Fix dialplan function NULL channel safety issues

(closes issue ASTERISK-23391)
Reported by: Corey Farrell
Review: https://reviewboard.asterisk.org/r/3386/
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Merged revisions 411313 from http://svn.asterisk.org/svn/asterisk/branches/1.8
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Merged revisions 411314 from http://svn.asterisk.org/svn/asterisk/branches/11
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Merged revisions 411315 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@411328 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 15 insertions, 0 deletions

diff --git a/funcs/func_strings.c b/funcs/func_strings.c
index 3dd0168f1..ac889ec04 100644
--- a/funcs/func_strings.c
+++ b/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);