[src/trunk]: src/sys/dev Reject unaligned writes to cgd.

[riastradh <riastradh%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c10a44e8a3e4
branches:  trunk
changeset: 765111:c10a44e8a3e4
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Thu May 19 20:34:13 2011 +0000

description:
Reject unaligned writes to cgd.

Fixes the following PRs:

PR kern/44515 (cgd dies on non-aligned writes to the raw device)
PR kern/44964 (cgd seems to panic on unaligned writes instead of giving EINVAL)

ok christos

diffstat:

 sys/dev/cgd.c |  19 +++++++++++++++++--
 1 files changed, 17 insertions(+), 2 deletions(-)

diffs (40 lines):

diff -r 8ff4d799578a -r c10a44e8a3e4 sys/dev/cgd.c
--- a/sys/dev/cgd.c     Thu May 19 15:18:29 2011 +0000
+++ b/sys/dev/cgd.c     Thu May 19 20:34:13 2011 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cgd.c,v 1.71 2010/11/19 06:44:39 dholland Exp $ */
+/* $NetBSD: cgd.c,v 1.72 2011/05/19 20:34:13 riastradh Exp $ */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.71 2010/11/19 06:44:39 dholland Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cgd.c,v 1.72 2011/05/19 20:34:13 riastradh Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -293,6 +293,21 @@
 
        DPRINTF_FOLLOW(("cgdstrategy(%p): b_bcount = %ld\n", bp,
            (long)bp->b_bcount));
+
+       /*
+        * Reject unaligned writes.  We can encrypt and decrypt only
+        * complete disk sectors, and we let the ciphers require their
+        * buffers to be aligned to 32-bit boundaries.
+        */
+       if (bp->b_blkno < 0 ||
+           (bp->b_bcount % DEV_BSIZE) != 0 ||
+           ((uintptr_t)bp->b_data & 3) != 0) {
+               bp->b_error = EINVAL;
+               bp->b_resid = bp->b_bcount;
+               biodone(bp);
+               return;
+       }
+
        /* XXXrcd: Should we test for (cs != NULL)? */
        dk_strategy(di, &cs->sc_dksc, bp);
        return;