Rewrite blockdata_retrieve() and expand_buf() to use realloc().

If iovcnt is exhausted and the first vector element's operation
is satisfied, the while loop will read past the end of the
iovec array.  This triggers the address sanitizer and leads to
undefined program state.  Avoid reading too far.

src/blockdata.c

@@ -193,22 +193,20 @@ void *blockdata_retrieve(struct blockdata *block, size_t len, void *data)
 {
   size_t blen;
   struct  blockdata *b;
-  uint8_t *new, *d;
+  uint8_t *d;
   
-  static unsigned int buff_len = 0;
-  static unsigned char *buff = NULL;
-   
   if (!data)
     {
+      static unsigned int buff_len = 0;
+      static unsigned char *buff = NULL;
+      uint8_t *new;
+      
       if (len > buff_len)
 	{
 	  blen = len + 1024;
-	  if (!(new = whine_malloc(blen)))
+	  if (!(new = whine_realloc(buff, blen)))
 	    return NULL;
 
-	  if (buff)
-	    free(buff);
-
 	  buff = new;
 	  buff_len = blen;
 	}

src/dnsmasq.c

@@ -1450,8 +1450,6 @@ void send_event(int fd, int event, int data, char *msg)
     while (writev(fd, iov, msg ? 2 : 1) == -1 && errno == EINTR);
 }
 
-/* NOTE: the memory used to return msg is leaked: use msgs in events only
-   to describe fatal errors. */
 static int read_event(int fd, struct event_desc *evp, char **msg)
 {
   char *buf;
@@ -1461,12 +1459,22 @@ static int read_event(int fd, struct event_desc *evp, char **msg)
   
   *msg = NULL;
   
-  if (evp->msg_sz != 0 && 
-      (buf = malloc(evp->msg_sz + 1)) &&
-      read_write(fd, (unsigned char *)buf, evp->msg_sz, RW_READ))
+  if (evp->msg_sz != 0)
     {
-      buf[evp->msg_sz] = 0;
-      *msg = buf;
+      if (!(buf = whine_malloc(evp->msg_sz + 1)))
+	{
+	  int i;
+	  unsigned char a;
+	  
+	  /* Keep the stream synchronised if malloc fails. */
+	  for (i = 0; i < evp->msg_sz; i++)
+	    read_write(fd, &a, 1, RW_READ);
+	}
+      else if (read_write(fd, (unsigned char *)buf, evp->msg_sz, RW_READ))
+	{
+	  buf[evp->msg_sz] = 0;
+	  *msg = buf;
+	}
     }
 
   return 1;
@@ -1529,9 +1537,6 @@ static void async_event(int pipe, time_t now)
   int wstatus, i, check = 0;
   char *msg;
   
-  /* NOTE: the memory used to return msg is leaked: use msgs in events only
-     to describe fatal errors. */
-  
   if (read_event(pipe, &ev, &msg))
     switch (ev.event)
       {
@@ -1637,7 +1642,6 @@ static void async_event(int pipe, time_t now)
       case EVENT_SCRIPT_LOG:
 	my_syslog(MS_SCRIPT | LOG_DEBUG, "%s", msg ? msg : "");
         free(msg);
-	msg = NULL;
 	break;
 
 	/* necessary for fatal errors in helper */

src/dnssec.c

@@ -1423,7 +1423,10 @@ static int base32_decode(char *in, unsigned char *out)
 	    oc |= 1;
 	  mask = mask >> 1;
 	  if (((++on) & 7) == 0)
-	    *p++ = oc;
+	    {
+	      *p++ = oc;
+	      oc = 0;
+	    }
 	  oc = oc << 1;
 	}
     }
@@ -1553,7 +1556,7 @@ static int prove_non_existence_nsec3(struct dns_header *header, size_t plen, uns
 {
   unsigned char *salt, *p, *digest;
   int digest_len, i, iterations, salt_len, base32_len, algo = 0;
-  struct nettle_hash const *hash;
+  struct nettle_hash const *hash = NULL;
   char *closest_encloser, *next_closest, *wildcard;
   
   if (nons)

