From 3d774f0cd909b05fa445e9033c2f9762d26bb42a 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/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 +-
 10 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/include/libnetlink.h b/include/libnetlink.h
index 6bff6bae..ca09dbc8 100644
--- a/include/libnetlink.h
+++ b/include/libnetlink.h
@@ -174,7 +174,7 @@ 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) \
@@ -238,7 +238,7 @@ 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 9c697770..539e7ab7 100644
--- a/ip/ipfou.c
+++ b/ip/ipfou.c
@@ -232,7 +232,7 @@ 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 475c35b5..0540d1d9 100644
--- a/ip/ipila.c
+++ b/ip/ipila.c
@@ -96,7 +96,7 @@ 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/ipl2tp.c b/ip/ipl2tp.c
index f090390f..edbe0f2f 100644
--- a/ip/ipl2tp.c
+++ b/ip/ipl2tp.c
@@ -345,7 +345,7 @@ 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 bf48e8b5..eecb7e48 100644
--- a/ip/ipmacsec.c
+++ b/ip/ipmacsec.c
@@ -1001,7 +1001,7 @@ 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 5f490f00..f53dcab8 100644
--- a/ip/ipmptcp.c
+++ b/ip/ipmptcp.c
@@ -247,7 +247,7 @@ 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)
@@ -358,7 +358,7 @@ 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]) {
@@ -447,7 +447,7 @@ static int mptcp_monitor_msg(struct rtnl_ctrl_data *ctrl,
 
 	printf("[%14s]", 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);
 
 	printf(" token=%08x", rta_getattr_u32(tb[MPTCP_ATTR_TOKEN]));
 
diff --git a/ip/ipseg6.c b/ip/ipseg6.c
index 56a76996..1c3c3bf5 100644
--- a/ip/ipseg6.c
+++ b/ip/ipseg6.c
@@ -115,7 +115,7 @@ 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 acbd745a..051ddc63 100644
--- a/ip/tcp_metrics.c
+++ b/ip/tcp_metrics.c
@@ -178,7 +178,7 @@ 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 2f2cc1fe..05006fdc 100644
--- a/lib/libnetlink.c
+++ b/lib/libnetlink.c
@@ -1328,7 +1328,7 @@ 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;
 }
@@ -1343,7 +1343,7 @@ 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;
 }
 
@@ -1359,9 +1359,9 @@ 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;
 }
@@ -1433,7 +1433,7 @@ 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;
 }
@@ -1482,7 +1482,7 @@ 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 93ae0c55..33cf199e 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -1532,7 +1532,7 @@ 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;
 
-- 
2.32.0