Possible crash when CDIGIPEAT did not have optional alias.

Author: wb2osz

CHANGES.md

@@ -1,6 +1,21 @@
 
 # Revision History #
 
+## Version 1.5 -- Development snapshot C -- September 2017 ##
+
+This is a snapshot of ongoing development towards version of 1.5.  Some features might be incomplete or broken or not documented properly.
+
+### New Features: ###
+
+- "kissutil" for troubleshooting a KISS TNC or interfacing to an application via files.
+
+
+### Bugs Fixed: ###
+
+- Possible crash when CDIGIPEAT did not include the optional alias.
+
+
+
 ## Version 1.5 -- Development snapshot B -- June 2017 ##
 
 This is a snapshot of ongoing development towards version of 1.5.  Some features might be incomplete or broken or not documented properly.
@@ -37,7 +52,7 @@ This is a snapshot of ongoing development towards version of 1.5.  Some features
 
 ### Bugs Fixed: ###
 
-- Little spelling errors in messages ????
+- Little typographical / spelling errors in messages.
 
 ----------
 

cdigipeater.c

@@ -1,7 +1,7 @@
 //
 //    This file is part of Dire Wolf, an amateur radio packet TNC.
 //
-//    Copyright (C) 2016  John Langner, WB2OSZ
+//    Copyright (C) 2016, 2017  John Langner, WB2OSZ
 //
 //    This program is free software: you can redistribute it and/or modify
 //    it under the terms of the GNU General Public License as published by
@@ -59,7 +59,7 @@
 
 
 static packet_t cdigipeat_match (int from_chan, packet_t pp, char *mycall_rec, char *mycall_xmit, 
-				regex_t *alias, int to_chan, char *filter_str);
+				int has_alias, regex_t *alias, int to_chan, char *cfilter_str);
 
 
 /*
@@ -149,9 +149,10 @@ void cdigipeater (int from_chan, packet_t pp)
 	      packet_t result;
 
 	      result = cdigipeat_match (from_chan, pp, save_audio_config_p->achan[from_chan].mycall, 
-					   save_audio_config_p->achan[to_chan].mycall, 
-			&save_cdigi_config_p->alias[from_chan][to_chan], to_chan,
-				save_cdigi_config_p->filter_str[from_chan][to_chan]);
+					   save_audio_config_p->achan[to_chan].mycall,
+			save_cdigi_config_p->has_alias[from_chan][to_chan],
+			&(save_cdigi_config_p->alias[from_chan][to_chan]), to_chan,
+				save_cdigi_config_p->cfilter_str[from_chan][to_chan]);
 	      if (result != NULL) {
 	        tq_append (to_chan, TQ_PRIO_0_HI, result);
 	        cdigi_count[from_chan][to_chan]++;
@@ -171,9 +172,10 @@ void cdigipeater (int from_chan, packet_t pp)
 	      packet_t result;
 
 	      result = cdigipeat_match (from_chan, pp, save_audio_config_p->achan[from_chan].mycall, 
-					   save_audio_config_p->achan[to_chan].mycall, 
-			&save_cdigi_config_p->alias[from_chan][to_chan], to_chan,
-				save_cdigi_config_p->filter_str[from_chan][to_chan]);
+					   save_audio_config_p->achan[to_chan].mycall,
+	                save_cdigi_config_p->has_alias[from_chan][to_chan],
+			&(save_cdigi_config_p->alias[from_chan][to_chan]), to_chan,
+				save_cdigi_config_p->cfilter_str[from_chan][to_chan]);
 	      if (result != NULL) {
 	        tq_append (to_chan, TQ_PRIO_0_HI, result);
 	        cdigi_count[from_chan][to_chan]++;
@@ -203,12 +205,15 @@ void cdigipeater (int from_chan, packet_t pp)
  *				  packet is to be transmitted.  Could be the same as
  *				  mycall_rec or different.
  *
- *		alias		- Compiled pattern for my station aliases.
- *				  Could be NULL if no aliases.
+ *		has_alias	- True if we have an alias.
+ *
+ *		alias		- Optional compiled pattern for my station aliases.
+ *				  Do NOT attempt to use this if 'has_alias' is false.
  *
  *		to_chan		- Channel number that we are transmitting to.
  *
- *		filter_str	- Filter expression string or NULL.
+ *		cfilter_str	- Filter expression string for the from/to channel pair or NULL.
+ *				  Note that only a subset of the APRS filters are applicable here.
  *		
  * Returns:	Packet object for transmission or NULL.
  *		The original packet is not modified.  The caller is responsible for freeing it.
@@ -227,20 +232,38 @@ void cdigipeater (int from_chan, packet_t pp)
 
 
 static packet_t cdigipeat_match (int from_chan, packet_t pp, char *mycall_rec, char *mycall_xmit, 
-				regex_t *alias, int to_chan, char *filter_str)
+				int has_alias, regex_t *alias, int to_chan, char *cfilter_str)
 {
 	int r;
 	char repeater[AX25_MAX_ADDR_LEN];
 	int err;
 	char err_msg[100];
 
+#if DEBUG
+	text_color_set(DW_COLOR_DEBUG);
+	dw_printf ("cdigipeat_match (from_chan=%d, pp=%p, mycall_rec=%s, mycall_xmit=%s, has_alias=%d, alias=%p, to_chan=%d, cfilter_str=%s\n",
+			from_chan, pp, mycall_rec, mycall_xmit, has_alias, alias, to_chan, cfilter_str);
+#endif
+
 /*
  * First check if filtering has been configured.
+ * Note that we have three different config file filter commands:
+ *
+ *	FILTER		- APRS digipeating and IGate client side.
+ *				Originally this was the only one.
+ *				Should we change it to AFILTER to make it clearer?
+ *	CFILTER		- Similar for connected moded digipeater.
+ *	IGFILTER	- APRS-IS (IGate) server side - completely diffeent.
+ *				Confusing with similar name but much different idea.
+ *				Maybe this should be renamed to SUBSCRIBE or something like that.
+ *
+ * Logically this should come later, after an address/alias match.
+ * But here we only have to do it once.
  */
 
