[PATCH] segfault in grub-probe when spare or faulty disks are found

[Martin Schitter <ms@mur.at>]

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the actual raid implementation doesn't handle spare or faulty drives in 
a linux software raid array in a sane way. grub-probe will reproducible 
crash in such a setup.

please include the attached trivial patch to fix this problem.

for more information see:

https://savannah.gnu.org/bugs/?31119
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=593652


[-- Attachment #2: grub2-raid-better.diff --]
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=== modified file 'grub-core/disk/raid.c'
--- grub-core/disk/raid.c	2010-09-13 21:59:22 +0000
+++ grub-core/disk/raid.c	2010-09-25 22:20:29 +0000
@@ -501,7 +501,8 @@
           grub_dprintf ("raid", "array->nr_devs > array->total_devs (%d)?!?",
 			array->total_devs);
 
-        if (array->device[new_array->index] != NULL)
+        if ((new_array->index < GRUB_RAID_MAX_DEVICES) &&
+	    (array->device[new_array->index] != NULL))
           /* We found multiple devices with the same number. Again,
              this shouldn't happen.  */
           grub_dprintf ("raid", "Found two disks with the number %d?!?",
@@ -609,9 +610,14 @@
     }
 
   /* Add the device to the array. */
-  array->device[new_array->index] = disk;
-  array->start_sector[new_array->index] = start_sector;
-  array->nr_devs++;
+
+  /* ignore spare/faulty disks and more then GRUB_RAID_MAX_DEVICES */
+  if (new_array->index < GRUB_RAID_MAX_DEVICES)
+    {
+      array->device[new_array->index] = disk;
+      array->start_sector[new_array->index] = start_sector;
+      array->nr_devs++;
+    }
 
   return 0;
 }