Author: trociny
Date: Mon Sep 17 07:32:53 2012
New Revision: 240595
URL: http://svn.freebsd.org/changeset/base/240595
Log:
In snmp_hostres, device_map table is used for consistent device table
indexing. When a device has gone it is not removed from device_map
table but just its entry_p field is set to NULL.
So when traversing device_map in disk_OS_get_ATA_disks() and
disk_OS_get_MD_disks() check for entry_p being NULL, otherwise the
bsnmpd crash is possible when a removed map entry is dereferenced.
Before the fix, for disk_OS_get_ATA_disks() the crash could be easily
reproduced running:
atacontrol detach ata1
The crash was not observed in disk_OS_get_MD_disks() because currently
snmp_hostres does no see md(4) disks: to get the device list it uses
devinfo(3), which does not return md devices.
Reported by: Miroslav Lachman 000.fbsd quip.cz
MFC after: 1 week
Modified:
head/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_diskstorage_tbl.c
Modified: head/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_diskstorage_tbl.c
==============================================================================
--- head/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_diskstorage_tbl.c Mon Sep
17 07:14:07 2012 (r240594)
+++ head/usr.sbin/bsnmpd/modules/snmp_hostres/hostres_diskstorage_tbl.c Mon Sep
17 07:32:53 2012 (r240595)
@@ -287,6 +287,9 @@ disk_OS_get_ATA_disks(void)
/* Walk over the device table looking for ata disks */
STAILQ_FOREACH(map, &device_map, link) {
+ /* Skip deleted entries. */
+ if (map->entry_p == NULL)
+ continue;
for (found = lookup; found->media != DSM_UNKNOWN; found++) {
if (strncmp(map->name_key, found->dev_name,
strlen(found->dev_name)) != 0)
@@ -345,6 +348,9 @@ disk_OS_get_MD_disks(void)
/* Look for md devices */
STAILQ_FOREACH(map, &device_map, link) {
+ /* Skip deleted entries. */
+ if (map->entry_p == NULL)
+ continue;
if (sscanf(map->name_key, "md%d", &unit) != 1)
continue;
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