src/edns0.c

@@ -103,7 +103,7 @@ unsigned char *find_pseudoheader(struct dns_header *header, size_t plen, size_t
 size_t add_pseudoheader(struct dns_header *header, size_t plen, unsigned char *limit, 
 			int optno, unsigned char *opt, size_t optlen, int set_do, int replace)
 { 
-  unsigned char *lenp, *datap, *p, *udp_len, *buff = NULL;
+  unsigned char *lenp = NULL, *datap = NULL, *p, *udp_len, *buff = NULL;
   int rdlen = 0, is_sign, is_last;
   unsigned short flags = set_do ? 0x8000 : 0, rcode = 0;
 

src/option.c

@@ -5734,7 +5734,7 @@ struct hostsfile *expand_filelist(struct hostsfile *list)
   struct dirent **namelist;
 
   /* find largest used index */
-  for (i = SRC_AH, ah = list; ah; ah = ah->next)
+  for (last = NULL, i = SRC_AH, ah = list; ah; ah = ah->next)
     {
       last = ah;
       

src/rfc3315.c

@@ -21,7 +21,7 @@
 
 struct state {
   unsigned char *clid;
-  int multicast_dest, clid_len, ia_type, interface, hostname_auth, lease_allocate;
+  int clid_len, ia_type, interface, hostname_auth, lease_allocate;
   char *client_hostname, *hostname, *domain, *send_domain;
   struct dhcp_context *context;
   struct in6_addr *link_address, *fallback, *ll_addr, *ula_addr;
@@ -34,8 +34,8 @@ struct state {
 };
 
 static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz, 
-			     struct in6_addr *client_addr, int is_unicast, time_t now);
-static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, int is_unicast, time_t now);
+			     struct in6_addr *client_addr, time_t now);
+static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, time_t now);
 static void log6_opts(int nest, unsigned int xid, void *start_opts, void *end_opts);
 static void log6_packet(struct state *state, char *type, struct in6_addr *addr, char *string);
 static void log6_quiet(struct state *state, char *type, struct in6_addr *addr, char *string);
@@ -80,6 +80,10 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
     return 0;
   
   msg_type = *((unsigned char *)daemon->dhcp_packet.iov_base);
+
+  /* request from a client must be multicast RFC-9915 section 16 */
+  if (msg_type != DHCP6RELAYFORW && !multicast_dest)
+    return 0;
   
   /* Mark these so we only match each at most once, to avoid tangled linked lists */
   for (vendor = daemon->dhcp_vendors; vendor; vendor = vendor->next)
@@ -87,7 +91,6 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
   
   reset_counter();
   state.context = context;
-  state.multicast_dest = multicast_dest;
   state.interface = interface;
   state.iface_name = iface_name;
   state.fallback = fallback;
@@ -97,8 +100,7 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
   state.tags = NULL;
   state.link_address = NULL;
 
-  if (dhcp6_maybe_relay(&state, daemon->dhcp_packet.iov_base, sz, client_addr, 
-			IN6_IS_ADDR_MULTICAST(client_addr), now))
+  if (dhcp6_maybe_relay(&state, daemon->dhcp_packet.iov_base, sz, client_addr, now))
     return msg_type == DHCP6RELAYFORW ? DHCPV6_SERVER_PORT : DHCPV6_CLIENT_PORT;
 
   return 0;
@@ -106,7 +108,7 @@ unsigned short dhcp6_reply(struct dhcp_context *context, int multicast_dest, int
 
 /* This cost me blood to write, it will probably cost you blood to understand - srk. */
 static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t sz, 
-			     struct in6_addr *client_addr, int is_unicast, time_t now)
+			     struct in6_addr *client_addr, time_t now)
 {
   uint8_t *end = inbuff + sz;
   uint8_t *opts = inbuff + 34;
@@ -184,7 +186,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	  return 0;
 	}
 
-      return dhcp6_no_relay(state, msg_type, inbuff, sz, is_unicast, now);
+      return dhcp6_no_relay(state, msg_type, inbuff, sz, now);
     }
 
