Module Name: src
Committed By: chs
Date: Thu May 14 17:31:24 UTC 2015
Modified Files:
src/sys/kern: subr_disk.c
Log Message:
in bounds_check_with_*, reject negative block numbers and avoid
a potential overflow in calculating the size of the request.
To generate a diff of this commit:
cvs rdiff -u -r1.112 -r1.113 src/sys/kern/subr_disk.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/subr_disk.c
diff -u src/sys/kern/subr_disk.c:1.112 src/sys/kern/subr_disk.c:1.113
--- src/sys/kern/subr_disk.c:1.112 Tue May 5 22:09:24 2015
+++ src/sys/kern/subr_disk.c Thu May 14 17:31:24 2015
@@ -1,4 +1,4 @@
-/* $NetBSD: subr_disk.c,v 1.112 2015/05/05 22:09:24 mlelstv Exp $ */
+/* $NetBSD: subr_disk.c,v 1.113 2015/05/14 17:31:24 chs Exp $ */
/*-
* Copyright (c) 1996, 1997, 1999, 2000, 2009 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.112 2015/05/05 22:09:24 mlelstv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_disk.c,v 1.113 2015/05/14 17:31:24 chs Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
@@ -314,7 +314,18 @@ bounds_check_with_mediasize(struct buf *
{
int64_t sz;
- sz = howmany(bp->b_bcount, secsize);
+ if (bp->b_blkno < 0) {
+ /* Reject negative offsets immediately. */
+ bp->b_error = EINVAL;
+ return 0;
+ }
+
+ sz = howmany((int64_t)bp->b_bcount, secsize);
+
+ /*
+ * bp->b_bcount is a 32-bit value, and we rejected a negative
+ * bp->b_blkno already, so "bp->b_blkno + sz" cannot overflow.
+ */
if (bp->b_blkno + sz > mediasize) {
sz = mediasize - bp->b_blkno;
@@ -348,6 +359,12 @@ bounds_check_with_label(struct disk *dk,
uint64_t p_size, p_offset, labelsector;
int64_t sz;
+ if (bp->b_blkno < 0) {
+ /* Reject negative offsets immediately. */
+ bp->b_error = EINVAL;
+ return -1;
+ }
+
/* Protect against division by zero. XXX: Should never happen?!?! */
if (lp->d_secpercyl == 0) {
bp->b_error = EINVAL;
@@ -363,8 +380,14 @@ bounds_check_with_label(struct disk *dk,
#endif
labelsector = (labelsector + dk->dk_labelsector) << dk->dk_blkshift;
- sz = howmany(bp->b_bcount, DEV_BSIZE);
- if ((bp->b_blkno + sz) > p_size) {
+ sz = howmany((int64_t)bp->b_bcount, DEV_BSIZE);
+
+ /*
+ * bp->b_bcount is a 32-bit value, and we rejected a negative
+ * bp->b_blkno already, so "bp->b_blkno + sz" cannot overflow.
+ */
+
+ if (bp->b_blkno + sz > p_size) {
sz = p_size - bp->b_blkno;
if (sz == 0) {
/* If exactly at end of disk, return EOF. */
