Fix dialplan function NULL channel safety issues

(closes issue ASTERISK-23391)
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/3386/
........

Merged revisions 411313 from http://svn.asterisk.org/svn/asterisk/branches/1.8


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@411314 65c4cc65-6c06-0410-ace0-fbb531ad65f3

apps/app_jack.c

@@ -951,6 +951,11 @@ static int jack_hook_write(struct ast_channel *chan, const char *cmd, char *data
 {
 	int res;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!strcasecmp(value, "on"))
 		res = enable_jack_hook(chan, data);
 	else if (!strcasecmp(value, "off"))

apps/app_speech_utils.c

@@ -284,7 +284,11 @@ static struct ast_speech *find_speech(struct ast_channel *chan)
 {
 	struct ast_speech *speech = NULL;
 	struct ast_datastore *datastore = NULL;
-	
+
+	if (!chan) {
+		return NULL;
+	}
+
 	datastore = ast_channel_datastore_find(chan, &speech_datastore, NULL);
 	if (datastore == NULL) {
 		return NULL;

apps/app_stack.c

@@ -687,6 +687,11 @@ static int local_read(struct ast_channel *chan, const char *cmd, char *data, cha
 	struct gosub_stack_frame *frame;
 	struct ast_var_t *variables;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 	if (!(stack_store = ast_channel_datastore_find(chan, &stack_info, NULL))) {
 		ast_channel_unlock(chan);
@@ -721,6 +726,11 @@ static int local_write(struct ast_channel *chan, const char *cmd, char *var, con
 	struct gosub_stack_list *oldlist;
 	struct gosub_stack_frame *frame;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 	if (!(stack_store = ast_channel_datastore_find(chan, &stack_info, NULL))) {
 		ast_log(LOG_ERROR, "Tried to set LOCAL(%s), but we aren't within a Gosub routine\n", var);

apps/app_voicemail.c

@@ -12045,7 +12045,9 @@ static int acf_vm_info(struct ast_channel *chan, const char *cmd, char *args, ch
 		} else if (!strncasecmp(arg.attribute, "pager", 5)) {
 			ast_copy_string(buf, vmu->pager, len);
 		} else if (!strncasecmp(arg.attribute, "language", 8)) {
-			ast_copy_string(buf, S_OR(vmu->language, ast_channel_language(chan)), len);
+			const char *lang = S_OR(vmu->language, chan ?
+				ast_channel_language(chan) : defaultlanguage);
+			ast_copy_string(buf, lang, len);
 		} else if (!strncasecmp(arg.attribute, "locale", 6)) {
 			ast_copy_string(buf, vmu->locale, len);
 		} else if (!strncasecmp(arg.attribute, "tz", 2)) {

apps/confbridge/conf_config_parser.c

@@ -354,6 +354,11 @@ int func_confbridge_helper(struct ast_channel *chan, const char *cmd, char *data
 		AST_APP_ARG(option);
 	);
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	/* parse all the required arguments and make sure they exist. */
 	if (ast_strlen_zero(data)) {
 		return -1;

channels/chan_iax2.c

@@ -10013,10 +10013,16 @@ static int socket_process_meta(int packet_len, struct ast_iax2_meta_hdr *meta, s
 
 static int acf_iaxvar_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
 {
-	struct ast_datastore *variablestore = ast_channel_datastore_find(chan, &iax2_variable_datastore_info, NULL);
+	struct ast_datastore *variablestore;
 	AST_LIST_HEAD(, ast_var_t) *varlist;
 	struct ast_var_t *var;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
+	variablestore = ast_channel_datastore_find(chan, &iax2_variable_datastore_info, NULL);
 	if (!variablestore) {
 		*buf = '\0';
 		return 0;
@@ -10036,10 +10042,16 @@ static int acf_iaxvar_read(struct ast_channel *chan, const char *cmd, char *data
 
