Merge pull request #44 from bwhacks/alignment-fixes

Alignment fixes

5 files changed, 44 insertions, 19 deletions

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index c5f11f1..3e128bc 100644
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -110,6 +110,14 @@ static uint8_t reconf_key[16];
 static unsigned int client_options = 0;
 
 
+static uint32_t ntohl_unaligned(const uint8_t *data)
+{
+	uint32_t buf;
+
+	memcpy(&buf, data, sizeof(buf));
+	return ntohl(buf);
+}
+
 int init_dhcpv6(const char *ifname, unsigned int options, int sol_timeout)
 {
 	client_options = options;
@@ -577,7 +585,9 @@ int dhcpv6_request(enum dhcpv6_msg type)
 		// Receive rounds
 		for (; len < 0 && (round_start < round_end);
 				round_start = odhcp6c_get_milli_time()) {
-			uint8_t buf[1536], cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))];
+			uint8_t buf[1536];
+			uint8_t cmsg_buf[CMSG_SPACE(sizeof(struct in6_pktinfo))]
+				__aligned(__alignof__(struct cmsghdr));
 			struct iovec iov = {buf, sizeof(buf)};
 			struct sockaddr_in6 addr;
 			struct msghdr msg = {.msg_name = &addr, .msg_namelen = sizeof(addr),
@@ -692,7 +702,8 @@ static bool dhcpv6_response_is_valid(const void *buf, ssize_t len,
 				continue;
 
 			md5_ctx_t md5;
-			uint8_t serverhash[16], secretbytes[64], hash[16];
+			uint8_t serverhash[16], secretbytes[64];
+			uint32_t hash[4];
 			memcpy(serverhash, r->key, sizeof(serverhash));
 			memset(r->key, 0, sizeof(r->key));
 
@@ -804,12 +815,12 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 		} else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
 			cand.wants_reconfigure = true;
 		} else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
-			uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
+			uint32_t sol_max_rt = ntohl_unaligned(odata);
 			if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 					sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 				cand.sol_max_rt = sol_max_rt;
 		} else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
-			uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
+			uint32_t inf_max_rt = ntohl_unaligned(odata);
 			if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 					inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 				cand.inf_max_rt = inf_max_rt;
@@ -1027,7 +1038,7 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 			} else if (otype == DHCPV6_OPT_SIP_SERVER_D) {
 				odhcp6c_add_state(STATE_SIP_FQDN, odata, olen);
 			} else if (otype == DHCPV6_OPT_INFO_REFRESH && olen >= 4) {
-				refresh = ntohl(*((uint32_t*)odata));
+				refresh = ntohl_unaligned(odata);
 				passthru = false;
 			} else if (otype == DHCPV6_OPT_AUTH) {
 				if (olen == -4 + sizeof(struct dhcpv6_auth_reconfigure)) {
@@ -1044,13 +1055,13 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
 					odhcp6c_add_state(STATE_AFTR_NAME, odata, olen);
 				passthru = false;
 			} else if (otype == DHCPV6_OPT_SOL_MAX_RT && olen == 4) {
-				uint32_t sol_max_rt = ntohl(*((uint32_t *)odata));
+				uint32_t sol_max_rt = ntohl_unaligned(odata);
 				if (sol_max_rt >= DHCPV6_SOL_MAX_RT_MIN &&
 						sol_max_rt <= DHCPV6_SOL_MAX_RT_MAX)
 					dhcpv6_retx[DHCPV6_MSG_SOLICIT].max_timeo = sol_max_rt;
 				passthru = false;
 			} else if (otype == DHCPV6_OPT_INF_MAX_RT && olen == 4) {
-				uint32_t inf_max_rt = ntohl(*((uint32_t *)odata));
+				uint32_t inf_max_rt = ntohl_unaligned(odata);
 				if (inf_max_rt >= DHCPV6_INF_MAX_RT_MIN &&
 						inf_max_rt <= DHCPV6_INF_MAX_RT_MAX)
 					dhcpv6_retx[DHCPV6_MSG_INFO_REQ].max_timeo = inf_max_rt;
diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index 59f6390..ba568bd 100644
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -570,8 +570,9 @@ static struct odhcp6c_entry* odhcp6c_find_entry(enum odhcp6c_state state, const
 	uint8_t *start = odhcp6c_get_state(state, &len);
 
 	for (struct odhcp6c_entry *c = (struct odhcp6c_entry*)start;
-			(uint8_t*)c < &start[len] && &c->auxtarget[c->auxlen] <= &start[len];
-			c = (struct odhcp6c_entry*)(&c->auxtarget[c->auxlen]))
+			(uint8_t*)c < &start[len] &&
+			(uint8_t*)odhcp6c_next_entry(c) <= &start[len];
+			c = odhcp6c_next_entry(c))
 		if (!memcmp(c, new, cmplen) && !memcmp(c->auxtarget, new->auxtarget, new->auxlen))
 			return c;
 
