Merge branch 'pan/epmd-vulnerabilities/OTP-8780' into dev

* pan/epmd-vulnerabilities/OTP-8780:
  Teach testcases to survive TIME_WAIT overload
  Update erl_interface doc and testsuite for epmd changes
  Restore null termination of input buffer
  Teach testcase epmd_SUITE:too_large to accept econnaborted
  Teach epmd_cli.c to not respond 'Killed' when killing denied
  Calculate minimal packet size for ALIVE2 requests correctly
  Document epmd and it's options properly and fixup help text
  Fix anomalies in epmd not yet reported as security issues
  Remove two buffer overflow vulnerabilities in EPMD
  Remove all support for ancient EPMD protocol
  Remove very old protocol from EPMD

Conflicts:
	lib/erl_interface/src/epmd/epmd_port.c

1 files changed, 43 insertions, 10 deletions

diff --git a/erts/epmd/src/epmd.c b/erts/epmd/src/epmd.c
index 9c2ce065bb..65ff0cd6b2 100644
--- a/erts/epmd/src/epmd.c
+++ b/erts/epmd/src/epmd.c
@@ -23,6 +23,7 @@
 #endif
 #include "epmd.h"     /* Renamed from 'epmd_r4.h' */
 #include "epmd_int.h"
+#include "erl_printf.h"
 
 #ifdef HAVE_STDLIB_H
 #  include <stdlib.h>
@@ -33,6 +34,7 @@
 static void usage(EpmdVars *);
 static void run_daemon(EpmdVars*);
 static int get_port_no(void);
+static int check_relaxed(void);
 #ifdef __WIN32__
 static int has_console(void);
 #endif
@@ -161,6 +163,7 @@ int main(int argc, char** argv)
 
     g->silent         = 0; 
     g->is_daemon      = 0;
+    g->brutal_kill    = check_relaxed();
     g->packet_timeout = CLOSE_TIMEOUT; /* Default timeout */
     g->delay_accept   = 0;
     g->delay_write    = 0;
@@ -196,6 +199,9 @@ int main(int argc, char** argv)
 	} else if (strcmp(argv[0], "-daemon") == 0) {
 	    g->is_daemon = 1;
 	    argv++; argc--;
+	} else if (strcmp(argv[0], "-relaxed_command_check") == 0) {
+	    g->brutal_kill = 1;
+	    argv++; argc--;
 	} else if (strcmp(argv[0], "-kill") == 0) {
 	    if (argc == 1)
 		kill_epmd(g);
@@ -388,9 +394,10 @@ static void run_daemon(EpmdVars *g)
 static void usage(EpmdVars *g)
 {
     fprintf(stderr, "usage: epmd [-d|-debug] [DbgExtra...] [-port No] [-daemon]\n");
-    fprintf(stderr, "            [-d|-debug] [-port No] [-names|-kill|-stop name]\n\n");
-    fprintf(stderr, "See the Erlang epmd manual page for info about the usage.\n");
-    fprintf(stderr, "The -port and DbgExtra options are\n\n");
+    fprintf(stderr, "            [-relaxed_command_check]\n");
+    fprintf(stderr, "       epmd [-d|-debug] [-port No] [-names|-kill|-stop name]\n\n");
+    fprintf(stderr, "See the Erlang epmd manual page for info about the usage.\n\n");
+    fprintf(stderr, "Regular options\n");
     fprintf(stderr, "    -port No\n");
     fprintf(stderr, "        Let epmd listen to another port than default %d\n",
 	    EPMD_PORT_NO);
@@ -400,8 +407,16 @@ static void usage(EpmdVars *g)
     fprintf(stderr, "        the standard error stream. It will shorten\n");
     fprintf(stderr, "        the number of saved used node names to 5.\n\n");
     fprintf(stderr, "        If you give more than one debug flag you may\n");
-    fprintf(stderr, "        get more debugging information.\n\n");
-    fprintf(stderr, "    -packet_timout Seconds\n");
+    fprintf(stderr, "        get more debugging information.\n");
+    fprintf(stderr, "    -daemon\n");
+    fprintf(stderr, "        Start epmd detached (as a daemon)\n");
+    fprintf(stderr, "    -relaxed_command_check\n");
+    fprintf(stderr, "        Allow this instance of epmd to be killed with\n");
+    fprintf(stderr, "        epmd -kill even if there "
+	    "are registered nodes.\n");
+    fprintf(stderr, "        Also allows forced unregister (epmd -stop).\n");
+    fprintf(stderr, "\nDbgExtra options\n");
+    fprintf(stderr, "    -packet_timeout Seconds\n");
     fprintf(stderr, "        Set the number of seconds a connection can be\n");
     fprintf(stderr, "        inactive before epmd times out and closes the\n");
     fprintf(stderr, "        connection (default 60).\n\n");
@@ -413,6 +428,18 @@ static void usage(EpmdVars *g)
     fprintf(stderr, "    -delay_write Seconds\n");
     fprintf(stderr, "        Also a simulation of a busy server. Inserts\n");
     fprintf(stderr, "        a delay before a reply is sent.\n");
+    fprintf(stderr, "\nInteractive options\n");
+    fprintf(stderr, "    -names\n");
+    fprintf(stderr, "        List names registered with the currently "
+	    "running epmd\n");
+    fprintf(stderr, "    -kill\n");
+    fprintf(stderr, "        Kill the currently runniing epmd\n");
+    fprintf(stderr, "        (only allowed if -names show empty database or\n");
+    fprintf(stderr, "        -relaxed_command_check was given when epmd was started).\n");
+    fprintf(stderr, "    -stop Name\n");
+    fprintf(stderr, "        Forcibly unregisters a name with epmd\n");
+    fprintf(stderr, "        (only allowed if -relaxed_command_check was given when \n");
+    fprintf(stderr, "        epmd was started).\n");
     epmd_cleanup_exit(g,1);
 }
 
