm_sock *sock)
 {
 	int ret;
 
-	ret = bind(sock->fd, (const struct sockaddr *) &sock->sockaddr.addr.sin,
+	ret = bind(sock->fd, (const struct sockaddr *) ALIGNED_CONST_PTR(
+			sock->sockaddr.addr.sin),
 			sizeof(sock->sockaddr.addr.sin));
 	if (ret < 0) {
 		PERROR("bind inet");
@@ -114,7 +115,9 @@ int lttcomm_bind_inet_sock(struct lttcomm_sock *sock)
 static
 int connect_no_timeout(struct lttcomm_sock *sock)
 {
-	return connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin,
+	return connect(sock->fd,
+			(const struct sockaddr *) ALIGNED_CONST_PTR(
+					sock->sockaddr.addr.sin),
 			sizeof(sock->sockaddr.addr.sin));
 }
 
@@ -147,11 +150,11 @@ int connect_with_timeout(struct lttcomm_sock *sock)
 	}
 
 	connect_ret = connect(sock->fd,
-		(struct sockaddr *) &sock->sockaddr.addr.sin,
-		sizeof(sock->sockaddr.addr.sin));
-	if (connect_ret == -1 && errno != EAGAIN
-			&& errno != EWOULDBLOCK
-			&& errno != EINPROGRESS) {
+			(const struct sockaddr *) ALIGNED_CONST_PTR(
+					sock->sockaddr.addr.sin),
+			sizeof(sock->sockaddr.addr.sin));
+	if (connect_ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK &&
+			errno != EINPROGRESS) {
 		goto error;
 	} else if (!connect_ret) {
 		/* Connect succeeded */
@@ -267,6 +270,7 @@ struct lttcomm_sock *lttcomm_accept_inet_sock(struct lttcomm_sock *sock)
 	socklen_t len;
 	struct lttcomm_sock *new_sock;
 	unsigned long timeout;
+	struct sockaddr_in new_addr = {};
 
 	if (sock->proto == LTTCOMM_SOCK_UDP) {
 		/*
@@ -281,15 +285,15 @@ struct lttcomm_sock *lttcomm_accept_inet_sock(struct lttcomm_sock *sock)
 		goto error;
 	}
 
-	len = sizeof(new_sock->sockaddr.addr.sin);
+	len = sizeof(new_addr);
 
 	/* Blocking call */
-	new_fd = accept(sock->fd, (struct sockaddr *) &new_sock->sockaddr.addr.sin,
-			&len);
+	new_fd = accept(sock->fd, (struct sockaddr *) &new_addr, &len);
 	if (new_fd < 0) {
 		PERROR("accept inet");
 		goto error;
 	}
+	new_sock->sockaddr.addr.sin = new_addr;
 	timeout = lttcomm_get_network_timeout();
 	if (timeout) {
 		int ret;
@@ -362,6 +366,7 @@ ssize_t lttcomm_recvmsg_inet_sock(struct lttcomm_sock *sock, void *buf,
 	struct iovec iov[1];
 	ssize_t ret = -1;
 	size_t len_last;
+	struct sockaddr_in addr = sock->sockaddr.addr.sin;
 
 	memset(&msg, 0, sizeof(msg));
 
@@ -370,7 +375,7 @@ ssize_t lttcomm_recvmsg_inet_sock(struct lttcomm_sock *sock, void *buf,
 	msg.msg_iov = iov;
 	msg.msg_iovlen = 1;
 
-	msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin;
+	msg.msg_name = (struct sockaddr *) &addr;
 	msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
 
 	do {
@@ -414,9 +419,13 @@ ssize_t lttcomm_sendmsg_inet_sock(struct lttcomm_sock *sock, const void *buf,
 
 	switch (sock->proto) {
 	case LTTCOMM_SOCK_UDP:
-		msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin;
+	{
+		struct sockaddr_in addr = sock->sockaddr.addr.sin;
+
+		msg.msg_name = (struct sockaddr *) &addr;
 		msg.msg_namelen = sizeof(sock->sockaddr.addr.sin);
 		break;
+	}
 	default:
 		break;
 	}
diff --git a/src/common/sessiond-comm/inet6.c b/src/common/sessiond-comm/inet6.c
index 60fe44f1e..e8c761603 100644
--- a/src/common/sessiond-comm/inet6.c
+++ b/src/common/sessiond-comm/inet6.c
@@ -100,7 +100,8 @@ int lttcomm_bind_inet6_sock(struct lttcomm_sock *sock)
 {
 	int ret;
 
