align CMSG buffer

3 files changed, 17 insertions, 7 deletions

diff --git a/src/dhcp.c b/src/dhcp.c
index 3fd72f85..bcb4ee9b 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -3609,15 +3609,18 @@ dhcp_readudp(struct dhcpcd_ctx *ctx, struct interface *ifp)
 		.iov_base = buf,
 		.iov_len = sizeof(buf),
 	};
+	union {
+		struct cmsghdr hdr;
 #ifdef IP_RECVIF
-	unsigned char ctl[CMSG_SPACE(sizeof(struct sockaddr_dl))] = { 0 };
+		uint8_t buf[CMSG_SPACE(sizeof(struct sockaddr_dl))];
 #else
-	unsigned char ctl[CMSG_SPACE(sizeof(struct in_pktinfo))] = { 0 };
+		uint8_t buf[CMSG_SPACE(sizeof(struct in_pktinfo))];
 #endif
+	} cmsgbuf = { .buf = { 0 } };
 	struct msghdr msg = {
 	    .msg_name = &from, .msg_namelen = sizeof(from),
 	    .msg_iov = &iov, .msg_iovlen = 1,
-	    .msg_control = ctl, .msg_controllen = sizeof(ctl),
+	    .msg_control = buf, .msg_controllen = sizeof(cmsgbuf.buf),
 	};
 	int s;
 	ssize_t bytes;
diff --git a/src/dhcp6.c b/src/dhcp6.c
index 3103e7e0..db3c7e2e 100644
--- a/src/dhcp6.c
+++ b/src/dhcp6.c
@@ -3642,11 +3642,14 @@ dhcp6_recv(struct dhcpcd_ctx *ctx, struct ipv6_addr *ia)
 		.iov_base = buf,
 		.iov_len = sizeof(buf),
 	};
-	unsigned char ctl[CMSG_SPACE(sizeof(struct in6_pktinfo))] = { 0 };
+	union {
+		struct cmsghdr hdr;
+		uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
+	} cmsgbuf = { .buf = { 0 } };
 	struct msghdr msg = {
 	    .msg_name = &from, .msg_namelen = sizeof(from),
 	    .msg_iov = &iov, .msg_iovlen = 1,
-	    .msg_control = ctl, .msg_controllen = sizeof(ctl),
+	    .msg_control = cmsgbuf.buf, .msg_controllen = sizeof(cmsgbuf.buf),
 	};
 	int s;
 	ssize_t bytes;
diff --git a/src/ipv6nd.c b/src/ipv6nd.c
index 1b048db9..f1f83d5f 100644
--- a/src/ipv6nd.c
+++ b/src/ipv6nd.c
@@ -1909,11 +1909,15 @@ ipv6nd_handledata(void *arg)
 		.iov_base = buf,
 		.iov_len = sizeof(buf),
 	};
-	unsigned char ctl[CMSG_SPACE(sizeof(struct in6_pktinfo)) + CMSG_SPACE(sizeof(int))] = { 0 };
+	union {
+		struct cmsghdr hdr;
+		uint8_t buf[CMSG_SPACE(sizeof(struct in6_pktinfo)) +
+		    CMSG_SPACE(sizeof(int))];
+	} cmsgbuf = { .buf = { 0 } };
 	struct msghdr msg = {
 	    .msg_name = &from, .msg_namelen = sizeof(from),
 	    .msg_iov = &iov, .msg_iovlen = 1,
-	    .msg_control = ctl, .msg_controllen = sizeof(ctl),
+	    .msg_control = cmsgbuf.buf, .msg_controllen = sizeof(cmsgbuf.buf),
 	};
 	ssize_t len;