res_geolocation: Fix segfault when there's an empty element

Fixed a segfault caused by var_list_from_loc_info() encountering
an empty location info element.

Fixed an issue in ast_strsep() where a value with only whitespace
wasn't being preserved.

Fixed an issue in ast_variable_list_from_quoted_string() where
an empty value was considered a failure.

ASTERISK-30215
Reported by: Dan Cropp

Change-Id: Ieca64e061a6d9298f0196c694b60d986ef82613a

include/asterisk/strings.h

@@ -265,6 +265,7 @@ enum ast_strsep_flags {
   \param sep A single character delimiter.
   \param flags Controls post-processing of the result.
   AST_STRSEP_TRIM trims all leading and trailing whitespace from the result.
+  If the result containes only whitespace, it'll be passed through unchanged.
   AST_STRSEP_STRIP does a trim then strips the outermost quotes.  You may want
   to trim again after the strip.  Just OR both the TRIM and STRIP flags.
   AST_STRSEP_UNESCAPE unescapes '\' sequences.

main/config.c

@@ -646,15 +646,16 @@ struct ast_variable *ast_variable_list_sort(struct ast_variable *start)
 struct ast_variable *ast_variable_list_append_hint(struct ast_variable **head, struct ast_variable *search_hint, struct ast_variable *newvar)
 {
 	struct ast_variable *curr;
+	struct ast_variable *sh = search_hint;
 	ast_assert(head != NULL);
 
 	if (!*head) {
 		*head = newvar;
 	} else {
-		if (search_hint == NULL) {
+		if (sh == NULL) {
-			search_hint = *head;
+			sh = *head;
 		}
-		for (curr = search_hint; curr->next; curr = curr->next);
+		for (curr = sh; curr->next; curr = curr->next);
 		curr->next = newvar;
 	}
 
@@ -752,12 +753,8 @@ struct ast_variable *ast_variable_list_from_quoted_string(const char *input, con
 		}
 
 		item_value = ast_strsep_quoted(&item, nv_sep, quote, AST_STRSEP_ALL);
-		if (!item_value) {
-			ast_variables_destroy(new_list);
-			return NULL;
-		}
 
-		new_var = ast_variable_new(item_name, item_value, "");
+		new_var = ast_variable_new(item_name, item_value ?: "", "");
 		if (!new_var) {
 			ast_variables_destroy(new_list);
 			return NULL;

main/utils.c

@@ -1849,7 +1849,10 @@ char *ast_strsep(char **iss, const char sep, uint32_t flags)
 	}
 
 	if (flags & AST_STRSEP_TRIM) {
-		st = ast_strip(st);
+		char *trimmed = ast_strip(st);
+		if (!ast_strlen_zero(trimmed)) {
+			st = trimmed;
+		}
 	}
 
 	if (flags & AST_STRSEP_UNESCAPE) {
@@ -1910,7 +1913,10 @@ char *ast_strsep_quoted(char **iss, const char sep, const char quote, uint32_t f
 	}
 
 	if (flags & AST_STRSEP_TRIM) {
-		st = ast_strip(st);
+		char *trimmed = ast_strip(st);
+		if (!ast_strlen_zero(trimmed)) {
+			st = trimmed;
+		}
 	}
 
 	if (flags & AST_STRSEP_UNESCAPE) {

res/res_geolocation/geoloc_eprofile.c

@@ -498,6 +498,7 @@ static struct ast_variable *var_list_from_loc_info(struct ast_xml_node *locinfo,
 	enum ast_geoloc_format format, const char *ref_str)
 {
 	struct ast_variable *list = NULL;
+	struct ast_variable *locinfo_list = NULL;
 	struct ast_xml_node *container;
 	struct ast_variable *var = NULL;
 	const char *attr;
@@ -531,7 +532,12 @@ static struct ast_variable *var_list_from_loc_info(struct ast_xml_node *locinfo,
 		ast_variable_list_append(&list, var);
 	}
 
-	ast_variable_list_append(&list, var_list_from_node(container, ref_str));
+	locinfo_list = var_list_from_node(container, ref_str);
+	if (locinfo_list == NULL) {
+		ast_log(LOG_WARNING, "%s: There were no elements in the location info\n", ref_str);
+		SCOPE_EXIT_RTN_VALUE(list, "%s: There were no elements in the location info\n", ref_str);
+	}
+	ast_variable_list_append(&list, locinfo_list);
 
 	if (TRACE_ATLEAST(5)) {
 		struct ast_str *buf = NULL;

tests/test_config.c

@@ -1961,13 +1961,13 @@ AST_TEST_DEFINE(variable_list_from_string)
 		break;
 	}
 
-	parse_string = "abc = 'def', ghi = 'j,kl', mno='pq=r', stu = 'vwx=\"yz\", ABC = \"DEF\"'";
+	parse_string = "000= '', 111=, 222 = , 333 = ' ', abc = 'def', ghi = 'j,kl', mno='pq=r', stu = 'vwx=\"yz\", ABC = \"DEF\"'";
 	list = ast_variable_list_from_quoted_string(parse_string, ",", "=", "'");
 	ast_test_validate(test, list != NULL);
 	str = ast_variable_list_join(list, "|", "^", "@", NULL);
 
 	ast_test_validate(test,
-		strcmp(ast_str_buffer(str), "abc^@def@|ghi^@j,kl@|mno^@pq=r@|stu^@vwx=\"yz\", ABC = \"DEF\"@") == 0);
+		strcmp(ast_str_buffer(str), "000^@@|111^@@|222^@@|333^@ @|abc^@def@|ghi^@j,kl@|mno^@pq=r@|stu^@vwx=\"yz\", ABC = \"DEF\"@") == 0);
 
 	return AST_TEST_PASS;
 }