 static int acf_iaxvar_write(struct ast_channel *chan, const char *cmd, char *data, const char *value)
 {
-	struct ast_datastore *variablestore = ast_channel_datastore_find(chan, &iax2_variable_datastore_info, NULL);
+	struct ast_datastore *variablestore;
 	AST_LIST_HEAD(, ast_var_t) *varlist;
 	struct ast_var_t *var;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
+	variablestore = ast_channel_datastore_find(chan, &iax2_variable_datastore_info, NULL);
 	if (!variablestore) {
 		variablestore = ast_datastore_alloc(&iax2_variable_datastore_info, NULL);
 		if (!variablestore) {
@@ -14307,8 +14319,9 @@ static int function_iaxpeer(struct ast_channel *chan, const char *cmd, char *dat
 	/* if our channel, return the IP address of the endpoint of current channel */
 	if (!strcmp(peername,"CURRENTCHANNEL")) {
 	        unsigned short callno;
-		if (ast_channel_tech(chan) != &iax2_tech)
+		if (!chan || ast_channel_tech(chan) != &iax2_tech) {
 			return -1;
+		}
 		callno = PTR_TO_CALLNO(ast_channel_tech_pvt(chan));	
 		ast_copy_string(buf, iaxs[callno]->addr.sin_addr.s_addr ? ast_inet_ntoa(iaxs[callno]->addr.sin_addr) : "", len);
 		return 0;

channels/chan_sip.c

@@ -21992,7 +21992,12 @@ static int func_header_read(struct ast_channel *chan, const char *function, char
 	);
 	int i, number, start = 0;
 
- 	if (ast_strlen_zero(data)) {
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
+	if (ast_strlen_zero(data)) {
 		ast_log(LOG_WARNING, "This function requires a header name.\n");
 		return -1;
 	}
@@ -22177,8 +22182,13 @@ static int function_sipchaninfo_read(struct ast_channel *chan, const char *cmd,
 	static int deprecated = 0;
 
 	*buf = 0;
-	
- 	if (!data) {
+
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
+	if (!data) {
 		ast_log(LOG_WARNING, "This function requires a parameter name.\n");
 		return -1;
 	}

funcs/func_blacklist.c

@@ -61,6 +61,11 @@ static int blacklist_read(struct ast_channel *chan, const char *cmd, char *data,
 	char blacklist[1];
 	int bl = 0;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (ast_channel_caller(chan)->id.number.valid && ast_channel_caller(chan)->id.number.str) {
 		if (!ast_db_get("blacklist", ast_channel_caller(chan)->id.number.str, blacklist, sizeof (blacklist)))
 			bl = 1;

funcs/func_callcompletion.c

@@ -74,6 +74,11 @@ static int acf_cc_read(struct ast_channel *chan, const char *name, char *data,
 	struct ast_cc_config_params *cc_params;
 	int res;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", name);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 	if (!(cc_params = ast_channel_get_cc_config_params(chan))) {
 		ast_channel_unlock(chan);
@@ -91,6 +96,11 @@ static int acf_cc_write(struct ast_channel *chan, const char *cmd, char *data,
 	struct ast_cc_config_params *cc_params;
 	int res;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 	if (!(cc_params = ast_channel_get_cc_config_params(chan))) {
 		ast_channel_unlock(chan);

funcs/func_callerid.c

@@ -900,6 +900,11 @@ static int callerpres_deprecate_notify;
  */
 static int callerpres_read(struct ast_channel *chan, const char *cmd, char *data, char *buf, size_t len)
 {
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!callerpres_deprecate_notify) {
 		callerpres_deprecate_notify = 1;
 		ast_log(LOG_WARNING, "CALLERPRES is deprecated."
@@ -926,6 +931,11 @@ static int callerpres_write(struct ast_channel *chan, const char *cmd, char *dat
 {
 	int pres;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!callerpres_deprecate_notify) {
 		callerpres_deprecate_notify = 1;
 		ast_log(LOG_WARNING, "CALLERPRES is deprecated."

funcs/func_channel.c

@@ -405,6 +405,11 @@ static int func_channel_read(struct ast_channel *chan, const char *function,
 	int ret = 0;
 	struct ast_format_cap *tmpcap;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
 	if (!strcasecmp(data, "audionativeformat")) {
 		char tmp[512];
 
@@ -703,6 +708,11 @@ static int func_channel_write(struct ast_channel *chan, const char *function, ch
 		.value = value,
 	};
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
 	res = func_channel_write_real(chan, function, data, value);
 	ast_channel_setoption(chan, AST_OPTION_CHANNEL_WRITE, &write_info, sizeof(write_info), 0);
 