@@ -604,10 +605,10 @@ bool odhcp6c_update_entry(enum odhcp6c_state state, struct odhcp6c_entry *new,
 			x->t2 = new->t2;
 			x->iaid = new->iaid;
 		} else {
-			odhcp6c_add_state(state, new, sizeof(*new) + new->auxlen);
+			odhcp6c_add_state(state, new, odhcp6c_entry_size(new));
 		}
 	} else if (x) {
-		odhcp6c_remove_state(state, ((uint8_t*)x) - start, sizeof(*x) + x->auxlen);
+		odhcp6c_remove_state(state, ((uint8_t*)x) - start, odhcp6c_entry_size(x));
 	}
 	return true;
 }
@@ -618,7 +619,8 @@ static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 	size_t len;
 	uint8_t *start = odhcp6c_get_state(state, &len);
 	for (struct odhcp6c_entry *c = (struct odhcp6c_entry*)start;
-			(uint8_t*)c < &start[len] && &c->auxtarget[c->auxlen] <= &start[len];
+			(uint8_t*)c < &start[len] &&
+			(uint8_t*)odhcp6c_next_entry(c) <= &start[len];
 			) {
 		if (c->t1 < elapsed)
 			c->t1 = 0;
@@ -641,10 +643,10 @@ static void odhcp6c_expire_list(enum odhcp6c_state state, uint32_t elapsed)
 			c->valid -= elapsed;
 
 		if (!c->valid) {
-			odhcp6c_remove_state(state, ((uint8_t*)c) - start, sizeof(*c) + c->auxlen);
+			odhcp6c_remove_state(state, ((uint8_t*)c) - start, odhcp6c_entry_size(c));
 			start = odhcp6c_get_state(state, &len);
 		} else {
-			c = (struct odhcp6c_entry*)(&c->auxtarget[c->auxlen]);
+			c = odhcp6c_next_entry(c);
 		}
 	}
 }
diff --git a/src/odhcp6c.h b/src/odhcp6c.h
index 928f82f..08a816f 100644
--- a/src/odhcp6c.h
+++ b/src/odhcp6c.h
@@ -18,6 +18,7 @@
 
 #define _unused __attribute__((unused))
 #define _packed __attribute__((packed))
+#define __aligned(n) __attribute__((aligned(n)))
 
 #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
 
@@ -302,6 +303,14 @@ struct odhcp6c_entry {
 	uint8_t auxtarget[];
 };
 
+// Include padding after auxtarget to align the next entry
+#define odhcp6c_entry_size(entry) \
+	(sizeof(struct odhcp6c_entry) +	(((entry)->auxlen + 3) & ~3))
+
+#define odhcp6c_next_entry(entry) \
+	((struct odhcp6c_entry *)((uint8_t *)(entry) + odhcp6c_entry_size(entry)))
+
+
 struct odhcp6c_request_prefix {
 	uint32_t iaid;
 	uint16_t length;
diff --git a/src/ra.c b/src/ra.c
index 1c121e6..dd5962a 100644
--- a/src/ra.c
+++ b/src/ra.c
@@ -274,7 +274,8 @@ bool ra_process(void)
 {
 	bool found = false;
 	bool changed = false;
-	uint8_t buf[1500], cmsg_buf[128];
+	uint8_t buf[1500] __aligned(4);
+	uint8_t cmsg_buf[128] __aligned(__alignof__(struct cmsghdr));
 	struct nd_router_advert *adv = (struct nd_router_advert*)buf;
 	struct odhcp6c_entry *entry = alloca(sizeof(*entry) + 256);
 	const struct in6_addr any = IN6ADDR_ANY_INIT;
@@ -444,8 +445,9 @@ bool ra_process(void)
 			size_t ra_dns_len;
 			uint8_t *start = odhcp6c_get_state(states[i], &ra_dns_len);
 			for (struct odhcp6c_entry *c = (struct odhcp6c_entry*)start;
-						(uint8_t*)c < &start[ra_dns_len] && &c->auxtarget[c->auxlen] <= &start[ra_dns_len];
-						c = (struct odhcp6c_entry*)(&c->auxtarget[c->auxlen]))
+						(uint8_t*)c < &start[ra_dns_len] &&
+						(uint8_t*)odhcp6c_next_entry(c) <= &start[ra_dns_len];
+						c = odhcp6c_next_entry(c))
 				if (IN6_ARE_ADDR_EQUAL(&c->router, &from.sin6_addr) &&
 						c->valid > router_valid)
 					c->valid = router_valid;
diff --git a/src/script.c b/src/script.c
index b20e94c..fdc050b 100644
--- a/src/script.c
+++ b/src/script.c
@@ -220,8 +220,9 @@ static void search_to_env(const char *name, const uint8_t *start, size_t len)
 	*c++ = '=';
 
 	for (struct odhcp6c_entry *e = (struct odhcp6c_entry*)start;
-				(uint8_t*)e < &start[len] && &e->auxtarget[e->auxlen] <= &start[len];
-				e = (struct odhcp6c_entry*)(&e->auxtarget[e->auxlen])) {
+				(uint8_t*)e < &start[len] &&
+				(uint8_t*)odhcp6c_next_entry(e) <= &start[len];
+				e = odhcp6c_next_entry(e)) {
 		c = mempcpy(c, e->auxtarget, e->auxlen);
 		*c++ = ' ';
 	}