Fix for buffer overflow in ldm_frag_add not sufficient

As Ben Hutchings discovered [1], the patch for CVE-2011-1017 (buffer overflow in ldm_frag_add) is not sufficient. The original patch in commit c340b1d ("fs/partitions/ldm.c: fix oops caused by corrupted partition table") does not consider that, for subsequent fragments, previously allocated memory is used. [1] http://lkml.org/lkml/2011/5/6/407 Reported-by: Ben Hutchings <[email protected]> Signed-off-by: Timo Warns <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
ambv · May 20, 2011 · cae13fe · cae13fe
1 parent e6c9366
commit cae13fe
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/fs/partitions/ldm.c b/fs/partitions/ldm.c
@@ -1335,6 +1335,11 @@ static bool ldm_frag_add (const u8 *data, int size, struct list_head *frags)
 
 	list_add_tail (&f->list, frags);
 found:
+	if (rec >= f->num) {
+		ldm_error("REC value (%d) exceeds NUM value (%d)", rec, f->num);
+		return false;
+	}
+
 	if (f->map & (1 << rec)) {
 		ldm_error ("Duplicate VBLK, part %d.", rec);
 		f->map &= 0x7F;			/* Mark the group as broken */