@@ -776,8 +786,15 @@ static struct ast_custom_function channels_function = {
 static int func_mchan_read(struct ast_channel *chan, const char *function,
 			     char *data, struct ast_str **buf, ssize_t len)
 {
-	struct ast_channel *mchan = ast_channel_get_by_name(ast_channel_linkedid(chan));
+	struct ast_channel *mchan;
 	char *template = ast_alloca(4 + strlen(data));
+
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
+	mchan = ast_channel_get_by_name(ast_channel_linkedid(chan));
 	sprintf(template, "${%s}", data); /* SAFE */
 	ast_str_substitute_variables(buf, len, mchan ? mchan : chan, template);
 	if (mchan) {
@@ -789,7 +806,14 @@ static int func_mchan_read(struct ast_channel *chan, const char *function,
 static int func_mchan_write(struct ast_channel *chan, const char *function,
 			      char *data, const char *value)
 {
-	struct ast_channel *mchan = ast_channel_get_by_name(ast_channel_linkedid(chan));
+	struct ast_channel *mchan;
+
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
+	mchan = ast_channel_get_by_name(ast_channel_linkedid(chan));
 	pbx_builtin_setvar_helper(mchan ? mchan : chan, data, value);
 	if (mchan) {
 		ast_channel_unref(mchan);

funcs/func_dialplan.c

@@ -96,20 +96,23 @@ static int isexten_function_read(struct ast_channel *chan, const char *cmd, char
 		int priority_num;
 		if (sscanf(args.priority, "%30d", &priority_num) == 1 && priority_num > 0) {
 			int res;
-			res = ast_exists_extension(chan, args.context, args.exten, priority_num, 
+			res = ast_exists_extension(chan, args.context, args.exten, priority_num,
+				!chan ? NULL :
 				S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL));
 			if (res)
 				strcpy(buf, "1");
 		} else {
 			int res;
 			res = ast_findlabel_extension(chan, args.context, args.exten, args.priority,
+				!chan ? NULL :
 				S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL));
 			if (res > 0)
 				strcpy(buf, "1");
 		}
 	} else if (!ast_strlen_zero(args.exten)) {
 		int res;
-		res = ast_exists_extension(chan, args.context, args.exten, 1, 
+		res = ast_exists_extension(chan, args.context, args.exten, 1,
+			!chan ? NULL :
 			S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL));
 		if (res)
 			strcpy(buf, "1");
@@ -133,6 +136,11 @@ static int acf_isexten_exec(struct ast_channel *chan, const char *cmd, char *par
 		AST_APP_ARG(priority);
 	);
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	AST_STANDARD_APP_ARGS(args, parse);
 
 	if (ast_strlen_zero(args.context)) {

funcs/func_frame_trace.c

@@ -157,6 +157,11 @@ static int frame_trace_helper(struct ast_channel *chan, const char *cmd, char *d
 	};
 	int i = 0;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!(framedata = ast_calloc(1, sizeof(*framedata)))) {
 		return 0;
 	}

funcs/func_global.c

@@ -155,6 +155,9 @@ static int shared_read(struct ast_channel *chan, const char *cmd, char *data, ch
 			return -1;
 		}
 		chan = c_ref;
+	} else if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
 	}
 
 	ast_channel_lock(chan);
@@ -213,6 +216,9 @@ static int shared_write(struct ast_channel *chan, const char *cmd, char *data, c
 			return -1;
 		}
 		chan = c_ref;
+	} else if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
 	}
 
 	ast_channel_lock(chan);

funcs/func_groupcount.c

@@ -104,6 +104,11 @@ static int group_count_function_read(struct ast_channel *chan, const char *cmd,
 	int count = -1;
 	char group[80] = "", category[80] = "";
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_app_group_split_group(data, group, sizeof(group), category,
 				  sizeof(category));
 
