recGbl: Prevent record alarm severities > INVALID_ALARM

documentation/RELEASE_NOTES.html

@@ -16,6 +16,15 @@ Base-3.15 series or to EPICS 7.</p>
 
 <!-- Insert new items immediately below here ... -->
 
+<h3>Prevent illegal alarm severities</h3>
+
+<p>A check has been added to <tt>recGblResetAlarms()</tt> that prevents records
+from getting an alarm severity higher than INVALID_ALARM. It is still possible
+for a field like HSV to get set to a value that is not a legal alarm severity,
+but the core IOC code should never copy such a value into a record's SEVR or
+ACKS fields. With this fix the record's alarm severity will be limited to
+INVALID_ALARM.</p>
+
 <h3>Fixes for Launchpad bugs</h3>
 
 <p>The following launchpad bugs have fixes included:</p>

src/db/recGbl.c

@@ -19,6 +19,7 @@
 #include <limits.h>
 
 #include "dbDefs.h"
+#include "alarm.h"
 #include "epicsMath.h"
 #include "epicsTime.h"
 #include "epicsPrint.h"
@@ -222,6 +223,9 @@ unsigned short epicsShareAPI recGblResetAlarms(void *precord)
     epicsEnum16 val_mask = 0;
     epicsEnum16 stat_mask = 0;
 
+    if (new_sevr > INVALID_ALARM)
+        new_sevr = INVALID_ALARM;
+
     pdbc->stat = new_stat;
     pdbc->sevr = new_sevr;
     pdbc->nsta = 0;