-	ret = bind(sock->fd, (const struct sockaddr *) &sock->sockaddr.addr.sin6,
+	ret = bind(sock->fd, (const struct sockaddr *) ALIGNED_CONST_PTR(
+			sock->sockaddr.addr.sin6),
 			sizeof(sock->sockaddr.addr.sin6));
 	if (ret < 0) {
 		PERROR("bind inet6");
@@ -112,7 +113,9 @@ int lttcomm_bind_inet6_sock(struct lttcomm_sock *sock)
 static
 int connect_no_timeout(struct lttcomm_sock *sock)
 {
-	return connect(sock->fd, (struct sockaddr *) &sock->sockaddr.addr.sin6,
+	return connect(sock->fd,
+			(const struct sockaddr *) ALIGNED_CONST_PTR(
+					sock->sockaddr.addr.sin6),
 			sizeof(sock->sockaddr.addr.sin6));
 }
 
@@ -145,11 +148,11 @@ int connect_with_timeout(struct lttcomm_sock *sock)
 	}
 
 	connect_ret = connect(sock->fd,
-		(struct sockaddr *) &sock->sockaddr.addr.sin6,
-		sizeof(sock->sockaddr.addr.sin6));
-	if (connect_ret == -1 && errno != EAGAIN
-			&& errno != EWOULDBLOCK
-			&& errno != EINPROGRESS) {
+			(const struct sockaddr *) ALIGNED_CONST_PTR(
+					sock->sockaddr.addr.sin6),
+			sizeof(sock->sockaddr.addr.sin6));
+	if (connect_ret == -1 && errno != EAGAIN && errno != EWOULDBLOCK &&
+			errno != EINPROGRESS) {
 		goto error;
 	} else if (!connect_ret) {
 		/* Connect succeeded */
@@ -265,6 +268,7 @@ struct lttcomm_sock *lttcomm_accept_inet6_sock(struct lttcomm_sock *sock)
 	int new_fd;
 	socklen_t len;
 	struct lttcomm_sock *new_sock;
+	struct sockaddr_in6 new_addr = {};
 
 	if (sock->proto == LTTCOMM_SOCK_UDP) {
 		/*
@@ -279,16 +283,15 @@ struct lttcomm_sock *lttcomm_accept_inet6_sock(struct lttcomm_sock *sock)
 		goto error;
 	}
 
-	len = sizeof(new_sock->sockaddr.addr.sin6);
+	len = sizeof(new_addr);
 
 	/* Blocking call */
-	new_fd = accept(sock->fd,
-			(struct sockaddr *) &new_sock->sockaddr.addr.sin6, &len);
+	new_fd = accept(sock->fd, (struct sockaddr *) &new_addr, &len);
 	if (new_fd < 0) {
 		PERROR("accept inet6");
 		goto error;
 	}
-
+	new_sock->sockaddr.addr.sin6 = new_addr;
 	new_sock->fd = new_fd;
 	new_sock->ops = &inet6_ops;
 
@@ -342,6 +345,7 @@ ssize_t lttcomm_recvmsg_inet6_sock(struct lttcomm_sock *sock, void *buf,
 	struct iovec iov[1];
 	ssize_t ret = -1;
 	size_t len_last;
+	struct sockaddr_in6 addr = sock->sockaddr.addr.sin6;
 
 	memset(&msg, 0, sizeof(msg));
 
@@ -350,7 +354,7 @@ ssize_t lttcomm_recvmsg_inet6_sock(struct lttcomm_sock *sock, void *buf,
 	msg.msg_iov = iov;
 	msg.msg_iovlen = 1;
 
-	msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin6;
+	msg.msg_name = (struct sockaddr *) &addr;
 	msg.msg_namelen = sizeof(sock->sockaddr.addr.sin6);
 
 	do {
@@ -394,9 +398,13 @@ ssize_t lttcomm_sendmsg_inet6_sock(struct lttcomm_sock *sock, const void *buf,
 
 	switch (sock->proto) {
 	case LTTCOMM_SOCK_UDP:
-		msg.msg_name = (struct sockaddr *) &sock->sockaddr.addr.sin6;
+	{
+		struct sockaddr_in6 addr = sock->sockaddr.addr.sin6;
+
+		msg.msg_name = (struct sockaddr *) &addr;
 		msg.msg_namelen = sizeof(sock->sockaddr.addr.sin6);
 		break;
+	}
 	default:
 		break;
 	}