@@ -174,9 +179,14 @@ static int group_function_read(struct ast_channel *chan, const char *cmd,
 {
 	int ret = -1;
 	struct ast_group_info *gi = NULL;
-	
+
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_app_group_list_rdlock();
-	
+
 	for (gi = ast_app_group_list_head(); gi; gi = AST_LIST_NEXT(gi, group_list)) {
 		if (gi->chan != chan)
 			continue;
@@ -201,6 +211,11 @@ static int group_function_write(struct ast_channel *chan, const char *cmd,
 {
 	char grpcat[256];
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!value) {
 		return -1;
 	}

funcs/func_jitterbuffer.c

@@ -325,6 +325,11 @@ static int jb_helper(struct ast_channel *chan, const char *cmd, char *data, cons
 	};
 	int i = 0;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!(framedata = ast_calloc(1, sizeof(*framedata)))) {
 		return 0;
 	}

funcs/func_math.c

@@ -392,6 +392,11 @@ static int crement_function_read(struct ast_channel *chan, const char *cmd,
 		return -1;
 	}
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 
 	if (!(var = pbx_builtin_getvar_helper(chan, data))) {

funcs/func_odbc.c

@@ -801,6 +801,11 @@ static int acf_fetch(struct ast_channel *chan, const char *cmd, char *data, char
 	struct odbc_datastore *resultset;
 	struct odbc_datastore_row *row;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 	store = ast_channel_datastore_find(chan, &odbc_info, data);
 	if (!store) {

funcs/func_pitchshift.c

@@ -200,6 +200,11 @@ static int pitchshift_helper(struct ast_channel *chan, const char *cmd, char *da
 	int new = 0;
 	float amount = 0;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 	if (!(datastore = ast_channel_datastore_find(chan, &pitchshift_datastore, NULL))) {
 		ast_channel_unlock(chan);

funcs/func_speex.c

@@ -202,6 +202,11 @@ static int speex_write(struct ast_channel *chan, const char *cmd, char *data, co
 	struct speex_direction_info **sdi = NULL;
 	int is_new = 0;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (strcasecmp(data, "rx") && strcasecmp(data, "tx")) {
 		ast_log(LOG_ERROR, "Invalid argument provided to the %s function\n", cmd);
 		return -1;

funcs/func_strings.c

@@ -1097,6 +1097,11 @@ static int hashkeys_read(struct ast_channel *chan, const char *cmd, char *data,
 	struct ast_var_t *newvar;
 	struct ast_str *prefix = ast_str_alloca(80);
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_str_set(&prefix, -1, HASH_PREFIX, data);
 	memset(buf, 0, len);
 
@@ -1119,6 +1124,11 @@ static int hashkeys_read2(struct ast_channel *chan, const char *cmd, char *data,
 	struct ast_str *prefix = ast_str_alloca(80);
 	char *tmp;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_str_set(&prefix, -1, HASH_PREFIX, data);
 
 	AST_LIST_TRAVERSE(ast_channel_varshead(chan), newvar, entries) {
@@ -1188,6 +1198,11 @@ static int hash_read(struct ast_channel *chan, const char *cmd, char *data, char
 			AST_APP_ARG(col)[100];
 		);
 
+		if (!chan) {
+			ast_log(LOG_WARNING, "No channel and only 1 parameter was provided to %s function.\n", cmd);
+			return -1;
+		}
+
 		/* Get column names, in no particular order */
 		hashkeys_read(chan, "HASHKEYS", arg.hashname, colnames, sizeof(colnames));
 		pbx_builtin_setvar_helper(chan, "~ODBCFIELDS~", colnames);

funcs/func_volume.c

@@ -156,12 +156,17 @@ static int volume_write(struct ast_channel *chan, const char *cmd, char *data, c
 	int is_new = 0;
 
 	/* Separate options from argument */
-	
+
 	AST_DECLARE_APP_ARGS(args,
 		AST_APP_ARG(direction);
 		AST_APP_ARG(options);
 	);
-	
+
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	AST_STANDARD_APP_ARGS(args, data);
 
 	ast_channel_lock(chan);

main/features.c

@@ -8913,6 +8913,11 @@ static int feature_read(struct ast_channel *chan, const char *cmd, char *data,
 {
 	int res = 0;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!strcasecmp(data, "parkingtime")) {
 		snprintf(buf, len, "%u", get_parkingtime(chan, NULL) / 1000);
 	} else {
@@ -8929,6 +8934,11 @@ static int feature_write(struct ast_channel *chan, const char *cmd, char *data,
 	int res = 0;
 	struct feature_ds *feature_ds;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 
 	if (!(feature_ds = get_feature_ds(chan))) {
@@ -8961,6 +8971,11 @@ static int featuremap_read(struct ast_channel *chan, const char *cmd, char *data
 {
 	int res;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_rdlock_call_features();
 