-	if (filter_str != NULL) {
+	if (cfilter_str != NULL) {
 
-	  if (pfilter(from_chan, to_chan, filter_str, pp, 0) != 1) {
+	  if (pfilter(from_chan, to_chan, cfilter_str, pp, 0) != 1) {
 	    return(NULL);
 	  }
 	}
@@ -286,7 +309,11 @@ static packet_t cdigipeat_match (int from_chan, packet_t pp, char *mycall_rec, c
 /*
  * If we have an alias match, substitute MYCALL.
  */
-	if (alias != NULL) {
+	if (has_alias) {
+#if DEBUG
+	  text_color_set(DW_COLOR_DEBUG);
+	  dw_printf ("Checking %s for alias match.\n", repeater);
+#endif
 	  err = regexec(alias,repeater,0,NULL,0);
 	  if (err == 0) {
 	    packet_t result;
@@ -304,6 +331,12 @@ static packet_t cdigipeat_match (int from_chan, packet_t pp, char *mycall_rec, c
 	    dw_printf ("%s\n", err_msg);
 	  }
 	}
+	else {
+#if DEBUG
+	  text_color_set(DW_COLOR_DEBUG);
+	  dw_printf ("No alias was specified.\n");
+#endif
+	}
 
 /*
  * Don't repeat it if we get here.

cdigipeater.h

@@ -23,15 +23,18 @@ struct cdigi_config_s {
 /*
  * Rules for each of the [from_chan][to_chan] combinations.
  */
-
+	int	enabled[MAX_CHANS][MAX_CHANS];	// Is it enabled for from/to pair?
+
+	int has_alias[MAX_CHANS][MAX_CHANS];	// If there was no alias in the config file,
+						// the structure below will not be set up
+						// properly and an attempt to use it could
+						// result in a crash.  (fixed v1.5)
+						// Not needed for [APRS] DIGIPEAT because
+						// the alias is mandatory there.
 	regex_t	alias[MAX_CHANS][MAX_CHANS];
 
-	int	enabled[MAX_CHANS][MAX_CHANS];
-
-	char *filter_str[MAX_CHANS+1][MAX_CHANS+1];
+	char *cfilter_str[MAX_CHANS][MAX_CHANS];
 						// NULL or optional Packet Filter strings such as "t/m".
-						// Notice the size of arrays is one larger than normal.
-						// That extra position is for the IGate.
 };
 
 /*

config.c

@@ -798,9 +798,9 @@ void config_init (char *fname, struct audio_s *p_audio_config,
 	p_audio_config->achan[0].valid = 1;
 
 
-	memset (p_digi_config, 0, sizeof(struct digi_config_s));
+	memset (p_digi_config, 0, sizeof(struct digi_config_s));	// APRS digipeater
 	p_digi_config->dedupe_time = DEFAULT_DEDUPE;
-	memset (p_cdigi_config, 0, sizeof(struct cdigi_config_s));
+	memset (p_cdigi_config, 0, sizeof(struct cdigi_config_s));	// Connected mode digipeater
 
 	memset (p_tt_config, 0, sizeof(struct tt_config_s));	
 	p_tt_config->gateway_enabled = 0;
@@ -2276,7 +2276,10 @@ void config_init (char *fname, struct audio_s *p_audio_config,
 	    t = split(NULL,0);
 	    if (t != NULL) {
 	      e = regcomp (&(p_cdigi_config->alias[from_chan][to_chan]), t, REG_EXTENDED|REG_NOSUB);
-	      if (e != 0) {
+	      if (e == 0) {
+	        p_cdigi_config->has_alias[from_chan][to_chan] = 1;
+	      }
+	      else {
 	        regerror (e, &(p_cdigi_config->alias[from_chan][to_chan]), message, sizeof(message));
 	        text_color_set(DW_COLOR_ERROR);
 	        dw_printf ("Config file: Invalid alias matching pattern on line %d:\n%s\n",
@@ -2303,6 +2306,19 @@ void config_init (char *fname, struct audio_s *p_audio_config,
  * FILTER  from-chan  to-chan  filter_specification_expression
  * FILTER  from-chan  IG       filter_specification_expression
  * FILTER  IG         to-chan  filter_specification_expression
+ *
+ *
+ * Note that we have three different config file filter commands:
+ *
+ *	FILTER		- Originally for APRS digipeating but later enhanced
+ *			  to include IGate client side.  Maybe it should be
+ *			  renamed AFILTER to make it clearer after adding CFILTER.
+ *
+ *	CFILTER		- Similar for connected moded digipeater.
+ *
+ *	IGFILTER	- APRS-IS (IGate) server side - completely diffeent.
+ *			  I'm not happy with this name because IG sounds like IGate
+ *			  which is really the client side.  More comments later.
  */
 
 	  else if (strcasecmp(t, "FILTER") == 0) {
@@ -2442,7 +2458,7 @@ void config_init (char *fname, struct audio_s *p_audio_config,
 	      t = " ";				/* Empty means permit nothing. */
 	    }
 
-	    p_cdigi_config->filter_str[from_chan][to_chan] = strdup(t);
+	    p_cdigi_config->cfilter_str[from_chan][to_chan] = strdup(t);
 
 //TODO1.2:  Do a test run to see errors now instead of waiting.