[Asterisk-code-review] app macro: Prevent infinite loop in find matching priority. (asterisk[13])

[Corey Farrell]

Corey Farrell has uploaded this change for review. ( https://gerrit.asterisk.org/8931


Change subject: app_macro: Prevent infinite loop in find_matching_priority.
......................................................................

app_macro: Prevent infinite loop in find_matching_priority.

Use AST_PBX_MAX_STACK to escape if we recurse 128 times.  This will
prevent crash if dialplan contains an include loop.  Log an error when
this occurs, at most one message per call to Macro() so we avoid logger
spam.

ASTERISK-26570 #close

Change-Id: I6c71b76998c31434391b150de055ae9a531e31da
---
M apps/app_macro.c
1 file changed, 16 insertions(+), 3 deletions(-)



  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/31/8931/1

diff --git a/apps/app_macro.c b/apps/app_macro.c
index 5c50a9f..3aee5b0 100644
--- a/apps/app_macro.c
+++ b/apps/app_macro.c
@@ -38,6 +38,7 @@
 #include "asterisk/channel.h"
 #include "asterisk/pbx.h"
 #include "asterisk/module.h"
+#include "asterisk/extconf.h"
 #include "asterisk/config.h"
 #include "asterisk/utils.h"
 #include "asterisk/lock.h"
@@ -187,11 +188,20 @@
 	}
 }
 
-static struct ast_exten *find_matching_priority(struct ast_context *c, const char *exten, int priority, const char *callerid)
+static struct ast_exten *find_matching_priority(struct ast_context *c, const char *exten,
+	int priority, const char *callerid, int iter, int *had_error)
 {
 	struct ast_exten *e;
 	struct ast_include *i;
 	struct ast_context *c2;
+
+	if (iter >= AST_PBX_MAX_STACK) {
+		if (!(*had_error)) {
+			*had_error = 1;
+			ast_log(LOG_ERROR, "Potential infinate loop detected, will not recurse further.\n");
+		}
+		return NULL;
+	}
 
 	for (e=ast_walk_context_extensions(c, NULL); e; e=ast_walk_context_extensions(c, e)) {
 		if (ast_extension_match(ast_get_extension_name(e), exten)) {
@@ -213,7 +223,7 @@
 	for (i=ast_walk_context_includes(c, NULL); i; i=ast_walk_context_includes(c, i)) {
 		for (c2=ast_walk_contexts(NULL); c2; c2=ast_walk_contexts(c2)) {
 			if (!strcmp(ast_get_context_name(c2), ast_get_include_name(i))) {
-				e = find_matching_priority(c2, exten, priority, callerid);
+				e = find_matching_priority(c2, exten, priority, callerid, iter + 1, had_error);
 				if (e)
 					return e;
 			}
@@ -250,6 +260,7 @@
 	char *save_macro_offset;
 	int save_in_subroutine;
 	struct ast_datastore *macro_store = ast_channel_datastore_find(chan, &macro_ds_info, NULL);
+	int had_infinite_include_error = 0;
 
 	if (ast_strlen_zero(data)) {
 		ast_log(LOG_WARNING, "Macro() requires arguments. See \"core show application macro\" for help.\n");
@@ -418,7 +429,9 @@
 						ast_log(LOG_WARNING, "Unable to lock context?\n");
 					} else {
 						e = find_matching_priority(c, ast_channel_exten(chan), ast_channel_priority(chan),
-							S_COR(ast_channel_caller(chan)->id.number.valid, ast_channel_caller(chan)->id.number.str, NULL));
+							S_COR(ast_channel_caller(chan)->id.number.valid,
+							ast_channel_caller(chan)->id.number.str, NULL),
+							0, &had_infinite_include_error);
 						if (e) { /* This will only be undefined for pbx_realtime, which is majorly broken. */
 							ast_copy_string(runningapp, ast_get_extension_app(e), sizeof(runningapp));
 							ast_copy_string(runningdata, ast_get_extension_app_data(e), sizeof(runningdata));

-- 
To view, visit https://gerrit.asterisk.org/8931
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Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-MessageType: newchange
Gerrit-Change-Id: I6c71b76998c31434391b150de055ae9a531e31da
Gerrit-Change-Number: 8931
Gerrit-PatchSet: 1
Gerrit-Owner: Corey Farrell <git at cfware.com>
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