[asterisk-commits] alecdavis: trunk r253490 - /trunk/main/astobj2.c

[SVN commits to the Asterisk project]

Author: alecdavis
Date: Fri Mar 19 02:37:00 2010
New Revision: 253490

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=253490
Log:
prevent segfault if bad magic number is encountered.

internal_ao2_ref uses INTERNAL_OBJ which mzy report 'bad magic number', but
internal_ao2_ref continues on, causing segfault.

Although AO2_MAGIC number is checked by INTERNAL_OBJ before internal_ao2_ref is
called, A02_MAGIC is being destroyed (or a wrong pointer) by the time
internal_ao2_ref uses INTERNAL_OBJ.

internal_ao2_ref now returns -1 if INTERNAL_OBJ encouters a bad magic number.

(issue #17037)
Reported by: alecdavis
Patches:
      bug17037.diff.txt uploaded by alecdavis (license 585)
Tested by: alecdavis



Modified:
    trunk/main/astobj2.c

Modified: trunk/main/astobj2.c
URL: http://svnview.digium.com/svn/asterisk/trunk/main/astobj2.c?view=diff&rev=253490&r1=253489&r2=253490
==============================================================================
--- trunk/main/astobj2.c (original)
+++ trunk/main/astobj2.c Fri Mar 19 02:37:00 2010
@@ -261,6 +261,9 @@
 	struct astobj2 *obj = INTERNAL_OBJ(user_data);
 	int current_value;
 	int ret;
+
+	if (obj == NULL)
+		return -1;
 
 	/* if delta is 0, just return the refcount */
 	if (delta == 0)
@@ -499,7 +502,7 @@
 	struct bucket_list *p;
 	struct astobj2 *obj = INTERNAL_OBJ(user_data);
 
-	if (!obj)
+	if (obj == NULL)
 		return NULL;
 
 	if (INTERNAL_OBJ(c) == NULL)