@@ -432,20 +459,20 @@ static void usage(EpmdVars *g)
  *      args...      Arguments to print out according to the format
  *      
  */
-
+#define DEBUG_BUFFER_SIZE 2048
 static void dbg_gen_printf(int onsyslog,int perr,int from_level,
 			   EpmdVars *g,const char *format, va_list args)
 {
   time_t now;
   char *timestr;
-  char buf[2048];
+  char buf[DEBUG_BUFFER_SIZE];
 
   if (g->is_daemon)
     {
 #ifndef NO_SYSLOG
       if (onsyslog)
 	{
-	  vsprintf(buf, format, args);
+	  erts_vsnprintf(buf, DEBUG_BUFFER_SIZE, format, args);
 	  syslog(LOG_ERR,"epmd: %s",buf);
 	}
 #endif
@@ -456,9 +483,10 @@ static void dbg_gen_printf(int onsyslog,int perr,int from_level,
 
       time(&now);
       timestr = (char *)ctime(&now);
-      sprintf(buf, "epmd: %.*s: ", (int) strlen(timestr)-1, timestr);
+      erts_snprintf(buf, DEBUG_BUFFER_SIZE, "epmd: %.*s: ",
+		    (int) strlen(timestr)-1, timestr);
       len = strlen(buf);
-      vsprintf(buf + len, format, args);
+      erts_vsnprintf(buf + len, DEBUG_BUFFER_SIZE - len, format, args);
       if (perr == 1)
 	perror(buf);
       else
@@ -545,4 +573,9 @@ static int get_port_no(void)
     char* port_str = getenv("ERL_EPMD_PORT");
     return (port_str != NULL) ? atoi(port_str) : EPMD_PORT_NO;
 }
+static int check_relaxed(void)
+{
+    char* port_str = getenv("ERL_EPMD_RELAXED_COMMAND_CHECK");
+    return (port_str != NULL) ? 1 : 0;
+}