 	if ((res = builtin_feature_get_exten(chan, data, buf, len))) {
@@ -8978,6 +8993,11 @@ static int featuremap_write(struct ast_channel *chan, const char *cmd, char *dat
 	struct feature_ds *feature_ds;
 	struct feature_exten *fe;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (!ast_find_call_feature(data)) {
 		ast_log(LOG_WARNING, "Invalid argument '%s' to FEATUREMAP()\n", data);
 		return -1;

main/message.c

@@ -867,6 +867,11 @@ static int msg_func_read(struct ast_channel *chan, const char *function,
 	struct ast_datastore *ds;
 	struct ast_msg *msg;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 
 	if (!(ds = ast_channel_datastore_find(chan, &msg_datastore, NULL))) {
@@ -903,6 +908,11 @@ static int msg_func_write(struct ast_channel *chan, const char *function,
 	struct ast_datastore *ds;
 	struct ast_msg *msg;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 
 	if (!(ds = msg_datastore_find_or_create(chan))) {
@@ -959,6 +969,11 @@ static int msg_data_func_read(struct ast_channel *chan, const char *function,
 	struct ast_msg *msg;
 	const char *val;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 
 	if (!(ds = ast_channel_datastore_find(chan, &msg_datastore, NULL))) {
@@ -989,6 +1004,11 @@ static int msg_data_func_write(struct ast_channel *chan, const char *function,
 	struct ast_datastore *ds;
 	struct ast_msg *msg;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", function);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 
 	if (!(ds = msg_datastore_find_or_create(chan))) {

res/res_calendar.c

@@ -1673,6 +1673,11 @@ static int calendar_event_read(struct ast_channel *chan, const char *cmd, char *
 	struct ast_datastore *datastore;
 	struct ast_calendar_event *event;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	if (ast_strlen_zero(data)) {
 		ast_log(LOG_WARNING, "%s requires an argument\n", cmd);
 		return -1;

res/res_jabber.c

@@ -837,7 +837,7 @@ static int acf_jabberreceive_read(struct ast_channel *chan, const char *name, ch
 
 	start = ast_tvnow();
 
-	if (ast_autoservice_start(chan) < 0) {
+	if (chan && ast_autoservice_start(chan) < 0) {
 		ast_log(LOG_WARNING, "Cannot start autoservice for channel %s\n", ast_channel_name(chan));
 		ASTOBJ_UNREF(client, ast_aji_client_destroy);
 		return -1;
@@ -909,7 +909,7 @@ static int acf_jabberreceive_read(struct ast_channel *chan, const char *name, ch
 	}
 
 	ASTOBJ_UNREF(client, ast_aji_client_destroy);
-	if (ast_autoservice_stop(chan) < 0) {
+	if (chan && ast_autoservice_stop(chan) < 0) {
 		ast_log(LOG_WARNING, "Cannot stop autoservice for channel %s\n", ast_channel_name(chan));
 	}
 

res/res_mutestream.c

@@ -235,6 +235,11 @@ static int func_mute_write(struct ast_channel *chan, const char *cmd, char *data
 	int is_new = 0;
 	int turnon;
 
+	if (!chan) {
+		ast_log(LOG_WARNING, "No channel was provided to %s function.\n", cmd);
+		return -1;
+	}
+
 	ast_channel_lock(chan);
 	if (!(datastore = ast_channel_datastore_find(chan, &mute_datastore, NULL))) {
 		if (!(datastore = initialize_mutehook(chan))) {

res/res_xmpp.c

@@ -1923,7 +1923,7 @@ static int acf_jabberreceive_read(struct ast_channel *chan, const char *name, ch
 
 	start = ast_tvnow();
 
-	if (ast_autoservice_start(chan) < 0) {
+	if (chan && ast_autoservice_start(chan) < 0) {
 		ast_log(LOG_WARNING, "Cannot start autoservice for channel %s\n", ast_channel_name(chan));
 		return -1;
 	}
@@ -1995,7 +1995,7 @@ static int acf_jabberreceive_read(struct ast_channel *chan, const char *name, ch
 		diff = ast_tvdiff_ms(ast_tvnow(), start);
 	}
 
-	if (ast_autoservice_stop(chan) < 0) {
+	if (chan && ast_autoservice_stop(chan) < 0) {
 		ast_log(LOG_WARNING, "Cannot stop autoservice for channel %s\n", ast_channel_name(chan));
 	}