From a5c387d23c3309296d852e6f7fae8eb6ca99bd47 Mon Sep 17 00:00:00 2001
From: Michael Forney <mforney@mforney.org>
Date: Tue, 12 Mar 2019 19:12:31 -0700
Subject: [PATCH] Avoid pointer arithmetic on `void *`

---
 include/libnetlink.h |  4 ++--
 ip/ipfou.c           |  2 +-
 ip/ipila.c           |  2 +-
 ip/ipioam6.c         |  3 ++-
 ip/ipl2tp.c          |  2 +-
 ip/ipmacsec.c        |  2 +-
 ip/ipmptcp.c         |  6 +++---
 ip/ipseg6.c          |  2 +-
 ip/tcp_metrics.c     |  2 +-
 lib/libnetlink.c     | 12 ++++++------
 lib/utils.c          |  2 +-
 11 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/include/libnetlink.h b/include/libnetlink.h
index ad7e7127..09145d77 100644
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -219,7 +219,7 @@ struct rtattr *rta_nest(struct rtattr *rta, int maxlen, int type);
 int rta_nest_end(struct rtattr *rta, struct rtattr *nest);
 
 #define RTA_TAIL(rta) \
-		((struct rtattr *) (((void *) (rta)) + \
+		((struct rtattr *) (((char *) (rta)) + \
 				    RTA_ALIGN((rta)->rta_len)))
 
 #define parse_rtattr_nested(tb, max, rta) \
@@ -287,7 +287,7 @@ int rtnl_from_file(FILE *, rtnl_listen_filter_t handler,
 		   void *jarg);
 
 #define NLMSG_TAIL(nmsg) \
-	((struct rtattr *) (((void *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
+	((struct rtattr *) (((char *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
 
 #ifndef IFA_RTA
 #define IFA_RTA(r) \
diff --git a/ip/ipfou.c b/ip/ipfou.c
index 760cfee2..8b9dde00 100644
--- a/ip/ipfou.c
+++ b/ip/ipfou.c
@@ -228,7 +228,7 @@ static int print_fou_mapping(struct nlmsghdr *n, void *arg)
 		return -1;
 
 	ghdr = NLMSG_DATA(n);
-	parse_rtattr(tb, FOU_ATTR_MAX, (void *) ghdr + GENL_HDRLEN, len);
+	parse_rtattr(tb, FOU_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN), len);
 
 	open_json_object(NULL);
 	if (tb[FOU_ATTR_PORT])
diff --git a/ip/ipila.c b/ip/ipila.c
index f4387e03..c12aa23f 100644
--- a/ip/ipila.c
+++ b/ip/ipila.c
@@ -97,7 +97,7 @@ static int print_ila_mapping(struct nlmsghdr *n, void *arg)
 		return -1;
 
 	ghdr = NLMSG_DATA(n);
-	parse_rtattr(tb, ILA_ATTR_MAX, (void *) ghdr + GENL_HDRLEN, len);
+	parse_rtattr(tb, ILA_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN), len);
 
 	open_json_object(NULL);
 	print_ila_locid("locator_match", ILA_ATTR_LOCATOR_MATCH, tb);
diff --git a/ip/ipioam6.c b/ip/ipioam6.c
index b63d7d5c..c7c9aceb 100644
--- a/ip/ipioam6.c
+++ b/ip/ipioam6.c
@@ -110,7 +110,8 @@ static int process_msg(struct nlmsghdr *n, void *arg)
 		return -1;
 
 	ghdr = NLMSG_DATA(n);
-	parse_rtattr(attrs, IOAM6_ATTR_MAX, (void *)ghdr + GENL_HDRLEN, len);
+	parse_rtattr(attrs, IOAM6_ATTR_MAX,
+		     (struct rtattr *)((char *)ghdr + GENL_HDRLEN), len);
 
 	open_json_object(NULL);
 	switch (ghdr->cmd) {
diff --git a/ip/ipl2tp.c b/ip/ipl2tp.c
index 9d1e566c..76ba20c0 100644
--- a/ip/ipl2tp.c
+++ b/ip/ipl2tp.c
@@ -341,7 +341,7 @@ static int get_response(struct nlmsghdr *n, void *arg)
 	if (len < 0)
 		return -1;
 