   /* must have at least msg_type+hopcount+link_address+peer_address+minimal size option
@@ -250,9 +252,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
 	      /* RFC6221 para 4 */
 	      if (!IN6_IS_ADDR_UNSPECIFIED(&align))
 		state->link_address = &align;
-	      /* zero is_unicast since that is now known to refer to the 
-		 relayed packet, not the original sent by the client */
-	      if (!dhcp6_maybe_relay(state, opt6_ptr(opt, 0), opt6_len(opt), client_addr, 0, now))
+	      if (!dhcp6_maybe_relay(state, opt6_ptr(opt, 0), opt6_len(opt), client_addr, now))
 		return 0;
 	    }
 	  else
@@ -264,7 +264,7 @@ static int dhcp6_maybe_relay(struct state *state, unsigned char *inbuff, size_t
   return 1;
 }
 
-static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, int is_unicast, time_t now)
+static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbuff, size_t sz, time_t now)
 {
   void *opt;
   int i, o, o1, start_opts, start_msg;
@@ -340,22 +340,17 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 
   opt = opt6_find(state->packet_options, state->end, OPTION6_SERVER_ID, 1);
   
-  if (msg_type == DHCP6SOLICIT || msg_type == DHCP6CONFIRM || msg_type == DHCP6REBIND || msg_type == DHCP6IREQ)
+  if (msg_type == DHCP6SOLICIT || msg_type == DHCP6CONFIRM || msg_type == DHCP6REBIND)
     {
-      /* Above message types must be multicast 3315 Section 15. */
-      if (!state->multicast_dest)
+      /* SOLICIT, CONFIRM and REBIND messages MUST NOT have a server-id.  3315 para 15.x */
+      if (opt) 
 	return 0;
-
-      /* server-id must match except for SOLICIT, CONFIRM and REBIND messages, which MUST NOT
-	 have a server-id.  3315 para 15.x */
-      if (msg_type == DHCP6IREQ)
-	{
-	  /* If server-id provided in IREQ, it must match. */
-	  if (opt && (opt6_len(opt) != daemon->duid_len ||
-		      memcmp(opt6_ptr(opt, 0), daemon->duid, daemon->duid_len) != 0))
-	    return 0;
-	}
-      else if (opt) 
+    }
+  else if (msg_type == DHCP6IREQ)
+    {
+      /* If server-id provided in IREQ, it must match. */
+      if (opt && (opt6_len(opt) != daemon->duid_len ||
+		  memcmp(opt6_ptr(opt, 0), daemon->duid, daemon->duid_len) != 0))
 	return 0;
     }
   else
@@ -370,18 +365,6 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
   put_opt6(daemon->duid, daemon->duid_len);
   end_opt6(o);
 
-  if (is_unicast &&
-      (msg_type == DHCP6REQUEST || msg_type == DHCP6RENEW || msg_type == DHCP6RELEASE || msg_type == DHCP6DECLINE))
-    
-    {  
-      outmsgtype = DHCP6REPLY;
-      o1 = new_opt6(OPTION6_STATUS_CODE);
-      put_opt6_short(DHCP6USEMULTI);
-      put_opt6_string("Use multicast");
-      end_opt6(o1);
-      goto done;
-    }
-
   /* match vendor and user class options */
   for (vendor = daemon->dhcp_vendors; vendor; vendor = vendor->next)
     {
@@ -1304,7 +1287,6 @@ static int dhcp6_no_relay(struct state *state, int msg_type, unsigned char *inbu
 
   log_tags(tagif, state->xid);
 
- done:
   /* Fill in the message type. Note that we store the offset,
      not a direct pointer, since the packet memory may have been 
      reallocated. */

src/util.c

@@ -680,18 +680,12 @@ int expand_buf(struct iovec *iov, size_t size)
   if (size <= (size_t)iov->iov_len)
     return 1;
 
-  if (!(new = whine_malloc(size)))
+  if (!(new = whine_realloc(iov->iov_base, size)))
     {
       errno = ENOMEM;
       return 0;
     }
 
-  if (iov->iov_base)
-    {
-      memcpy(new, iov->iov_base, iov->iov_len);
-      free(iov->iov_base);
-    }
-
   iov->iov_base = new;
   iov->iov_len = size;
 
@@ -790,7 +784,7 @@ int read_writev(int fd, struct iovec *iov, int iovcnt, int rw)
 	return 0;
       
       done += n;
-      while ((size_t)done >= iov[cur].iov_len)
+      while (cur < iovcnt && (size_t)done >= iov[cur].iov_len)
 	done -= iov[cur++].iov_len;
     }