Handle "extra" field according to specs in ALIVE2_REQ and PORT2_RESP.

Don't let the length field pollute the value of the "extra" field in
ALIVE2_REQ.  Extra was read, starting at the second byte of the two
byte length field, which meant that it was included in the result and
the last byte of the value was skipped:

    if "extra" is <<1, 2>>, return <<0, 2, 1, 2>> not <<0, 2, 2, 1>>

Increment the offset correctly when sending PORT2_RESP, in order to
make sure the "extra" field won't be truncated:

    if "extra" is <<>>, return <<0, 0>> not <<0>>
    if "extra" is <<1, 2>>, return <<0, 2, 1, 2>> not <<0, 2, 1>>

Allow null characters in "extra".

2 files changed, 11 insertions, 8 deletions

diff --git a/erts/epmd/src/epmd_int.h b/erts/epmd/src/epmd_int.h
index b120b44579..30f731d49e 100644
--- a/erts/epmd/src/epmd_int.h
+++ b/erts/epmd/src/epmd_int.h
@@ -294,6 +294,7 @@ struct enode {
   char protocol;                /* 0 = tcp/ipv4 */
   unsigned short highvsn;       /* 0 = OTP-R3 erts-4.6.x, 1 = OTP-R4 erts-4.7.x*/
   unsigned short lowvsn;
+  int extralen;
   char extra[MAXSYMLEN+1];
 };
 
diff --git a/erts/epmd/src/epmd_srv.c b/erts/epmd/src/epmd_srv.c
index b71e27cffd..27d30eee6b 100644
--- a/erts/epmd/src/epmd_srv.c
+++ b/erts/epmd/src/epmd_srv.c
@@ -99,7 +99,7 @@ static int conn_close_fd(EpmdVars*,int);
 
 static void node_init(EpmdVars*);
 static Node *node_reg(EpmdVars*,char*,int,int);
-static Node *node_reg2(EpmdVars*,char*, int, int, unsigned char, unsigned char, int, int, char*);
+static Node *node_reg2(EpmdVars*,char*, int, int, unsigned char, unsigned char, int, int, int, char*);
 static int node_unreg(EpmdVars*,char*);
 static int node_unreg_sock(EpmdVars*,int);
 
@@ -558,11 +558,11 @@ static void do_request(g, fd, s, buf, bsize)
 	    }
 	name = &buf[11];
 	name[namelen]='\000';
-	extra = &buf[11+namelen+1];
+	extra = &buf[11+namelen+2];
 	extra[extralen]='\000';
 	wbuf[0] = EPMD_ALIVE2_RESP;
 	if ((node = node_reg2(g, name, fd, eport, nodetype, protocol,
-			      highvsn, lowvsn, extra)) == NULL) {
+			      highvsn, lowvsn, extralen, extra)) == NULL) {
 	    wbuf[1] = 1; /* error */
 	    put_int16(99, wbuf+2);
 	} else {
@@ -622,10 +622,10 @@ static void do_request(g, fd, s, buf, bsize)
 		offset = 12;
 		strcpy(wbuf + offset,node->symname);
 		offset += strlen(node->symname);
-		put_int16(strlen(node->extra),wbuf + offset);
+		put_int16(node->extralen,wbuf + offset);
 		offset += 2;
-		strcpy(wbuf + offset,node->extra);
-		offset += (strlen(node->extra)-1);
+		memcpy(wbuf + offset,node->extra,node->extralen);
+		offset += node->extralen;
 		if (reply(g, fd, wbuf, offset) != offset)
 		  {
 		    dbg_tty_printf(g,1,"** failed to send PORT2_RESP (ok) for \"%s\"",name);
@@ -994,7 +994,7 @@ static int node_unreg_sock(EpmdVars *g,int fd)
 
 static Node *node_reg(EpmdVars *g,char *name,int fd, int port)
 {
-    return node_reg2(g, name, fd, port, 0, 0, 0, 0, NULL);
+    return node_reg2(g, name, fd, port, 0, 0, 0, 0, 0, NULL);
 }
 
 static Node *node_reg2(EpmdVars *g,
@@ -1005,6 +1005,7 @@ static Node *node_reg2(EpmdVars *g,
 		       unsigned char protocol,
 		       int highvsn,
 		       int lowvsn,
+		       int extralen,
 		       char* extra)
 {
   Node *prev;			/* Point to previous node or NULL */
@@ -1103,7 +1104,8 @@ static Node *node_reg2(EpmdVars *g,
   node->protocol = protocol;
   node->highvsn  = highvsn;
   node->lowvsn   = lowvsn;
-  strcpy(node->extra,extra);
+  node->extralen = extralen;
+  memcpy(node->extra,extra,extralen);
   strcpy(node->symname,name);
   FD_SET(fd,&g->orig_read_mask);