Author: kib
Date: Thu Nov 22 16:20:08 2012
New Revision: 243408
URL: http://svnweb.freebsd.org/changeset/base/243408
Log:
MFC r242744:
Zero the newly allocated md(4) swap-backed page to prevent random
kernel memory leakage to userspace.
Modified:
stable/9/sys/dev/md/md.c
Directory Properties:
stable/9/sys/ (props changed)
stable/9/sys/dev/ (props changed)
Modified: stable/9/sys/dev/md/md.c
==============================================================================
--- stable/9/sys/dev/md/md.c Thu Nov 22 16:14:41 2012 (r243407)
+++ stable/9/sys/dev/md/md.c Thu Nov 22 16:20:08 2012 (r243408)
@@ -677,6 +677,15 @@ mdstart_swap(struct md_s *sc, struct bio
sched_unpin();
vm_page_wakeup(m);
break;
+ } else if (rv == VM_PAGER_FAIL) {
+ /*
+ * Pager does not have the page. Zero
+ * the allocated page, and mark it as
+ * valid. Do not set dirty, the page
+ * can be recreated if thrown out.
+ */
+ bzero((void *)sf_buf_kva(sf), PAGE_SIZE);
+ m->valid = VM_PAGE_BITS_ALL;
}
bcopy((void *)(sf_buf_kva(sf) + offs), p, len);
cpu_flush_dcache(p, len);
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