-	parse_rtattr(attrs, L2TP_ATTR_MAX, (void *)ghdr + GENL_HDRLEN, len);
+	parse_rtattr(attrs, L2TP_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN), len);
 
 	if (attrs[L2TP_ATTR_PW_TYPE])
 		p->pw_type = rta_getattr_u16(attrs[L2TP_ATTR_PW_TYPE]);
diff --git a/ip/ipmacsec.c b/ip/ipmacsec.c
index fc4c8631..3e65e11f 100644
--- a/ip/ipmacsec.c
+++ b/ip/ipmacsec.c
@@ -1083,7 +1083,7 @@ static int process(struct nlmsghdr *n, void *arg)
 	if (ghdr->cmd != MACSEC_CMD_GET_TXSC)
 		return 0;
 
-	parse_rtattr(attrs, MACSEC_ATTR_MAX, (void *) ghdr + GENL_HDRLEN, len);
+	parse_rtattr(attrs, MACSEC_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN), len);
 	if (!validate_dump(attrs)) {
 		fprintf(stderr, "incomplete dump message\n");
 		return -1;
diff --git a/ip/ipmptcp.c b/ip/ipmptcp.c
index 9847f95b..d37f1269 100644
--- a/ip/ipmptcp.c
+++ b/ip/ipmptcp.c
@@ -286,7 +286,7 @@ static int print_mptcp_addr(struct nlmsghdr *n, void *arg)
 		return -1;
 
 	ghdr = NLMSG_DATA(n);
-	parse_rtattr_flags(tb, MPTCP_PM_ATTR_MAX, (void *) ghdr + GENL_HDRLEN,
+	parse_rtattr_flags(tb, MPTCP_PM_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN),
 			   len, NLA_F_NESTED);
 	addrinfo = tb[MPTCP_PM_ATTR_ADDR];
 	if (!addrinfo)
@@ -402,7 +402,7 @@ static int print_mptcp_limit(struct nlmsghdr *n, void *arg)
 		return -1;
 
 	ghdr = NLMSG_DATA(n);
-	parse_rtattr(tb, MPTCP_PM_ATTR_MAX, (void *) ghdr + GENL_HDRLEN, len);
+	parse_rtattr(tb, MPTCP_PM_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN), len);
 
 	open_json_object(NULL);
 	if (tb[MPTCP_PM_ATTR_RCV_ADD_ADDRS]) {
@@ -497,7 +497,7 @@ static int mptcp_monitor_msg(struct rtnl_ctrl_data *ctrl,
 
 	printf("[%16s]", event_to_str[ghdr->cmd]);
 
-	parse_rtattr(tb, MPTCP_ATTR_MAX, (void *) ghdr + GENL_HDRLEN, len);
+	parse_rtattr(tb, MPTCP_ATTR_MAX, (struct rtattr *) ((char *) ghdr + GENL_HDRLEN), len);
 
 	if (tb[MPTCP_ATTR_TOKEN])
 		printf(" token=%08x", rta_getattr_u32(tb[MPTCP_ATTR_TOKEN]));
diff --git a/ip/ipseg6.c b/ip/ipseg6.c
index 305b8961..4103a1c6 100644
--- a/ip/ipseg6.c
+++ b/ip/ipseg6.c
@@ -112,7 +112,7 @@ static int process_msg(struct nlmsghdr *n, void *arg)
 
 	ghdr = NLMSG_DATA(n);
 
