svn commit: r240595 - head/usr.sbin/bsnmpd/modules/snmp_hostres

[John Rumbaugh]

<http://i.imgur.com/vZXZW.jpg>



http://www.chumleaf.com

On Monday, September 17, 2012 12:34:10 AM UTC-7, Mikolaj Golub wrote:
>
> 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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