[asterisk-commits] russell: branch 1.8 r335497 - in /branches/1.8: include/asterisk/ main/ res/ais/

[SVN commits to the Asterisk project]

Author: russell
Date: Tue Sep 13 02:11:36 2011
New Revision: 335497

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=335497
Log:
Fix a crash in res_ais.

This patch resolves a crash observed in a load testing environment that
involved the use of the res_ais module.  I observed some crashes where
the event delivery callback would get called, but the length parameter
incidcating how much data there was to read was 0.  The code assumed
(with good reason I would think) that if this callback got called, there
was an event available to read.  However, if the rare case that there's
nothing there, catch it and return instead of blowing up.

More specifically, the change always ensure that the size of the received
event in the cluster is always big enough to be a real ast_event.

Review: https://reviewboard.asterisk.org/r/1423/

Modified:
    branches/1.8/include/asterisk/event.h
    branches/1.8/main/event.c
    branches/1.8/res/ais/evt.c

Modified: branches/1.8/include/asterisk/event.h
URL: http://svnview.digium.com/svn/asterisk/branches/1.8/include/asterisk/event.h?view=diff&rev=335497&r1=335496&r2=335497
==============================================================================
--- branches/1.8/include/asterisk/event.h (original)
+++ branches/1.8/include/asterisk/event.h Tue Sep 13 02:11:36 2011
@@ -743,6 +743,13 @@
  */
 uint16_t ast_event_iterator_get_ie_raw_payload_len(struct ast_event_iterator *iterator);
 
+/*!
+ * \brief Get the minimum length of an ast_event.
+ *
+ * \return minimum amount of memory that will be consumed by any ast_event.
+ */
+size_t ast_event_minimum_length(void);
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }
 #endif

Modified: branches/1.8/main/event.c
URL: http://svnview.digium.com/svn/asterisk/branches/1.8/main/event.c?view=diff&rev=335497&r1=335496&r2=335497
==============================================================================
--- branches/1.8/main/event.c (original)
+++ branches/1.8/main/event.c Tue Sep 13 02:11:36 2011
@@ -1769,3 +1769,8 @@
 
 	return 0;
 }
+
+size_t ast_event_minimum_length(void)
+{
+	return sizeof(struct ast_event);
+}

Modified: branches/1.8/res/ais/evt.c
URL: http://svnview.digium.com/svn/asterisk/branches/1.8/res/ais/evt.c?view=diff&rev=335497&r1=335496&r2=335497
==============================================================================
--- branches/1.8/res/ais/evt.c (original)
+++ branches/1.8/res/ais/evt.c Tue Sep 13 02:11:36 2011
@@ -132,6 +132,13 @@
 		ast_log(LOG_ERROR, "Event received with size %u, which is too big\n"
 			"for the allocated size %u. Change the code to increase the size.\n",
 			(unsigned int) event_datalen, (unsigned int) len);
+		return;
+	}
+
+	if (event_datalen < ast_event_minimum_length()) {
+		ast_debug(1, "Ignoring event that's too small. %u < %u\n",
+			(unsigned int) event_datalen,
+			(unsigned int) ast_event_minimum_length());
 		return;
 	}