-	parse_rtattr(attrs, SEG6_ATTR_MAX, (void *)ghdr + GENL_HDRLEN, len);
+	parse_rtattr(attrs, SEG6_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN), len);
 
 	open_json_object(NULL);
 	switch (ghdr->cmd) {
diff --git a/ip/tcp_metrics.c b/ip/tcp_metrics.c
index 9c8fb072..f451c8f2 100644
--- a/ip/tcp_metrics.c
+++ b/ip/tcp_metrics.c
@@ -175,7 +175,7 @@ static int process_msg(struct nlmsghdr *n, void *arg)
 	if (ghdr->cmd != TCP_METRICS_CMD_GET)
 		return 0;
 
-	parse_rtattr(attrs, TCP_METRICS_ATTR_MAX, (void *) ghdr + GENL_HDRLEN,
+	parse_rtattr(attrs, TCP_METRICS_ATTR_MAX, (struct rtattr *)((char *)ghdr + GENL_HDRLEN),
 		     len);
 
 	if (attrs[TCP_METRICS_ATTR_ADDR_IPV4]) {
diff --git a/lib/libnetlink.c b/lib/libnetlink.c
index 01648229..80adabf4 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -1396,7 +1396,7 @@ int addraw_l(struct nlmsghdr *n, int maxlen, const void *data, int len)
 	}
 
 	memcpy(NLMSG_TAIL(n), data, len);
-	memset((void *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
+	memset((char *) NLMSG_TAIL(n) + len, 0, NLMSG_ALIGN(len) - len);
 	n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + NLMSG_ALIGN(len);
 	return 0;
 }
@@ -1411,7 +1411,7 @@ struct rtattr *addattr_nest(struct nlmsghdr *n, int maxlen, int type)
 
 int addattr_nest_end(struct nlmsghdr *n, struct rtattr *nest)
 {
-	nest->rta_len = (void *)NLMSG_TAIL(n) - (void *)nest;
+	nest->rta_len = (char *)NLMSG_TAIL(n) - (char *)nest;
 	return n->nlmsg_len;
 }
 
@@ -1427,9 +1427,9 @@ struct rtattr *addattr_nest_compat(struct nlmsghdr *n, int maxlen, int type,
 
 int addattr_nest_compat_end(struct nlmsghdr *n, struct rtattr *start)
 {
-	struct rtattr *nest = (void *)start + NLMSG_ALIGN(start->rta_len);
+	struct rtattr *nest = (struct rtattr *)((char *)start + NLMSG_ALIGN(start->rta_len));
 
-	start->rta_len = (void *)NLMSG_TAIL(n) - (void *)start;
+	start->rta_len = (char *)NLMSG_TAIL(n) - (char *)start;
 	addattr_nest_end(n, nest);
 	return n->nlmsg_len;
 }
@@ -1501,7 +1501,7 @@ struct rtattr *rta_nest(struct rtattr *rta, int maxlen, int type)
 
 int rta_nest_end(struct rtattr *rta, struct rtattr *nest)
 {
-	nest->rta_len = (void *)RTA_TAIL(rta) - (void *)nest;
+	nest->rta_len = (char *)RTA_TAIL(rta) - (char *)nest;
 
 	return rta->rta_len;
 }
@@ -1550,7 +1550,7 @@ int __parse_rtattr_nested_compat(struct rtattr *tb[], int max,
 	if (RTA_PAYLOAD(rta) < len)
 		return -1;
 	if (RTA_PAYLOAD(rta) >= RTA_ALIGN(len) + sizeof(struct rtattr)) {
-		rta = RTA_DATA(rta) + RTA_ALIGN(len);
+		rta = (struct rtattr *)((char *)RTA_DATA(rta) + RTA_ALIGN(len));
 		return parse_rtattr_nested(tb, max, rta);
 	}
 	memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
diff --git a/lib/utils.c b/lib/utils.c
index 6c1c1a8d..040b935c 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -1543,7 +1543,7 @@ int get_rtnl_link_stats_rta(struct rtnl_link_stats64 *stats64,
 
 	len = RTA_PAYLOAD(rta);
 	if (len < size)
-		memset(s + len, 0, size - len);
+		memset((char *)s + len, 0, size - len);
 	else
 		len = size;
 
-- 
2.44.0